Microwave detection module for realizing transceiver separation by passive microstrip isolator

Abstract

The application provides a microwave detection module for realizing transceiver separation by using a passive microstrip isolator, wherein the passive microstrip isolator can realize transceiver separation of an antenna designed by using a transceiver combination structure at a higher isolation degree, so as to match a microwave chip designed by using a transceiver separation structure, thereby ensuring cost advantages of the corresponding microwave detection module and a miniaturization trend of products based on matching between the antenna designed by using the transceiver combination structure and the microwave chip designed by using the transceiver separation structure, and ensuring stability and detection precision of the microwave detection module based on transceiver separation of the antenna at the higher isolation degree.

Description

Technical Field

[0001] This invention relates to the field of microwave Doppler detection, and more specifically to a microwave detection module that achieves transmit-receive separation using a passive microstrip isolator. Background Technology

[0002] With the development of IoT technology, artificial intelligence, smart homes, and smart security technologies are increasingly demanding environmental detection, especially the detection of human presence, movement, and micro-motion characteristics. Microwave detection technology, based on the Doppler effect, serves as a crucial link between people and objects, and between objects themselves, possessing unique advantages in behavior and presence detection technologies. It can detect moving objects, such as human motion characteristics, movement characteristics, and micro-motion characteristics, and even heartbeat and breathing characteristics, without infringing on human privacy, thus having broad application prospects. Existing microwave detection modules, considering cost and size, mainly adopt a combined transmit and receive antenna structure design. That is, the antenna uses the same feed port as both the transmit feed port for the excitation signal and the receive feed port for the feedback signal, thus simultaneously serving as the transmitting and receiving antennas of the microwave detection module. This reduces antenna cost and size, helping to maintain the cost advantage of the microwave detection module and conforming to the trend of product miniaturization. Furthermore, with the rapid development of the domestic chip industry and continuous cost optimization, current microwave detection modules generally tend to replace discrete component-based RF oscillation circuits and mixer processing circuits with microwave chips. This further reduces the size of the microwave detection module while leveraging the high integration advantage of microwave chips over discrete components to simplify the circuit design and enrich the functional design of the microwave detection module. However, among current microwave chips, those that can simultaneously maintain advantages in cost, stability, and isolation mainly adopt a transmit-receive separation design, where different ports are used as the transmitting port for outputting the excitation signal and the receiving port for receiving the feedback signal.

[0003] To achieve transmit / receive separation for antennas with a combined transmit / receive structure and to match them with microwave chips with a separate transmit / receive design, current microwave detection modules mainly correspond to... Figure 1A A 3dB bridge is used to achieve antenna transmit / receive separation, or a method corresponding to... Figure 1B A ring bridge is used to separate the transmit and receive signals of the antenna. For example... Figure 1AAs shown, the microwave detection module includes an antenna 10P, a 3dB bridge 20P, and a microwave chip 30P. The antenna 10P adopts a combined transmit and receive design, using the same feed port 101P as both the transmit feed port for the excitation signal and the receive feed port for the feedback signal. The 3dB bridge 20P has an input terminal 201P, a first output terminal 202P, a second output terminal 203P, and an isolation terminal 204P connected sequentially by microstrip interconnects. The input terminal 201P and the isolation terminal 204P are connected, making the 3dB bridge 20P a ring-shaped four-port configuration. The input terminal 201P, the first output terminal 202P, the second output terminal 203P, and the isolation terminal 204P are... The design employs an equal impedance design, with the impedance defined as Z0. The microstrip connection lines between the input terminal 201P and the isolation terminal 204P, and between the first output terminal 202P and the second output terminal 203P, are all designed with an impedance of Z0 and an equal length of one-quarter wavelength. The microstrip connection lines between the input terminal 201P and the first output terminal 202P, and between the second output terminal 202P and the isolation terminal 204P, are all designed with an impedance of Z0 / √2 and an equal length of one-quarter wavelength. The microwave chip 30P uses a transmit / receive separation design, with different ports serving as the transmitting port 301P for outputting the excitation signal and the receiving port 302P for receiving the feedback signal. This design ensures that, in accordance with... Figure 1A With the input terminal 201P connected to the transmit port 301P, the isolation terminal 204P connected to the receive port 302P, and the first output terminal 201P connected to the feed port 101P of the antenna 10P, the excitation signal output from the transmit port 301P can be transmitted to the feed port 101P of the antenna 10P but not to the receive port 302P, while the feedback signal output from the feed port 101P of the antenna 10P can be transmitted to the receive port 302P. This achieves the transmission and reception separation of the antenna 10P, which adopts a combined transmit and receive structure, and matches the microwave chip 30P, which adopts a transmission and reception separation design.

