Antenna for receiving meter waves,built in a window glass together with a heating of a motor vehicle.

p0001The invention relates to an antenna for the reception of meter waves in motor vehicle windows with meatllischem frame in the form of a substantially vertical Unipols in the region of the vertical center of the pane.

p0002With antenna structures in vehicle windows, it is known possible to receive all the waveband (eg LMS and FM radio) with good performance. It is advantageous that the antenna through the integration into the vehicle body vehicle-specific requirements such as mechanical robustness, high durability, simple fitting and avoid unnecessary air turbulence much better than the corresponding standard rod.

p0003The invention relates to an antenna with very good suitability for frequencies of VHF range, as is 2136 759 known from P. This antenna uses a Unipol in a metallic frame, which is formed, for example by the frame of a vehicle window, wherein the Unipol is applied in this particular application to the glass pane therein. Such an antenna comprises both for horizontally polarized waves as well as vertically polarized waves or zircular excellent reception characteristics and provides in embodiments according to the invention average signal level, a passive telescopic antenna, as it is common for vehicles, which are nearly equivalent.

p0004An overlap of the Unipols with other conductive structures in the disc, for example with heating structures, such as are present in the vehicle rear windows of modern vehicles is usually, 2136 759, however, not allowed for an antenna according to P. Thus, an antenna to be P 2136 759 not used in vehicles in which a significant portion of the disk surface is covered by the heating wires of the defogger.

p0005The object of the invention is in an antenna of the type described a heating field of conventional embodiment with horizontal grid lines incorporate such that the antenna achieves a high sensitivity independent of the polarization of the receiving field of meter waves in the receiver.

p0006This object is achieved in a generic antenna by the characterizing features of claim 1.

p0007The advantages attainable with the invention consist in the excellent reception qualities of the antenna thus formed for horizontally and vertically or circularly polarized waves in the meter wave range and very largely uncritical dimensioning with respect to the required number of Ahtennenleiter, their distance between themselves and the gesamtene height of the structure. Under aspects of the technological requirements is particularly advantageous that each has the same technology is used for the realization of the antenna conductor and the heating conductors, wherein both types of conductors in the same operation up to the plate or with inserted wires between the layers of a laminated glass pane in the screen printing process or can be introduced. These aspects are the prerequisite for an extremely cost-effective implementation. The galvanic connection of antenna conductors and heating conductors has Moreover, in the printed conductors has the advantage that no further contact is needed in the electroplating operation, as it is in contrast with antennas required without galvanic connection.

p0008Embodiments of the invention are represented by the specified drawings and described in more detail.

p0009In detail:<ul><li>FIG. 1: antenna arranged according to the invention with 5 vertical antennas in 1 area and 3 vertical antenna conductors in the 2nd area, arranged asymmetrically to the disk center and at a short distance to the frame further antenna conductor</li><li>FIG. 2 shows equipotential lines in the heated plate and identification of the area, in which the antenna conductor (11) and (12) are to be placed</li><li>Fig. 3: An antenna according to the invention with only one each of antenna conductor in the first and second region and the coupling-out point on the symmetry line of the disc in the vicinity of the frame.</li><li>Fig. 4: Exemplary labeling the reception zone of the preferred acting Unipols shown in FIGURE 3.</li><li>FIG. 5 shows vehicle window with two antennas according to the invention and a divided heating area</li><li>Fig. 6: Inventive antenna with in each case 2 and parallel at a distance (56) guided antenna conductors and with a separate LMS reception structure (24)</li><li>Fig. 7: Exemplary labeling the reception zone of the preferred acting Unipols of FIG. 6</li><li>FIG. 8: detail in Figure 6 for the identification of the division of the heating currents for the heating conductor (38)</li><li>Fig. 9: equivalent circuit diagram of Figure 8</li><li>Fig. 10: Equivalent circuit</li><li>Fig. 11: Avoid the allocation of the heating current by capacitive connections in together leading antenna conductor </li><li>Fig. 12: avoiding the breakdown of the heating current by capacitive connections between the antenna conductors (12) and the heating conductor (38)</li><li>Fig. 13: antenna according to the invention with a large distance in parallel guided by the frame further antenna conductor and separate LMK structure</li><li>Fig. 14: antenna extended according to the invention for diversity systems to a second antenna to the coupling-out point (61).</li><li>Fig. 15: Preferred embodiments of the Heizfeldnetzwerke</li></ul>

p00101 shows the basic arrangement of an inventive antenna. The metallic frame (21) representing the body of the vehicle enclosing a vehicle window (34) on which a structure of horizontal heating conductors (2), wherein the heating conductors at the boundary zwischem the 1.Bereich (40) and the is arranged 2.Bereich (41) is called (38). These horizontal heating conductors are printed in modern vehicles either the screen printing method on the surface of the vehicle window, and then electrically amplified in order to achieve a low resistance value required for heating purposes or, for vehicle windows of two disks laminated glass between the two panes of glass, eg in the form of tungsten wires, inserted.

