EP3159967A1 - Multiband gnss antenna - Google Patents

Abstract

Multiband GNSS antenna (10), comprising an electrically conductive base plate (12), a first dielectric resonator antenna (14) disposed on the base plate (12), characterized by a side facing away from the base plate (12) immediately above first dielectric resonator antenna (14) arranged second dielectric resonator antenna (16), wherein the first dielectric resonator antenna (14) and the second dielectric resonator antenna (16) have different diameters and thus different resonance frequencies. The multiband antenna according to the invention can thus be designed to be particularly small and nevertheless achieves a good reception power and bandwidth in two or more GNSS bands.

Description

The invention a multiband GNSS antenna.

When using GNSS antennas in, for example, automobiles or aircraft, great efforts have been made to make the antennas known in the art smaller. This is particularly important because GNSS antennas must often be mounted outside a vehicle or at least on the outside surface of a vehicle or aircraft. In order to be able to integrate GNSS antennas better in vehicles, airplanes, etc., it is constantly trying to make these antennas smaller.

These efforts are in most cases associated with losses in the performance of the antennas (in terms of maximum achievable gain and available bandwidth). Thus, an optimal compromise between still acceptable performance and reduced dimensions of an antenna must be found.

Further, in view of reduced susceptibility to interference, it is useful to use multi-band GNSS antennas so that as many signal bands as possible can be covered. However, the use of multiband GNSS antennas is not possible or very difficult for antennas with very small dimensions.

Furthermore, it is known to use antenna arrays. These are advantageous to suppress interference, for example, by maximizing signals originating from the satellite and minimizing spurious signals from other directions.

Commercially available GNSS antennas can now measure about 1 cm in size and can be used in cell phones, for example. However, a strong limitation of the performance is accepted: For example, the achievable gain is well below 0 dBi. Furthermore, only a few MHz of bandwidth (in the L1 / E1 band) are available. Furthermore, the antennas behave as linearly as possible in terms of their polarization, while RHCP polarization (right hand circular polarization) would be desirable. This corresponds to the polarization of the satellite signals. Such antennas can thus not be used for precise and trouble-free navigation.

If, on the other hand, multiband antennas covering several frequency bands are used, for example the L1 / E1 band as well as one or more of the E5 / L2 / E6 bands, then larger antenna elements must be used. Furthermore, special measures must be taken for the adaptation to the different frequency bands. In the prior art there exist either antennas that are multiband capable but whose bandwidth decreases with the size of the antenna or broadband antennas are known which cover the entire L band and not just the navigation signal bands. However, the latter can only be miniaturized to a very limited extent.

Previous GNSS antennas known in the prior art which cover both the upper bands (L1 / E1) and one or more of the lower bands (E5 / L2 / E6) have so far had dimensions of at least 3.5 cm x 3.5 cm up.

The object of the invention is to provide a multiband GNSS antenna with reduced dimensions.

The object is achieved according to the invention by the features of claim 1.

The multiband GNSS antenna according to the invention comprises an electrically conductive base plate and a first dielectric resonator antenna which is arranged on the base plate. As far as the GNSS antenna according to the invention corresponds to known from the prior art dielectric resonator antennas.

According to the invention, a second dielectric resonator antenna is arranged directly above the first dielectric resonator antenna on the side facing away from the base plate. Immediately, it is understood that no other components are disposed between the first and second dielectric resonator antennas so that the first dielectric resonator antenna contacts the second dielectric resonator antenna. If, for example, the first and second dielectric resonator antennas are circular-cylindrical, then the lower base surface of the second dielectric resonator antenna can be in full contact with the upper base surface of the first dielectric resonator antenna. An adhesive layer may be disposed between the two dielectric resonator antennas to connect the two antennas together. Furthermore, the first dielectric resonator antenna may be fixed on the base plate by means of an adhesive. According to the invention, the first dielectric resonator antenna and the second dielectric resonator antenna have different diameters and thus different resonance frequencies.