[0004] Based on the above description, it can be seen that the total length of the microstrip connection lines connecting only the four ports of the 3dB bridge 20P is already as long as one wavelength, which corresponds to a large area occupied during circuit board layout, thus hindering the miniaturization of the microwave detection module. Compared to using the 3dB bridge 20P to achieve transmit / receive separation of the antenna 10P, when using... Figure 1BWhen the ring bridge is used to separate the transmit and receive signals of the antenna 10P, it occupies a larger area on the circuit board because the ring bridge is structurally equivalent to extending the microstrip connection between the first output terminal 202P and the second output terminal 203P of the 3dB bridge 20P from a quarter wavelength to a three-quarter wavelength. Furthermore, both the 3dB bridge 20P and the ring bridge are four-port rings, and the impedance matching between the ports is complex due to the accuracy of the corresponding microstrip connection, making it difficult to guarantee the isolation between the input terminal and the isolation terminal. Therefore, in practical applications, local oscillator leakage and DC deviation are prone to occur, resulting in self-mixing and thus deteriorating the signal-to-noise ratio. Summary of the Invention

[0005] One objective of this invention is to provide a microwave detection module that achieves transmit / receive separation using a passive microstrip isolator. The passive microstrip isolator enables transmit / receive separation of an antenna with a combined transmit / receive structure at a high degree of isolation, thus matching it with a microwave chip designed for transmit / receive separation. Therefore, based on the matching between the antenna with a combined transmit / receive structure and the microwave chip with a transmit / receive separation design, the cost advantage of the microwave detection module and its adaptation to product miniaturization trends are ensured. Furthermore, the transmit / receive separation of the antenna at a high degree of isolation guarantees the stability and detection accuracy of the microwave detection module.

[0006] Another objective of this invention is to provide a microwave detection module that achieves transmit / receive separation using a passive microstrip isolator. The passive microstrip isolator adopts a three-port structure design, which simplifies impedance matching between ports and reduces the accuracy requirements of the corresponding microstrip connection lines for impedance matching between ports compared to a 3dB bridge and a ring bridge. Therefore, it is beneficial to ensure the stability of the isolation between the corresponding ports, thereby ensuring the consistency and stability of the microwave detection module.

[0007] Another objective of this invention is to provide a microwave detection module that achieves transmit-receive separation using a passive microstrip isolator, wherein the passive microstrip isolator has a significantly shorter microstrip connection line length compared to a 3dB bridge and a ring bridge, thus reducing the area of ​​the circuit board layout and facilitating further miniaturization of the microwave detection module.

[0008] Another objective of this invention is to provide a microwave detection module that achieves transmit / receive separation using a passive microstrip isolator. This passive microstrip isolator is configured as a Wilkinson power divider. Moving beyond the traditional application of Wilkinson power dividers as bidirectional dividers to split a signal into two or combine two signals into one, this invention leverages the three-port structure of the Wilkinson power divider and its significantly shortened microstrip connection length compared to 3dB and ring bridges. This simplifies impedance matching of the passive microstrip isolator and reduces the area of ​​the circuit board layout.

[0009] Another objective of this invention is to provide a microwave detection module that achieves transmit / receive separation using a passive microstrip isolator, wherein the Wilkinson power divider is disposed between the antenna and the microwave chip in the form of a passive device. Besides establishing an electrical connection between the Wilkinson power divider and the antenna and the microwave chip based on corresponding circuit connection or coupling structures, no additional power supply is required based on the electrical connection. Therefore, it is advantageous to simplify the circuit layout of the passive microstrip isolator when the Wilkinson power divider serves as the passive microstrip isolator.

[0010] Another object of the present invention is to provide a microwave detection module that achieves transmit / receive separation using a passive microstrip isolator, wherein the Wilkinson power divider has a first port, a second port, and a third port, and includes a first microstrip connection line connected between the first port and the second port, a second microstrip connection line connected between the first port and the third port, and a resistor connected between the second port and the third port. The Wilkinson power divider is disposed passively between the antenna and the microwave chip, and is electrically connected at the second port to the transmit port of the microwave chip, and at the first port... The third port is electrically connected to the feed port of the antenna, and the third port is electrically connected to the receiver port of the microwave chip. Thus, the excitation signal output from the transmit port of the microwave chip can be transmitted to the feed port of the antenna and isolated from the receiver port with a high degree of isolation. Conversely, the feedback signal output from the feed port of the antenna can be transmitted to the receiver port of the microwave chip. This ensures that the feedback signal received by the receiver port is isolated from the excitation signal with a high degree of isolation. This achieves transmit / receive separation of the antenna with its combined transmit / receive structure design, matching the transmit / receive separation design of the microwave chip.

[0011] Another objective of this invention is to provide a microwave detection module that achieves transmit-receive separation using a passive microstrip isolator, wherein the resistance value of the Wilkinson power divider is set to the sum of the impedance of the second port and the impedance of the third port, thereby improving the aforementioned isolation and ensuring the stability and detection accuracy of the microwave detection module.

