Wireless communication device having a reduced sar value

p0001BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a radio communication device with a reduced SAR value with at least one printed circuit board and with at least one antenna coupled thereto, for radiating and / or receiving electromagnetic radiation fields, the antenna being arranged on that mounting surface of the printed circuit board which, when the radio communication device is worn on the body and Or, when the radio communication device is inserted, for facing and / or hearing into the head region of the respective user.

p0002In the case of radio communication devices, it is desirable to keep the load dose of electromagnetic radiation in the body tissue of a user as low as possible during wearing of the radio communication device on the body and / or during insertion of the radio communication device for speaking and / or hearing into the head region of the respective user. A specific measurement criterion for which radiation exposures the respective user is actually exposed to is, in particular, the so-called SAR (Specific Absorption Rate) value. This specifies the specific absorption rate in watts per kilogram, with which a predetermined tissue volume range, such as in the head of the respective user, is thermally stressed by the electromagnetic radio radiation fields.

p0003From the <patcit id="pcit0001" dnum="US6246374B1"><text>US 6,246,374 B1</text></patcit> A folding mobile radio device with a main antenna and a parasitic antenna element integrated into the flap of the mobile radio device is known. The parasitic antenna element is coupled to the main antenna in the folded-up state of the folding mobile radio device in order to act as a passive radiation element.

p0004The invention is based on the object of showing a way in which the SAR value of a radio communication device can be further reduced in a simple manner in a targeted manner.

p0005This object is achieved in a radio communication device of the type mentioned in the introduction in that at least one first additional, current-conducting correcting element for SAR reduction is coupled and formed on a front side of the printed circuit board opposite the antenna and on the first corrective element and / Wherein the amplitude and / or phase position of electrical currents on the antenna, the printed circuit board and the correcting element are adjusted in a resultant, superimposed total current flow to one another in such a way that the amplitude and /Characterized in that the maximum SAR distribution resulting from these streams is reduced in the body tissue of a user during carrying of the radio communication device or during the introduction of the radio communication device for talking and / or hearing into the head region of this user.

p0006Thus, at least one additional, electrically conductive correcting element is coupled to the printed circuit board at the component side opposite the antenna in such a way that the electrical current flowing on it is adapted in terms of the amplitude and / or phase position to the electrical currents on the antenna and the printed circuit board Is that a SAR field with a minimized or lowered maximum is caused overall due to these currents.

p0007In this way, highly dispensed "hot spots", ie, tissue volume regions of higher thermal load, are largely avoided in comparison to tissue volume regions of lower heating during the intended use of the respective radio communication device, such as when worn on the body or during insertion and / or hearing into the head region of this user . In other words, the SAR value characteristic of the respective radio communication device can be further reduced.

p0008The invention further relates to a printed circuit board with at least one additional SAR value-reducing correcting element for a radio communication device according to the invention.

p0009Other developments of the invention are reproduced in the subclaims.

p0010The invention and its further developments are explained in more detail below with the aid of drawings.

Show it:

p0011<dl id="dl0001"><dt>FIG</dt><dd>A second exemplary embodiment of a radio communication device according to the invention is shown schematically in perspective representation, to the printed circuit board of which a second current-conducting correcting element which reduces SAR values ​​is coupled, into which a second current-conducting corrective element is integrated for tuning or for tuning the current current there,</dd><dt>FIG</dt><dd>In a schematic representation the printed circuit board of the radio communication device <figref idrefs="f0001">FIG</figref> With the first coupled, SAR-value-reducing correcting element, into which, for the purpose of tuning the current flow there, an opposing <figref idrefs="f0001">FIG</figref> Modified, second current-conducting correction element,</dd><dt>FIG</dt><dd>A simplified, electrical equivalent circuit diagram for the SAR-value-reducing first correcting element of FIG <figref idrefs="f0001">FIG</figref> With the associated, second corrective element with respect to its coupling to the printed circuit board,</dd><dt>FIG</dt><dd>Schematically depicts an idealized, largely harmonized SAR field over the entire area of ​​the printed circuit board of the radio communication device <figref idrefs="f0001">FIG</figref> Which due to the superimposed total current flow of the electrical currents on the printed circuit board, the first and second corrective element coupled thereto, as well as the antenna as a whole, is set to be smaller than without corrective action,</dd><dt>FIG</dt><dd>A further variant of a radio communication device according to the invention in which the means for matching the phase position and / or the amplitude of the electrical current on the first corrective element are arranged opposite the tuning or tuning means of the radio communication device of FIG <figref idrefs="f0001">FIG</figref> Are modified,</dd><dt>FIG</dt><dd>Schematically in a three-dimensional view a further embodiment of a radio communication device according to the invention with further alternative tuning means for the SAR-value-reducing corrective element of this radio communication device, and FIG</dd><dt>FIG</dt><dd>In a schematic representation the local distribution of the electrical sum current which is effective for the SAR effect, which during operation of the radio communication device according to FIG <figref idrefs="f0001">FIG</figref> Along the longitudinal extent of the printed circuit board without and with a corrective element tuned according to the invention.</dd></dl>

p0012Elements with the same function and mode of operation are shown in the <figref idrefs="f0001">FIGS</figref> 7 are respectively provided with the same reference numerals.

p0013<figref idrefs="f0001">FIG</figref> 13 shows schematically, in a spatial representation, a first radio communication device MP. For the sake of simplicity, only components which have a primary effect on the SAR (specific absorption rate) effect of the radio communication device MP are shown for the sake of simplicity. Specifically, this is a circuit board or printed circuit board LP, as well as a radio antenna AT1 which is coupled thereto, which together form an electromagnetic coupling structure for transmitting and / or receiving radio-radiation fields. Both components are accommodated together in the interior of a housing GH of thickness H, the external contours of which in the<figref idrefs="f0001">FIG</figref> Are merely indicated by dashed lines in order to allow a view into the interior of the radio communication device MP. The usual electrical assemblies for the transmission and / or reception of radio signals, such as a high-frequency module, a power supply unit (such as a battery or an accumulator), as well as one or more further electrical assemblies for controlling the input and / or output elements of the electronic circuit board Radio communication device (such as, for example, its keyboard, display, loudspeaker, etc.) and for signal processing of the radio signals received by means of the radio-frequency module and / or transmitted via these radio signals. These electrical assemblies are in the<figref idrefs="f0001">FIG</figref> For the sake of clarity. Only a part of a high-frequency module HB1 is shown in the region of the upper end face SRO of the printed circuit board LP. This high-frequency module HB1 is provided in a partial region of the upper half of the circuit board LP. The transmitting / receiving antenna AT1 is connected to it via a mechanical and electrical contact COA for emitting and / or receiving electromagnetic radio waves. From there, it receives electrical energy from a power supply unit, which is shown here in the<figref idrefs="f0001">FIG</figref> For the sake of clarity, has also been omitted. The antenna AT1 is expediently arranged on the mounting surface of the printed circuit board LP, which is turned away from the body when the radio communication device is worn and / or when the radio communication device is inserted for speaking and / or listening into the head region of the respective user. Here, in the embodiment of FIG<figref idrefs="f0001">FIG</figref> The antenna AT1 is arranged on the rear side of the printed circuit board LP, the front side of the radio communication device being assigned to the outer surface of the housing which has a display device, in particular a display, for the user.

