Transmitting/Receiving apparatus for high frequencies and usage of the apparatus

0001The invention relates to a transmitting and receiving device for high frequency radiation with the features of the preamble of claim 1 and the use of the transmitting and receiving device for high frequency transmission. High-frequency connections, for example according to the DECT or GSM standard, form an important link in the transmission of information. Both mobile and stationary transmission / reception systems are used here. A typical field of application of the present invention is in the field of mobile telecommunications.

0002A commercially available mobile handset that works according to the GSM standard emits a total high-frequency power of approximately 2 W in order to establish a connection to a fixed base station. The required transmission power, the reception field strength and ultimately also the transferable data rate (bandwidth) are given by the geometry (distance between transmitter and receiver) and by elementary thermodynamic laws (signal-to-noise ratio). High-frequency transmitters, such as those used in a cell phone, radiate their energy essentially in a 4πr²Geometry from. However, only the solid angle component that is directed towards the receiver is used for the high-frequency connection. Mobile transmitters and receivers in particular often have to be operated with an independent energy source, such as batteries, which has only a limited energy supply. The resulting relatively short operating time is a major problem with these devices.

0003A transmitting and receiving device with the features of the preamble of claim 1 is known from the German patent application DE-A-44 35 344. This laid-open specification describes a group antenna with a plurality of individual elements that are identical to one another, with a runtime compensation between the individual elements. In particular, this antenna detects the phase shift between the individual elements and maintains it during transmission, so that there is automatically a directional effect in the direction from which it was previously received.

0004A disadvantage of this transmitting and receiving device, however, is that the radiation characteristics of the group antenna can not be aligned in real time. More precisely, several wave fronts have to be waited for to determine the phase shift. Therefore, a problem can arise if the transmitting and receiving device is moved spatially, since the radiation characteristic does not instantly align itself accordingly. Thus, the result of the transmission may not be satisfactory due to the insufficient alignment of the radiation characteristic.

0005The present invention is therefore based on the object of specifying a transmitting and receiving device for high-frequency radiation which has an increased operating time with the same energy reserve and nevertheless achieves satisfactory transmission results. Furthermore, an improvement in the high-frequency connection is to be made possible.

0006The object is achieved with the features of the applicable claims 1 and 18. Advantageous refinements are the subject of the dependent claims.

0007According to the invention, a transmitting and receiving device for high-frequency radiation is provided, with an antenna device which is suitable for emitting a directional radiation characteristic which can be changed without inertia, and a device which is suitable for aligning the radiation characteristic without inertia in real time in the direction of a second transmitting / receiving device, the device comprising means for determining the current spatial position, which are suitable in the event of a change in the spatial position of the device, the alignment of the radiation characteristic can be carried out on the basis of the calculated current position, so that the alignment of the radiation characteristic takes place in real time.

0008With this device, by bundling the transmission lobe (directional radiation characteristic) in the direction of the second device, the required transmission power with unchanged field strength at the receiver is significantly reduced compared to conventional devices (by at least one order of magnitude). This leads to significant energy savings and thus to an increase in the operating time of the device, particularly in the case of battery-operated or battery-operated devices. The additional energy required for the automatic tracking of the transmission lobe in real time is negligibly small compared to the total energy savings that can be achieved.

0009In the case of permanently installed transmitters and receivers, in addition to the energy saving, there is the advantage that the directional radiation characteristics are automatically aligned when the device is installed or commissioned at a new location, so that no separate adjustment is required. Likewise, if the position of the second device is changed, no new adjustment is necessary, since the first device automatically adapts its radiation characteristics to the new conditions in real time, ie aligns it to the new position.

0010Another advantage of the invention lies in the reduction of high-frequency energy unnecessarily dissipated in the bypass (<img file="EP0883206A2_D0001.tif" />Electro smog ").

0011The directional radiation characteristic also brings with it an increase in the effectively usable transmission channels, since this allows overlapping to be avoided.