p0011In both cases, the heating conductors (2) are wire-shaped. The area covered by heating panel surface of a vehicle window is typically large so that above and remain free below the heating field only comparatively narrow strips whose dimensions do not allow the realization of antennas for the meter wave range with the good properties specified in P 2136 759th

p0012According to FIG. 1 overlap at an inventive antenna, the antenna conductor (11) with the horizontal grid lines (2) or (38) in the manner shown in 1.Bereich (40) with the horizontal dimension (4) and the vertical dimension ( 6), (7) is the vertical dimension of the heating field. Essential for an antenna according to the invention in 1.Bereich (40) is inter alia that a galvanic connection is present at the crossing points (35) between the horizontal heating conductors (2) and the antenna conductors (11).

p0013In the case of information printed on the plate heat conductors (2), the electrical connection between the antenna conductors (11) and aerial ladders (12) returns automatically and even represents the requirement for cost-effective production, because the isolated intersection of printed conductors technologically more difficult to is realized.

p0014In the case of inserted between the individual panes of a laminated glass sheet heating conductors (2) and antenna conductors (11) and (12) and (10) and (22) of the galvanic contact between the conductors results in the bonding of the two individual panes through the interposed plastic film at high temperature likewise, if the two types of conductors are placed on the same side of the plastic in the preparation. Here, it is not necessarily required for an antenna according to the invention in that at each of the crossing points, a galvanic contact is even made, since the spacing of the heating conductors in such disks is so low (about 5 mm), that a significantly greater number zon points of intersection exists, and also without an existing everywhere at the crossing points galvanic contact the capacitive coupling of Heizlei tern and antenna conductors (11) for the frequencies of the meter waveband electrically the same has effect.

p0015In Hinblich on the selection of the structure of the antenna conductor result of an inventive antenna manufacturing aspects hardly any restrictions. So even complex conductor structures and cross-sectional and thus resistance changes of the conductors can be realized by a corresponding sieve at no extra cost and in the same operation, in which the heating conductors are printed. There are restrictions, however, especially with respect to the thinnest line width that can be achieved without risk of interruption. Therefore printed structures are clearly visible and, therefore, visually striking. therefore A wesentlcher side aspect of the selection of the arrangement of the antenna conductor is to consider also from stylistic viewpoints, allowing the use of unnecessarily many antenna conductor is suggested for an antenna according to the invention.

p0016For between the individual panes of laminated glass pane inserted heating conductors and antenna conductors very thin tungsten wires or copper wires are used, which are almost invisible. Consequently, stylistic aspects of much less importance than the printed conductor in the selection of the antenna conductor arrangement. In contrast, every other conductor to be introduced increases the manufacturing costs, since in the wesentlchen each conductor of the antenna structure must be placed individually on the plastic film. Therefore, using the smallest possible number of antenna conductors with clearest possible arrangement is desirable also in such vehicle windows for an antenna according to the invention.

p0017From the viewpoint of heating the disc, these vertical antenna conductor (11) undesirable shunts represent, on the transient currents between the horizontal grid lines (2) can flow, whereby the heated window Abtaueigenschaften be undesirably changed. In an antenna according to the invention, this is avoided by the antenna conductor (11) crossing the horizontal heating conductors (2) in a manner that the individual crossing points in each case on one of the antenna conductor (11) and the cut horizontal heating conductors (2) on the equipotential lines (37) are with respect to the DC voltages of the heated plate according Fig.2, so that no equalizing currents in the antenna conductor (11) to flow.

p0018According to Figure 2 presents obvious as the line of symmetry (3) of the disc such equipotential represents, along which exactly half the voltage of Bordakkumulators (36) is provided with the heater switched relative to the frame. More equipotential lines (37) shows Fig.2. Obviously, the equipotential lines are mutually not exactly parallel, the deviation from parallelism relative is greater toward the equipotential line in the wheel center to the edge of the disk and the more so, the more pronounced is the trapezoidal shape of the disc compared to a rectangle. The antenna conductor (11) thus arranged exclusively in a sufficiently narrow range around the vertical symmetry line of the disc (3), so can be used as a good approximation to the equipotential lines, the parallel arrangement of the antenna conductor (11).

