System for ultra-wide band (UWB) ranging and / or radar

Abstract

A system for Ultra-Wide Band (UWB) ranging and / or RADAR, the system including a circuit provided on a circuit board, the circuit including: two receive antennas each capable of emitting a radiation pattern having an intended region of operation; one transmit antenna capable of emitting a radiation pattern having an intended region of operation; the receive antennas being positioned on the circuit board such that the radiation patterns of the receive antennas are emitted in opposite directions relative to each other; and wherein the transmit antenna is positioned between the receive antennas such that the radiation pattern of the transmit antenna is approximately overlapping with the radiation pattern of the receive antennas.

Description

SYSTEM FOR ULTRA-WIDE BAND (UWB) RANGING AND / OR RADARTechnical Field

[0001] The present invention relates to improvements in Passive Entry Passive Start (PEPS) and vehicle occupancy detection.Background of Invention

[0002] Ultra-Wide Band (UWB) ranging applications in an automotive environment for applications such as Passive Entry Passive Start (PEPS) are desirable. The main objective of an UWB ranging device is to provide a distance estimate between an initiator and a responder but it is also desirable for the system to be capable of RADAR (radio detection and ranging). A problem with providing these applications is achieving an antenna configuration capable of providing a high fidelity, undistorted signal for the entirety of the required operating region of the system, i.e., the Field of View (FoV).

[0003] It will be appreciated that the discussion of the background to the invention is included to explain the context of the invention. This is not to be taken as an admission that any of the material referred to is published, known or part of the common general knowledge.Summary of Invention

[0004] According to a first aspect, the present invention provides a system for Ultra- Wide Band (UWB) ranging and / or RADAR, the system including a circuit provided on a circuit board, the circuit including: two receive antennas each capable of emitting a radiation pattern having an intended operating region I Field of View (FoV); one transmit antenna capable of emitting a radiation pattern having an intended region of operation; the receive antennas being positioned on the circuit board such that the radiation patterns of the receive antennas are emitted in opposite directions relative to each other; and wherein the transmit antenna is positioned between the receive antennas such that the radiation pattern of the transmit antenna is approximately overlapping with the radiation pattern of the receive antennas.

[0005] Advantageously, the use of multiple antennas (i.e. providing antenna diversity) in the proposed orientation alleviates limitations such as signal loss at certainpoints and distortion causing ranging errors in the operating region I Field of View (FoV). Advantageously, the arrangement of the present invention improves the communications link between a vehicle and a fob or mobile phone as well as providing a high-fidelity signal in the FoV - enabling accurate ranging (i.e. time of flight calculations) and further providing the necessary antenna isolation allowing the system to function as a RADAR, which can detect the presence of passengers in a vehicle.

[0006] The UWB antenna configuration of the present invention can be used seamlessly with a Bluetooth (including Bluetooth Low Energy (BLE)) system incorporating a Bluetooth antenna oriented in the manner proposed so its implementation does not impair the performance of the UWB system.

[0007] It will be appreciated that the antenna configuration may be a stand-alone antenna design with an interface to an external circuit board or may be part of an embedded circuit. The circuit board may take any suitable form such as a printed circuit board (PCB) or the like as the skilled person would appreciate.

[0008] The system further includes adequate ground area separation provided between the transmit antenna and the receive antennas whereby the receive antennas are positioned on a different plane to the transmit antenna. This is required in order to allow ground metal above the receive antennas thereby providing improved isolation between the antennas. Advantageously, the improved isolation provides improved RADAR functionality.

[0009] In an embodiment, the receive antennas are not positioned in substantially the same horizontal plane.

[0010] Preferably, the radiation pattern of the receive antennas are primarily emitted in opposite directions relative to each other and includes a leftmost direction and a rightmost direction.

[0011] Preferably, the transmit antenna is positioned approximately in-between the receive antennas.

[0012] Preferably, the receive antennas and the transmit antennas are wide-band antennas. The wide-band antennas may include circular, elliptical or rectangular monopole antennas or any other type of wide-band antenna.

[0013] The system may further include a further antenna in close proximity to the UWB antennas for use in a Bluetooth system. The one or more further antennas may be an inverted-F antenna or the like.

[0014] Preferably, the receive antennas and the transmit antennas are provided on receiver pins and transmitter pins provided on an UWB integrated circuit.

[0015] Alternatively, the receive antennas and the transmit antennas are provided on transceiver pins on an UWB integrated circuit.

[0016] In an embodiment, the receive antennas and the transmit antennas are provided on a single pin, 2 pin or 4 or more pin UWB integrated circuit by a series of RF switchers and / or RF combiners / splitters. It will be appreciated that the antenna configuration may be a stand-alone antenna design with an interface to an external device.