[0012] To achieve at least one of the above objectives, the present invention provides a microwave detection module that achieves transmit / receive separation using a passive microstrip isolator, the microwave detection module comprising:

[0013] An antenna, wherein the antenna adopts a combined transmit and receive structure design, with the same feed port serving as both the transmit feed port for receiving the excitation signal and the receive feed port for outputting the feedback signal;

[0014] A passive microstrip isolator, wherein the passive microstrip isolator has a first port, a second port, and a third port, and includes a first microstrip connection line connected between the first port and the second port, a second microstrip connection line connected between the first port and the third port, and a resistor connected between the second port and the third port, wherein the sum of the lengths of the first microstrip connection line and the second microstrip connection line approaches half the wavelength electrical length within a 20% error range; and

[0015] A microwave chip, wherein the microwave chip adopts a transmit / receive separation design with different ports serving as a transmit port for outputting excitation signals and a receive port for receiving feedback signals, wherein a passive microstrip isolator is disposed between the antenna and the microwave chip in the form of a passive device, and is electrically connected to the transmit port of the microwave chip at the second port, electrically connected to the feed port of the antenna at the first port, and electrically connected to the receive port of the microwave chip at the third port.

[0016] In one embodiment, the first microstrip connector and the second microstrip connector are designed with equal impedance.

[0017] In one embodiment, the resistance value of the resistor is set to the sum of the impedance of the second port and the impedance of the third port.

[0018] In one embodiment, the second port and the third port are designed to have equal impedance.

[0019] In one embodiment, the resistance value of the resistor is set to 100Ω.

[0020] In one embodiment, the first microstrip connection and the second microstrip connection are designed with different impedances.

[0021] In one embodiment, the impedance of the first microstrip connection is greater than the impedance of the second microstrip connection.

[0022] In one embodiment, the first microstrip connection line and the second microstrip connection line are strip conductors carried on a circuit board, wherein the first microstrip connection line and the second microstrip connection line, which are strip conductors, extend from the first port and define an isolation region on the circuit board with an opening between the second port and the third port, wherein the resistor is connected between the second port and the third port at the opening of the isolation region.

[0023] In one embodiment, the first microstrip connection line and the second microstrip connection line extend from the first port in opposite, same, and opposite directions, respectively, and the corresponding isolation area is rectangular in shape.

[0024] In one embodiment, the antenna is designed as an array antenna composed of multiple antenna elements, and each antenna element adopts a transmit-receive integrated structure design, with the same feed port serving as both the transmit feed port for receiving the excitation signal and the receive feed port for outputting the feedback signal. The feed ports of each antenna element are electrically connected to the first port.

[0025] In one embodiment, the passive microstrip isolator extends from the first port with a feed segment to form an electrical connection between the first port and the feed port of the antenna based on the electrical connection between the feed segment and the feed port of the antenna, wherein the feed segment is located within the isolation region.

[0026] In one embodiment, the passive microstrip isolator has at least one metal sheet disposed in the isolation region.

[0027] In one embodiment, the metal sheet is grounded.

[0028] In one embodiment, the first microstrip connector and the second microstrip connector are designed to be of equal length.

[0029] In one embodiment, the passive microstrip isolator is packaged as an independent component. Attached Figure Description

[0030] Figure 1A This is a schematic diagram of the existing microwave detection module that uses a 3dB bridge to achieve antenna transmit / receive separation.

[0031] Figure 1B This is a schematic diagram of an existing ring bridge.

[0032] Figure 2 This is a schematic diagram of the structure of a microwave detection module according to an embodiment of the present invention.

[0033] Figure 3 The above-described embodiment of the present invention provides the S-parameter curve between the second and third ports of the microwave detection module.

[0034] Figure 4 This is a schematic diagram of the structure of a microwave detection module according to another embodiment of the present invention.

[0035] Figure 5 The above-described embodiment of the present invention provides the S-parameter curve between the second and third ports of the microwave detection module.

[0036] Figure 6 This is a schematic diagram of the structure of a microwave detection module according to another embodiment of the present invention.

[0037] Figure 7 This is a schematic diagram of a further modified structure of a passive microstrip isolator for a microwave detection module according to another embodiment of the present invention.

[0038] Figure 8A A schematic diagram of the structure of a passive microstrip isolator for a microwave detection module according to another embodiment of the present invention.

[0039] Figure 8B The S-parameter curve between the second port and the third port of the microwave detection module according to the above embodiment of the present invention. Detailed Implementation

[0040] The following description is intended to disclose the present invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0041] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting this invention.

[0042] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0043] This invention provides a microwave detection module that achieves transmit / receive separation using a passive microstrip isolator. The passive microstrip isolator enables transmit / receive separation of an antenna with a combined transmit / receive structure design at a high degree of isolation, thus matching it with a microwave chip with a separate transmit / receive design. Therefore, based on the matching between the antenna with a combined transmit / receive structure design and the microwave chip with a separate transmit / receive design, the cost advantage of the microwave detection module and its adaptation to the trend of product miniaturization are ensured. Furthermore, the transmit / receive separation of the antenna at a high degree of isolation ensures the stability and detection accuracy of the microwave detection module.

