Tunable cavity filtering coupler, antenna device and communication equipment

Abstract

The embodiment of the invention provides a tunable cavity filtering coupler, an antenna device and communication equipment, and relates to the technical field of mobile communication. The tunable cavity filtering coupler comprises a dielectric substrate, a base layer and a metal layer arranged on the surface of at least one side of the base layer, the metal layer is provided with an annular coupler and a bias circuit, the annular coupler comprises four center loading branch resonators which are sequentially distributed in the circumferential direction, and the four center loading branch resonators are connected with the bias circuit. Each center loading branch resonator is connected with a variable capacitance diode. The metal layer further comprises feed ports which are in one-to-one correspondence with the center loading branch resonators and are connected with the center loading branch resonators. The biasing circuit is arranged on the periphery of the annular coupler in a surrounding mode, and the biasing circuit is electrically connected with the variable capacitance diode. According to the tunable cavity filtering coupler, the antenna device and the communication equipment provided by the invention, frequency selectivity and passband tunable functions are realized, and multi-band operation requirements are met.

Description

Technical Field

[0001] The present application relates to the field of mobile communication technology, and in particular to a tunable cavity filter coupler, an antenna device and a communication device. Background Art

[0002] The filtering Rat-Race coupler is a directional coupler whose internal transmission path is a ring structure, so that the signal produces a specific phase difference and power distribution during the transmission process. Specifically, the traditional filtering Rat-Race coupler usually cascades two bandpass filters with the Rat-Race coupler.

[0003] However, most traditional filtered Rat-Race couplers have the problem of fixed filter coupler response. The design lacks reconfigurability and flexibility, and is difficult to adapt to the needs of various functions such as different frequency bands, bandwidths, phase shifts or power distribution. Summary of the invention

[0004] The embodiments of the present application provide a tunable cavity filter coupler, an antenna device and a communication device, which realize frequency selectivity and passband tunable functions and meet the requirements of multi-band operation.

[0005] In a first aspect, an embodiment of the present application provides a tunable cavity filter coupler, comprising:

[0006] A dielectric substrate, comprising a base layer and a metal layer disposed on at least one side of the base layer, wherein the metal layer is provided with an annular coupler and a bias circuit, wherein the annular coupler comprises four center-loaded branch resonators sequentially distributed along the circumferential direction, each of the center-loaded branch resonators is connected to a varactor diode, and the metal layer further comprises a feeding port corresponding to and connected to the center-loaded branch resonators one by one;

[0007] The bias circuit is disposed around the outer periphery of the annular coupler, and the bias circuit is electrically connected to the varactor diode.

[0008] In a possible implementation, the four center-loaded branch resonators include a first branch resonator and a second branch resonator arranged opposite to each other along a first direction, and a third branch resonator and a fourth branch resonator arranged opposite to each other along a second direction.

[0009] The feeding port connected to the first branch resonator is an in-phase input port, and the feeding port connected to the second branch resonator is an in-phase input port.

[0010] The third stub resonator and the fourth stub resonator are configured to split a signal input from the in-phase input port into sub-signals of equal amplitude and in-phase, and to split a signal input from the inverting input port into sub-signals of equal amplitude and inverted phase.

[0011] In a possible implementation, the feeding port includes a first output port and a second output port, the first output port and the second output port are connected to a third branch resonator and a fourth branch resonator respectively,

[0012] The first branch resonator and the second branch resonator are configured to split a signal flowing from the first output port to the second output port into equal-amplitude and opposite-phase branch signals, and to split a signal flowing from the non-inverting input port to the opposite-phase input port into equal-amplitude and opposite-phase branch signals.

[0013] In a possible implementation, the four center-loaded branch resonators each include a main body segment and a branch segment, the main body segments of the first branch resonator, the third branch resonator, and the fourth branch resonator each extend in a straight line, and the branch segment is located inside the corresponding main body segment and vertically connected to the main body segment.

[0014] The branch section of the second branch resonator is located outside the corresponding main section.