[0017] According to a second aspect, the present invention provides a system for Ultra-Wide Band (UWB) ranging and / or RADAR, the system including a circuit provided on a circuit board, the circuit including: two transmit antennas each capable of emitting a radiation pattern having an intended operating region I Field of View (FoV); one receive antenna capable of emitting a radiation pattern having an intended region of operation; the transmit antennas being positioned on the circuit board such that the radiation patterns of the transmit antennas are emitted in opposite directions relative to each other; and wherein the receive antenna is positioned between the transmit antennas such that the radiation pattern of the receive antennas is approximately overlapping with the radiation pattern of the transmit antennas.

[0018] According to a third aspect, the present invention provides a system for Ultra-Wide Band (UWB) ranging and / or RADAR, the system including a circuit provided on a circuit board, the circuit board including: two receive antennas each capable of emitting a radiation pattern having an intended region of operation; one transmit antenna each capable of emitting a radiation pattern having an intended region of operation; the receive antennas and transmit antenna being oriented on the circuit board such that an isolation value between each of the receive antennas and transmit antenna is below -15dB in the required frequency band(s) of operation.

[0019] According to a fourth aspect, the present invention provides a system for Ultra-Wide Band (UWB) ranging and / or RADAR, the system including a circuit provided on a circuit board, the circuit board including: two transmit antennas each capable of emitting a radiation pattern having an intended region of operation; one receive antenna each capable of emitting a radiation pattern having an intended region of operation; the transmit antennas and receive antenna being oriented on the circuit board such that an isolation value between each of the transmit antennas and the receive antenna is below -15dB in the required frequency band(s) of operation.

[0020] According to a fifth aspect, the present invention provides a system for Ultra- Wide Band (UWB) ranging and / or RADAR substantially as hereinbefore described with reference to the drawings.

[0021] The system of claim one or more of the first, second, third, fourth or fifth aspects, wherein there is provided two or more receive antennas and two or more transmit antennas.Brief Description of Drawings

[0022] Figure 1 is a schematic diagram illustrating the antenna configuration design on a PCB according to the system of the present invention;

[0023] Figure 2 is a schematic diagram illustrating simplified radiation patterns associated with the antennas of Figure 1 ;

[0024] Figures 3A - 3D is a schematic diagram illustrating a vehicle where the system described with reference to Figure 1 and Figure 2 are provided in the vehicle; and

[0025] Figure 4 is a chart of Isolation (dB) vs Frequency illustrating the operating region I Field of View (FoV) of the antennas of Figure 1 .Detailed Description

[0026] Figure 1 is a schematic diagram illustrating a PCB design 100 using three UWB antennas 105, 110, 115 for an embedded circuit design utilizing an Ultra-Wide Band (UWB) Integrated Circuit (IC) with two receiver pins and one transmitter pin (ICnot displayed in diagram). A Bluetooth antenna (120) may also be included for a system incorporating Bluetooth if required.

[0027] In order to meet the design criteria for an UWB and / or Radar System, a specific arrangement of antennas 105, 110, 115 is provided utilizing two receive antennas 105, 110 and one transmit antenna 115 on a PCB design 100.

[0028] It will also be appreciated that the reverse is also possible in that there may be two transmit antennas and one receive antenna.

[0029] In addition, the antenna configuration can be a stand-alone antenna design with an interface to an external device.

[0030] In Figure 1 , the required three antennas are represented by antenna 105, 110, 115 which may be circular, elliptical or rectangular monopole antennas. It will be appreciated that any suitable wide-band antenna type may be used. A further antenna 120 is provided which may, be, for example, an inverted-F antenna for a Bluetooth system - that is to say that this antenna 120 is not part of the UWB system. In an embodiment, the present invention includes the option of providing a suitable location and orientation for a Bluetooth antenna without impairing the UWB performance in case both UWB and Bluetooth systems are required.

[0031] Preferably the two receive antennas are capable of emitting radiation patterns whereby the combination of the two radiation patterns cover the intended region of operation. Further, the transmit antenna is also capable of emitting a radiation pattern having the same intended region of operation. As noted above it will be appreciated that the reverse may also be provided.

[0032] The receive antennas are positioned on the circuit board 100 such that the radiation patterns of the receive antennas 105, 110 are emitted in opposite directions relative to each other. Further, the transmit antenna 115 is preferably positioned approximately between the receive antennas 105, 110 such that the radiation pattern of the transmit antenna 115 is approximately overlapping with the radiation pattern of the receive antennas 105, 110. This will be further described and shown with reference to Figure 2.

