Description:TECHNICAL FIELD

[001] The present disclosure generally relates to antennas. More particularly, the present disclosure relates to an antenna system for vehicular communication.

BACKGROUND

[002] Wireless communication technology is playing an important role in various vehicle applications. Intelligent Transportation System (ITS) is crucial for vehicular communication as it caters advanced driving experience, vehicle safety, vehicle platooning, vehicle internet, and the like. The vehicular communication includes Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I), Vehicle-to-everything (V2X) communication, and the like. The ITS works at various operating bands such as 5.855-5.925 GHz, 5.850-5.925 GHz, and the like. Vehicular communication technologies are classified under ITS based on 5.9 GHz IEEE 802.11p standard. The ITS includes multiple requirements for an antenna system such as, ultra-high reliability, low latency communication, and the like.

[003] Conventional ITS systems implement single antenna configurations. Such single antenna configurations include a low profile integrated microstrip antenna for dual band application. Further, certain conventional ITS systems implement a stacked slot antenna structure with additional slots on top metallic part, floating metal layer and reflector metal with additional dielectric layers. However, such configuration is quite bulky and may face integration issues in a vehicle. Similarly, a single Left-Hand Circularly Polarised (LHCP) antenna is implemented in the conventional ITS systems. However, the requirement of ITS includes multi-antenna configuration, with 5G connectivity, installed at different parts of the vehicle to provide 360° field-of-view. Hence, single antenna configuration is not suitable for the ITS to cater the requirements of the ultra-high reliability and the low latency communication.

[004] The multi-antenna configuration based on Full-Duplex (FD) technology is required for the ITS. Simultaneous transmission and reception capability of the FD technology increases spectral efficiency compared to Half-Duplex (HD) technology, which eventually reduces latency. Also, the FD technology improves throughput and provides high-speed ultra-reliable communication. Moreover, the FD technology is one of the candidate technologies for future 6G services. However, a key challenge in implementation of the FD technology in the antenna system is the issue of Self-Interference (SI) due to infliction of high-power local transmit signal from transmitter upon its own receiver, which leads to device saturation and failure in receiving actual signal of interest. To combat the self-interference, a high isolation between the transmitter and the receiver is highly desirable. In general, such high isolation is achieved jointly by passive(p) and active(a) SI Cancellation (SIC) techniques, where p-SIC deals with antenna domain SIC and a-SIC deals with analog and digital domain SIC. However, the analog-SIC is not sufficient to provide enough isolation to restrict saturation of active components such as, low noise amplifier, analog-to-digital converter, and the like. In contrary, antenna is very first component in Radio Frequency (RF) front end which experiences all external stimuli and activates other RF components. Therefore, to reduce system cost and to reinforce a-SIC technique, p-SIC technique or antenna isolation is very much essential in the antenna system implementing FD technology.

[005] Conventional systems improve inter-element isolation between antenna elements, but either only in transmitting or receiving mode i.e., in HD scenario. Such conventional systems implement parallel coupled line resonator between two microstrip antennas, defected ground structure, split-ring resonator, frequency selective surface, and the like. However, such systems are suitable only for the antenna system implementing the HD technology. There are some conventional systems that implement SIC techniques in FD antenna configuration. Such configurations include polarization multiplexing with hybrid-coupler, a dual-polarized multi-layered antenna configuration with additional feeding network and dual polarized horn antenna configuration with high inter-port isolation for FD communication. However, due to multi-layered and bulky structure, these configurations are not suitable to integrate in compact modules in the vehicle. Some other conventional systems include a dual polarized rectangular cavity backed antenna with high inter-port isolation, co-linearly polarized compact size microstrip antenna with Fence-Strip Resonator (FSR), a stacked structure FD antenna with the combination of a microstrip and a surface integrated wave guide cavity backed slot antenna with Cavity-Patch Coupling (CPC) path, and the like. However, these conventional systems provide the SIC between 30-40 dB, which is quite limited for the FD communication.

[006] The information disclosed in this background of the disclosure section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

SUMMARY

[007] In an embodiment, the present disclosure discloses an antenna system for vehicular communication. The antenna system comprises one or more transmitting antennas and one or more receiving antennas. The one or more transmitting antennas and the one or more receiving antennas are fabricated on a substrate at a pre-defined distance and at a pre-defined angle from each other. Further, a plurality of U-shaped slots is etched on a ground plane associated with the one or more transmitting antennas and the one or more receiving antennas. A plurality of metallic vias is placed at a plurality of pre-determined locations of each of the one or more transmitting antennas and the one or more receiving antennas.