p0014The antenna AT1 is preferably designed as a planar or flat antenna. For them, a so-called PIFA antenna (Planar Inverted F antenna) can be used in particular. Of course, it may also be expedient to provide other usual radio antennas, such as, for example, stub antenna antennas protruding out of the housing GH, on the circuit board LP.

p0015In the exemplary embodiment of FIG <figref idrefs="f0001">FIG</figref> Approximately rectangular. With the help of the contacting COA, it is positioned out of the upper side edge SRO of the printed circuit board LP in a region which is enclosed by the four side edges SRL, SRR, SRO, SRU of the printed circuit board along the surface normal of the mounting surface thereof. The imaginary orthogonal projection of the antenna AT1 onto the component mounting surface of the printed circuit board LP thus lies essentially within the limiting area which is clamped by the side edges SRL, SRR, SRO, SRU of the printed circuit board LP. In other words, the antenna AT1 does not protrude beyond the four side edges of the component mounting surface of the circuit board LP. Thus, the circuit board surface is neither extended nor widened by the coupled antenna AT1. The antenna AT1 thus lies as a further layer above and / or below the layer plane of the printed circuit board LP within the area of ​​the area bounded by the four lateral edges thereof. Advantageously, compact device dimensions can be achieved by this antenna arrangement.

p0016The circuit board LP of <figref idrefs="f0001">FIG</figref> Has essentially a flat rectangular parallelepipedal shape, ie its four lateral edges SRL, SRR, SRO, SRU together form the outer contour of a rectangle. The dimensions of the printed circuit board LP, ie, their length L and their width B, are preferably dimensioned in such a way that the longitudinal extent L of the printed circuit board LP is greater than the width B thereof. Their spatial geometric relationships are described in the<figref idrefs="f0001">FIG</figref> Is illustrated by the fact that the coordinates X, Y and Z of a Cartesian coordinate system are additionally indicated there. In this case, the X coordinate extends along the longitudinal sides SRL, SRR of the printed circuit board LP, while the Y direction extends parallel to the wide sides SRO, SRU of the printed circuit board LP. The component mounting surface of the circuit board LP thus lies substantially in the X, Y plane. The Z direction is assigned to the height or thickness D of the printed circuit board LP with its various components such as, for example, the high-frequency module HB1 as well as other evaluation / control modules.

p0017The rectangular shape of the printed circuit board is preferably suitable for installation in a flat, essentially parallelepipedal housing such as, for example, GH of FIG <figref idrefs="f0001">FIG</figref>. In the exemplary embodiment of FIG<figref idrefs="f0001">FIG</figref> Is dimensioned in terms of its dimensions, ie, length L and width B, as well as thickness D, in such a way that, together with the components coupled thereto, such as, for example, the antenna, as well as the assemblies attached thereto, In practice, the dimensions of the circuit board, ie their length, width and thickness, are essentially limited by the respectively desired geometry of the housing. Depending on the design form of the housing, the external contours of the circuit board are suitably selected to match the dimensions and geometry of this housing. The printed circuit board can thus also have circular, oval or other geometry shapes.

p0018In such a coupling structure of at least one printed circuit board and at least one radio antenna connected thereto, a current flow occurs on the printed circuit board in the radio mode, ie during the emission and / or reception of electromagnetic radiation fields. In the first approximation, the respective printed circuit board, such as LP, acts as a kind of complementary second antenna branch to the actual radio antenna, such as, for example, AT1, in relation to the current supply point, such as, for example, COA, of its antenna, which is coupled on the front side, such as AT1 Circuit board and the antenna coupled thereto, a radiation dipipole is formed. The respective printed circuit board, such as, for example, LP, is formed on the basis of its electrical assemblies, their electromagnetic shielding housings,

p0019In particular, when the transmitting and / or receiving antenna AT1 of the radio communication apparatus MP of FIG <figref idrefs="f0001">FIG</figref> Is formed as a λ / 4 antenna, it forms a radiation dipole together with the printed circuit board LP. When the radio antenna AT1 is switched to transmit and / or receive, a current flow I1 is generated on the printed circuit board LP with a main preferred direction along its longitudinal extent L. In the<figref idrefs="f0001">FIG</figref> This directional current flow I1 on the circuit board LP is characterized by an arrow in the X direction. In this case, it represents the sum current I1 (X) at each longitudinal locus position X of the printed circuit board LP, which results from the fact that at each longitudinal locus position X the partial currents with the main preferential direction are summed up or integrated in the X direction over the total cross section width B, ie in the Y direction have been. This length-dependent distribution of the sum current I1 (X) is for the circuit board LP of FIG<figref idrefs="f0001">FIG</figref> in the <figref idrefs="f0003">FIG</figref> Schematically with reference to a current diagram.

p0020In the <figref idrefs="f0003">FIG</figref> The X direction is plotted along the abscissa, while the sum current I1 (X) accumulated over the total cross section width B of the printed circuit board LP is assigned to the ordinates for different longitudinal position positions X along the longitudinal extent of the printed circuit board LP. The local distribution of this sum current flow is, on the one hand, H and / or E fields, ie, magnetic and / or electric fields, correspondingly in alternating relationship, which, when the radio communication device is worn on a user's body, in particular when the respective radio communication device is introduced for speech and / Or hearing into the head region of the respective user can effect a corresponding thermal heating of the organic tissue there, depending on the local distribution of maxima and minima.

