Apparatus for wireless communication using back-to-back antennas

Abstract

The device (20) for wireless communication includes a first antenna (12), a second antenna (22), and a hybrid coupler (11), wherein the hybrid coupler (11) is used to connect the first antenna (12) and the second antenna (22) to opposite transmission paths (TX), thereby potentially doubling the TX coverage area in space. The first antenna (12) is connected to a first port (2) of the hybrid coupler (11), and the second antenna (22) is connected to a second port (3) of the hybrid coupler (11). The first antenna (12) and the second antenna (22) are isolated from each other and arranged in a back-to-back configuration.

Description

Technical Field

[0001] This invention relates to a device and method for wireless communication. Background Technology

[0002] In wireless communication, simultaneous transmission and reception (STR) is a highly valuable technical requirement. To meet this requirement, technologies such as frequency division duplex (FDD) or full-duplex (FD) have been developed or are under development. For example, the IEEE standard 802.11be (also known as "Wi-Fi 7") implements support for FDD.

[0003] However, to achieve true on-chip FD, many technical obstacles still need to be overcome. One of these obstacles is improving self-interference cancellation (SIC) performance, in other words, reducing the leakage of high-power transmit signals to the receiver chain.

[0004] Several solutions have been proposed to address this problem. One approach is to use two antennas, one dedicated to transmission (TX) and the other to reception (RX). This method achieves inherent isolation between the transmission and reception chains and eliminates reflections. However, to achieve maximum coverage, this method requires a large number of antennas, resulting in bulky and expensive transceivers.

[0005] Another approach is to use a single antenna for both transmission and reception, combined with a balanced duplexer. For example, US 2010 / 304701 A1 proposes a method for transmitting a leaking signal, which includes a reflection coefficient adjustment unit that outputs a signal with the same amplitude and opposite phase to the signal leaking from the transmission path to the reception path. However, this approach requires distributing the transmit power between the antenna and the adjustment unit, and simultaneously distributing the received signal between the power amplifier (PA) and the low-noise amplifier (LNA). Therefore, using the adjustment unit results in approximately 3 dB of power loss on both the TX and RX sides.

[0006] In view of this, one object of the present invention is to provide an improved device for wireless communication. Summary of the Invention

[0007] In a first aspect of the invention, this objective is achieved by the device according to claim 1. The implementation methods are set forth in the dependent claims.

[0008] The device according to the first aspect includes a first antenna, a second antenna, and a hybrid coupler, wherein the hybrid coupler is used to connect the first antenna and the second antenna to mutually independent transmission paths, namely a first transmission path of the first antenna and a second transmission path of the second antenna. The first antenna is connected to a first port of the hybrid coupler, and the second antenna is connected to a second port of the hybrid coupler, the first antenna and the second antenna being arranged back-to-back.

[0009] Specifically, the device can be a radio frequency front-end (RFFE).

[0010] In this document, the term "back-to-back configuration" generally refers to a first and second antenna facing opposite sides, i.e., opposite hemispheres. Furthermore, the antennas are spatially adjacent. For example, the first and second antennas can be directional antennas, such as patch antennas positioned facing opposite hemispheres. For instance, the first and second antennas can be mounted on opposite surfaces of the same substrate. However, each antenna can also be mounted on a separate substrate, but facing opposite directions. Moreover, the first and second antennas are preferably isolated from each other, especially electrically isolated. This isolation prevents the received signals from the antennas within the hybrid coupler from canceling each other out.

[0011] The term "hybrid coupler" should be understood in its usual technical sense, that is, a directional coupler designed to distribute power evenly between two ports.

[0012] A back-to-back configuration allows signals to be transmitted through a first and a second antenna in both hemispheres. In other words, a high spatial coverage range can be achieved. Furthermore, in a back-to-back configuration, reflected signals from the first antenna can be canceled out by corresponding reflected signals from the second antenna, and vice versa, without the need for additional electronic conditioning circuitry.

[0013] In other words, unlike the prior art which shapes half of the TX signal in a dedicated circuit, the present invention shapes half of the TX signal in the same antenna that transmits signals in different directions, thereby achieving high SIC and increasing the spatial coverage from 180° to 360°.

[0014] The implementation method of the first aspect will be explained below.

[0015] The hybrid coupler can be used to: provide power from the first transmission path to the first antenna and power from the second transmission path to the second antenna, such that reflected signals from the first antenna are at least partially canceled out by reflected signals from the second antenna, and vice versa. Specifically, the hybrid coupler can be used to provide power such that the signals in the first antenna and the second antenna have a phase difference.