p0019For an antenna according to the invention is in each case electrically connected to the completion of the heating field forming horizontal grid lines (38) one end of the antenna conductor (11), so that the 1.Bereich (40) and the 2.Bereich (41) are immediately adjacent. From this horizontal grid lines (38) crossing each of the antenna conductor (11) at least one more heat conductors (2), in the example of Fig.1 are 6 of 9 horizontal grid lines (2) or (38) crossed.

p0020The number of the antenna conductor (12) in 2.Bereich (41) can in principle on the number of the antenna conductor (11) in 1.Bereich (40) may be different, as shown in Figure 1, are at the three antenna conductor (12) present , These start at the edge of the heating field forming heating conductor (38), with which they are electrically connected, and end at the converging antenna conductor (10), with which they are connected through low resistance for the frequencies of the useful frequency band within the meter band.

p0021According to the characteristics of the 1.Anspruchs are all antenna conductor (11) and (12) for an antenna according to the invention in a line of symmetry (3) of the disc symmetric region (42) of half the average disk width (5) is disposed (Figure 2).

p0022The assessment of the performance of each antenna of the invention with a variation of the arrangement and the number of antenna conductor (11) and (12) is carried out in practice with known statistically evaluating computer-aided measuring method which determine the antenna output levels using a test receiver, and in which through testing at each typical reception fields with the respectively to be examined frequency and polarization of the incident wave, the mean signal level and the level of the test statistics antenna compared to a reference antenna are determined.

p0023Such measurements show that inventive antennas change their properties only in good-natured way in changing the arrangement and the number of antenna conductors.

p0024The simplest arrangement of the antenna conductor for an antenna according to the invention is in each case a single vertical conductor (11) in 1.Bereich and (12) in 2.Bereich, which merge into one another. The pooling antenna conductor (10) degenerate in this particular case, to the connection point (8), substantially parallel to the two narrow sides of the frame, that is along the line of symmetry (3) to the vicinity of the frame for from which the secondary antenna conductor (22) decoupling point (23) leads and the immediate continuation of the antenna conductor (12) is (Figure 3).

p0025In the following the function of such an antenna according to the invention is described as an example based on Fig.3. It is known that the conductive frame (21) enclosed disc aperture is approximately regarded as slot radiators, of the disc oriented electric field vector is excited optimally by a wave in the direction of the vertical line of symmetry (3). At frequencies where the wheel width is approximately one-half wavelength, as is the case with today's cars is usually in the middle of the frequency range of the meter waves, additionally arises a resonance-like elevation of the electric fields in Bull's. In the case of vehicle windows with heating field this resonance is more damped compared to discs without heating field and in accordance with broadband as the heating conductors are inevitably coupled to the radio frequency field within the frame and achieve significant losses for the high-frequency field arise because the heating element in accordance with their task already for DC have a considerable ohmic series resistance and electrical conductivity both today's printed grid lines as well as the inserted wires further decreases with increasing frequency.

p0026Both horizontally and vertically in and circularly polarized receiving field are due to the inclined plate in the vehicle field components in the direction of the line of symmetry (3) available that stimulate the window opening electrically. The Unipol, which consists in an inventive antenna sections (11) and (12) is, therefore, strongly coupled to the receiving item. The coupling is maximum when the antenna conductor is arranged in the line of symmetry of the disc, because due to the short circuit of the electric field through the lateral frame parts sets are used, a symmetrical distribution of the electric field strength with a maximum in the center of the pane. However, due to the known and sinusoidal first approximation characteristic of the field intensity distribution assumes the decoupled from the Unipol signal beginning only slightly, with increasing proximity to the edge of the disk but then rapidly when it is mounted asymmetrically. With increasing distance of Unipols of the line of symmetry (3) of the disc, consequently, the reception powers worse, so that is preferably arranged in an inventive antenna this Unipol in the central area of ​​the disc.

p0027However, it may also be necessary and useful, the Unipol asymmetrically arranging the line of symmetry (3) in the disc. Thus stylistic considerations make this necessary or to realize the necessity of a plurality of antennas according to the invention with different reception behavior eg for antenna diversity systems or for different partial frequency ranges of the meter wave range in a vehicle window. In such cases, in an antenna according to the invention without loss of the essential properties of the antenna of the Unipol to the edge of the area (42) are moved, which is arranged according to the characterizing part of 1.Anspruchs symmetrically to the symmetry line of the disc and the width as large as half of the average disk width.

