A UWB radar antenna

Abstract

A UWB radar antenna comprising at least a first feed layer (4) and at least a second radiating layer (5). The first feed layer (4) comprises: at least two conductive tracks (7) side by side and arranged parallel to each other at least for a section thereof so as to generate at least one differential electromagnetic signal; at least two feed points (8) each operatively connected to a respective one of the two conductive tracks (7) and arranged symmetrically with respect to an axis parallel to and equidistant from them; at least two conductive surfaces (10) shaped so as to diverge from the two conductive tracks (7). In addition, the second radiating layer (5), which is operatively connected to the two feed points (8), is shaped so as to radiate the differential electromagnetic signal.

Description

[0001] A UWB RADAR ANTENNA DESCRIPTION

[0002] Field of application

[0003] The present invention is generally applicable to the telecommunications field, and in particular, the present invention relates to a UWB radar antenna.

[0004] Background of the invention

[0005] In the field of telecommunications, the transmission technique called UWB, namely Ultra WideBand, is known, which has been developed to transmit and receive signals using pulses in radio frequency with extremely short duration and, therefore, with very wide spectral occupation. These pulses are represented by a few wave cycles of a radio frequency carrier, and therefore the frequency spectrum associated with this waveform is extremely large.

[0006] The advantage of this technique lies in the fact that the shortness of the pulse makes the signal transmission insensitive to the interferences due to the reflections of the wave itself.

[0007] The bandwidth means that the power spectral density is very low, limiting, among other things, the interferences towards the surrounding applications. This band, which can reach significant widths, is obtainable with extremely low electrical powers in the antenna.

[0008] For these characteristics this technique is also used in the field of radar.

[0009] As is well known, radar is a system that uses electromagnetic waves to detect and determine the position, and possibly the speed, of both fixed and mobile objects.

[0010] In particular, the operation of radar is based on the physical phenomenon of the reflection of electromagnetic radiation when it hits an object whose dimensions are larger than the wavelength of the incident radiation. Relevant characteristics are that the signal must have excellent directivity, must allow the highest possible resolution of the detection and have a reduced dispersion in the module and in the phase in order to ensure that the radiated signal is as much as possible coincident with that to power the antenna in order to increase the spatial resolution of the radar.

[0011] Since, as mentioned, it is important that the antennas and radar signals allow to accentuate directivity, high resolution and reduced signal dispersion, it is evident how more and more radar systems of the UWB type are spreading.

[0012] However, the results obtained, while improving compared to other types of radar, are not always optimized. In particular, a relevant aspect is determined by the fact that the used antennas do not always allow to maximize the aforementioned characteristics, worsening the overall quality of the radar system.

[0013] Document CN 112 886 235 A is also known which describes a low-profile ultra-wideband differential radar antenna comprising a first dielectric plate, a second dielectric plate and a third dielectric plate which are arranged in sequence from top to bottom. However, even this antenna does not allow to accentuate the directivity, resolution and dispersion of the signal.

[0014] In addition, documents WO 2020 / 178669 A1 and US 2009 / 146883 A1 are also known, which describe respectively an antenna and a patch antenna equipped with a ground plane but which, however, do not resolve the drawbacks highlighted above.

[0015] Presentation of the invention

[0016] The object of the present invention is to provide a UWB radar antenna which allows to at least partially overcome the drawbacks highlighted above.

[0017] Another object of the present invention is to provide a UWB radar antenna that allows to optimize the antenna itself with respect to devices present in the prior art. In particular, the object of this invention is to provide a UWB radar antenna that improves impedance matching.

[0018] Furthermore, a further object of the present invention is to provide an antenna whose realization is economically advantageous compared to the known equivalent antennas.

[0019] Said objects, as well as others that will appear more clearly below, are achieved by a UWB radar antenna comprising at least a first feed layer and at least a second radiating layer in accordance with the following claims, which are to be considered an integral part of the present patent.

[0020] In particular, the first feed layer comprises at least two conductive tracks side by side and arranged parallel to each other at least for a section thereof so as to generate at least one differential electromagnetic signal.

[0021] Furthermore, the first layer also comprises at least two feed points operatively connected to the two conductive tracks and arranged symmetrically with respect to an axis parallel to and equidistant from the aforementioned conductive tracks.

[0022] According to another aspect of the invention, the first feed layer also comprises at least two conductive surfaces, operatively interposed between the two conductive tracks and the two feed points, shaped so as to diverge from the conductive tracks.

[0023] According to a further aspect of the invention, the second radiating layer is operatively connected to the two feed points and is shaped so as to radiate the differential electromagnetic signal generated in the first layer.

[0024] Advantageously, the arrangement and, in particular, the proximity of the two conductive tracks in the section in which they are positioned parallel to each other allows to generate a differential electromagnetic signal.

[0025] In addition, the conductive surfaces allow to distance the feed points from the tracks so that, by means of the antenna of the invention, it is possible to perform a transmission on parallel and close sides, allowing to facilitate the transmission of the differential signal with respect to the known equivalent devices.