[0016] Specifically, the hybrid coupler can be a 0 / 180° hybrid coupler. In other words, the hybrid coupler can be used to add a first antenna and a second antenna with a phase difference of 180°. In this case, the reflected signal from the second antenna can achieve a high degree of cancellation of the reflected signal from the first antenna, and vice versa, especially without the need for additional electronics. Specifically, although the first antenna and the second antenna transmit in the same phase, the reflected signal from the first antenna will be cancelled by the reflected signal from the second antenna within the hybrid coupler at the receiving port.

[0017] The first and second antennas can be of the same type. For example, the first and second antennas can be directional antennas, such as patch antennas.

[0018] The first and second antennas can have the same internal structure. By using the same type of antenna, the cancellation of reflected signals from the second antenna to reflected signals from the first antenna can be further improved, and vice versa.

[0019] The hybrid coupler can also connect the first and second antennas to the receiving path. Therefore, both antennas can be used for transmission. On the other hand, synchronous reception may affect reception quality because the receiver cannot distinguish between the two RX signals. Therefore, this can only be used in special cases, and the usual practice is to receive from only one direction while transmitting in the opposite direction. Thus, the device can be used as a transceiver with high spatial coverage and low self-interference STR capabilities.

[0020] The device may further include a first antenna array and a second antenna array, wherein the first antenna array includes the first antenna, the second antenna array includes the second antenna, and the first antenna array and the second antenna array are arranged back-to-back. Using back-to-back antenna arrays can further improve the efficiency of the device.

[0021] The device may further include: a first antenna tuner disposed between the first port and the first antenna; and a second antenna tuner disposed between the second port and the second antenna. Using the first and second antenna tuners can improve impedance matching between the respective ports and antennas, resulting in lower signal loss. Specifically, the antenna tuners can eliminate differences between reflected signals from the first and second antennas, which may arise from differences in the properties of the first and second antennas and / or differences in the signal path from the first port to the first antenna and from the second port to the second antenna. Furthermore, the antenna tuners can be used to compensate for internal leakage in hybrid couplers.

[0022] Specifically, the first antenna tuner and / or the second antenna tuner include Chebyshev-type antenna tuners. A Chebyshev-type antenna tuner may include an n-order Chebyshev bandpass filter, where n ranges from 1 to infinity, preferably between 2 (to achieve 2 degrees of tuning freedom) and 8, thereby minimizing power loss and maintaining a compact circuit size. A Chebyshev-type antenna tuner can be an antenna tuner, for example, as described by D. Regev, I. Melamed, N. Ginzberg, and E. Cohen in "A Full Duplex RF Front End Employing an Electrical Balanced Duplexer and a Chebyshev Load-Balancing Filter" (…). 2023 IEEE / MTT-S International Microwave Symposium - IMS 2023 The antenna tuner disclosed in (San Diego, CA, USA, 2023, pp.378-381, doi: 10.1109 / IMS37964.2023.10188090) can further improve the impedance matching between the corresponding port and the antenna.

[0023] According to a second aspect, the present invention provides a method for wireless communication, particularly using a device including one or more of the features defined above. The method includes: The transmitted signal is provided to the first and second antennas via a hybrid coupler, wherein... The first antenna is connected to the first port of the hybrid coupler; The second antenna is connected to the second port of the hybrid coupler; The first antenna and the second antenna are arranged back to back; The transmitted signal is transmitted through the first antenna and / or the second antenna.

[0024] In one implementation of the second aspect, the method may further include: The impedance of the first antenna is matched by adapting the first antenna tuner located between the first port and the first antenna. The impedance of the second antenna is matched by a second antenna tuner positioned between the second port and the second antenna.

[0025] In another implementation, the method may further include receiving signals via the first antenna or the second antenna.

[0026] Other implementations of the second aspect correspond to the implementations described in conjunction with the first aspect.

[0027] The advantages of the device described above with respect to the first aspect and its implementation are applied in a similar manner to the corresponding features of the method described with respect to the second aspect and its implementation.

[0028] According to a third aspect, the present invention provides a computer-readable medium including instructions that, when executed by a computer, cause the computer to perform the method described according to the second aspect or any implementation thereof. Attached Figure Description

[0029] Embodiments of the present invention will now be described with reference to the accompanying drawings.