[0044] Example, referring to the accompanying drawings of the specification of the present invention. Figure 2As shown, the structural principle of a microwave detection module with transmit / receive separation using a passive microstrip isolator according to an embodiment of the present invention is illustrated. The microwave detection module includes an antenna 10, a passive microstrip isolator 20, and a microwave chip 30. The antenna 10 adopts a transmit / receive integrated design, using the same feed port 101 as both the transmit feed port for receiving the excitation signal and the receive feed port for outputting the feedback signal. The passive microstrip isolator 20 is configured with a Wilkinson power divider and has a first port 201, a second port 202, and a third port 203. It includes a first microstrip connection line 21 connected between the first port 201 and the second port 202, a second microstrip connection line 22 connected between the first port 201 and the third port 203, and a resistor 23 connected between the second port 202 and the third port 203. The microwave chip 30 adopts a transmit / receive separation design, using different ports as the transmit port 301 for outputting the excitation signal and the receive port 302 for receiving the feedback signal, respectively. An Elkinson power divider, in the form of a passive device, is disposed between the antenna 10 and the microwave chip 30. It is electrically connected to the transmitting port 301 of the microwave chip 30 via the second port 202, electrically connected to the feed port 101 of the antenna 10 via the first port 201, and electrically connected to the receiving port 302 of the microwave chip 30 via the third port 203. Therefore, the excitation signal output from the transmitting port 301 of the microwave chip 30 can be transmitted to the feed port 301 of the antenna 10. 1. It is isolated from the receiving port 302 of the microwave chip 30 under a high degree of isolation, while the feedback signal output from the feed port 101 of the antenna 10 can be transmitted to the receiving port 302 of the microwave chip 30. Correspondingly, the feedback signal received by the receiving port 302 of the microwave chip 30 can be isolated from the excitation signal under a high degree of isolation. In this way, the antenna 10 with a combined transmit and receive structure design can achieve transmit and receive separation under a high degree of isolation and match the microwave chip 30 with a transmit and receive separation design.

[0045] It is worth mentioning that, in the traditional application of Wilkinson power dividers, a Wilkinson power divider, as a bidirectional power divider, is used to input a signal from the first port 201 and split that signal into two signals, which are output from the second port 202 and the third port 203 respectively; or to input a signal from the second port 202 and the third port 203 respectively and combine the two signals into a single signal, which is output from the first port 201. Its special feature lies in the resistor 23 connected between the second port 202 and the third port 203. The resistor 23 is used to suppress the imbalance between the output signals caused by the unbalanced state of the first microstrip connection line 21 and the second microstrip connection line 22.

[0046] In other words, the application of the Wilkinson power divider in the microwave detection module of this invention breaks away from the traditional application of the Wilkinson power divider as a bidirectional power divider. Specifically, in this embodiment of the invention, the microwave detection module inputs an excitation signal to the second port 202 of the Wilkinson power divider, enabling the antenna 10, which is fed to the first port 201, to be transmitted and fed. Utilizing the structural feature that the sum of the lengths of the first microstrip connection line 21 and the second microstrip connection line 22 of the Wilkinson power divider is close to half the electrical length of the wavelength, the excitation signal sequentially transmitted to the third port 203 via the first microstrip connection line 21 and the second microstrip connection line 22 can cancel out the excitation signal transmitted to the third port 203 via the resistor 23. Correspondingly, the excitation signal output from the transmitting port 301 of the microwave chip 30 can be isolated from the receiving port 302 of the microwave chip 30 with a high degree of isolation. The feedback signal output from the feed port 101 of the antenna 10 can be transmitted to the transmit port 301 and the receive port 302 of the microwave chip 30 via the first microstrip line 21 and the second microstrip line 22, respectively. Therefore, the feedback signal received by the receive port 302 of the microwave chip 30 can be isolated from the excitation signal with a high degree of isolation, thereby achieving transmit-receive separation with a high degree of isolation for the antenna 10, which adopts a transmit-receive integrated structure design, and matching the microwave chip 30, which adopts a transmit-receive separation design.

[0047] It is worth mentioning that the sum of the lengths of the first microstrip connection line 21 and the second microstrip connection line 22 of the Wilkinson power divider is close to half the wavelength electrical length, which is a significantly shorter microstrip connection line length compared to the 3dB bridge and the ring bridge. Therefore, it is beneficial to reduce the circuit board area of ​​the microwave detection module, which is conducive to the further miniaturization design of the microwave detection module.

[0048] Furthermore, the Wilkinson power divider has a three-port structure, which, compared to a 3dB bridge and a ring bridge, reduces the complexity of impedance matching between ports being affected by the accuracy of the corresponding microstrip interconnects. This simplifies impedance matching between ports and reduces the accuracy requirements of the corresponding microstrip interconnects, thus helping to ensure the stability of the aforementioned isolation and correspondingly ensuring the consistency and stability of the microwave detection module.