p0028Due to the galvanic and thus effective also for the frequencies of the meter shaft portion connection between the antenna conductor (11) and crossed by him heating conductors (38) and (2) are at the outcoupling of the electric field at an antenna according to the invention the heat conductor (38) and ( 2) mitbeteiligt. Opposite around, each of the conductors in the disc a conduit having an over conventional coaxial high-ohmic impedance and high losses. With increasing distance from the output point (23) is thus increasing the degree of decoupling quickly, so that the highest contributions to the received signal from the vicinity of Auskoppelpunkts (23) as submitted.

p0029Fig.4 shows exemplarily highlights the most effective part of the overall conductor structure of Figure 3 to illustrate this characteristic of the decoupling. This with distance from the output point (23) increasing decoupling makes the balanced characteristics of an antenna according to the invention with respect to changes in the number of antenna conductors and the geometry of course, if these changes are carried out at a sufficient distance from the output point.

p0030So arise as minor and insignificant for practical deterioration in reception performance when the antenna conductor (11) is no longer, as shown in Figure 3, all 9 heat conductor (2) or (38) of the heating field crosses, but, for example, as shown in Figure 5, only the 5 heating conductor of a Teilheizfeldes crosses. The good reception performance of an antenna according to the invention are essentially retained as long as at least two heating conductors are crossed. Preferably, however, will select the number of grid lines crossed greater than 2, as this occur no dissimilar disadvantages generally and the reception characteristics tend to be better. Also stylistic aspects suggest it, as shown in Figure 3 to select the length (6) of the antenna conductor (11) as great as the height of the heated surface (7), if not for example the requirement, more independent antennas in the disc realizing is given.

p0031An advantageous embodiment of an inventive antenna is further therein, two or more antenna conductor (11) and (12) on the 1st and use 2.Bereich. Thereby, the preferred effective for the receiving zone can be widened, as will be explained in the following with reference to Fig.6 and Fig.7.

p0032In Figure 6, two antenna conductors (11) and (12) are led almost parallel in the 1st and 2nd area, where for reasons of appearance, the antenna conductor (11) and (12) again pass directly into each other. The distance (56) between the two antenna conductors is to be selected advantageously in the range between 1/30 and 1/10 of the average operating wavelength.

p00337 shows an example of the preferred contributing in Unipolstruktur to Figure 6 for the reception area. Will (56) selected in the range between 1/30 and 1/10 of the operating wavelength, the result is a particularly efficient widening of the preferred effective reception zone. If you choose the spacing (56) is less than specified above, the effect is almost identical to that of a single antenna conductor chooses to the distance (56) is greater than indicated above, so this results in no further advantage. If the structure width (4) or (9) is greater than 1/10 of the wavelength of operation, so the use of additional antenna conductors is recommended.

p0034A structure as in Figure 6 provides for the wider, preferably acting reception zone again slightly better reception performance than the structure of Figure 3. At the same time it has the further advantage that, when an interruption of one of the two conductor runs the reception power, although falling, but only in one in practice hardly noticeable degree, while a structure according to Figure 3 during an interruption especially in the field of the antenna conductor (12 ) the reception is decisively worse. The danger of a circuit interruption is added with printed conductors, since these fibers can be relatively easily damaged, especially in slices.

p0035The use of more than two each antenna conductors (11) and (12) for an antenna according to the invention is harmful in any case, however, the effect of an increase in the received power is the smaller, the more the newly launched aerial ladder from due to the decoupling described above are removed decoupling point (23). Therefore, the region (42) can be specified as the upper limit for a reasonable designed Unipol for an antenna according to the invention, within which the conductor (11) and (12) are to be arranged.

p0036The low-resistance connection of the antenna conductor (12) by the converging antenna conductor (10) takes place in the simplest case by a galvanic connection.

p0037Such electrical connection through the converging antenna conductor (10) leads to a shunt for the heating current through the antenna conductor (12) in combination with the converging antenna conductor (10). Particularly affected is due to the proximity of the current in the heating element (38). For this heating conductor (38) below, the situation on the basis of Figure 8 is illustrated, which represents a section of Figure 1 for the range of Bull's near the heating element (38).