0012In an advantageous embodiment, the transceiver comprises means that adjust the half-width of the radiation characteristic in a main beam direction (direction with maximum power density) in real time so that an optimal transmission of data with the high-frequency radiation is ensured. The half width is the angle between the directions with half the power density as in the main beam direction (3 dB width). On the one hand, optimal transmission of data can mean that the transmission process can take place through the spatial bundling with drastically reduced transmission energy; on the other hand, higher transmission rates can be achieved while maintaining or only slightly reducing the transmission energy, since the bundling results in significantly higher field strengths at the receiving location.

0013According to the present invention, the means for determining the current spatial position can be implemented in different ways.

0014For example, the transceiver can contain one or more acceleration sensors. The output signal of these sensors is fed into a device that calculates the current spatial position of the device or a fictitious device axis, for example in the normal direction to the plane of the antenna array, with respect to a reference axis. The reference axis can be any one, for example the geometric connecting line between the two devices.

0015If the spatial position of the device changes, the alignment of the radiation characteristics is carried out automatically on the basis of this calculated current position. Movements of the device can be detected with high precision using micromechanically manufactured and optionally integrated acceleration sensors. The extremely high computing power of microelectronic circuits makes it possible to convert the device's own movement into a current position description of the device in real time with the help of the integrated sensors. Hand-held telephones in particular are usually moved during operation. With these movements, angular speeds of up to 5 s^-1 occur, so that the automatic tracking of the directional radiation characteristics in hand-held telephones at speeds in this order of magnitude.

0016Significant simplification in tracking the radiation characteristics can be achieved by including the determined values ​​of the mechanical device movement in the alignment of the radiation characteristics. To do this, one or more acceleration sensors determine the device's own movement. This movement is converted into a current alignment of the device axis with respect to a reference axis. A computing processor in the device then has the task of tracking the radiation characteristics, taking into account the current alignment of the device axis.

0017The motion detection with the aid of acceleration sensors can support the alignment of the radiation characteristic in the direction of the second device, for example a base station, obtained by determining the direction of reception. In particular, in periods when there is no or very little intrinsic movement of the device, there is no need to constantly re-determine the direction and / or realignment of the radiation characteristic and the computational effort involved. For example, at a certain start time, for example when the device is switched on, the direction of the second device can be determined and the radiation characteristics of the antenna can be aligned accordingly. From this point in time, the automatic tracking can be carried out solely on the basis of the detection of the device's own movement by means of the acceleration sensors. If necessary, the direction of the second device can be determined again at regular intervals or if the transmission quality deteriorates (new start time).

0018The determination of the intrinsic movement of the device with acceleration sensors and their use for the alignment of the radiation characteristics also has the advantage that these sensors can detect very fast movements precisely, so that errors in the alignment due to a fast movement are avoided.

0019Alternatively, the transceiver according to the invention can also contain a position sensor that aligns the radiation characteristics in the most likely direction of a remote station. When operating with a terrestrial, such a position sensor aligns the radiation characteristic, for example horizontally, for a satellite as a remote station, for example, vertically.

0020According to a further embodiment of the present invention, the direction of incidence of the high-frequency radiation received by the second device (remote station) is determined via the signals of a phase array antenna. The definition of the radiation characteristic of an antenna for both transmitting and receiving operation can be carried out by means of several phase-shifted dipoles or similarly acting radiation elements. This principle is known as the phase array antenna. Phase arrays are mainly used in the military sector as rapidly swiveling radar lobes for scanning a certain solid angle component. The achievable bundling properties of phase array antennas are essentially a function of the quotient antenna dimension / wavelength. For example, at 12 GHz for the vertical radiation of a 3x3 array with overall dimensions of 4x4 cm² estimate a maximum beam opening angle of 32 ° (drop of 3dB). This corresponds to a solid angle ratio of 1: 0.0625 (factor 16). To determine the direction of incidence of the high-frequency radiation received by the opposite station, the device has a unit for determining the phase relationship of the signals detected by the individual dipoles of the array. An integrated processor calculates the direction of incidence of the high-frequency radiation received from the opposite station from the phase relationship. This direction is related to a reference axis of the device, and the radiation characteristics are aligned to the optimal field strength in the direction of the opposite station.