[0049] Those skilled in the art should understand that the Wilkinson power divider is disposed between the antenna 10 and the microwave chip 30 in the form of a passive device. In addition to establishing an electrical connection relationship between the Wilkinson power divider and the antenna 10 and the microwave chip 30 based on the corresponding circuit connection structure or circuit coupling structure, no external power supply is required based on the additional electrical connection relationship. Therefore, it is beneficial to simplify the circuit layout of the passive microstrip isolator 20 when the Wilkinson power divider is used as the passive microstrip isolator 20.

[0050] In other words, the Wilkinson power divider is electrically connected at the second port 202 to the transmitting port 301 of the microwave chip 30, and at the first port 201 to the feeding port 101 of the antenna 10, and at the third port 203 to the receiving port 302 of the microwave chip 30. Under the above electrical connection relationship, the description that the Wilkinson power divider is set between the antenna 10 and the microwave chip 30 in the form of a passive device is a limitation that the Wilkinson power divider does not require an external power supply based on additional electrical connection relationships.

[0051] Therefore, the microwave detection module of the present invention breaks away from the traditional application of the Wilkinson power divider as a bidirectional power divider. Instead, it uses the Wilkinson power divider to replace the 3dB bridge and the ring bridge as the passive microstrip isolator 20. This eliminates the need to make any changes to the original structural design of the Wilkinson power divider that deviate from its original structural range, and also eliminates the need to add any active circuitry based on additional electrical connections between the Wilkinson power divider, the antenna 10, and the microwave chip 30. This simplifies the circuit layout of the passive microstrip isolator 20.

[0052] In this embodiment of the present invention, the first microstrip connection line 21 and the second microstrip connection line 22 are strip-shaped conductors carried on a circuit board. The first microstrip connection line 21 and the second microstrip connection line 22, which are strip-shaped conductors, extend from the first port 201 and define an isolation region 200 on the circuit board with the gap between the second port 202 and the third port 203 as the opening. The resistor 23 is connected between the second port 202 and the third port 203 at the opening of the isolation region 200. The specific shape of the first microstrip connection line 21 and the second microstrip connection line 22, which are strip-shaped conductors, does not constitute a limitation on the present invention. The shape of the defined isolation region 200 can be any shape such as triangle, rectangle, rhombus, trapezoid, and circle.

[0053] Specifically, in this embodiment of the present invention, the first microstrip connection line 21 and the second microstrip connection line 22 extend from the first port 201 in opposite directions, in the same direction, and in opposite directions, respectively, and the shape of the corresponding defined isolation area 200 is rectangular.

[0054] It is worth mentioning that, since the sum of the lengths of the first microstrip connection line 21 and the second microstrip connection line 22 of the Wilkinson power divider is close to half the wavelength electrical length, and thus has a significantly shorter microstrip connection line length compared to the 3dB bridge and the ring bridge, in some embodiments of the present invention, the passive microstrip isolator 20 configured as a Wilkinson power divider can also be packaged as an independent component, which also helps to reduce the circuit board area of ​​the microwave detection module.

[0055] Furthermore, in this embodiment of the invention, the first microstrip connection line 21 and the second microstrip connection line 22 are designed with equal impedance, and the first microstrip connection line 21 and the second microstrip connection line 22, which are corresponding to strip-shaped conductors, have the same linewidth, so as to simplify the impedance matching design between the Wilkinson power divider and the antenna 10 and the microwave chip 30.

[0056] Specifically, within the original structure of the Wilkinson power divider, the resistance value of resistor 23 is set to the sum of the impedance of the second port 202 and the impedance of the third port 203. To further simplify the impedance matching design between the Wilkinson power divider and the microwave chip 30, in this embodiment of the invention, the second port 202 and the third port 203 are designed with equal impedance.

[0057] To ensure the compatibility of the microwave detection module, in this embodiment of the invention, the impedances of the first port 201, the second port 202, and the third port 203 are all designed to be 50Ω, and the resistance of the resistor 23 is set to 100Ω.

[0058] Further reference is made to the accompanying drawings of this invention. Figure 3 As shown, the S-parameter curves between the second port 202 and the third port 203 of the Wilkinson power divider in this embodiment of the present invention are illustrated. Under simulation conditions where the excitation signal is connected to the second port 202, the S-parameter associated with the energy ratio of the excitation signal output by the third port 203 at the 5.8 GHz frequency point is as low as -30 dB. This corresponds to the state where the second port 202 of the Wilkinson power divider is electrically connected to the transmitting port 301 of the microwave chip 30, and the third port 203 is electrically connected to the receiving port 302 of the microwave chip 30. The excitation signal output from the transmit port 301 of the microwave chip 30 can be isolated from the receive port 302 of the microwave chip 30 with a high degree of isolation. Thus, when the Wilkinson power divider is further electrically connected to the feed port 101 of the antenna 10 at the first port 201, the feedback signal received by the receive port 302 of the microwave chip 30 can be isolated from the excitation signal with a high degree of isolation. This achieves the transmission and reception separation of the antenna 10 with the integrated transmission and reception structure design with a high degree of isolation, thus matching the microwave chip 30 with the transmission and reception separation design.