p0038the heating current (46) is divided at the branch point (45) in the portion (47) and (48), the ratio of which in a known manner by the ohmic component resistors (53) and (54) on the two current paths between the branching point ( 45) and the junction point (50) is determined, as shown in the equivalent electrical circuit for the current branch in Figure 9. At the same specific conductivity of the antenna conductor (12) and heat conductors (38) of the respective sub-resistance of each path length between (45) and (50) is proportional. Due to the fact that in the line of symmetry of the structure is an equipotential, the current (49) in Figure 8 basically zero and therefore must no longer be considered in the following.

p0039In the following, the effect of the length of the current paths on the ratio of currents (47) and (48) and on the heating power between the points (45) and (50) should be approximately considered. This simplicity is to be expected because of the geometry of Figure 8, wherein the antenna conductor (12) with each other are exactly parallel and each of the same length, so that the composite leading antenna conductor (10) the same length as the distance between (45 ) and (50). In the arrangement shown in Figure 8 is obtained under these conditions, a path difference between the two current paths corresponding to twice the length (52) of the antenna conductor (12). Also to be assumed that the introduction of the current path via the antenna conductor (12) and the antenna together leading conductor (10) does not change the total power (46). The following considerations can be applied analogously to different geometrical arrangements.

p0040For a very small length (52) of the antenna conductor (12), that for the immediately adjacent heat conductor (38) and converging antenna conductor (10), the two ohmic resistors (53) and (54) are of equal size and equally, the two streams (47 ) and (48). The total resistance between the points (45) and (50) is therefore half as large as the resistance in the absence of the antenna conductor (12) and the converging antenna conductor (10) would be effective, if no cross-sectional adjustment of the two conductors is carried out in the considered area. The heating of the disc between the points (45) and (50) is at a small distance between the antenna conductor (12) and together leading antenna conductor (10) because of the proportionality of the unreacted active power to the entire resistor (55) extending from the parallel connection of (53 ) and (54) yields, also just half as large as in the absence of the antenna conductor (12) and the converging antenna conductor (10). In such an embodiment of an inventive antenna deviates from the remainder of the heating field defrosting is therefore present in the region between the points (45) and (50). therefore, the conductor cross-section of the conductor (38) between the points (45) and (50) and the composite leading antenna conductor (10) is halved advantageous for an antenna according to the invention, a measure which simply possible with printed screen printed conductors by a corresponding design of the screen is.

p0041If the length (52) of the antenna conductor (12) not so small that the disc (45) and (50) as heated by a single conductor in the region between the points, so the connections are complicated. In general, one will be interested to limit the heating of the disc to the region around the heating conductor (38) and consequently seek to dimensioning in which the via the antenna conductor (12) and the converging antenna conductor (10) unreacted heat remains low , This objective can (45) and (50) can be achieved on the other hand for an antenna according to the invention by an appropriate selection of the cross sections of the antenna conductor (12) and the converging antenna conductor (10) on the one hand and the portion of the heating conductor (38) between the points.

p0042A general analysis leads to the conclusion that with respect to the values ​​of the resistors (54) = R1 and (53) = R2 each case based on the resistance value (55) = R, which in default executed heat conductors, without the antenna conductor (12) and the converging antenna conductor (10) between the points (45) and (50) would result, perform the following combinations of values ​​for the desired behavior: <tables id="tabl0001" num="0001"><table frame="all"><title>Table 1</title><tgroup cols="10" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="15.75mm" /><colspec colnum="2" colname="col2" colwidth="15.75mm" /><colspec colnum="3" colname="col3" colwidth="15.75mm" /><colspec colnum="4" colname="col4" colwidth="15.75mm" /><colspec colnum="5" colname="col5" colwidth="15.75mm" /><colspec colnum="6" colname="col6" colwidth="15.75mm" /><colspec colnum="7" colname="col7" colwidth="15.75mm" /><colspec colnum="8" colname="col8" colwidth="15.75mm" /><colspec colnum="9" colname="col9" colwidth="15.75mm" /><colspec colnum="10" colname="col10" colwidth="15.75mm" /><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">R1 / R =</entry><entry namest="col2" nameend="col2" align="right">4</entry><entry namest="col3" nameend="col3" align="right">==</entry><entry namest="col4" nameend="col4" align="left">R2 / R =</entry><entry namest="col5" nameend="col5" align="char" char=".">4</entry><entry namest="col6" nameend="col6" align="left">R1 / R =</entry><entry namest="col7" nameend="col7" align="char" char=".">4.5</entry><entry namest="col8" nameend="col8" align="right">==</entry><entry namest="col9" nameend="col9" align="left">R2 / R =</entry><entry namest="col10" nameend="col10" align="char" char=".">2.6</entry></row><row><entry namest="col1" nameend="col1" align="left">R1 / R =</entry><entry namest="col2" nameend="col2" align="right">5</entry><entry namest="col3" nameend="col3" align="right">==</entry><entry namest="col4" nameend="col4" align="left">R2 / R =</entry><entry namest="col5" nameend="col5" align="char" char=".">2</entry><entry namest="col6" nameend="col6" align="left">R1 / R =</entry><entry namest="col7" nameend="col7" align="char" char=".">6</entry><entry namest="col8" nameend="col8" align="right">==</entry><entry namest="col9" nameend="col9" align="left">R2 / R =</entry><entry namest="col10" nameend="col10" align="char" char=".">1.6</entry></row><row><entry namest="col1" nameend="col1" align="left">R1 / R =</entry><entry namest="col2" nameend="col2" align="right">10</entry><entry namest="col3" nameend="col3" align="right">==</entry><entry namest="col4" nameend="col4" align="left">R2 / R =</entry><entry namest="col5" nameend="col5" align="char" char=".">1.2</entry><entry namest="col6" nameend="col6" /><entry namest="col7" nameend="col7" /><entry namest="col8" nameend="col8" /><entry namest="col9" nameend="col9" /><entry namest="col10" nameend="col10" /></row></tbody></tgroup></table></tables>