p0021In the investigation of the SAR effect, extensive tests with an H-field and / or E-field probe in a model head filled with a glucose solution and to which a radio communication device with a conventional, conventional circuit board corresponding to LP from <figref idrefs="f0001">FIG</figref> It was shown that the thermal heating of the glucose solution in the model head fluctuates locally, that is to say a local three-dimensional SAR distribution with maxima and minima is present. This locally varying, three-dimensional SAR field corresponds, in a first approximation, to a correspondingly locally different distribution of the sum current I1 (X) on the circuit board LP.

p0022In the <figref idrefs="f0003">FIG</figref> The origin UR of the X axis is the upper side edge SRO, ie, the upper end face, of the circuit board LP of FIG <figref idrefs="f0001">FIG</figref> , While the lower side edge SRU corresponds to the longitudinal location X = L. In the region of the electrical contact point COA between the antenna AT1 and the printed circuit board LP at the longitudinal point X = 0 cm, the antenna AT1 supplies the feed or ground point current FS ≠ 0 A. In the preferred use of a λ / 4 antenna, approximately this feed current or at least a portion thereof also flows to the longitudinal end X = 0 cm at the upper end face of the printed circuit board LP, since the printed circuit board LP acts as an antenna extension branch to the λ / 4 antenna . The current flow in the longitudinal direction is interrupted at the lower end side SRU of the printed circuit board LP, which is opposite the antenna AT1, due to the free end and thus by the edge limitation there,

p0023The further course of the sum current distribution I1 (X) between the upper end face SRO and the lower end face SRU of the printed circuit board LP is influenced by a plurality of electromagnetic propagation / coupling factors. This preferably includes the geometry shape as well as the spatial dimensions of the printed circuit board LP. In particular, their length L has, at the respective radio frequency used, an effect on the electromagnetic waves propagating along the circuit board in the form of E and / or H fields and thus on the resulting summation current distribution I1 (X). In the case that a λ / 4 antenna is used and the length L of the conductor board is selected to be λ / 4, the printed circuit board LP together with the λ / 4 antenna forms a resonant radiation dipole. The printed circuit board thereby acts as a kind of complementary λ / 4 antenna to the antenna AT1 in a first approximation. In this way, standing waves of the sum current I1 (X) can form on the overall structure of the circuit board LP and the λ / 4 antenna coupled thereto, with current nodes and current creeps.

p0024A local distribution of the sum current I1 (X), which is not constant in the X direction, that is to say along the longitudinal extent of the printed circuit board LP, also arises in practice with other coupling ratios of the coupling structure formed from the circuit board and antenna. A decisive influencing factor on the local distribution of the sum current I1 (X) when using a rectangular circuit board is in particular its length in relation to the electrically effective antenna length at the wavelength used for radiating and / or receiving electromagnetic radiation fields in radio mode.

p0025In the vicinity of this local summation current distribution I1 (X), a corresponding, corresponding electromagnetic field is generated which induces a heating during the intended use of the radio communication device MP in the organic body tissue of a user and is primarily responsible for the location-dependent SAR distribution . By intended use, on the one hand, this means that the respective radio communication device is held or supported at a point on the body of a user. For example, the radio communication device can be attached to the belt, hanged on a belt around the user's neck, or carried in the chest pocket of a jacket, and can be set to receive and / or transmit. In practice, the respective user often also uses a so-called headset, ie he communicates with the radio communication device via a cable with a connected micro-earphone and microphone. On the other hand, the respective cordless, mobile radio communication device is usually inserted into a position of use in the head region of the respective user for speech and / or hearing and there applied between the ear and mouth to the cheek of the user. The SAR effect which is effective in the vicinity of the respective radio communication device is, in particular, the location region which is below the distance 2D Mobile radio communication device is usually placed in a position of use in the head region of the respective user for talking and / or listening and is applied there between the ear and mouth to the cheek of the user. The SAR effect which is effective in the vicinity of the respective radio communication device is, in particular, the location region which is below the distance 2D Mobile radio communication device is usually placed in a position of use in the head region of the respective user for talking and / or listening and is applied there between the ear and mouth to the cheek of the user. The SAR effect which is effective in the vicinity of the respective radio communication device is, in particular, the location region which is below the distance 2D²/ Λ (λ is the wavelength, D is the device length).

p0026For example, a GSM system (Global System for Mobile Communications) operates in a frequency range between 880 and 960 MHz (center frequency 900 MHz), which corresponds to an operating wavelength λ of approximately 35 cm. In the case of a GSM radio system, this results in a penetration depth of the electromagnetic near-field of approximately 1.7 cm due to the local current distribution on the printed circuit board. In the private commercial network (PCN) network with a frequency band between 1710 and 1880 MHz, the wavelength is approximately 17 cm so that the electromagnetic near field resulting from the local current distribution of the circuit board has a penetration depth of approximately 1.0 Cm. In a UMTS radio communication system with a frequency transmission range between 1920 and 2170 MHz, the wavelength λ is approximately 15 cm, So that the penetration depth of the electromagnetic near field reaches approximately 0.8 to 1 cm due to the local cumulative current distribution on the main board. The lower the local penetration depth into the tissue of a user, the higher the measured SAR value can be for the same assumed transmission power of the antenna. For a given tissue volume, a higher electromagnetic field density is produced, so that a larger current flowing to the flow and thus a higher field concentration are produced.