[0059] It is worth mentioning that the structural feature of the first microstrip connection line 21 and the second microstrip connection line 22 being designed with equal impedance is neither a limitation on the original structural range of the Wilkinson power divider, nor does it constitute a structural limitation on the Wilkinson power divider serving as the passive microstrip isolator 20 in the microwave detection module of the present invention. In other embodiments of the present invention, the first microstrip connection line 21 and the second microstrip connection line 22 can also be designed with different impedances, thus having a more flexible impedance matching structure compared to the 3dB bridge and the ring bridge. This is beneficial to ensuring the flexibility of the circuit layout of the passive microstrip isolator 20 to adapt to different structural and functional design requirements.

[0060] Example, referring to the accompanying drawings of the specification of the present invention. Figure 4 As shown, the structural principle of the microwave detection module according to another embodiment of the present invention is illustrated. Unlike the microwave detection module of the previous embodiment, in this embodiment of the present invention, the first microstrip connection line 21 and the second microstrip connection line 22, which are the Wilkinson power divider of the passive microstrip isolator 20, are designed with different impedances.

[0061] Specifically, in this embodiment of the present invention, the impedance of the first microstrip connection line 21 is greater than the impedance of the second microstrip connection line 22, and the linewidth of the first microstrip connection line 21, which is a strip-shaped conductor, is narrower than that of the second microstrip connection line 22. Thus, in the state where the Wilkinson power divider is electrically connected at the second port 202 to the transmit port 301 of the microwave chip 30, at the first port 201 to the feed port 101 of the antenna 10, and at the third port 203 to the receive port 302 of the microwave chip 30, the feedback signal output from the feed port 101 of the antenna 10 can be transmitted to the receive port 302 of the microwave chip 30 with a larger power division ratio, thereby improving the detection accuracy of the microwave detection module.

[0062] It is worth mentioning that when the impedance of the first microstrip connection 21 is greater than the impedance of the second microstrip connection 22, the S-parameter curves between the second port 202 and the third port 203 of the Wilkinson power divider correspond as follows: Figure 5 As shown, under simulation conditions where the excitation signal is input to the second port 202, the S-parameter associated with the energy ratio of the excitation signal output by the third port 203 at the 5.8GHz frequency point is still as low as -30dB, specifically further reduced to below -33dB compared to the previous embodiment. This corresponds to the state where the Wilkinson power divider is electrically connected to the transmitting port 301 of the microwave chip 30 at the second port 202, and electrically connected to the receiving port 302 of the microwave chip 30 at the third port 203, from the microwave chip 30's... The excitation signal output from the transmit port 301 can be isolated from the receive port 302 of the microwave chip 30 with a higher degree of isolation. Thus, when the Wilkinson power divider is further electrically connected to the feed port 101 of the antenna 10 at the first port 201, the feedback signal received by the receive port 302 of the microwave chip 30 can be isolated from the excitation signal with a higher degree of isolation. This corresponds to the antenna 10 with a transmit / receive integrated structure design achieving transmit / receive separation with a higher degree of isolation, thus matching the microwave chip 30 with a transmit / receive separation design.

[0063] It is understood that in the above embodiments of the present invention, when the antenna 10 adopts a combined transmit and receive structure design and uses the same feed port 101 as both the transmit feed port for receiving the excitation signal and the receive feed port for outputting the feedback signal, the specific type and structure of the antenna 10 (including the number of feed ports and the structure of the feed ports corresponding to different feed methods) do not constitute a limitation of the present invention.

[0064] For example, when the antenna 10 is configured as a microstrip antenna (also known as a planar antenna), the antenna 10 has one or more feed ports, and the same feed port 101 serves simultaneously as a transmit feed port for receiving excitation signals and a receive feed port for outputting feedback signals.

[0065] In other words, the specific type and structure of the antenna 10 do not constitute a limitation on the microwave detection module of the present invention. In the microwave detection module of the present invention, the antenna 10 can be one of many existing antennas such as microstrip antenna, cylindrical antenna, dipole antenna, inverted F antenna, inverted L antenna, helical antenna and half-wave folding antenna, as long as the antenna 10 adopts a combined transmit and receive structure design and uses the same feed port 101 as both the transmit feed port for the excitation signal and the receive feed port for the feedback signal.

[0066] Furthermore, when the antenna 10 adopts a combined transmit and receive structure design, using the same feed port 101 as both the transmit feed port for receiving the excitation signal and the receive feed port for outputting the feedback signal, the antenna 10 can also correspond to... Figure 6 The antenna is designed as an array antenna composed of multiple antenna elements of the same or different types. Each antenna element adopts a transmit-receive integrated structure design, with the same feed port 101 serving as both the transmit feed port for receiving the excitation signal and the receive feed port for outputting the feedback signal. The feed port 101 of each antenna element is electrically connected to the first port 201 of the Wilkinson power divider. The antenna 10 still conforms to the description of "adopting a transmit-receive integrated structure design with the same feed port 101 serving as both the transmit feed port for receiving the excitation signal and the receive feed port for outputting the feedback signal".