[008] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[009] The novel features and characteristic of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:

[0010] Figure 1 shows an exemplary antenna system, in accordance with embodiments of the present disclosure;

[0011] Figure 2 illustrates a first design stage of the antenna system, in accordance with some embodiments of the present disclosure;

[0012] Figure 3 illustrates electric field distribution and magnetic field distribution of the antenna system at the first design stage, in accordance with some embodiments of the present disclosure;

[0013] Figure 4 illustrates a second design stage of the antenna system, in accordance with some embodiments of the present disclosure;

[0014] Figure 5 illustrates a third design stage of the antenna system, in accordance with some embodiments of the present disclosure;

[0015] Figure 6 illustrates a transmission line designed at 5.9 GHz operating frequency and S-parameter response curve, in accordance with some embodiments of the present disclosure;

[0016] Figure 7 illustrates E-field and H-field distributions of the antenna system at the third design stage, in accordance with embodiments of the present disclosure; and

[0017] Figure 8 illustrates multi-antenna receiver system, in accordance with embodiments of the present disclosure.

[0018] It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative systems embodying the principles of the present subject matter. Similarly, it will be appreciated that any flow charts, flow diagrams, state transition diagrams, pseudo code, and the like represent various processes which may be substantially represented in computer readable medium and executed by a computer or processor, whether or not such computer or processor is explicitly shown.

DETAILED DESCRIPTION

[0019] In the present document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

[0020] While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.

[0021] The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.

[0022] Intelligent Transportation System (ITS) is crucial for vehicular communication and provides advanced driving experience, vehicle safety, vehicle platooning, vehicle internet, and the like. The ITS includes multiple requirements for an antenna system such as, ultra-high reliability, low latency communication, and the like. Multi-antenna configuration based on Full-Duplex (FD) technology is required for the ITS to achieve these requirements. Also, isolation between antenna elements needs to be improved to reduce self-interference due to infliction of high-power local transmit signal from transmitter upon its own receiver.

[0023] The present disclosure discloses an antenna system for vehicular communication. The present disclosure provides the multi-antenna configuration, i.e., the antenna system comprises one or more transmitting antennas and one or more receiving antennas on a substrate. The present disclosure provides a plurality of metallic vias at different locations of the antenna system that reduces surface waves. This helps to reduce high field coupling zone i.e., reduce strong inter-element coupling between the one or more transmitting antennas and the one or more receiving antenna and to limit power flow between the one or more transmitting antennas and the one or more receiving antennas. Further, the one or more transmitting antennas and the one or more receiving antennas are placed at pre-defined angle and a plurality of U-shaped slots achieves desired p-SIC or antenna isolation between the the one or more transmitting antennas and the one or more receiving antennas.

[0024] Figure 1 shows an exemplary antenna system 100, in accordance with embodiments of the present disclosure. The present disclosure provides the antenna system 100 for vehicular communication. Particularly, the present disclosure relates to the vehicular communication realised using Intelligent Transportation System (ITS) technology. The vehicular communication includes Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I), Vehicle-to-everything (V2X) communication, and the like. The ITS is a control and information system that uses integrated communications and data processing technologies for the purposes of improving mobility of people and goods, increasing safety, reducing traffic congestion, managing incidents effectively, and the like. The antenna systems plays an important role in achieving efficient vehicular communication. The ITS includes various requirements for the antenna system 100 used in the vehicular communication such as, multi-antenna configuration, improved isolation, and the like. The antenna system 100 comprises one or more transmitting antennas 101 and one or more receiving antennas 102. Figure 1 shows one transmitting antenna 101 and one receiving antenna 102 for illustrative purposes only, and this should not be considered as limiting. Each of the one or more transmitting antennas 101 and the one or more receiving antennas 102 are configured as inset-fed antenna. The inset-fed antenna is a microstrip patch antenna which is fed via a microstrip feed line connected to a specific point within a patch of the microstrip patch antenna. By varying location of where the microstrip feed line connects to the microstrip patch antenna, input impedance can be controlled. Figure 1 shows the microstrip line of the one or more transmitting antennas 101 and the one or more receiving antennas 102 connected to a feed location 105. The inset-feed of the one or more transmitting antennas 101 and the one or more receiving antennas 102 may be powered through a co-axial probe.