[0030] Figure 1 This illustration schematically shows a device for reducing self-interference according to the prior art; Figure 2 and Figure 3 An embodiment of a device for wireless transmission is illustrated schematically; Figure 4 The illustration shows two antennas in a back-to-back configuration. Detailed Implementation

[0031] Figure 1 A schematic diagram illustrates a device 10 for reducing self-interference according to the prior art. Device 10 includes a four-port duplexer 11. The four-port duplexer 11 includes a first port 1, a second port 2, a third port 3, and a fourth port 4. The first port 1 is connected to the transmit path TX of a device for wireless communication. The fourth port 4 is connected to the receive path RX of a device for wireless communication. For example, the four-port duplexer 11 can be a 0 / 180° hybrid coupler.

[0032] Device 10 also includes an antenna 12 for transmitting and receiving. Antenna 12 is connected to the second port 2 of a four-port duplexer 11. Antenna 12 has a reflection coefficient... The device 10 also includes a load balancing module 13 connected to the third port 3 of the four-port duplexer 11. For example, the load balancing module 13 may include known circuitry as described in US 2010 / 304701 A1. The load balancing module 13 has a reflection coefficient. .

[0033] The device 10 also includes a power amplifier (PA) 14 disposed in the transmit path TX and a low noise amplifier (LNA) 15 disposed in the receive path RX.

[0034] During operation, the transmitted signal passes through the transmission path TX and power amplifier 14 at power P. TX The signal enters the four-port duplexer 11 from port 1. Due to the characteristics of the four-port duplexer 11, the signal is distributed to ports 2 and 3, resulting in a 3 dB power loss. Therefore, the signal is distributed to antenna 12 and load balancing module 13, reducing the power to P. TX '.

[0035] At antenna 12, the transmitted signal is reflected, and the reflection coefficient is... The reflected signal is transmitted back to the four-port duplexer 11 through port 2.

[0036] Load balancing module 13 reduces the power to P. TX The transmitted signal generates a SiC signal, the reflection coefficient of which is... The signal is transmitted through port 3 at power P. SIC Feedback is sent to the four-port duplexer 11.

[0037] The four-port duplexer 11 distributes the signals received from the antenna 12 and the load balancing module 13 via ports 2 and 3 to ports 1 and 4, respectively. The signal is attenuated again by 3 dB. Specifically, the power of the SIC signal after reduction is P. SIC '.

[0038] from Figure 1 As can be seen, these signals are also transmitted to the RX path and LNA 15. To prevent unwanted noise caused by the reflection of the transmitted signals, the SIC signal arriving at the RX path needs to cancel the reflected signals.

[0039] Therefore, the cancellation condition is usually: reflection coefficient It is the reflection coefficient The reciprocal of, or their absolute values ​​are equal:

[0040]

[0041] More specifically, the total power leakage S between port 4 and port 1 of the four-port duplexer from the TX path to the RX path. 41,D The following formula can be used to approximate the calculation:

[0042] Here, S represents the conventional S-parameters, used to represent the transfer function of the square root of the power transfer function.

[0043] Among them, S 41 This refers to direct leakage between port 1 and port 4 of a four-port duplexer. This represents the reflected transmitted signal from antenna 12. This item includes the component S corresponding to the transmitted signal transmitted from port 1 to port 2. 21 and by reflection coefficient The corrected component passed from port 2 to port 4 (i.e., the RX path). Similarly, the item... This represents the SIC signal generated by the load balancing module 13. This item includes the component S corresponding to the transmitted signal transmitted from port 1 to port 3. 31 And during the reflection process, the reflection coefficient The corrected component passed from port 3 to port 4 (i.e., the RX path).

[0044] Typically, compared to the reflection component, direct leakage S 41 Smaller:

[0045]

[0046] Therefore, in order to achieve a smaller total power leakage S from the TX path to the RX path 41,D ,Right now The following conditions must be met:

[0047] exist Figure 1 In the prior art shown, this requires fine-tuning of the load balancing module 13 to match the reflected signal from the antenna 12.

[0048] It should be noted that the above only applies to the case of transmitting a signal. If a signal is received simultaneously, an additional signal will be emitted at power P. RXThe signal is transmitted from antenna 12 to the receiving path RX, and is attenuated by 3 dB due to the presence of the four-port duplexer 11. However, since the circuit is linear, this does not change the cancellation condition discussed above.

[0049] Figure 2 A device 20 for wireless communication according to the present invention is shown. Specifically, device 20 may be part of an RFFE.