0021Due to the technical developments in recent years, in particular the possibilities for inexpensive integration of electronic components up to the upper Ghz range, for example due to the progress of SiGe transistors, it is also possible to inexpensively integrate all electronic elements of the device on a single substrate .

0022The invention is explained in more detail below on the basis of exemplary embodiments in conjunction with the drawings.

0023Here show:<dl id="dl0001" compact="compact"><dt>Figure 1</dt><dd>an example of the schematic structure of a transceiver according to the present invention;</dd><dt>Figure 2a</dt><dd>a device according to Figure 1, which is designed as a hand-held telephone; and</dd><dt>Figure 2b</dt><dd>a section of Figure 2a, which shows schematically the structure of the phase array antenna.</dd></dl>

0024The invention is explained below using a mobile hand-held telephone 11.

0025The basic structure of the device according to the invention is shown in FIG. 1. The antenna device consists of a phase array antenna 1, which are connected to a transmit / receive split element 5 via amplifiers 2, transmission / reception switches 3 and units for phase shifting / weighting 4 of the individual elements 12 of the antenna. On the one hand, the splitting element 5 establishes a connection to the further signal-processing components of the hand-held telephone (conventional cell-phone components). On the other hand, a signal is derived to element 6 for determining the angle of the incident high-frequency radiation, and from this to an element 7 for determining the optimal radiation direction, from which the units 4 for phase shifting the individual elements are finally controlled via split element 5. Furthermore, the device can contain acceleration sensors 8, from whose data a rapid angle correction of the radiation direction can be carried out in an element 9. A device 10 for determining the absolute position of the device by means of the GPS method can also be provided.

0026The bundling of high-frequency radiation always requires a correlated wavefront. This can be done by reflection (for example by means of parabolic mirrors), diffraction (for example by means of lenses or electrically controllable dielectric phase shift plates) as well as by direct phase-related control of neighboring individual radiators. The latter represents the quickest and simplest way of realizing an antenna device with directed radiation characteristics. The associated high-frequency and radiation properties, in particular the resulting bundling factors, the solid angle and a further increase in the directional characteristic through a reflector behind the antenna array, are known to the person skilled in the art and are not described in more detail here.

0027A prerequisite for a sensible application of the invention in a hand-held telephone is that the high-frequency wavelength used corresponds approximately to the antenna dimension. This condition cannot be met in the current GSM standard (frequency range of 900 MHz or 1.8 GHz corresponding to a wavelength range of 33 cm or 17 cm), since the dimensions of a phase array antenna must not be too large for a hand-held telephone. However, it is foreseeable that in the near future increasingly shorter wavelengths will be released for the operation of hand-held telephones for reasons of the required bandwidth or number of channels.

0028A hand-held telephone according to the invention is shown in FIG. 2a. The hand-held telephone 11, which works for example in the frequency range of 12 GHz, contains a phase array antenna 1 integrated in the housing. The phase array antenna consists, for example, of 3x3 dipoles 12. To shorten the effective wavelength, this dipole array is additionally made of a material with a comparatively high dielectric constant and low loss angle embedded. In particular, polymers such as polycarbonate (ε ≈ 2.2 at 10 GHz) are suitable as materials, which can also be processed relatively easily as casting compounds. With a dielectric constant of 2, such an array has overall dimensions of about 4x4 cm in the frequency range mentioned² on. This corresponds to the usable area of ​​a handheld system or a chip card.

0029FIG. 2b schematically shows the phase array antenna 1 integrated in the housing with the dipole arrangement. By suitable control of the dipoles 12, the beam characteristic can be controlled such that the main beam direction 14 deviates from the surface normal 15 of the array plane at any angle. The phase array antenna is provided on the back with a shield 13. This shielding can be implemented, for example, by integrating the antenna array into a material with properties that are electrically shielding on one side, as is known, for example, from DE 4433330.

0030Methods for controlling the dipole array in accordance with the phase, for switching between transmitting and receiving operation, or the selection of the wavelengths according to the heterodyne or PLL method are already known from high-frequency technology. The extensive integration of all transmit drivers and receive amplifiers on a single substrate is advantageous. This is made possible by new developments in integration technology, such as the development of SiGe transistors for high transmission frequencies and SOI techniques (Silicon On Insulator).