[0025] The one or more transmitting antennas 101 and one or more receiving antennas 102 may be configured in a vehicle for transmitting and receiving radio signals from other vehicles communicating to the vehicle in the ITS. The one or more transmitting antennas 101 and the one or more receiving antennas 102 are fabricated on a substrate 103 at a pre-defined distance and at a pre-defined angle from each other. The substrate 103 may be a RTD 5880 dielectric substrate. A person skilled in the art will appreciate that any other kind of materials may be used for constructing the substrate 103. In an example, the substrate 103 may have a dielectric constant ε_r of 2.2, dielectric loss tangent (tanδ) of 0.0009, and thickness (h) of 1.6 mm thickness (h). The overall substrate dimension is denoted as Lg x Wg. In an example, the overall substrate dimension may be 38mm x 80mm. A plurality of U-shaped slots 104 is etched on a ground plane associated with the one or more transmitting antennas 101 and the one or more receiving antennas 102. A plurality of metallic vias 106 is placed at a plurality of pre-determined locations of each of the one or more transmitting antennas 101 and the one or more receiving antennas 102. Different design stages of the antenna system 100 is explained in detail in subsequent part of the present description.

[0026] Figure 2 illustrates a first design stage of the antenna system 100, in accordance with embodiments of the present disclosure. The one or more transmitting antennas 101 and the one or more receiving antennas 102 are placed at the pre-defined distance (g) from each other. The one or more transmitting antennas 101 and the one or more receiving antennas 102 are placed in close proximity with respect to each other. In an embodiment, the pre-defined distance between the one or more transmitting antennas 101 and the one or more receiving antennas 102 is one-tenth of a wavelength of the antenna system 100. For example, the pre-defined distance is 6mm considering a frequency of the antenna system 100 as 5.9GHz. Full-Duplex (FD) technology is implemented for communication between the one or more transmitting antennas 101 and the one or more receiving antennas 102. In an example, a length ‘l’ and a width ‘w’ of each of the one or more transmitting antennas 101 and the one or more receiving antennas 102 may be 16.2 mm and 20mm, respectively. In an example, a length lf and a width wf of the inset-feed may be 8mm and 2.75 mm, respectively. l1 = 5, g1 = 0.625, In an example, a physical notch width ‘l1’ may be 5mm and an inset depth ‘g1’ may be 0.625mm. Values provided in above-examples are considered to maintain input impedance of the one or more transmitting antennas 101 and the one or more receiving antennas 102 at operating frequency of the antenna system 100.

[0027] Reference is now made to Figure 3 illustrating Electric (E) field distribution (refer a) and Magnetic (H) field distribution (refer b) at the first design stage, in accordance with embodiments of the present disclosure. A strong inter-element coupling between the one or more transmitting antennas 101 and the one or more receiving antennas 102 is shown in 301, which can also be observed from S-parameter curve in 302 having very high value of |S21| = |S12| = -12 dB, which is a high value and is not desired. S-parameters describe input-output relationship between ports of the antenna system 100. For instance, consider 2 ports as port 1 and port 2. S12 represents power transferred from Port 2 to Port 1. S21 represents power transferred from port 1 to port 2. One of the objectives of the present disclosure is to reduce high field coupling zone i.e., reduce the strong inter-element coupling between the one or more transmitting antennas 101 and the one or more receiving antennas 102 and to limit power flow between the one or more transmitting antennas 101 and the one or more receiving antennas 102.