[0026] On closer inspection, therefore, the arrangement of the feed points, which are moved away from the tracks through the diverging conductive surfaces, allows the antenna of the invention to be optimized with respect to the UWB radar antennas present in the state of the art.

[0027] Brief description of the drawings

[0028] Further characteristics and advantages of the invention will become more apparent in the light of the detailed description of some preferred, but not exclusive, embodiments of a UWB radar antenna according to the invention, illustrated by way of non-limiting example with the aid of the accompanying drawing tables in which:

[0029] Figure 1 represents the UWB radar antenna of the invention,

[0030] Figure 2 represents the first layer of the antenna of Fig. 1 ,

[0031] Figure 3 represents the second layer of the antenna of Fig. 1 ,

[0032] Figure 4 represents the intermediate layer of the antenna of Fig. 1 .

[0033] Detailed description of an exemplary preferred embodiment

[0034] With reference to the attached figures, in particular Figure 1 , a UWB radar antenna 1 is described comprising a first feed layer 4 and a second radiating layer 5 according to the invention.

[0035] According to an aspect of the invention, the first layer 4, which can be observed in Figure 2, comprises two conductive tracks 7 side by side and arranged for a section parallel to each other so as to generate a differential electromagnetic signal.

[0036] Advantageously, the arrangement of the conductive tracks 7 facing onto parallel sides makes it possible to facilitate the transmission of differential signals.

[0037] In addition, the parallel sections of the conductive tracks 7 allow to maintain the balance of the antenna 1 , whose radiation diagram would otherwise undergo shifts.

[0038] In particular, according to the embodiment of the invention being described, the two tracks 7 have equal and predetermined lengths. This advantageously allows to limit, if not eliminate, the differential irradiation loss.

[0039] Furthermore, again according to the embodiment of the invention being described, the conductive tracks 7 are arranged at a predetermined distance, for example, equal to 0.2 mm.

[0040] Advantageously, the proximity of the conductive tracks 7 further improves the transmission of the differential signals.

[0041] Obviously, both the value of the length and the space between the two conductive tracks should not be understood as limiting the different embodiment variants of the invention where these values can be obtained by means of numerical optimizations within the reach of a person skilled in the art based on the characteristics of the differential signal to be originated.

[0042] According to the embodiment being described, the first feed layer 1 also comprises three feed points 8 for each polarity of the differential signal. That is, each of the two conductive tracks 7 is operatively connected to three feed points 8.

[0043] These feed points 8 are arranged symmetrically with respect to an axis, not represented in the figures, parallel to and equidistant from the two conductive tracks 7 in the section in which they are arranged parallel to each other.

[0044] Advantageously, the tripling of the feed points 8, i.e. the presence of three feed points 8 that lie on three different points of the antenna 1 , allows to widen the matching band.

[0045] Furthermore, still advantageously, the three feed points 8 allow to optimize the impedance matching of the antenna 1.

[0046] Obviously, the number of feed points should not be understood as limiting the different embodiment variants of the invention, where the feed points may be in any number.

[0047] According to a further aspect of the invention, the first feed layer 4 also comprises two conductive surfaces 10 operatively interposed between the two conductive tracks 7 and the feed points 8. These conductive surfaces 10 are shaped so as to diverge from the conductive tracks 7, i.e. they are shaped so as to move the feed points 8 away from the tracks 7 by distancing the feed points 8 operatively connected to different conductive tracks 7 from each other.

[0048] In addition, these conductive surfaces 10 also have a predetermined length and can be obtained by a person skilled in the art by means of numerical optimizations on the basis of the sought impedance.

[0049] According to the embodiment of the invention being described, the three feed points 8 are arranged at a predetermined mutual distance.

[0050] For example, according to the non-limiting embodiment represented in the aforementioned Figure 2, the three feed points 8 are not aligned and the conductive surfaces 10 that carry the signal from the tracks 7 to the points 8, near the latter are spaced 1.1 mm apart.

[0051] Obviously, also the distance between the feed points, or between the conductive surfaces that carry the signal from the tracks to the points themselves, should not be understood as limiting the different embodiment variants of the invention and is easily predetermined by experts in the field by means of numerical optimizations depending on the type of signal to be originated.

[0052] With regard to the second radiating layer 5, which can be observed in Figure 3, it is operatively connected to the feed points 8 and is shaped so as to radiate the differential electromagnetic signal originated in the first feed layer 4.

[0053] On closer inspection, therefore, the UWB radar antenna 1 of the invention allows to optimize the antenna compared to the equivalent devices present in the prior art. In fact, the parallel arrangement of the conductive tracks 2 allows to originate a differential signal and at the same time to improve the impedance matching.

[0054] According to the embodiment being described, the second radiating layer 5 comprises several notches 14 of predetermined dimensions.

[0055] Advantageously, the notches 14 allow to widen the matching band of the UWB radar antenna 1 of the invention.

[0056] According to the embodiment described, the notches 14, as can be observed in Figure 3, are symmetrical and for each polarity they provide a succession of a first notch 15 1.4 mm wide and 2.65 mm deep, a second notch 16 (0.55 mm apart from the first) 0.35 mm wide and 3.6 mm deep and at a distance of 1.6 mm a further first notch 15 and a second notch 16 again 0.55 mm apart from the first.