[0033] It will be appreciated that respective antennas are positioned such that, for example: radiation patterns for both the transmit antennas and receive antennas cover a required operating region I Field of View (FoV). Further, they are positioned such that there is isolation between all of the antennas such as to be below the requirement for RADAR performance - for example less than -15dB in the required frequency band(s) of operation. Further, it is preferrable all of the antennas have a return loss greater than a minimum requirement - for example >7dB in the required frequency band(s) of operation. Further, the antennas are designed such that the frequency of operation covers all UWB frequencies required in the system.

[0034] The system of the present invention meets the design criteria for an UWB ranging and / or RADAR system such that a specific arrangement of antennas utilizing two receive antennas 105, 110 and one transmit antennas 115 (or vice versa) on an PCB module 100 is provided. As will be appreciated, the arrangement and positioning of the UWB antennas and the adjacent PCB ground area must ensure that the above criteria are achieved simultaneously since all criteria are dependent on this positioning. The placement of the antennas will be described further with reference to Figure 2.

[0035] Figure 2 is a schematic diagram 200 illustrating simplified radiation patterns associated with the antennas of Figure 1 at frequencies of 6.5 GHz (denoted 205) and 8 GHz (denoted 210) which are within the desired frequency bands of operation. As can be seen from Figure 2, the placement of receive antennas 105 and 110 causes a left and right oriented radiation pattern respectively. The combined received radiation pattern of the two antennas 105, 110 is therefore in both the left and right directions. This advantageously constitutes the required operating region I Field of View (FoV) of the UWB system. In addition, the transmitter antenna 115 as can be seen in Figure 2 is approximately centrally located. It achieves a radiation pattern in both the left and right directions i.e. in the required FoV of the UWB system.

[0036] The Bluetooth antenna 120 can be oriented in the manner shown in Figure 1 without adversely disturbing the UWB radiation patterns for a system requiring both UWB and Bluetooth.

[0037] In Figure 2 and 3, simplified radiation patterns of antenna gain (dBi) are presented. These simplified images are for demonstration purposes , i.e., the signal willcontinue to radiate beyond the represented images into the distance at dimensioning signal levels as the distance from the antenna increases as the skilled person would appreciate. It will also be appreciated that for complete UWB coverage around a vehicle (for example), several modules may be positioned in the vehicle in order for the required operating region I Field of View (FoV) to be satisfied. This will be shown further with reference to Figure 3. In addition, operational areas both external and internal to the vehicle may be required.

[0038] Figures 3A-3D shows a vehicle 300 within which several modules, that is to say the system described with reference to Figure 1 and Figure 2 are provided in the vehicle. These include module 305 placed, for example in the front left panel of the vehicle, module 310 placed, for example in the front right panel of the vehicle, module 315 placed, for example in the centre console of the vehicle, module 320 placed, for example in the right rear panel of the vehicle and module 325, for example placed in the left rear panel of the vehicle.

[0039] It will be appreciated that depending on the application the positioning of the modules may be provided in any suitable form and in any number of modules depending on the application. The operating region I Field of View (FoV) for each of the modules is shown. For example, in relation to module 320 where there is shown a FoV 325 which extends to the exterior trunk area of the vehicle and the exterior area along one side of the vehicle. By superimposing the radiation pattern from, for example, Figure 2, onto the vehicle 300, the radiation patterns for antenna 115 shown in Figure 3C can be seen and the radiation patterns for antennas 105 and 110 (again with reference to Figure 2) can also be seen. In short, by superimposing the radiation patterns, it can be seen that it covers the FoV for the vehicle. This is repeated for each of modules 305, 310, 315, 320 and 325 which provides coverage for the entire vehicle 300.

[0040] For each module 305, 310, 315, 320 and 325, the radiation patterns with the vehicle allow for left and right placement of the receive antennas 105, 110 causing left and right oriented radiation patterns respectively as shown in Figure 3B and 3D. The combined radiation pattern of the two antennas is therefore in both the left and right directions. This constitutes the required operating region I Field of View (FoV) of the UWB system. In addition, the approximately centrally located transmitter antenna 115achieves a radiation pattern in both the left and right directions shown in Figure 3C i.e. the required FoV of the UWB system.

[0041] It will also be appreciated that, with reference to Figure 1 , ground area separations on the PCB 125 and 130 must be provided above the receive antennas 105 and 110 and between transmit antenna 115 and receive antennas 105 and 110. These are critical for obtaining significant isolation between the antennas. This is shown in the chart 400 of Figure 4 in which plots of dB of antenna 110 and antenna 105 (S2, 1 ) as well as antennas 115 and 105 (S3, 1 ) and antennas 110 and 115 (S2, 3).

[0042] As will be seen from Figure 4, all plots are below the -15dB isolation requirement between the required bandwidth in an operating frequency of approximately 6 to 10 GHz. The ground separation and the orientation of the three antennas is unique and critical to achieving this design criteria. This ground antenna arrangement is unique in providing the design criteria and is reached over a significant bandwidth.