The multiband GNSS antenna according to the invention can be used along a wider frequency band, although it has smaller dimensions. For example, when choosing a suitable material for the electrical resonator antennas in both the upper and in the lower navigation band a gain of more than 0 dBi can be achieved, while the antenna size does not exceed 3.5 cm x 3.5 cm x 4 cm. For this purpose, for example, a glass-ceramic material can be used which has a dielectric constant between 30 and 35. The antenna according to the invention can thus be made particularly small and still achieve good performance and bandwidth in two or more GNSS bands. It can thus be used particularly advantageously in mobile applications such as cars, airplanes, UAVs, drones, etc.

It is preferable that one of the electric resonator antennas, particularly the first dielectric resonator antenna, has a resonant frequency in the band between 1164 to 1214 MHz or 1215 to 1239.6 MHz or 1260 to 1300 MHz, while the other antenna, in particular the second dielectric resonator antenna has a resonant frequency in the band between 1563 to 1587 MHz.

Furthermore, it is preferred that the first and second dielectric resonator antennas comprise a ceramic or glass-ceramic material.

Further, it is preferable that each dielectric resonator antenna has on its upper side, that is, the side facing away from the base plate, a metal lid, wherein the metal lid of the first dielectric resonator antenna serves as a base plate for the second dielectric resonator antenna. The metal lid may completely or partially cover the respective dielectric resonator antenna. Furthermore, it is possible that the first dielectric resonator antenna has a metal cover and the second not. The metal lid of the first dielectric resonator antenna is considered to be part of the first dielectric resonator antenna and, according to the invention, apart from a possible adhesive layer, is the only element which is interposed between the dielectric material of the first dielectric resonator dielectric resonator antenna and the dielectric material of the second dielectric resonator antenna.

Furthermore, it is preferred that both dielectric resonator antennas are connected to two common connection lines, via which the electrical signals are received, which are received by the antennas.

The two common connection lines extend from the base plate along the outer wall of the first dielectric resonator antenna to the second dielectric resonator antenna, and preferably along at least a part of the outer wall of the second dielectric resonator antenna. It is preferred that the two connecting lines extend at a right angle to the base plate and preferably adjacent to the lateral surface of the first dielectric resonator antenna and the first and second dielectric resonator antenna.

Furthermore, it is preferred that the two connecting lines are arranged at an angle of 90 ° to each other relative to the central axis of the two dielectric resonator antennas. Each connection line is thus associated with an electrical signal on the x- and y-axis, which are phase-shifted relative to each other by 90 °. Thus, a RHCP polarization of the antenna can be achieved (Right Hand Circular Polarization). Preferably, the connection lines are formed as metal strips, which bear against the lateral surface of the one or both dielectric resonator antennas.

It is further preferred for the two connecting lines to have a frequency-dependent matching device, by means of which the effective length of the connecting lines is adapted as a function of the frequency of the signal conducted via the two connecting lines. Thus, the effective length of the two leads for the first dielectric resonator antenna may be at the resonant frequency of the first dielectric Resonatorantenne be adapted while the effective length of the leads for the second dielectric resonator antenna is adapted to the resonant frequency of the second dielectric resonator antenna. This is of great importance, since the dimensions and in particular the length of the connecting line must be adapted to the resonance frequency of an antenna, so that an optimal adaptation to the frequency band to be operated can be achieved. Since the GNSS antenna according to the invention is multiband capable, in particular dual-band capable, it is important to provide a possibility for separately determining the effective length of the connection lines which are in contact with the two dielectric resonator antennas for each antenna. This can be done by the inventive frequency-dependent length adjustment device, without it being necessary to provide two separate connection lines for each dielectric resonator antenna.

The length adjusting device can be designed, for example, to block a signal with the frequency assigned to the first dielectric resonator antenna and to pass on a signal having the frequency associated with the second dielectric resonator antenna. For example, the length adjusting device can be designed as a resonance circuit for this purpose. For this purpose, electrical components such as capacitors, resistors, etc. may be used. Alternatively, it is possible to achieve said function by a special geometric structure of the connection lines, without the need for explicit electrical components, such as resistors, capacitors, etc., must be used. Such devices for blocking certain frequencies and forwarding other frequencies are known in the art and are commonly referred to as "RF traps".