[0057] Obviously, the number and the dimensions of the notches should not be understood as limiting the different embodiment variants of the invention and may be any. In fact, similar to what was previously mentioned, the dimensions of the notches can be predetermined by means of numerical optimizations as a function of the signal to be transmitted.

[0058] According to another aspect of the invention, the UWB radar antenna 1 is couplable to an additional board, not represented in the figures, which comprises an electrically conductive surface serving as a ground plane for the antenna 1 itself.

[0059] In other words, the antenna 1 of the invention does not itself comprise a ground plane but, when coupled to an additional board comprising an electrically conductive surface, uses that board as if it were its own ground plane.

[0060] This advantageously allows to use different materials for the ground plane and for the antenna 1. In other words, since the antenna 1 and the ground plane are separate, it is possible to use more functionally effective but more expensive materials for the realization of the UWB radar antenna 1 and less expensive materials for the realization of the ground plane.

[0061] Consequently, the antenna 1 of the invention allows to limit the execution costs with the same quality of the signal transmitted by equivalent devices present in the prior art.

[0062] Obviously, the materials used for antenna and ground plane should not be understood as limiting different embodiment variants of the invention where, for example, the same materials are used.

[0063] According to a further aspect of the invention, the UWB radar antenna 1 also comprises an intermediate layer 18, interposed between the first feed layer 4 and the second radiating layer 5. In particular, said intermediate layer 18 comprises a pair of metal elements 19 adapted to improve the impedance matching of the antenna 1 itself.

[0064] Advantageously, the metal elements 19, which are substantially floating between the first and second layers 4 and 5, allow to improve the reactive part of the impedance by neutralizing the natural inductance.

[0065] Obviously, the number of the metal elements should not be considered limiting to different variants of the invention where, for example, they are not present or are present in any number.

[0066] In addition, according to a non-limiting example they are rectangular, 1 ,4mm x 7.4mm in size, and spaced 0.85 mm apart. Obviously, the distance and geometry of the metal elements should not be understood as limiting the different embodiment variants of the invention.

[0067] In light of the foregoing, it is therefore understood that the UWB radar antenna of the invention achieves all the set purposes.

[0068] In particular, the antenna of the invention is shaped to originate a differential electromagnetic signal which is characterized by a better impedance matching than that originated by equivalent devices. Therefore, the UWB radar antenna of the invention is optimized with respect to equivalent antennas present in the prior art.

[0069] The invention is subject to numerous modifications and variations, all falling within the appended claims. All the details and steps can be replaced by other technically equivalent elements, and the materials can be different depending on the needs, without departing from the scope of protection of the invention defined by the attached claims.

Claims

C L A I M S1 . A UWB radar antenna comprising at least a first feed layer (4) and at least a second radiating layer (5), said UWB radar antenna (1) being characterized in that: said at least one first feed layer (4) comprises: o at least two conductive tracks (7) side by side and arranged parallel for at least a section of said at least two conductive tracks (7) so as to generate at least one differential electromagnetic signal; o at least two feed points (8) each operatively connected to a respective one of said at least two conductive tracks (7) and arranged symmetrically with respect to an axis parallel to and equidistant from said at least two conductive tracks (7); o at least two conductive surfaces (10) operatively interposed between said at least two conductive tracks (7) and said at least two feed points (8), said at least two conductive surfaces (10) being shaped so as to diverge from said at least two conductive tracks (7); said at least one second radiating layer (5) being operatively connected to said at least two feed points (8) and said at least one second radiating layer (5) being shaped so as to radiate the differential electromagnetic signal.

2. UWB radar antenna according to claim 1 , wherein said one UWB radar antenna (1) is couplable to at least one additional board comprising at least one electrically conductive surface serving as a ground plane for said at least one UWB radar antenna (1) when coupled to the additional board.

3. UWB radar antenna according to claim 1 or 2, comprising at least one intermediate layer (18) interposed between said at least one first feed layer (4) and said at least one second radiating layer (5), said at least one intermediate layer (18) comprising at least one pair of metal elements (19) adapted to improve the impedance matching of said UWB radar antenna (1).

4. UWB radar antenna according to one or more of the preceding claims, comprising at least three feed points (8) for each polarity of the differential signal.

5. UWB radar antenna according to claim 4, wherein said at least three feed points (8) are arranged at predetermined distances.

6. UWB radar antenna according to claim 4 or 5, wherein said at least three feed points (8) are arranged at a centre distance of 1 .1 mm.

7. UWB radar antenna according to one or more of the preceding claims, wherein said at least two conductive tracks (7) have predetermined equal lengths.

8. UWB radar antenna according to one or more of the preceding claims, wherein said at least two conductive tracks (7) are arranged at a predetermined distance.

9. UWB radar antenna according to claim 8, wherein said at least two conductive tracks (7) are spaced 0.2 mm apart.UWB radar antenna according to one or more of the preceding claims, wherein said at least one second radiating layer (5) comprises several notches (14) of predetermined dimensions.

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