p0043For an advantageous embodiment of an inventive antenna therefore this table accordingly to a predetermined ratio R1 / R the R2 / R ratio by selecting a suitable conductor cross-section in the area of ​​the antenna conductor (12) between the points (45) and (50), ie in the region the structure width (9) set. So, for example, yields for conductor cross sections of antenna conductor (12) and together leading antenna conductor (10) similar to those for the heating conductors of the value of R1 / R = 5, when the distance (52) of the composite leading antenna conductor (10) to the closest and electrically connected HL (38) 2 times as large as the structure width (9) in 2.Bereich (41). In order to implement as in the remaining area of ​​the heating field under these conditions also related to the structural width (9) the same heating power per unit length must be doubled according to the table of the DC resistance, which is advantageously achieved by a reduction of the cross section in half.

p0044A further advantageous embodiment of an inventive antenna without cross-matching is possible if in the special vehicle window, the available strip between the heating conductor (38) and frame is so large that the length (52) of the antenna conductor (12) large compared with the width ( 9) of the structure in 2.Bereich (41) is selected. In this case, the ohmic resistance (54) is so large compared to the ohmic resistance (53), so that the current (47) almost corresponds to the current (46) and the stream (48) is negligibly small. This corresponds in the table above very high values ​​of R1 / R, for which R2 / R asymptotically the value "1" approaches.

p0045For these reasons, it is advantageous for the inventive antenna to locate the converging antenna conductor (10) as possible in the vicinity of the frame, because in this way the influence of the DC current flow and hence the heat distribution on the disc is the most favorable. For aesthetic reasons, it is further advantageous to together leading antenna conductor (10) parallel to the grid lines (2) or to the corresponding frame edge, so that they are horizontal.

p0046In a further advantageous embodiment of an antenna according to the invention the above problems are avoided in that such a galvanic connection of the antenna conductor (12) through the converging antenna conductor (10) is replaced by a compound which has no direct current passage, however, within the frequencies of the useful the frequency range of meter waves causes a sufficiently low-resistance connection. This can according to Figure 11 by applied to the disc capacitors (58), are achieved for example by soldered chip capacitors corresponding capacitance value.

p0047Electric behavior equivalent of an inventive antenna without affecting the heating current through the structure of the antenna conductor (12) in 2.Bereich may hereinafter also be erreciht that the electrical connection between the 1.Bereich and 2.Bereich is replaced by a connection, which no DC current passage has, however, results in a sufficiently low-ohmic connection within the frequency range of the meter waves for the frequencies of the useful band. This can be achieved in the same manner as in Figure 11 by applied to the plate capacitors (58) corresponding capacitance value corresponding to Fig.12.

p0048In the following advantageous features of the secondary antenna conductor (22) are described for inventive antenna.