Such a device thus has the effect of being permeable to the frequency of the second dielectric resonator antenna, so that the effective The length of the two connection lines for the second dielectric resonator antenna is longer than the effective length of the two connection lines for the first dielectric resonator antenna, for the frequency of which the length adaptation device is not permeable.

Furthermore, it is possible that the part of the leads of the second dielectric resonator antenna is electromagnetically coupled to the part of the leads of the first dielectric resonator antenna. In other words, the part of the connection line of the second dielectric resonator antenna is thus galvanically isolated from the part of the connection lines of the first dielectric resonator antenna and only permeable to signals of a certain frequency or a certain frequency range.

A similar effect can be achieved by using a metamaterial for the length adjusting device. For the same purpose, a Split Ring Resonator (SRR) can be used as well.

In a further preferred embodiment, only the supply of the first dielectric resonator antenna is performed by the connecting leads, the metal cover serving as the base plate for the second dielectric resonator antenna serving as an electromagnetic coupling device for coupling the electric field generated by the first dielectric resonator antenna to the second dielectric resonator antenna is trained. For this purpose, for example, the said metal lid may have slots, which are shown in more detail in the description of the figures.

Furthermore, it is preferred that the first and second dielectric resonator antenna have a circular cylindrical shape and in particular are arranged concentrically to one another.

The antenna according to the invention can be used as a single antenna or alternatively in an antenna array. An antenna array may have all the features of the previously described antennas and may be used to amplify signals originating from a satellite and attenuate signals originating from sources of interference coming from another direction. Thus, a lower susceptibility to interference can be achieved.

In a preferred embodiment, a plurality of, in particular four, first dielectric resonator antennas and a plurality, in particular four, second dielectric resonator antennas are arranged next to one another on a base plate. In this case, the base plate may in particular be circular and, for example, have a diameter of less than 9 cm. In the mentioned embodiment, more or fewer than four dielectric resonator antennas may also be arranged on a single base plate.

In the following, preferred embodiments of the invention will be explained with reference to figures.

Fig. 1a

eine Schrägansicht einer ersten Ausführungsform der erfindungsgemäßen Vorrichtung

Fig. 1b

eine Draufsicht derselben Ausführungsform wie in Fig. 1a,

Fig. 2

eine Schrägansicht einer zweiten Ausführungsform der erfindungsgemäßen Vorrichtung,

Fig. 3

eine Schrägansicht einer dritten Ausführungsform der erfindungsgemäßen Vorrichtung,

Fig. 4a

eine Schrägansicht einer vierten Ausführungsform der erfindungsgemäßen Vorrichtung,

Fig. 4b

eine Draufsicht derselben Ausführungsform wie in Fig. 4a.

Show it:

Fig. 1a

an oblique view of a first embodiment of the device according to the invention

Fig. 1b

a plan view of the same embodiment as in Fig. 1a .

Fig. 2

an oblique view of a second embodiment of the device according to the invention,

Fig. 3

an oblique view of a third embodiment of the device according to the invention,

Fig. 4a

an oblique view of a fourth embodiment of the device according to the invention,

Fig. 4b

a plan view of the same embodiment as in Fig. 4a ,

According to Fig. 1a the multi-band GNSS antenna 10 according to the invention is arranged on a base plate 12. It has a first dielectric resonator antenna 14 and a second dielectric resonator antenna 16 arranged directly above it. Both dielectric resonator antennas 14, 16 are circular-cylindrical in cross-section, with the second dielectric resonator antenna 16 resting against the upper base surface of the first dielectric resonator antenna 14 along its lower base surface. On the upper side of each dielectric resonator antenna 14, 16, that is to say on the side remote from the base plate 12, a metal plate 18, 20 is arranged in each case. The metal plate on the first dielectric resonator antenna 14 may be smaller in diameter than the diameter of the second dielectric resonator antenna 16, so that the terminal leads 22, 23 are not short-circuited by the metal plate. This makes it possible to achieve a further reduction in the dimensions of the antenna 10 according to the invention. Here, the metal plate 18 of the first dielectric resonator antenna 14 serves as a base plate for the second dielectric resonator antenna 16.