p0027In order to be able to adjust the SAR value of the respective radio communication device in a controlled manner, at least one first additional, current-conducting correction element for SAR reduction is coupled to the circuit board of this radio communication device. In this case, it is coupled to the circuit board in such a way that the amplitude and / or phase position of electrical currents on the antenna, the printed circuit board and the correcting element are set relative to one another such that the maximum SAR distribution resulting in total Body tissue of a user is minimized when the radio communication device is used as intended. In other words, the currents on the antenna, The circuit board and the correcting element can be coordinated with one another such that the magnitude of the initially set absolute maximum (or the possible maxima) becomes smallest in the local SAR field distribution of the electromagnetic fields which are effective as a result of these currents. As a result, highly dispensed "hot spots", ie, local tissue volume regions of higher thermal load compared to tissue volume regions of lower heating, are largely avoided during the intended use of the radio communication device. By lowering the SAR value peaks, a kind of homogenization of the resulting SAR distribution is achieved which results from the electrical currents on the antenna, the printed circuit board and the correcting element. (Or the possible maxima) becomes the smallest in the local SAR field distribution of the electromagnetic fields which are effective as a result of these currents. As a result, highly dispensed "hot spots", ie, local tissue volume regions of higher thermal load compared to tissue volume regions of lower heating, are largely avoided during the intended use of the radio communication device. By lowering the SAR value peaks, a kind of homogenization of the resulting SAR distribution is achieved which results from the electrical currents on the antenna, the printed circuit board and the correcting element. (Or the possible maxima) becomes the smallest in the local SAR field distribution of the electromagnetic fields which are effective as a result of these currents. As a result, highly dispensed "hot spots", ie, local tissue volume regions of higher thermal load compared to tissue volume regions of lower heating, are largely avoided during the intended use of the radio communication device. By lowering the SAR value peaks, a kind of homogenization of the resulting SAR distribution is achieved which results from the electrical currents on the antenna, the printed circuit board and the correcting element. Absolute (or any maxima) in the local SAR field distribution of the electromagnetic fields which are effective as a result of these currents becomes the smallest. As a result, highly dispensed "hot spots", ie, local tissue volume regions of higher thermal load compared to tissue volume regions of lower heating, are largely avoided during the intended use of the radio communication device. By lowering the SAR value peaks, a kind of homogenization of the resulting SAR distribution is achieved which results from the electrical currents on the antenna, the printed circuit board and the correcting element. Absolute (or any maxima) in the local SAR field distribution of the electromagnetic fields which are effective as a result of these currents becomes the smallest. As a result, highly dispensed "hot spots", ie, local tissue volume regions of higher thermal load compared to tissue volume regions of lower heating, are largely avoided during the intended use of the radio communication device. By lowering the SAR value peaks, a kind of homogenization of the resulting SAR distribution is achieved which results from the electrical currents on the antenna, the printed circuit board and the correcting element. Local tissue volume regions of higher thermal load compared to tissue volume regions of lower heating, are largely avoided during the intended use of the radio communication apparatus. By lowering the SAR value peaks, a kind of homogenization of the resulting SAR distribution is achieved which results from the electrical currents on the antenna, the printed circuit board and the correcting element. Local tissue volume regions of higher thermal load compared to tissue volume regions of lower heating, are largely avoided during the intended use of the radio communication apparatus. By lowering the SAR value peaks, a kind of homogenization of the resulting SAR distribution is achieved which results from the electrical currents on the antenna, the printed circuit board and the correcting element.

p0028Various types of first correcting elements are detailed in the earlier patent application with the sign-on reference <patcit id="pcit0002" dnum="DE10110982"><text>DE 101 10 982.2</text></patcit> Respectively.

p0029In the <figref idrefs="f0001">FIG</figref> A first, electrically conductive correction element is drawn over the front mounting surface of the printed circuit board LP. It is provided with the reference symbol CE1. It is arranged with the height gap HA to the printed circuit board LP as well as substantially parallel to the mounting surface thereof. The additional corrective element CE1 is preferably assigned to the mounting surface of the printed circuit board LP, which, when the radio communication device is worn on the body and / or when the radio communication device is placed for speaking and / or listening into the head region of the respective user, Direction to the respective user. In this case, it is expedient, as in the exemplary embodiment of FIG<figref idrefs="f0001">FIG</figref> The antenna AT1 is arranged on the component side of the circuit board LP opposite the correcting element CE1 (rear side in the <figref idrefs="f0001">FIG</figref>).

p0030The geometry shape of the first correcting element CE1 of FIG <figref idrefs="f0001">FIG</figref> Follows essentially the rectangular outer contour of the printed circuit board LP. Thus, the correcting element is formed as a rectangular ring or frame and, viewed in the X, Y plane, forms a type of closed loop which extends essentially only along the side edges SRL, SRO, SRR, SRU of the printed circuit board LP but orthogonally (ie In the Z direction) is open or freely open with respect to its inner surface which is fictitiously enclosed in the X, Y plane. In this case, the correcting element CE1 is positioned relative to the printed circuit board LP in such a way that the outer surface of its partial sections lies substantially congruent with the outer contour of the rectangular printed circuit board as a further layer. The loop-shaped correcting element CE1 forms a rectangular annular shape from its basic geometric shape or Frame shape suitable for the rectangular shape of the printed circuit board LP. For example, it can be formed by one or more wires, a single-layer or multi-layered strip-shaped film, or by another linear or flat element. Such an element may, for example, also be a metallization which has been applied by evaporation or electroplating to the inner surface of the housing. An electrically conductive material, possibly also a dielectric and / or magnetically conductive material, is preferably used for the respective correcting element such as, for example, CE1. In the present embodiment of FIG A single-layer or multi-layered strip-shaped film or by a further line-like or two-dimensional element. Such an element may, for example, also be a metallization which has been applied by evaporation or electroplating to the inner surface of the housing. An electrically conductive material, possibly also a dielectric and / or magnetically conductive material, is preferably used for the respective correcting element such as, for example, CE1. In the present embodiment of FIG A single-layer or multi-layered strip-shaped film or by a further line-like or two-dimensional element. Such an element may, for example, also be a metallization which has been applied by evaporation or electroplating to the inner surface of the housing. An electrically conductive material, possibly also a dielectric and / or magnetically conductive material, is preferably used for the respective correcting element such as, for example, CE1. In the present embodiment of FIG Also a dielectric and / or magnetically conductive material is used. In the present embodiment of FIG Also a dielectric and / or magnetically conductive material is used. In the present embodiment of FIG<figref idrefs="f0001">FIG</figref> The correcting element CE1 has strip-shaped partial sections in the region along the two longitudinal edges SRL, SRR of the printed circuit board LP, and rectangular strip sections in the region of the upper and lower end faces of the printed circuit board LP.

p0031In general terms, it is expedient to position the additional correcting element such that its imaginary orthogonal projection with respect to the component mounting surface of the printed circuit board lies essentially within a limiting surface clamped by its lateral edges. As a result, the additional correction element comes to lie in a second layer plane with respect to the first layer plane of the printed circuit board LP, as a result of which a compact construction of the radio communication device is achieved. The original longitudinal and width dimensions of the printed circuit board LP are thus largely retained.