0031When the transmission to a usually fixed base station is initiated, the receiver of the mobile part determines the direction of the incoming high-frequency radiation. This information can be obtained from the phase relationship of the signals detected by the individual dipoles 12 of the antenna array. The computing processor integrated in the mobile device determines this direction, sets it in relation to a geometric reference axis of the mobile device and optimizes the transmission and reception characteristics of the antenna for optimal field strength in the direction of the base station. After the beam characteristic has been aligned, the transmission energy is reduced to the level necessary to achieve the field strength required at the receiving location. This is done in the same way as the feedback method already used in the GSM standard.

0032The method described is suitable for both mobile devices and base stations. A development which is currently being driven forward relates to the replacement of wired transmission of data (for example telephone, etc.) over comparatively short distances using high-frequency connections (DECT standard). These are permanently installed high-frequency transmission lines. By setting up a device according to the invention with self-aligning bundling and alignment of the antenna lobe, such stations can be installed in a simplified manner on the one hand and on the other hand manage with considerably reduced transmission power.

0033It is also conceivable to design the transmitting and receiving device according to the invention in card form. Devices in the form of cards, with dimensions similar to the chip cards currently in use, may become increasingly important in the future, particularly for short-range transmission in the 1 to 100 m range. The area of ​​such a chip card is very well suited for receiving a phase array antenna. The reduction and geometrical alignment of the transmission energy helps to reduce the average exposure to electromagnetic radiation and, in addition, to be able to operate a higher number of directional links at the same frequency. In the case of these card-based transmitting and receiving devices which are operated essentially in a fixed position, the self-aligning alignment of the radiation characteristics and the self-regulating reduction in the transmission energy are particularly advantageous.

0034In a preferred exemplary embodiment, the hand-held telephone has one or more 3-axis acceleration sensors 8, which continuously record the device's own movement (cf. FIG. 1). This movement is converted into a current alignment of the device axis with respect to a reference axis. Here, for example, the spatial axis 15 perpendicular to the antenna array plane can be used as the device axis, which is identical to the axis of the radiation maximum (main beam direction) if all dipoles are in phase. The computing processor in the device then tracks the radiation characteristics taking into account the current alignment of the device axis. This movement detection can support the alignment of the radiation characteristic in the direction of the second device obtained by determining the direction of reception. Especially in the case of reflections and interference, such as occur when a radio connection is operated close to the ground, the determination of the transmitter position from the received signal or its phase position is a comparatively complex, iterative and time-consuming method. By including the data from the acceleration sensors 8, an unnecessarily frequent implementation of this method of determining the direction can be avoided. The mechanical position / acceleration determination can also be used to identify problems that result from a 180 ° rotation of the device in relation to the effective antenna axis (forward / backward characteristic of the antenna array) and, if necessary, to correct or display them. In particular, in periods when there is no or very little intrinsic movement of the device, there is no need to constantly re-determine the direction and / or realignment of the radiation characteristic and the computational effort involved Acceleration sensors for use in a device according to the invention can be produced very inexpensively using the methods of microsystem technology. In the foreseeable future, they will also be available as small, fully integrated components with low power consumption.

0035The method is not limited to a fixed base station as a second device, but can also be used between two mobile devices. Another advantageous application can be the alignment of the antenna lobe on earth satellites. The use of devices according to the invention can bring significant advantages, particularly in the case of so-called direct telecommunication via satellites serving as opposite stations, in near-Earth orbit.

0036In a further embodiment, provision can be made to support the alignment of the radiation characteristic and / or the selection of an optimal connection path by determining the absolute position of the mobile device. This position can be determined, for example, using the GPS system (see FIG. 1). For this purpose, the mobile device determines its position and uses a stored list to select the fixed remote stations in question. The list of remote stations can either be permanently stored in the device or, when the device is switched on, advantageously updated for the remote stations in question by transmitting information from the remote stations to the handset. This method of determining the position can also be used to determine the alignment of the radiation characteristic only in cases in which the spatial direction of the device axis of the transceiver is unchangeable (for example in the case of a permanently installed device).