[0028] Reference is now made to Figure 4 illustrating a second design stage of the antenna system 100, in accordance with embodiments of the present disclosure. The plurality of metallic vias 106 is placed at a plurality of pre-determined locations of each of the one or more transmitting antennas 101 and the one or more receiving antennas 102. The plurality of pre-determined locations may comprise at least one of, a zero-potential location, a first pre-determined distance from the zero-potential location, a second pre-determined distance from non-radiating edges of each of the one or more transmitting antennas 101 and the one or more receiving antennas 102. As it is evident from 301 in Figure 3, radiating edges of the antenna are most vulnerable locations of E-field coupling and non-radiating edges are most vulnerable locations of H-field coupling. The E-field is restricted by placing the plurality of metallic vias 106 along width of the patch at the zero potential location (y = 0, in Figure 2), which reduces antenna size. Further, the plurality of metallic vias 106 are placed at a first pre-determined distance from the zero-potential location (y= -l/2, in Figure 2). The first pre-determined distance is half of a length of the one or more transmitting antennas 101 and the one or more receiving antennas 102. The H-field is restricted by placing the plurality of metallic vias 106 at a second pre-determined distance from non-radiating edges of each of the one or more transmitting antennas 101 and the one or more receiving antennas 102. The second pre-determined distance is denoted as ‘g3’ in Figure 4. In an example, a diameter ‘d’ of each via from the plurality of vias 106 is 1mm and a distance ‘p’ between two consecutive vias is 1.5mm. In an example, a distance ‘g2’ between the plurality of metallic vias 106 placed on the non-radiating edges of the one or more transmitting antennas 101 and the one or more receiving antennas 102 may be 1.5mm and the second pre-determined distance ‘g3’ may be 1.25 mm. Further, a value of the physical notch width may be increased from ‘g1’ to ‘g11’ (for example, ‘g11’ may be 1.625 mm) for improving impedance matching of the antenna system 100. Values in the above-stated examples may vary based on fabrication tolerances of the antenna system 100. The plurality of metallic vias 106 placed is shorted to the ground plane. This helps to restrict surface waves and reduce the strong inter-element coupling.

[0029] Figure 5 illustrates a third design stage of the antenna system 100, in accordance with embodiments of the present disclosure. The one or more transmitting antennas 101 and the one or more receiving antennas 102 are fabricated on the substrate 103 at a pre-defined angle from each other. In an embodiment, the pre-defined angle is 180°. The one or more receiving antennas 102 is placed up-side down by rotating 180° with respect to the one or more transmitting antennas 101. Further, a plurality of U-shaped slots 104 is etched on a ground plane associated with the one or more transmitting antennas 101 and the one or more receiving antennas 102. The plurality of U-shaped slots 104 is etched near the feed location 105 of each of the one or more transmitting antennas 101 and the one or more receiving antennas 102. In an example, lengths ‘ld1’, ‘ld2’, and width ‘wd’ associated with each U-shaped slot 104 may be 3mm, 11.5mm, and 1mm, respectively. The one or more transmitting antennas 101 and the one or more receiving antennas 102 placed at the pre-defined angle and the plurality of U-shaped slots 104 achieves desired p-SIC or antenna isolation between the the one or more transmitting antennas 101 and the one or more receiving antennas 102.

[0030] Figure 6 illustrates a transmission line designed at 5.9 GHz operating frequency on the substrate 103. S-parameter response curve of the transmission line shows a pass band response centered at 5.9 GHz operating frequency. Further, the plurality of U-shaped slots 104 are incorporated in the ground plane of the transmission line near p1 and p2. The S-parameter response of the transmission line shows a smaller value of |S21| = |S12| indicating improved isolation and reduced inter-element coupling.

[0031] Figure 7 illustrates E-field (refer a) and H-field distributions (refer b) of the antenna system 100 at the first design stage, in accordance with embodiments of the present disclosure. As shown in 701, there is approximately no field coupling between the one or more transmitting antennas 101 and the one or more receiving antennas 102. Further, S-parameter curve (refer c) shown in 702 indicates isolation (|S21|) is 87.08 dB at the 5.9 GHz operating frequency and more the 50 dB over the operating band (5.85-5.944 GHz), which is very high and suitable for implementing the FD technology in the antenna system 100. In an embodiment, each of the one or more receiving antennas (102) are fabricated at a pre-determined level above the one or more transmitting antennas (101). The pre-determined level is denoted as ‘ys’ in Figure 5. It is observed that |S21| operating frequency decreases with increase in ‘ys’and provides maximum isolation at ys=0.95mm. A person skilled in the art will appreciate that the value of ‘ys’ may vary based on design and implementation of the antenna system 100. Similarly, there is very less impact of ‘g2’ variation on S-parameter performance, however it can be seen that ‘g2’ parameter improves the |S21| response and provides best isolation at ‘g2’ = 0.75mm. The inter-element antenna separation ‘g2’and antenna alignment ‘ys’ are optimized to obtain best possible antenna p-SIC or the antenna isolation.

[0032] Figure 8 illustrates multi-antenna receiver system comprising one transmitter antenna and two receiver antennas, in accordance with the embodiments of the present disclosure. The multi-antenna receiver system provides additional degree of freedom to improve system diversity, for example, the capability of multiple-input multiple-output (MIMO) configuration, in a multi-path crowded application environment as in the ITS.