p0032The first correcting element CE1 is galvanically connected to the ground of the printed circuit board LP in the region of the upper end face SRO of the printed circuit board LP, which is indicated by a grounding symbol ERD. Alternatively, it may also be expedient to couple the first corrective element CE1 to the printed circuit board LP capacitively or inductively, ie to omit the galvanic connection ERD. Possibly. A combination of galvanic, capacitive and / or inductive coupling can also be expedient. As a result of the electrical coupling of the corrective element CE1 to the printed circuit board LP, here in the exemplary embodiment, an electrical current I2 (X) flows in the loop structure of the corrective element CE1.

p0033In the present exemplary embodiment, the geometric relationships of the printed circuit board LP in the form of an elongated rectangle are selected so that the greatest current amplitude or current density of the summation current I1 (X) without the use of the corrective element CE1 is, for example, approximately in the center of the printed circuit board LP, Point of intersection, the surface diagonals thereof, while the current density to the two end- Width sides SRO, SRU. In the<figref idrefs="f0003">FIG</figref> The absolute maximum of the sum current I1 (X) on the circuit board at the longitudinal location XM1 is designated IM1. Since the additional correction element now has current-conducting paths where the local current distribution of the sum current I1 (X) of the printed circuit board LP is less than IM1, the total current level can be raised there and, overall, a comparison of the overall resulting current field (= .

p0034Because of the various electromagnetic coupling mechanisms, such as different geometrical shapes and / or dimensions of printed circuit board, antenna, and / or first correcting element, it can be critical in practice to determine the phase position and / or the amplitude level of the electrical currents with the first correcting element The antenna, the circuit board, and the correcting element to each other so that the resulting resulting SAR distribution is satisfactorily reduced.

p0035In order to provide an improved effect possibility on the resulting superimposed SAR current effect on the circuit board, the correcting element, and the antenna, it is expedient to provide additional tuning means for tuning and / or tuning the phase position and / Amplitude of the electric current on the first correcting element and / or the printed circuit board.

p0036In the <figref idrefs="f0001">FIG</figref> A second, electrically conductive correction element TE1 is in operative connection with the first correction element CE1 as tuning or tuning means for tuning the current flow on the first corrective element. It is an integral part of the first correcting element since it is inserted in the form of a meander-shaped loop structure into the rectangular, primary open loop of the first corrective element CE1 which is open in the interior, and thus is galvanically connected thereto. Due to the additional meander loops of the second corrective element, the current path in the interconnected overall structure of the first and second corrective element can advantageously be modified such that an electrical current flow I2 (X) is produced there which is largely antiphase to the current flow I1 (X) Circuit board LP.<figref idrefs="f0001">FIG</figref> The total current path of the overall structure of the first and second correcting element is lengthened with respect to a purely rectangular basic loop by the installation of the meanders of the second corrective element.

p0037In the <figref idrefs="f0003">FIG</figref> The local course of a sum current I2 * (X) is shown in the sum current diagram I (X), which could lead to a total flow on the first correcting element CE1 without the coupling of the second corrective element TE1. In a first approximation, this sum current I2 * (X) runs in phase with the sum current I1 (X) on the circuit board LP. At the longitudinal location XM2 *, it has a current level maximum which is below the current level distribution of the sum current I1 (X) and is offset longitudinally opposite the longitudinal position XM1 of the current level maximum IM1 of the sum current I1 (X). By superimposing these two electric sum current flows, the result is a total current profile RSV * (X) which is above the original sum current flow I1 (X) of the printed circuit board LP. In other words,

p0038The current length or current path length of the first corrective element CE1 can only be adjusted with the aid of the second, current-conducting corrective element TE1 improved by virtue of its additional meander loops, in such a way that an antiphase current flow I2 (X) to the total structure of the two corrective elements CE1, Current flow I1 (X). This antiphase current flow I2 (X) is in the<figref idrefs="f0003">FIG</figref> In the fourth quadrant with negative current level values ​​I (X) in addition to the positive current values ​​I (X) of the sum current I1 (X) in the first quadrant. The antiphase total current I2 (X) on the two interconnected correcting elements CE1, TE1 thus runs in the direction of the sum current I1 (X) on the circuit board LP. It has approximately a maximum NIM1 where the sum current I1 (X) of the circuit board LP also has an absolute maximum IM1. On the basis of this opposing complementary current-current profile I2 (X) on the two corrective elements CE1, TE1 which are coupled to one another, a maximum compensation effect results for the maximum of the sum current level I1 (X) of the circuit board LP. Thus, by superposing the local distribution of the sum current I1 (X) of the printed circuit board LP and the correcting total current I2 (X) on the first and second correction elements, a superimposed total current flow RSV (X) X) has a reduced, flattened current level maximum IM1 *. The local distribution of the superimposed total current flow RSV (X) is thus largely homogenized, ie, it proceeds to a first approximation with a constant level. At least unacceptably high current peak peaks are largely avoided. With such a uniform, resulting current-current profile of the superposition current from the sum current I1 (X) of the circuit board LP and the correction current I2 (X) of the first and second correction element CE1,<figref idrefs="f0002">FIG</figref> Shows an idealized two-dimensional SAR distribution S (X, Y) viewed over the total area L * B of the printed circuit board LP. Spatially considered, this three-dimensional SAR value distribution SAR (X, Y, Z) with an approximately homogeneous electromagnetic field strength profile is actually obtained by this additional tuningelement for the first SAR value correcting element. This three-dimensional SAR value distribution can be predetermined to a predeterminable volume range VOL around the housing GH of the respective radio communication device, which is described in the<figref idrefs="f0001">FIG</figref> Is indicated by dot-dashed lines.

p0039By means of a corresponding setting of the number and / or the length of the meanders of the second corrective element TE1, the correction current I2 (X) flowing in total in the two correction elements CE1, TE1 can be matched or adapted to different local courses of the sum current I1 (X) . be adjusted. In particular, the degree of the antiphase of the correction current I2 (X) as well as the amplitude magnitude of the absolute maximum of this correction current I2 (X) can be adjusted. By adjusting the phase position and / or the amplitude of the correction current I2 (X), the position of the maximum IM1 of the sum current I1 (X) of the printed circuit board LP can be shifted in particular<figref idrefs="f0003">FIG</figref> Is indicated by a displacement arrow VV along the X-direction. The displacement is expediently carried out in such a way that the SAR distribution is as homogeneous as possible. Such a displacement of the absolute maximum of the sum current on the printed circuit board into uncritical device regions, such as, for example, towards the lower end face SRU, may possibly already lead to an improvement in the measured SAR value.