p0049The common connection point (8) on the converging antenna conductor (10) is an antenna according to the invention is always in the region (42) of the disc, ie in an area symmetrically around the line of symmetry (3) and corresponding with a width of half of the average wheel width ( 5). By symmetry, however, is recommended primarily an overall symmetrical structure with the consequence that the connection point (8) is arranged on the line of symmetry (3) as a rule. Can as a mounting point for the further network (16) is also a point on the line of symmetry (3) on or in the vicinity of the frame (21) are used, it is optionally necessary between the connection point (8) and the coupling-out point (23 ) in the vicinity of the frame to establish a connection through the secondary antenna conductor (22), wherein expediently the further antenna conductor (22) then is also disposed along the line of symmetry. Figure 3 shows such a situation. If the mounting point of the secondary network is not (16) on the line of symmetry (3) of the disk, so it is usually the connection point (8) is also not on the line of symmetry (3) order the disk, but move parallel to the line of symmetry of the disc, so that under optical aspects of advantageous further antenna conductor (22) also parallel to the two lateral frame edges or the symmetry line can be performed.

p0050Often, however, decide, in the vehicle-specific aspects, a mounting point for the further network (16) in the area of ​​the sky of a vehicle due to circumstances of the production sequence or because of poor Errreichbarkeit the components. In such cases it is required the received signal available at the connection point (8) harmless with respect to the connection point (8) forward reached received powers to the vicinity of the outgoing network (16) and in the proximity of the frame (21).

p0051This object is solved in an inventive antenna by the secondary antenna conductor (22), which consists in the general case of a plurality of directly merging part conductors which is guided in parallel advantageous for optical reasons to one of the respective adjacent border edges. A typical arrangement according to the invention shows an example of FIG. 1, in which the further network (16) is mounted in the left side of the frame portion and the further antenna conductor (22) starting from the connection point (8) at first along the symmetry line of the disc up to the proximity is out of the frame, in the kink point (57) bends and is guided parallel to the upper edge of the frame to the right up to the vicinity of the upper right corner to the coupling-out point (23) in the other. Optionally may be required at the appropriate location of the secondary network (16) also further break points (57).

p0052The size of the distance (60) from Fig. 1, in which the secondary antenna conductor (22) is guided parallel to the respective frame edge is to choose, depending on which goal is desired in an antenna according to the invention.

p0053If, for example, a glass antenna can be realized whose behavior comes closest to a rod antenna with polarization changes, so must this distance (60) is small, ie in the range of about 1cm to 5cm selected. With this dimensioning of the exciting field strength for a for a horizontally polarized and the other for a vertically polarized wave field arises in the same values, a significant increase in level at the transition from horizontal polarization to vertical or circular polarization of a similar magnitude as of vertically mounted on the vehicle rod antennas has been known. This property results from the fact that an almost symmetrically arranged in Bull's inventive antenna having regard to their connection point (8) this property and a small distance (60) (Fig. 1) arranged by the disc edge of further antenna conductor (22) is approximately the character of a assumes line, coupled into the negligibly small signals from the reception field. Therefore, the point at the terminal (8) existing polarization behavior substantially even at the coupling (23) later on.

p0054However, this strong preference for the vertical field component is not always desirable, since this reduces the demands on the receiving system with respect to the intermodulation resistance are especially very large close to the transmitter vertically polarized stations. Often one is therefore interested in an antenna regardless of the polarization of an incident field strength in each case provides the same average antenna level. This desired behavior an antenna inventive approaches to when the secondary antenna conductor (22) is performed at a large distance parallel to the frame edges, as is also strongly coupled in this case, the secondary antenna conductor (22), especially with a horizontally polarized field. Such inventive antenna exemplifies Fig. 13.

p0055Is an antenna according to the invention provided substantially only for receiving horizontal polarized waves, the distance (60) of the secondary antenna conductor (22) to the frame can be freely chosen.

p0056For antenna diversity systems multiple antennas with different possible behavior in terms of interference are required. As is known, it makes sense to implement such systems for multiple antennas in a single vehicle window.

p0057Two such Diversity antennas can be executed with advantage as the present invention antennas when the heating field is divided into the respective vehicle wheel. Fig. 5 shows such an arrangement, the two secondary networks (16) are attached to almost diagonally opposite points in the frame area. Since the material to the receiving areas of the two antennas are each arranged in the region of the vertical symmetry line of the disc, having these two antennas in only slightly disturbed by multipath propagation wave fields due to their similarity of geometries no very pronounced different behavior.