[0033] The present disclosure discloses an antenna system for vehicular communication. The present disclosure provides the multi-antenna configuration, i.e., the antenna system comprises one or more transmitting antennas and one or more receiving antennas on a substrate. The present disclosure provides a plurality of metallic vias at different locations of the antenna system that reduces surface waves. This helps to reduce high field coupling zone i.e., reduce the strong inter-element coupling between the one or more transmitting antennas and the one or more receiving antenna and to limit power flow between the one or more transmitting antennas and the one or more receiving antennas. Further, the one or more transmitting antennas and the one or more receiving antennas placed at the pre-defined angle and the plurality of U-shaped slots achieves desired p-SIC or antenna isolation between the one or more transmitting antennas and the one or more receiving antennas.

[0034] The terms "an embodiment", "embodiment", "embodiments", "the embodiment", "the embodiments", "one or more embodiments", "some embodiments", and "one embodiment" mean "one or more (but not all) embodiments of the invention(s)" unless expressly specified otherwise.

[0035] The terms "including", "comprising", “having” and variations thereof mean "including but not limited to", unless expressly specified otherwise.

[0036] The enumerated listing of items does not imply that any or all of the items are mutually exclusive, unless expressly specified otherwise. The terms "a", "an" and "the" mean "one or more", unless expressly specified otherwise.

[0037] A description of an embodiment with several components in communication with each other does not imply that all such components are required. On the contrary a variety of optional components are described to illustrate the wide variety of possible embodiments of the invention.

[0038] When a single device or article is described herein, it will be readily apparent that more than one device/article (whether or not they cooperate) may be used in place of a single device/article. Similarly, where more than one device or article is described herein (whether or not they cooperate), it will be readily apparent that a single device/article may be used in place of the more than one device or article or a different number of devices/articles may be used instead of the shown number of devices or programs. The functionality and/or the features of a device may be alternatively embodied by one or more other devices which are not explicitly described as having such functionality/features. Thus, other embodiments of the invention need not include the device itself.

[0039] Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based here on. Accordingly, the disclosure of the embodiments of the invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.

[0040] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope being indicated by the following claims.

Referral Number Description
100 Antenna system
101 One or more transmitting antennas
102 One or more receiving antennas
103 Substrate
104 Plurality of U-shaped slots
105 Feed location
106 Plurality of metallic vias
, Claims:We claim:

1. An antenna system (100) for vehicular communication, comprising:
one or more transmitting antennas (101); and
one or more receiving antennas (102),
wherein the one or more transmitting antennas (101) and the one or more receiving antennas (102) are fabricated on a substrate (103) at a pre-defined distance and at a pre-defined angle from each other,
wherein a plurality of U-shaped slots (104) is etched on a ground plane associated with the one or more transmitting antennas (101) and the one or more receiving antennas (102), and
wherein a plurality of metallic vias (106) is placed at a plurality of pre-determined locations of each of the one or more transmitting antennas (101) and the one or more receiving antennas (102).

2. The antenna system (100) as claimed in claim 1, wherein the pre-defined angle is 180°.

3. The antenna system (100) as claimed in claim 1, wherein the pre-defined distance between the one or more receiving antennas (102) and the one or more transmitting antennas (101) is one-tenth of a wavelength of the antenna system (100).

4. The antenna system (100) as claimed in claim 1, wherein the plurality of metallic vias (106) placed on each of the one or more transmitting antennas (101) and the one or more receiving antennas (102) are shorted to the ground plane.

5. The antenna system (100) as claimed in claim 1, wherein the plurality of pre-determined locations comprises at least one of, a zero-potential location, a first pre-determined distance from the zero-potential location, a second pre-determined distance from non-radiating edges of each of the one or more transmitting antennas (101) and the one or more receiving antennas (102).

6. The antenna system (100) as claimed in claim 5, wherein the first pre-determined distance is half of a length of the one or more transmitting antennas (101) and the one or more receiving antennas (102).

7. The antenna system (100) as claimed in claim 1, wherein each of the one or more transmitting antennas (101) and the one or more receiving antennas (102) are configured as inset-fed antenna.

8. The antenna system (100) as claimed in claim 1, wherein each of the one or more receiving antennas (102) are fabricated at a pre-determined level above the one or more transmitting antennas (101).

9. The antenna system (100) as claimed in claim 1, wherein the plurality of U-shaped slots (104) is etched near a feed location (105) of each of the one or more transmitting antennas (101) and the one or more receiving antennas (102).