[0015] In a possible implementation manner, two ends of each of the main body segments are respectively formed with bending portions parallel to the diagonal lines of the square.

[0016] In a possible implementation, the varactor diode includes a first varactor diode, which is disposed at an end of the branch segment away from the main segment, and a current limiting resistor and a DC blocking capacitor are further disposed between the first varactor diode and the bias circuit.

[0017] In a possible implementation manner, the varactor further includes a second varactor, and the second varactor is disposed at a free end of the bent portion of the main body segment.

[0018] In a possible implementation manner, the varactor diode includes a third varactor diode, and the third varactor diode is disposed between two of the feeding ports that are adjacent to each other in the circumferential direction.

[0019] In a possible implementation, the varactor diode further includes:

[0020] A tapped varactor diode, disposed at the feeding port;

[0021] A grounding varactor diode, provided at the feeding port and used for grounding;

[0022] The tapped varactor diode and the grounded varactor diode are connected in series, one of the tapped varactor diode and the grounded varactor diode is arranged along a first direction, and the other is arranged along a second direction.

[0023] In a second aspect, the present application further provides an antenna device, comprising a tunable cavity filter coupler in any possible implementation manner described above.

[0024] In a third aspect, the present application also provides a communication device, comprising the antenna device in any possible implementation manner described above.

[0025] The tunable cavity filter coupler, antenna device and communication equipment provided by the present application have high flexibility by introducing varactor diodes and bias circuits, and can be optimized for different application scenarios. The response characteristics of the coupler can also be changed in real time by adjusting the bias voltage, so that it can adapt to different frequency bands, bandwidths, phase shifts or power distribution requirements. In addition, through precise design and optimization, the coupler can achieve high performance indicators such as low loss, high isolation and good phase balance. In this way, the tunable cavity filter coupler design of the present application solves the problem of fixed filter coupler response in traditional Rat-Race couplers by introducing varactor diodes and bias circuits, and realizes the high performance, reconfigurability and high flexibility design of the tunable cavity filter coupler. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0027] Figure 1 A schematic diagram of the structure of the tunable cavity filter coupler provided in this application;

[0028] Figure 2 A schematic diagram of the changing state of the center frequency of the tunable cavity filter coupler provided in the present application in the low frequency band;

[0029] Figure 3 A schematic diagram of the change in the center frequency of the tunable cavity filter coupler provided in the present application in a higher frequency band.

[0030] Reference numerals:

[0031] 100- dielectric substrate; 110- base layer;

[0032] 200-annular coupler; 210-center loaded branch resonator; 210a-main section; 210b-branch section; 210c-bend section; 211-first branch resonator; 212-second branch resonator; 213-third branch resonator; 214-fourth branch resonator;

[0033] 300-bias circuit;

[0034] 400-varicap diode; 410-first varactor diode; 420-second varactor diode; 430-third varactor diode; 440-tapped varactor diode; 450-grounded varactor diode;

[0035] 500 - feeding port; 510 - in-phase input port; 520 - inverting input port; 530 - first output port; 540 - second output port;

[0036] 600-current limiting resistor;

[0037] 700-DC blocking capacitor;

[0038] 800-external DC source;

[0039] 900-grounding hole.

[0040] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0041] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0042] The filter Rat-Race coupler is a directional coupler whose internal transmission path is a ring structure, which makes the signal produce a specific phase difference and power distribution during the transmission process. Traditional filter Rat-Race couplers usually cascade two bandpass filters with the Rat-Race coupler. However, it usually leads to a bulky circuit, high additional insertion loss and matching problems.

[0043] Specifically, the traditional method of cascading two bandpass filters to a rat-race coupler results in a large circuit size, increased insertion loss, and matching problems. Although the filter rat-race coupler solves some of these problems as a multifunctional monolithic device, previous FRC designs based on planar panels, low-temperature co-fired ceramic (LTCC) technology, substrate integrated waveguide (SIW), circular patch resonators, dielectric resonators, and rectangular cavity resonators have the problem of fixed filter coupler response, lack of reconfigurability, and flexibility.