[0050] and Figure 1 Similar to device 10, device 20 includes a four-port duplexer 11 with four ports 1, 2, 3, and 4, a power amplifier (PA) 14, and an low-noise block downconverter (LNA) 15. The first port 1 is connected to the transmit path TX of a device used for wireless communication, and the fourth port 4 is connected to the receive path RX of the same device. In the illustrated embodiment, the four-port duplexer 11 is a 0 / 180° hybrid coupler 11. Similar to device 10, device 20 also includes a first antenna 12, which is connected to the first transmit path TX1 via the second port 2 of the hybrid coupler 11.

[0051] However, with Figure 1 The device shown is different from device 10. Figure 2 The illustrated device 20 includes a second antenna 22, which is connected to a second transmit path TX2 via a third port 3 of a hybrid coupler 11. The first antenna 12 and the second antenna 22 are of the same type and are arranged back-to-back, as shown. Figure 2 The symbols for antennas 12 and 22 are shown in opposite directions.

[0052] The reflection coefficient of the first antenna 12 is The reflection coefficient of the second antenna 22 is Since antennas 12 and 22 are of the same type, their characteristics (especially their reflection coefficients) should be essentially the same:

[0053] As described above, the total power leakage S between port 4 and port 1 of the four-port duplexer from the TX path to the RX path is... 41,D The following formula can be used to approximate the calculation:

[0054] Secondly, assuming direct leakage S 41 Negligible, due to the identical properties of antennas 12 and 22, the second and third terms inherently have the same amplitude. Furthermore, since the hybrid coupler 11 is a 0 / 180° hybrid coupler, the signal supplied to antenna 12 has a 180° phase difference with the signal supplied to antenna 22, while other characteristics are the same. Therefore, the cancellation condition is:

[0055] If these antennas are identical, then this condition is satisfied due to the characteristics of the hybrid coupler 11.

[0056] Furthermore, since antennas 12 and 22 are arranged back-to-back, the transmitted signal is transmitted to the first hemisphere via antenna 12 and to the opposite hemisphere via antenna 22. Therefore, with Figure 1 Compared to existing technologies, the device 20 doubles the spatial coverage of the launch while fundamentally reducing self-interference.

[0057] It should be noted that, Figure 2 An embodiment including a first antenna 12 and a second antenna 22 is shown. However, the first antenna 12 may be part of a first antenna array connected to a second port 2 of the hybrid coupler 11, and the second antenna 22 may be part of a second antenna array connected to a third port 3 of the hybrid coupler 11. In this embodiment, the first and second antenna arrays are also arranged back-to-back.

[0058] Figure 3 Another embodiment of the device 20 for wireless communication according to the present invention is shown. Figure 2 Compared to the embodiments shown, Figure 3 The illustrated device 20 also includes an antenna tuner 16 disposed between the second port 2 of the four-port duplexer 11 and the first antenna 12, and an antenna tuner 16 disposed between the third port 3 of the four-port duplexer 11 and the second antenna 22. The antenna tuner 16 may be a Chebyshev-type antenna tuner; specifically, each antenna tuner 16 may include an nth-order Chebyshev bandpass filter, where n ranges from 1 to infinity, specifically between 2 and 8.

[0059] Antenna tuner 16 can be used to improve electrical balance. Specifically, antennas 12 and 22 may not have exactly the same properties, even if they are of the same type. Furthermore, their reflections may be affected by the different environments they are pointing to. Therefore, small differences may exist in the reflected signals, and complete cancellation of the reflected signals may not be possible without antenna tuner 16. For example, the reflection coefficient... Possibly related to the reflection coefficient There are slight differences. Antenna tuner 16 can be used to eliminate these minor differences by fine-tuning the impedance between port 2 and antenna 12, and between port 3 and antenna 22, respectively.

[0060] Furthermore, the antenna tuner 16 can be used to cancel direct leakage between port 1 and port 2 of the four-port duplexer 11. As described above, the first antenna 12 can be part of a first antenna array, and the second antenna 22 can be part of a second antenna array.

[0061] Figure 4 A portion of an embodiment of a device 20 for wireless communication according to the present invention is illustrated schematically. Figure 4 The first antenna 12 and the second antenna 22 are shown in a back-to-back configuration. The transmission directions of antennas 12 and 22 are indicated by corresponding arrows.

[0062] In the example shown, antennas 12 and 22 are patch antennas. Antennas 12 and 22 are isolated from each other and point in opposite directions. Furthermore, antennas 12 and 22 transmit only forward and not backward. Therefore, RFFE is transmitted in both directions, but received in most cases only from one direction. It can be seen that antennas 12 and 22 are positioned on opposite sides of substrate 100. For example, substrate 100 can be a printed circuit board. Connectors (not shown) can be provided on the substrate for connecting antenna 12 to a first port of the hybrid coupler and antenna 22 to a second port of the hybrid coupler.