Along the lateral surface of the first dielectric resonator antenna 14 extend adjacent to this, the two connecting lines 22, 23, through which both dielectric resonator antennas 14, 16 are supplied. The connecting lines 22, 23 thus extend in the illustrated embodiment at a right angle to the base plate 12 in the axial direction along the entire axial length of the lateral surface of the first dielectric resonator antenna 14 and along a portion of the axial length of the second dielectric resonator antenna 16 adjacent to its lateral surface. The first part of the lead 22, 23 applied to the first dielectric resonator antenna is indicated as 22a and 23a, respectively, while the second part which abuts the second dielectric resonator antenna 16 is indicated as 22b and 23b, respectively. A middle part of the connecting lines 22, 23, which is arranged between the first part 22a, 23a and the second part 22b, 23b thereof, does not run along the lateral surface of the first dielectric resonator antenna 14 but along a part of the upper base surface of the first dielectric resonator antenna 14 namely, from its circumference in the radial direction inwards to the smaller circumference of the second dielectric resonator antenna 16.

In the region of the first part 22a, 23a of the connection lines 22, 23, a first and second length adjustment device 24, 26 is arranged on the lateral surface of the first dielectric resonator antenna 14, by means of which an adaptation of the effective length of the connection lines 22, 23 takes place on the first dielectric resonator antenna 14 acts. The axial position at which the length adjusting devices 24, 26 are arranged along the axial extent of the first dielectric resonator antenna 14 is hereby selected as a function of the resonant frequency of the first dielectric resonator antenna 14 and thus depending on its diameter.

In Fig. 1b is a plan view of the same first embodiment as in Fig. 1a shown. Here, the upper base of the second dielectric resonator antenna 16 and a part of the upper base of the first dielectric resonator antenna 14 are visible from above. As can be seen, the two dielectric resonator antennas 14, 16 are arranged concentrically with one another and in particular concentrically with the circular base plate 12. The base plate may also have other geometric shapes in alternative embodiments.

Another alternative embodiment of a multiband GNSS antenna according to the invention is shown in FIG Fig. 2 shown. Here, the lower metal plate 18 covering the upper base of the first dielectric resonator antenna has four slits 28a to 28d from its circumference in the radial direction toward the center thereof, coupling the second dielectric resonator antenna 16 to the first dielectric Resonator antenna takes place by the electric field of the first dielectric resonator antenna 14 is coupled to the second dielectric resonator antenna. Instead of the four slots 28a-28d, more or fewer slots may be provided. Accordingly, the two leads 22, 23 need not extend in the axial direction to the second dielectric resonator, but extend only to the first dielectric resonator 14. This is thus mainly supplied by the leads 22, 23, while the upper dielectric resonator 16 through the antenna described coupling is controlled. The further features of this embodiment correspond to the previously described feature of the antenna 10 according to the invention.

A third embodiment of the multiband GNSS antenna according to the invention is in Fig. 3 shown. In contrast to the embodiment according to FIG. 2 here extend the connecting lines 22a, 22b, 23a, 23b to the second dielectric resonator 16. In this case, each of the first part 22a, 23a of the connecting leads to the first resonator 14, while the second part 22b, 23b abuts the second resonator 16 , The first part 22a, 23a has as a length adjusting device 24, 26 a so-called RF trap. This can be passed only from those frequencies associated with the second dielectric resonator antenna 16 while blocking the frequencies of the first dielectric resonator antenna 14.

An alternative embodiment of a GNSS antenna 10 according to the invention is shown in FIGS FIGS. 4a and 4b shown. Here are on a single base plate 12, four individual antennas each having a first dielectric resonator antenna 14a to 14d and a second dielectric resonator antenna 16a to 16d. Each of these dielectric resonator antennas is formed according to the features described so far. The four individual antennas are preferably arranged uniformly on the circular base plate 12, for example in the form of a square. This makes it possible to design the base plate with a diameter of less than 9 cm, so that a particularly compact multi-band GNSS antenna can be provided. The remaining features of this embodiment correspond to the previously described features of the device 10 according to the invention.