[0044] On the other hand, traditional reconfigurable filter couplers can be implemented using reconfigurable filter transmission lines, but most of them are single-band adjustable. There are also piezoelectric actuator-loaded substrate integrated waveguide cavity resonators and varactor-loaded step impedance resonators. However, the above-mentioned reconfigurations are all designed by replacing the quarter-wavelength transmission line of the coupler prototype with the proposed resonator. Although this design achieves a certain degree of reconfigurability, it has limitations in multiple performance aspects. For example, the comprehensive performance in terms of insertion loss, return loss, port isolation, phase imbalance, etc. is not ideal. Some designs may sacrifice other performance indicators when implementing reconfigurable functions, such as the circuit size may be larger.

[0045] It can be seen that most traditional filtered Rat-Race couplers have the problem of fixed filter coupler response. The design lacks reconfigurability and flexibility, and is difficult to adapt to the requirements of modern microwave circuits and communication systems for multiple functions such as different frequency bands, bandwidths, phase shifts or power distribution. It is also unable to meet the growing demand for multi-band or multi-functional microwave systems.

[0046] In view of this, the present application provides a tunable cavity filter coupler, an antenna device and a communication device. By introducing a varactor diode and a bias circuit, the coupler has high flexibility and can be optimized for different application scenarios. The bias voltage can also be adjusted to change the response characteristics of the coupler in real time, so that it can adapt to different frequency bands, bandwidths, phase shifts or power distribution requirements. In addition, through precise design and optimization, the coupler can achieve high performance indicators such as low loss, high isolation and good phase balance. In this way, the tunable cavity filter coupler design of the present application solves the problem of fixed filter coupler response in traditional Rat-Race couplers by introducing varactor diodes and bias circuits, and realizes the high performance, reconfigurability and high flexibility design of the tunable cavity filter coupler.

[0047] Combine the following Figures 1 to 3 A tunable cavity filter coupler according to an embodiment of the first aspect of the present application is described. Optionally, x is the first direction and y is the second direction.

[0048] Combination Figure 1 The tunable cavity filter coupler of this embodiment includes a dielectric substrate 100. The dielectric substrate 100 is the basis of the entire coupler and is usually made of high-performance microwave materials. The dielectric substrate 100 includes a base layer 110 and a metal layer disposed on at least one side of the base layer 110, which is used to construct a circuit structure.

[0049] Optionally, the dielectric substrate 100 may be Rogers RO4003C high frequency plate material, which has the advantages of low loss, stable dielectric constant, high temperature stability, etc. In some examples, the dielectric substrate 100 may have a dielectric constant of 3.55 F / m, a loss tangent of 0.0027, and a thickness of 0.508 cm.

[0050] The metal layer is provided with an annular coupler 200 and a bias circuit 300 , wherein the annular coupler 200 includes four center-loaded branch resonators 210 sequentially distributed along the circumferential direction to achieve signal coupling and phase shift.

[0051] Each center-loaded branch resonator 210 is connected to a varactor diode 400. It can be understood that the varactor diode 400 is an electronic component with the characteristic that the capacitance changes with the voltage. By adjusting the voltage across it, its capacitance value can be changed, thereby changing the resonant frequency of the resonator. In this way, the response of the entire coupler can become tunable.

[0052] The metal layer also includes feeding ports 500 corresponding to and connected to the center-loaded branch resonators 210 . These ports are used to input and output signals. In addition, better performance can be achieved by adjusting the impedance matching of the feeding end.

[0053] The bias circuit 300 is disposed around the outer periphery of the annular coupler 200 and is electrically connected to the varactor 400. It is understood that the bias circuit 300 is used to provide the required voltage to the varactor 400, thereby controlling its capacitance value. Specifically, by adjusting the bias voltage, the response characteristics of the coupler can be dynamically changed.

[0054] It can be seen that by introducing the varactor diode 400 and the bias circuit 300, the coupler has high flexibility and can be optimized for different application scenarios. The response characteristics of the coupler can be changed in real time by adjusting the bias voltage, so that it can adapt to different frequency bands, bandwidths, phase shifts or power distribution requirements. In addition, through precise design and optimization, the coupler can achieve high performance indicators such as low loss, high isolation and good phase balance.