[0063] exist Figure 4 In the illustrated embodiment, it can be seen that antenna 12 and antenna 22 completely overlap, meaning their respective planar projections on substrate 100 are identical. However, it should be noted that antenna 12 and antenna 22 may also partially overlap or not overlap at all. Each antenna may also be disposed on its own substrate.

[0064] Although the embodiments and examples of the invention have been described above, it should be understood that some or all of the features described above can be combined in different ways. The embodiments discussed above are not intended to be limiting, but rather to illustrate the features and advantages of the invention.

Claims

1. A device (20) for wireless communication, characterized in that, include: First antenna (12); Second antenna (22); A hybrid coupler (11) is used to: connect the first antenna (12) to the first transmission path (TX1) and connect the second antenna (22) to the second transmission path (TX2), wherein, The first antenna (12) is connected to the first port (2) of the hybrid coupler (11); The second antenna (22) is connected to the second port (3) of the hybrid coupler (11); The first antenna (12) and the second antenna (22) are arranged back to back.

2. The device (20) according to claim 1, characterized in that, The hybrid coupler (11) is used to: provide power from the first transmission path (TX1) to the first antenna (12) and power from the second transmission path (TX2) to the second antenna (22) such that the reflected signal from the first antenna (12) is at least partially canceled by the reflected signal from the second antenna (22), and vice versa.

3. The device (20) according to any one of the preceding claims, characterized in that, The hybrid coupler (11) is a 0 / 180° hybrid coupler.

4. The device (20) according to any one of the preceding claims, characterized in that, The first antenna (12) and the second antenna (22) are of the same type.

5. The device (20) according to any one of the preceding claims, characterized in that, The hybrid coupler (11) also connects the first antenna (12) and the second antenna (22) to the receiving path (RX).

6. The device (20) according to any one of the preceding claims, characterized in that, include: First antenna array; The second antenna array, in which... The first antenna array includes the first antenna (12); The second antenna array includes the second antenna (22); The first antenna array and the second antenna array are arranged back to back.

7. The device (20) according to any one of the preceding claims, characterized in that, Also includes: The first antenna tuner (16) is disposed between the first port (2) and the first antenna (12); The second antenna tuner (16) is disposed between the second port (3) and the second antenna (22).

8. The device (20) according to claim 6, characterized in that, The first antenna tuner (16) and / or the second antenna tuner (16) include Chebyshev type antenna tuners.

9. A method for wireless communication, particularly using the device according to any one of the preceding claims, characterized in that, include: The first transmit signal is provided to the first antenna (12) through the hybrid coupler (11), and the second transmit signal is provided to the second antenna (22). The first antenna (12) is connected to the first port (2) of the hybrid coupler (11); The second antenna (22) is connected to the second port (3) of the hybrid coupler (11); The first antenna (12) and the second antenna (22) are arranged back to back; The first transmission signal and / or the second transmission signal are transmitted through the first antenna (12) and / or the second antenna (22).

10. The method according to claim 9, characterized in that, The hybrid coupler (11) is used to: provide power from the first transmission path (TX1) to the first antenna (12) and power from the second transmission path (TX2) to the second antenna (22) such that the reflected signal from the first antenna (12) is at least partially canceled by the reflected signal from the second antenna (22), and vice versa.

11. The method according to any one of claims 9 or 10, characterized in that, The hybrid coupler (11) is a 0 / 180° hybrid coupler.

12. The method according to any one of claims 9 to 11, characterized in that, The first antenna (12) and the second antenna (22) are of the same type.

13. The method according to any one of claims 9 to 12, characterized in that, Also includes: The impedance of the first antenna (12) is matched by adapting the first antenna tuner (16) between the first port (2) and the first antenna (12); The impedance of the second antenna (22) is matched by adapting the second antenna (3) to the impedance of the second antenna (22) through a second antenna tuner (16) set between the second port (3) and the second antenna (22).

14. The method according to claim 13, characterized in that, The first antenna (12) tuner and / or the second antenna (22) tuner include a Chebyshev type antenna tuner.

15. The method according to any one of claims 9 to 14, characterized in that, Also includes: Signals are received via the first antenna (12) or the second antenna (22).

16. A computer-readable medium including instructions, characterized in that, When executed by a computer, the instructions cause the computer to perform the method according to any one of claims 9 to 15.

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