p0040The second correcting element TE1 is shown in FIG <figref idrefs="f0001">FIG</figref> With respect to the center line MI of the printed circuit board LP extending in the X direction through the center of the wide sides SRO, SRU is inserted largely axially symmetrically into the first correcting element CE1 so that overall a symmetrical structure with respect to the center line MI for the overall combination or for the entire structure of the first And second correcting element.

p0041If desired, a coupling structure of printed circuit board, antenna and / or corrective element can also be suitable, in which the correcting element projects in its imaginary orthogonal projection with respect to the printed circuit board surface over its lateral boundaries.

p0042Expediently, the respective second corrective element such as, for example, TE1 is dimensioned in such a way that the mounting surface of the printed circuit board, which is fictitiously enclosed, corresponds at most to 0.2 to 0.5 times the part of the printed circuit board area fictitiously bounded by the first corrective element such as CE1 .

p0043In practice, it is also expedient to arrange the first and / or second corrective element at a distance of between 0.1 and 0.6 cm from the mounting surface of the printed circuit board.

p0044<figref idrefs="f0001">FIG</figref> Shows schematically in a spatial representation the printed circuit board LP of FIG <figref idrefs="f0001">FIG</figref> With a coupled corrective element structure, which is composed of the first correcting element CE1 and an opposing element, <figref idrefs="f0001">FIG</figref> Modified second correcting element TE2. This second correction element TE2 is formed by strip-shaped current-conducting elements, so-called "patches". These strip-shaped, flat current conducting elements TE2 extend essentially orthogonal to the longitudinal extent L of the first corrective element CE1 in the same position plane. A strip element or elements may be provided for tuning or tuning the correction current I (X) flowing through this coupled structure of the first and second correction element CE1, TE2. The number of these stripping elements, their transverse spacing in the longitudinal direction from each other, and their stripe surface dimensions, are advantageously selected such that the correction current I2 (X) is essentially antiphase to the sum current I1 (X) of the printed circuit board LP. In the<figref idrefs="f0001">FIG</figref> Two striping elements (= strip element pair) which follow one another at a predeterminable longitudinal distance are connected in an axisymmetrical manner with respect to the center line MI of the printed circuit board LP to the first correcting element CE1 in such a manner that the strip elements point into the interior of the surface surrounded by the side edges of the printed circuit board LP. By means of this parallel coupling of the strip-shaped elements of the second corrective element TE2 to the first correcting element CE1, an additional capacitive load is provided with respect to the printed circuit board LP. By corresponding selection of the additional capacitive load, a superimposed total current flow RSV (X) can also be set, which is largely uniform (see FIG<figref idrefs="f0003">FIG</figref>). <figref idrefs="f0002">FIG</figref> Shows in simplified fashion this parallel coupling of an additional capacitive load CAP2 by the second corrective element TE2 in addition to the capacitive load CAP1 formed between the first corrective element CE1 and the printed circuit board LP.

p0045In the <figref idrefs="f0001">Figures 1 and 2</figref> The meander loops or stripping elements of the second corrective element TE1 or TE2 are in each case integrated into the rectangular basic loop of the first corrective element CE1, ie are galvanically connected to the first corrective element. In this case, the two correction elements can be composed of similar shaped elements or differently shaped elements which are different from one another. In the<figref idrefs="f0001">FIG</figref> The line-shaped longitudinal sides of the first corrective element CE1 are connected to the strip-shaped surface elements of the second corrective element TE2, for example. In addition, or independently thereof, it may also be sufficient to couple the first and the second correction element capacitively or inductively with one another.

p0046<figref idrefs="f0002">FIG</figref> Shows schematically in a three-dimensional view the coupling structure between the printed circuit board LP and the first correcting element CE1 of FIG <figref idrefs="f0001">FIG</figref>, A second correcting element TE3 being now provided separately from the first correcting element and separately from the printed circuit board LP as tuning means. This second correction element TE3 is, for example, formed by an ESD protective element (ESD = Electrostatic Discharge), in particular by a metallic display (window). The section for the display of the radio communication device MP is shown in FIG<figref idrefs="f0002">FIG</figref> With LDP. The second correcting element TE3 is positioned substantially in the region of the center line MI in the upper half of the printed circuit board LP in such a way that its imaginary orthogonal projection relative to the mounting surface of the printed circuit board LP in the X, Y plane inside the framing surface defined by the lateral edges Of the circuit board. This ESD protection element is designed in a flat manner and lies in a layer plane parallel to the mounting surface of the printed circuit board LP at a predetermined height spacing. Expediently, the first correcting element CE1 and the second correcting element TE3 are positioned approximately in the same position plane on the same side of the printed circuit board. Preferably, they are mounted on the front side of the radio communication device, ie, where its display is housed, And not on the back of the radio communication device. As a result, the antenna volume of the antenna AT1 on the rear side of the printed circuit board is largely unaffected by the correction elements on the front side, so that impermissibly large radiation losses of the antenna utility power are largely avoided. Possibly. It may also be expedient for the second correction element TE3 to be arranged in a positional plane which is different from the positional plane of the first corrective element CE1 but belongs to the same conductor plate side.

p0047The second correction element TE3 is coupled capacitively and / or inductively to the first correction element CE1 and / or to the circuit board LP. The correction current I2 (X) in the first correcting element CE1, together with the current flow I4, can be set on the second correction element I2 (X) in the first correcting element CE1, in particular by adapting the height distance to the placement plane of the printed circuit board LP as well as the geometry shape of the current-conducting ESD protection element surface and / (X), the correction current I4, and the circuit board current I1 (X), which is largely uniformed or viewed over the longitudinal extent of the printed circuit board LP, as a result of which a total superimposed current RSV (X) is produced Is homogenized.<figref idrefs="f0003">FIG</figref>).