p0058Frequently therefore with different types of antennas a greater degree of improved reception can be achieved by a diversity system, if an antenna according to the invention is combined with another type of antenna, as exemplified Fig. 14 shows. In this case, the second signal is coupled in a known manner to the busbar of the other Teilheizfeldes, resulting in very good diversity characteristics.

p0059A line of symmetry (3) of the disc pronounced asymmetrical arrangement of two antennas according to the invention in a total re-balanced manner, a further advantageous embodiment is, which have the advantage equivalent of further networks (16) and also a good diversity suitability due to a sufficient decoupling by relatively large spatial distance of the respective antenna conductor (11) and (12), also the two secondary networks (16) are identical with the corresponding advantages in terms of costs and simplified inventory.

p0060For sufficiently large free space above or below the heating field further Diversity antennas can also be combined in the vehicle window to the antenna according to the invention in a known manner.

p0061As is known, it is necessary, the connection between the output point (23) of an inventive antenna and the input terminal (15) of the secondary network (16) and the connection of the other input terminal (17) of the secondary network through the conductor (32) to the ground point (39) to make on the metal frame (21) each as short as possible. The antenna connection point forming the output terminals (18) and (19) of the secondary network (16) to which the antenna cable is connected. The continuing network can be designed exclusively passive and fulfill the role of power matching the impedance of Unipols at the coupling to the characteristic impedance of the antenna line (20) by suitable low-loss transformation elements according to known techniques.

p0062Advantageously, this further network to obtain the maximum possible signal-to-noise ratio is, however, actively running, so that there is an active antenna with the invention Unipol whose input transistor is operated in eingangsseitg noise matching.

p0063If the antenna of the invention can be used as a broadcast receiving antenna for the frequency range LMK, so can in an advantageous further embodiment, an independent from the heating field LMK structure are provided which can be attached in areas not covered by the heating field area of ​​the disc and the output point (29) is advantageous in near the Auskoppelpunkts (23) of the antenna according to the invention is mounted (Fig. 6 and Fig.13). The continuing network is preferably expanded in this case to a separate amplifier with capacitive high-impedance input resistance in a known technique for the frequencies of the LMK-range and the output point (29) of the LMK structure with the LMK input (27) of the secondary circuit. About a crossover frequency range LMK and the meter wave range within the secondary circuit (16) are brought together in a known technology then and supplied to the antenna line (20).

p0064The busbars (62) in the region of the disc edges, with which the heating conductors (2) and (38) are electrically combined, the Heizgleichstrom from the Bordakkumulator (36) is supplied to the minus terminal in the control over the connection (64) to the vehicle body connected is. This wiring of the heating field by the DC power supply lines (63) leading to the frequencies of the meter waveband firstly a generally undefined AC distributed load of the busbars (62) and secondly also to emission of noise signals in the heating field, as due to the vehicle units of DC the Bordakkumulators (36) partially significant interference signals are superimposed, the spectrum of frequencies LF reaches over the frequency range of the meter waves beyond.

p0065Both disturbances tend to be reduced by the described decoupling of preferred acting reception zone of the edge regions of the vehicle window. Nevertheless, you will avoid in the interest of optimum function of the antenna of the invention these disturbances by additional measures.

p0066Advantageously, this is done using the Heizfeldnetzwerke (25) which are arranged in the DC power supply lines (63) for heating field preferably in the vicinity of the connection points on the busbars (62).

p0067The suppression of the Bordakkumulator (36) superimposed noise occurs each simple and advantageous in the Heizfeldnetzwerken (25) by switched to ground shunt capacitors (64) (Fig. 15) of a capacitance value which is suitable for the frequencies of the meter wave range for implementing a capacitive short Schlußs , In this way, a defined connection of the busbars is also achieved with the sequence defined impedances of Unipols at the extraction (23).

p0068Such capacitive low-loading of the busbars of the heating field, however, shows how measurements show often unfavorable available signal level at the output point (23) of an inventive antenna. Therefore, in a further advantageous development of the invention in the connection between the capacitor (64) and the connection to the respective busbar (62) is connected an element (65) in series, which at low impedance DC continuity for the frequencies of the useful inside the meter wave range, a high-resistance series impedance has, whereby the AC even loading the busbars is sufficiently low. This series element (65) can for example be realized by an air coil a high inductance, and for the heating currents in the range of 10A to 30A sufficient conductor cross-section or by a parallel connection of a smaller air-core coil and a capacitor, when the resulting series-parallel resonant circuit is dimensioned such that its resonance frequency is approximately in the middle of the useful frequency range of the meter within the shaft portion.