[0067] It is worth mentioning that, in these embodiments of the present invention, the Wilkinson power divider, which is the passive microstrip isolator 20, extends a feed segment 2011 from the first port 201 to form an electrical connection between the first port 201 and the feed port 101 of the antenna 10 based on the electrical connection between the feed segment 2011 and the feed port 101 of the antenna 10. This allows the impedance of the first port 201 to be designed differently based on the impedance of the feed segment 2011 relative to the impedance of the first microstrip connection line 21 or the impedance of the second microstrip connection line 22, wherein the length of the feed segment 2011 is not included in the length of the first microstrip connection line 21 or the second microstrip connection line 22.

[0068] In particular, refer to the accompanying drawings of the specification of this invention. Figure 7As shown, a further modified structure of the Wilkinson power divider as the passive microstrip isolator 20 is illustrated, wherein the feed section 2011 is located within the isolation region 200, which is conducive to further reducing the circuit board area of ​​the microwave detection module, corresponding to the further miniaturization design of the microwave detection module.

[0069] Furthermore, the Wilkinson power divider may optionally correspond to Figure 7 At least one metal plate 24 is further provided in the isolation zone 200 to further improve the aforementioned isolation level. The metal plate 24 may optionally be further grounded.

[0070] In particular, in the above embodiments of the present invention, the first microstrip connection line 21 and the second microstrip connection line 22 are designed to be of equal length corresponding to the original structural range of the Wilkinson power divider, corresponding to the state where the sum of the lengths of the first microstrip connection line 21 and the second microstrip connection line 22 is close to half the wavelength electrical length, and the lengths of the first microstrip connection line 21 and the second microstrip connection line 22 are both close to a quarter wavelength electrical length.

[0071] However, in these embodiments of the present invention, the Wilkinson power divider is used as the passive microstrip isolator 20. The reason why the Wilkinson power divider is electrically connected at its second port 202 to the transmit port 301 of the microwave chip 30 and at its third port 203 to the receive port 302 of the microwave chip 30, allows the excitation signal output from the transmit port 301 of the microwave chip 30 to be isolated from the receive port 302 of the microwave chip 30 with a high degree of isolation, is essentially due to the utilization of… The Wilkinson power divider's structural feature, where the sum of the lengths of the first microstrip connection line 21 and the second microstrip connection line 22 is close to half the electrical length of the wavelength, allows the excitation signal sequentially transmitted to the third port 203 via the first microstrip connection line 21 and the second microstrip connection line 22 to cancel out the excitation signal transmitted to the third port 203 via the resistor 23. This enables the excitation signal output from the transmitting port 301 of the microwave chip 30 to be isolated from the receiving port 302 of the microwave chip 30 with a high degree of isolation.

[0072] Therefore, in some embodiments of the present invention, the passive microstrip isolator 20 may optionally deviate from the original structural limitations of the Wilkinson power divider in which the first microstrip connection line 21 and the second microstrip connection line 22 are designed to be of equal length.

[0073] In other words, in the microwave detection module of the present invention, the understanding and definition of the structural range of the Wilkinson power divider in the present invention allows for a departure from the limitation of the original structural range of the Wilkinson power divider where the first microstrip connection line 21 and the second microstrip connection line 22 are designed with equal lengths. Corresponding to a structural range where the sum of the lengths of the first microstrip connection line 21 and the second microstrip connection line 22 approaches half the electrical wavelength, in some embodiments of the present invention, the first microstrip connection line 21 and the second microstrip connection line 22 of the microwave detection module may optionally correspond to... Figure 8A Designed with different lengths, the S-parameter curves between the second port 202 and the third port 203 of the corresponding passive microstrip isolator 20 are as follows: Figure 8B As shown, under simulation conditions where the excitation signal is connected to the second port 202, the S-parameter associated with the energy ratio of the excitation signal output by the third port 203 at the 5.8GHz frequency point is as low as -26dB. The determination of the sum of the lengths of the first microstrip connection line 21 and the second microstrip connection line 22 is allowed a 20% error range due to the influence of the corresponding circuit board material. Within this 20% error range, the sum of the lengths of the first microstrip connection line 21 and the second microstrip connection line 22 approaches half the wavelength electrical length.

[0074] Specifically, the conventional wavelength λ and frequency f satisfy c = λf, where c is the speed of light. The electrical wavelength is the ratio of the actual physical length of the microstrip connector to the wavelength of the signal transmitted on the microstrip line. The wavelength of the signal transmitted on the microstrip line is affected by the electrical properties of the microstrip line itself and the environmental medium (such as the substrate of the circuit board supporting the microstrip line), differing from the conventional wavelength λ. Correspondingly, in the microwave detection module of this invention, when converting the actual physical length of the first microstrip connector 21 and the second microstrip connector 22 to the electrical wavelength, the transmitted signal frequency f, the actual physical length L of the microstrip connector, and the dielectric constant ε of the substrate of the circuit board supporting the microstrip connector can be used. r Substituting the circuit board thickness h, the microstrip interconnect line width w, and the speed of light c into the formula... Calculate the wavelength electrical length of the microstrip connector.