p0048If desired, it can also be sufficient that the electrical current in the first corrective element is matched with the aid of the at least second corrective element such that the latter is not in phase with the circuit board current I1 (X) but at the longitudinal locations in the X direction an increase in the total current level At which the original circuit board current level I1 (X) is less than IM1. In this way, to a certain extent, a uniformization of the total current level can already be achieved and thus a homogenization of the SAR distribution can be achieved.

p0049In order to achieve a SAR value distribution which is as uniform as possible in a predeterminable volume range, in which local maxima are largely avoided, it may also be expedient to provide a pair of corresponding correction elements also on the rear side of the printed circuit board, Where the antenna is arranged. This can be interesting if so-called "body worm" values ​​must also be observed on the back of the device. In this way, predetermined SAR values ​​can also be maintained when the radio communication device is worn on a belt in the abdominal area, where this usually lies with its rear side. The same applies when wearing a necklace or chest strap. In this case, a spatial arrangement or

p0050<figref idrefs="f0003">FIG</figref> Shows the coupling structure for the radio communication device MP formed from the printed circuit board LP and the antenna AT1 in a spatial view from the rear side, ie, from the antenna-side mounting surface. In contrast to<figref idrefs="f0001">FIG</figref> A first correcting element CE4 is now formed by a rectangular loop which is open in the X, Y plane (position plane of the printed circuit board LP), ie the first correcting element CE4 has stripping elements only in the edge zone region along the edges of the longitudinal sides SRL, SRR and along the upper side edge SRO Of the printed circuit board LP while the linear portion of the correcting element CE1 of FIG <figref idrefs="f0001">FIG</figref> In the region of the lower side edge SRU of the printed circuit board LP has been omitted. The first correcting element CE4 thus essentially has the geometry of a rectangular U, ie it is U-shaped in profile. It is arranged on the placement side of the circuit board which is remote from the antenna coupling for the antenna AT1. Its three different, strip-shaped partial sections lie approximately in the same position plane parallel to the mounting surface of the printed circuit board LP as well as with the height spacing HA. In detail, a strip-shaped or line-shaped side part of the first corrective element CE4 extends along the left-hand side edge SRL, corresponding to this, a second stripe-shaped side part along the right-hand side edge of the printed circuit board LP, And a third analogously formed partial section along the upper side edge SRO of the printed circuit board LP. This first correcting element CE4 is preferably positioned substantially congruent with the two longitudinal side edges SRL, SRR as well as with the upper side edge SRO of the printed circuit board LP in a layer plane with a height spacing HA.

p0051Generally speaking, it is expedient to position the first correcting element CE4 in a plane plane parallel to the printed circuit board LP in such a way that its imaginary orthogonal projection with respect to the component mounting surface of the printed circuit board LP lies essentially within a limiting surface stretched by its lateral edges SRL, SRR, SRO, SRU. For example, the first correcting element CE4 can be shortened in terms of its width and length so as to fictively frame only a part of the central area of ​​the mounting surface of the printed circuit board LP.

p0052To the first correcting element CE4 of FIG <figref idrefs="f0003">FIG</figref> A second correction element TE4 is coupled in the region of the right-hand side edge SRR of the printed circuit board LP which extends essentially transversely, in particular in the Y direction, ie orthogonally, to the longitudinal extent of the printed circuit board LP as a strip-shaped surface element. It is galvanically connected to the first correcting element CE4. It serves as an individual element for the adjustment of the correction current I2 (X), which flows in the first correcting element CE4 with the second corrective element TE4 coupled thereto, in the sense that overall a superimposed total current flow from the electric current I1 (X) Correction current I2 (X) on the corrective element structure CE4 and TE4, as well as the electric current I3 on ​​the antenna AT1, is largely homogenized or homogenized,

p0053In addition, or independently of the second correction element TE4, it may also be expedient, if appropriate, to provide a correction element for the adaptation of the current I1 (X) on the circuit board LP itself in addition to the first correction element CE4. In the<figref idrefs="f0003">FIG</figref> A third additional, electrically conductive correction element ZV6 as matching means is coupled to the printed circuit board LP in such a way that the phase position and / or the amplitude magnitude of the electric sum current I1 (X) can also be tuned or tuned on the printed circuit board LP. Such a tuning means for the circuit board current can in particular be formed by a virtual ground extension of the circuit board LP. Various possibilities of virtual current path extensions are in the older, non-pre-published patent application with the sign-in character<patcit id="pcit0003" dnum="DE10204877"><text>DE 10204877.0</text></patcit> Detailed. In the<figref idrefs="f0003">FIG</figref> A partial region of the ground plane of the printed circuit board itself is designed in such a way that an additional extending element ZV6 for virtual mass elongation is produced. The correcting element ZV6 is an integral component of the ground plane of the printed circuit board LP with an originally rectangular outer contour. In this case, a partial region of the ground plane of the printed circuit board LP is designed separately from the end face SRU opposite the antenna AT1 in such a way that it acts as an extension of the current path from the antenna feed point COA towards the lower end face SRU of the printed circuit board LP. The correction element ZV6 has a meandering shape by serially successive 90 ° bends or rectangular zig-zag bends of web sections.<figref idrefs="f0001">FIG</figref> Can be produced. The correcting element ZV6 is preferably provided in a corner region of the lower printed circuit front side SRU, which is arranged obliquely, in particular diagonally, offset relative to the antenna coupling in the corner region of the upper, opposite end face SRO. This greatest diagonal path between the antenna AT1 and the free end FE of the correcting element ZV6 provides the largest possible virtual path extension for the SAR current effect on the available printed circuit board area with the same predefined, rectangular outer contour.

p0054In general terms, the current path on the printed circuit board itself can thus be adjusted in a controlled manner by means of folds of a third corrective element within the printed circuit board mounting surface and / or possibly via the printed circuit board top side and / or circuit board bottom side. By means of a meandering shape, ie by a shaping of the correcting element, in which a respective partial section alternating in the longitudinal direction of the printed circuit board with a respective section transversely, in particular orthogonally, alternates with the longitudinal extent of the printed circuit board, and in each case two such successive subsections differ from 0 The length of the correcting element in the X direction can be kept relatively short. Because the zig-zag shape allows more running length to be achieved for the electric current compared to a correcting element with a straight-line strip shape. The maximum possible current path on the PCB LP of<figref idrefs="f0003">FIG</figref> Begins in the region of the antenna AT1 and ends at the free end FE of the corrective element ZV6 after passing through its meandering windings. Preferably, this third correcting element is mounted with its one or more folds in one or more layer planes which lie within the component plane bounded by the side edges of the printed circuit board. In this case, the correcting element can also be arranged with a height distance to the mounting surface of the printed circuit board. In this way, the originally predetermined dimensions of the printed circuit board are largely retained, so that a compact, miniaturized design can be achieved for the radio communication device.