Claims (13)

Multiband GNSS antenna (10), with
an electrically conductive base plate (12),
a first dielectric resonator antenna (14) disposed on the base plate (12),
marked by
a second dielectric resonator antenna (16) arranged directly on the base plate (12) directly above the first dielectric resonator antenna (14), wherein the first dielectric resonator antenna (14) and the second dielectric resonator antenna (16) have different diameters and thus different resonance frequencies , A multiband GNSS antenna (10) according to claim 1, characterized in that one of the dielectric resonator antennas, in particular the first dielectric resonator antenna (14), has a resonant frequency between 1164 to 1214 MHz or 1215 to 1239.6 MHz or 1260 to 1300 MHz and the other dielectric resonator antenna, in particular the second dielectric resonator antenna (16), has a resonant frequency between 1563 to 1587 MHz. Multiband GNSS antenna (10) according to claim 1 or 2, characterized in that the first and second dielectric resonator antenna (14, 16) comprise a ceramic or glass-ceramic material. Multiband GNSS antenna (10) according to one of Claims 1 to 3, characterized in that each dielectric resonator antenna (14, 16) has a metal cover (18, 20) on its upper side, that is, the side facing away from the base plate (12) wherein the metal lid 18 of the first dielectric resonator antenna (14) serves as a base plate for the second dielectric resonator antenna (16). Multiband GNSS antenna (10) according to one of claims 1 to 4, characterized in that both dielectric resonator antennas (14, 16) are supplied via two common connection lines (22, 23) extending from the base plate (12) along the outer wall the first dielectric resonator antenna (14) extend to the second dielectric resonator antenna (16) and preferably along at least a portion of the second dielectric resonator antenna (16),
wherein the two connecting lines (22, 23) in particular at an angle of 90 ° relative to the central axis of the two dielectric resonator antennas (14, 16) are arranged. Multiband GNSS antenna (10) according to claim 5, characterized in that the two connecting lines (22, 23) frequency-dependent Längenanpassvorrichtungen (24, 26), by the depending on the frequency of the over the two connecting lines (22, 23) discharged signal adjusting the effective length of the connecting leads (22, 23) so that the effective length of the two connecting leads (22, 23) for the first dielectric resonator antenna (14) matches the resonant frequency of the first dielectric resonator antenna (14) and the effective one Length of the two connecting lines (22, 23) for the second dielectric resonator antenna (16) is adapted to the resonant frequency of the second dielectric resonator antenna (16). A multiband GNSS antenna (10) according to claim 6, characterized in that the length adjuster (24, 26) is adapted to block the signal of the frequency associated with the first dielectric resonator antenna (14) and to propagate the signal of the frequency associated with the second dielectric resonator antenna .
wherein the length adjusting device (24, 26) is designed in particular as a resonance circuit. The multiband GNSS antenna (10) according to claim 7, characterized in that the part (22b, 23b) of the leads (22, 23) of the second dielectric resonator antenna (16) is electromagnetically connected to the part (22a, 23a) of the leads (22, 23) of the first dielectric resonator antenna (14). Multiband GNSS antenna (10) according to claim 6, characterized in that the length adjusting devices (24, 26) comprises a metamaterial and / or a split-ring resonator (SRR). Multiband GNSS antenna (10) according to one of Claims 4 to 5, characterized in that only the supply of the first dielectric resonator antenna (14) is effected by the connection lines (22, 23), the metal cover (18) serving as a base plate for the second dielectric resonator antenna (16) functions as a coupling device for coupling the electric field generated by the first dielectric resonant antenna (14) to the second dielectric resonant antenna. Multiband GNSS antenna (10) according to one of claims 1 to 10, characterized in that the first and second dielectric Resonator antenna (14, 16) have a circular cylindrical shape and in particular are arranged concentrically to each other. Multiband GNSS antenna (10) according to one of claims 1 to 11, characterized in that a plurality of, in particular four, first dielectric resonator antennas (14a to 14d) and second dielectric resonant antennae (16a to 16d) are arranged side by side on a base plate (12) , which are formed according to claims 1-11, wherein the base plate (12) is in particular circular and has a diameter of less than 9 cm. Multiband GNSS antenna (10) according to one of claims 1 to 12, characterized in that the base of the antenna has dimensions of less than 3.5 x 3.5 cm.

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