[0075] It will be understood by those skilled in the art that the above embodiments are merely examples, and features of different embodiments can be combined with each other to obtain implementation methods that are readily conceivable according to the content disclosed in the present invention but are not explicitly shown in the accompanying drawings.

[0076] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are merely examples and do not limit the present invention. The objectives of the present invention have been fully and effectively achieved. The functions and structural principles of the present invention have been demonstrated and explained in the embodiments, and any variations or modifications may be made to the implementation of the present invention without departing from the stated principles.

Claims

1. A microwave detection module that achieves transmit / receive separation using a passive microstrip isolator, characterized in that, include: An antenna, wherein the antenna adopts a combined transmit and receive structure design, with the same feed port serving as both the transmit feed port for receiving the excitation signal and the receive feed port for outputting the feedback signal; A passive microstrip isolator, wherein the passive microstrip isolator has a first port, a second port and a third port, and includes a first microstrip connection line connected between the first port and the second port, a second microstrip connection line connected between the first port and the third port, and a resistor connected between the second port and the third port, wherein the sum of the lengths of the first microstrip connection line and the second microstrip connection line approaches half the wavelength electrical length within a 20% error range; as well as A microwave chip, wherein the microwave chip adopts a transmit / receive separation design with different ports serving as a transmit port for outputting excitation signals and a receive port for receiving feedback signals, wherein a passive microstrip isolator is disposed between the antenna and the microwave chip in the form of a passive device, and is electrically connected to the transmit port of the microwave chip at the second port, electrically connected to the feed port of the antenna at the first port, and electrically connected to the receive port of the microwave chip at the third port.

2. The microwave detection module for transmitting and receiving separation using a passive microstrip isolator as described in claim 1, wherein the first microstrip connection line and the second microstrip connection line are designed with equal impedance.

3. The microwave detection module for transmitting and receiving separation using a passive microstrip isolator according to claim 2, wherein the resistance value is set to the sum of the impedance of the second port and the impedance of the third port.

4. The microwave detection module for achieving transmit / receive separation using a passive microstrip isolator according to claim 3, wherein the second port and the third port are designed with equal impedance.

5. The microwave detection module for achieving transmit / receive separation using a passive microstrip isolator according to claim 4, wherein the resistance value is set to 100Ω.

6. The microwave detection module for achieving transmit / receive separation using a passive microstrip isolator according to claim 1, wherein the first microstrip connection line and the second microstrip connection line are designed with different impedances.

7. The microwave detection module for achieving transmit / receive separation using a passive microstrip isolator according to claim 6, wherein the impedance of the first microstrip connection line is greater than the impedance of the second microstrip connection line.

8. The microwave detection module for transmitting and receiving separation using a passive microstrip isolator according to any one of claims 1 to 7, wherein the first microstrip connecting line and the second microstrip connecting line are strip-shaped conductors carried on a circuit board, wherein the first microstrip connecting line and the second microstrip connecting line, which are strip-shaped conductors, extend from the first port and define an isolation region on the circuit board with an opening between the second port and the third port, wherein the resistor is connected between the second port and the third port at the opening of the isolation region.

9. The microwave detection module for transmitting and receiving separation using a passive microstrip isolator according to claim 8, wherein the first microstrip connecting line and the second microstrip connecting line extend from the first port in opposite, same, and opposite directions respectively, and the shape of the corresponding defined isolation area is rectangular.

10. The microwave detection module for achieving transmit / receive separation using a passive microstrip isolator according to claim 8, wherein the antenna is designed as an array antenna composed of multiple antenna elements, and each antenna element adopts a transmit / receive integrated structure design with the same feed port serving as both the transmit feed port for receiving the excitation signal and the receive feed port for outputting the feedback signal, wherein the feed port of each antenna element is electrically connected to the first port.

11. The microwave detection module for transmitting and receiving separation using a passive microstrip isolator according to claim 8, wherein the passive microstrip isolator extends from the first port with a feed section to form an electrical connection between the first port and the feed port of the antenna based on the electrical connection between the feed section and the feed port of the antenna, wherein the feed section is located within the isolation region.

12. The microwave detection module for achieving transmit / receive separation using a passive microstrip isolator according to claim 8, wherein the passive microstrip isolator has at least one metal plate disposed in the isolation region.

13. The microwave detection module for achieving transmit / receive separation using a passive microstrip isolator according to claim 12, wherein the metal plate is grounded.

14. The microwave detection module for achieving transmit / receive separation using a passive microstrip isolator according to claim 8, wherein the first microstrip connecting line and the second microstrip connecting line are designed to be of equal length.

15. The microwave detection module for achieving transmit / receive separation using a passive microstrip isolator according to any one of claims 1 to 7, wherein the passive microstrip isolator is packaged as an independent component.

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