p0055Due to the fact that at least one correction element is galvanically, capacitively and / or inductively coupled as a tuning means of the circuit board current, the amplitude height and / or phase position of the electrical currents I3, I1, I2 can also be arranged on the antenna AT1, the circuit board LP, as well as the first correcting element CE4, in such a way that the respective absolute maximum of the SAR distribution resulting overall due to these currents I1, I2, I3 becomes minimal.

p0056With one or more of these different correction elements corresponding to the <figref idrefs="f0001">FIGS</figref> 7 is thus made possible to influence and reduce the SAR value of a radio communication device in a targeted manner during the development phase, and both in a plane parallel to the front and / or rear side of the radio communication device, and three-dimensionally in a predeterminable volume range around the housing Of the respective radio communication device.

p0057Extensive tests have successfully shown that a first advantageous way to reduce the SAR value is to provide an electrically conductive correction loop contacting atop the printed circuit board (PCB), which is partially or substantially substantially along the length of the printed circuit board Side edges of the printed circuit board. In this variant, the originally given SAR value can be reduced by up to 75% compared to the initial situation without a correcting element.

p0058However, this value can not be achieved with arbitrary correction loops since, in practice, a plurality of influencing variables (such as, for example, predefined geometry shapes and dimensions of antenna and printed circuit board) can enter uncontrollably into the SAR distribution of the coupling structure of printed circuit board and antenna. A targeted or controlled minimization of the absolute maximum or the maxima of the SAR distribution by a simple, single correction loop can thus be made more difficult in practice under certain circumstances. However, an optimization of the SAR distribution can be achieved with the aid of at least one second correcting element, which is coupled to the first corrective element and / or to the printed circuit board, and which determines the phase position and / or amplitude level of the electrical currents on the antenna, The circuit board and the correcting element are tuned to one another in such a way that the resulting SAR field in the body tissue is as uniform as possible. A further, optimized reduction in the SAR effect is thus produced if additional tuning means are provided for tuning the phase position and / or the amplitude of the electrical current on the first corrective element and / or circuit board in such a way that the overall resulting superimposed total current flow is increased The circuit board, the correcting element and the antenna, a SAR field which is homogeneous in the first approximation is viewed over the entire surface of the printed circuit board. This results in a more homogeneous SAR value distribution on the remaining pages (eg top side, bottom side, rear side) of the radio communication device.

p0059In summary, optimal SAR distribution can already be achieved by setting the first correction loop accordingly. Two measures are suitable for this purpose. A first convenient possibility is to modify the length of the loop. This results in a different phase position of the current on the correction loop. In addition or independently of this, the amplitude of the current on the correction loop can also be changed by varying the length. In this way, the local distribution of the correction current on the correction loop can be displaced in the longitudinal direction of the printed circuit board in such a way that the total current level is raised where previously the original circuit board current was smaller than the originally present maximum. Due to the spatial redistribution of the original circuit board current from its absolute maxima into those regions which previously had a lower current level, a certain equalization is achieved. In the case of the use of such a simple correction loop, however, its maximum length is limited by the length of the outer or inner edge of the housing of the radio communication device and thus also the possible tuning factor or tuning factor for the purpose of comparing the sum current distribution.

p0060If, due to the given size of the radio communication device and otherwise given electromagnetic coupling ratios, it is necessary to change the correction loop, in particular further, in order to achieve a further optimization of the SAR value, it is expedient to shape the loop in certain sub- As for example in the <figref idrefs="f0001">FIG</figref> Is shown. A second possibility for extending the correction loop while maintaining the original longitudinal and transverse dimensions of the coupling structure of circuit board and antenna is provided by the parallel coupling of at least one so-called patch structure to the first correction element. This is in the<figref idrefs="f0001">FIG</figref> Illustrated. The patches shown therein within the loop structure of the first corrective element can, if appropriate, also be connected capacitively or inductively. This also leads to a modified current distribution on the loop due to changed capacitive load conditions and thus to a changed SAR value. This patch structure can also be a metallic structure used for other purposes, such as an ESD protection element, which cooperates with the first-mentioned correcting element. This further variant is in the<figref idrefs="f0002">FIG</figref> Respectively.

p0061A further possibility for improving the SAR behavior is given by the additional variation of the currents on the circuit board by a virtual extension of the circuit board. This also ensures an optimum phase and amplitude position between the currents on the circuit board, correcting element and antenna.

p0062In general terms, therefore, a targeted combination of different measures is advantageous, which already partly shows a SAR value-influencing effect, but in their combination lead to a significantly better result than individually. In this case, strongly nonlinear superposition effects of the different measures are partially utilized. For this purpose, a first correction element can be lengthened mechanically and electrically in a targeted manner, in spite of limited device size, by means of a meandering design. On the other hand, a further improvement can be achieved by the targeted, simultaneous use of two different measures, namely correction loop and additional patch elements, which in themselves have an individual effect,<figref idrefs="f0001">FIG</figref>) Optimize the current distribution in the first correction loop. Another suitable combination option, in addition or independently of the influencing of the currents in the loop, is the currents on the printed circuit board itself by at least one further correcting element, such as ZV6 in FIG<figref idrefs="f0003">FIG</figref>, Specifically. This can be, in particular, a virtual printed circuit board extension. This also ensures an optimal amplitude and phase position. Measurements for a specific development model for a radio communication device have, for example, given the following reduced values ​​(in percent) relative to a radio communication device without a loop and without a metallic display window (100% = initial situation) for the SAR value:<ul><li>Device with first correction loop without metallic display window as tuning element: 86% (based on the initial situation)</li><li>Radio communication device without first correction loop with metallic display window as additional tuning element: 66% </li><li>Radio communications device with a first correction loop and a metallic display window as an additional tuning element <figref idrefs="f0002">FIG</figref>: 56%</li></ul>In particular, this constellation is sufficient for a multitude of practical circumstances and is advantageous because of its simple construction and operability.