[0043] It will be appreciated by the skilled person that additional antennas may be used. It will also be appreciated by the skilled person that the transmit and receive antennas are interchangeable. Further, a Bluetooth antenna may be added without impacting on UWB performance as shown in Figure 1. It will also be appreciated that the present invention may be used with other integrated circuit transmit and receive pin arrangements. Finally, it will be appreciated that a transmit antenna can be used with a ground inlay to improve omni-directional radiation pattern performance.

[0044] Future patent applications may be filed in Australia or overseas on the basis of or claiming priority from the present application. It is to be understood that the following provisional claims are provided by way of example only and are not intended to limit the scope of what may be claimed in any such future application. Features may be added to or omitted from the provisional claims at a later date so as to further define or re-define the invention or inventions.

Claims

The claims defining the invention are as follows:

1. A system for Ultra-Wide Band (UWB) ranging and / or RADAR, the system including a circuit provided on a circuit board, the circuit including: two receive antennas each capable of emitting a radiation pattern having an intended region of operation; one transmit antenna capable of emitting a radiation pattern having an intended region of operation; the receive antennas being positioned on the circuit board such that the radiation patterns of the receive antennas are emitted in opposite directions relative to each other; and wherein the transmit antenna is positioned between the receive antennas such that the radiation pattern of the transmit antenna is approximately overlapping with the radiation pattern of the receive antennas.

2. The system of claim 1 , further including ground area separation provided between the transmit antenna and the receive antennas; the receive antennas being positioned on a different plane to the transmit antenna in order to allow ground metal above the receive antennas thereby providing improved isolation between the antennas.

3. The system of claim 1 , wherein the receive antennas are not positioned in substantially the same horizontal plane.

4. The system of claim 1 , wherein the radiation pattern of the receive antennas emitted in opposite directions relative to each other includes a leftmost direction and a rightmost direction.

5. The system of claim 1 , wherein the transmit antenna is positioned approximately in-between the receive antennas.

6. The system of claim 1 , wherein the receive antennas and the transmit antennas are provided on receiver pins and transmitter pins provided on an UWB integrated circuit.

7. The system of claim 1 , wherein the receive antennas and the transmit antennas are provided on transceiver pins on an UWB integrated circuit.

8. The system of claim 1 , wherein the receive antennas and the transmit antennas are provided on a single pin, 2 pin or 4 or more pin UWB integrated circuit by a series of RF switchers and / or RF combiners / splitters.

9. The system of claim 1 , wherein the antenna configuration is a stand-alone antenna design with an interface to an external device.

10. The system of claim 1 , wherein the receive antennas and the transmit antennas are wide-band antennas.11 . The system of claim 9, wherein the wide-band antennas include circular, elliptical or rectangular monopole antennas or any other type of wide-band antenna.

12. A system for Ultra-Wide Band (UWB) ranging and / or RADAR, the system including a circuit provided on a circuit board, the circuit including: two transmit antennas each capable of emitting a radiation pattern having an intended region of operation; one receive antenna capable of emitting a radiation pattern having an intended region of operation; the transmit antennas being positioned on the circuit board such that the radiation patterns of the transmit antennas are emitted in opposite directions relative to each other; and wherein the receive antenna is positioned between the transmit antennas such that the radiation pattern of the receive antennas is approximately overlapping with the radiation pattern of the transmit antennas.

13. A system for Ultra-Wide Band (UWB) ranging and / or RADAR, the system including a circuit provided on a circuit board, the circuit board including: two receive antennas each capable of emitting a radiation pattern having an intended region of operation;one transmit antenna each capable of emitting a radiation pattern having an intended region of operation; the receive antennas and transmit antenna being oriented on the circuit board such that an isolation value between each of the receive antennas and transmit antenna is below -15dB in the required frequency band(s) of operation.

14. A system for Ultra-Wide Band (UWB) ranging and / or RADAR, the system including a circuit provided on a circuit board, the circuit board including: two transmit antennas each capable of emitting a radiation pattern having an intended region of operation; one receive antenna each capable of emitting a radiation pattern having an intended region of operation; the transmit antennas and receive antenna being oriented on the circuit board such that an isolation value between each of the transmit antennas and the receive antenna is below -15dB in the required frequency band(s) of operation.

15. A system for Ultra-Wide Band (UWB) ranging and / or RADAR substantially as hereinbefore described with reference to the accompanying drawings.

16. The system of claim 1 , 11 , 12 or 13, wherein there is provided two or more receive antennas and two or more transmit antennas.

17. The system of claim 1 including a further Bluetooth antenna in close proximity to the UWB antennas for use in a Bluetooth system.

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