[0055] In this way, the tunable cavity filter coupler design of the present application solves the problem of fixed filter coupler response in traditional rat-race couplers by introducing a varactor diode 400 and a bias circuit 300, thereby achieving high performance, reconfigurability and high flexibility design of the tunable cavity filter coupler.

[0056] Optionally, an external DC source 800 is further provided on the dielectric substrate 100 , and the external DC source 800 is used to connect to the bias circuit 300 .

[0057] In some embodiments, in combination Figure 1The four center-loaded branch resonators 210 include a first branch resonator 211 and a second branch resonator 212 arranged opposite to each other along a first direction, and a third branch resonator 213 and a fourth branch resonator 214 arranged opposite to each other along a second direction, wherein the feeding port 500 connected to the first branch resonator 211 is an in-phase input port 510, and the feeding port 500 connected to the second branch resonator 212 is an in-phase input port 520.

[0058] The third and fourth stub resonators 213 and 214 are configured to split a signal input from the in-phase input port 510 into equal-amplitude and in-phase sub-signals and to split a signal input from the inverting input port 520 into equal-amplitude and inverted sub-signals.

[0059] Optionally, the first direction and the second direction form a preset angle. Preferably, the first direction is arranged perpendicular to the second direction.

[0060] It can be understood that the first branch resonator 211 and the second branch resonator 212 are arranged opposite to each other along the first direction and are connected to the in-phase input port 510 and the inverting input port 520 respectively. This arrangement helps to achieve phase control and distribution of signals.

[0061] The third branch resonator 213 and the fourth branch resonator 214 are arranged relative to each other along the second direction, and are constructed to split the signal input from the in-phase input port 510 into equal-amplitude and in-phase sub-signals, and to split the signal input from the in-phase input port 520 into equal-amplitude and inverted sub-signals. This design enables the coupler to handle complex signal distribution and phase relationships.

[0062] When a signal is input from the in-phase input port 510 , the third branch resonator 213 and the fourth branch resonator 214 split the signal into sub-signals with equal amplitude and in-phase, so that the signals on the two output ports have the same amplitude and phase.

[0063] When a signal is input from the inverting input port 520 , the third branch resonator 213 and the fourth branch resonator 214 split the signal into sub-signals with equal amplitude and opposite phases. Thus, the signals on the two output ports have the same amplitude but opposite phases.

[0064] Specifically, the two input ports are respectively the in-phase input port 510 and the inverting input port 520, which are respectively located at two relative positions along the second direction. The two ports can be regarded as the "input pair" of the coupler. Accordingly, there are also two output ports along the second direction, which correspond to the input ports. When a signal enters from the input port, it passes through the coupler and is finally output from the output port.

[0065] It can be seen that by cleverly constructing the first branch resonator 211 and the second branch resonator 212 and their cooperative working relationship with the third and fourth branch resonators 214, the bidirectional transmission and phase adjustment functions of the signal are realized, and the flexibility and reconfigurability of the tunable cavity filter coupler are improved.

[0066] In some embodiments, in combination Figure 1 The feeding port 500 includes a first output port 530 and a second output port 540 , and the first output port 530 and the second output port 540 are connected to the third branch resonator 213 and the fourth branch resonator 214 , respectively.

[0067] The first branch resonator 211 or the second branch resonator 212 is configured to split the signal flowing from the first output port 530 to the second output port 540 into equal-amplitude and opposite-phase branch signals, and to split the signal flowing from the in-phase input port 510 to the opposite-phase input port 520 into equal-amplitude and opposite-phase branch signals.

[0068] Optionally, the signal flowing from the first output port 530 to the second output port 540 is an interference signal.

[0069] Thus, taking the first output port 530 and the second output port 540 as an example, when the interference signal at the first output port 530 flows to the second output port 540, the interference signal will be distributed to the first branch resonator 211 and the second branch resonator 212. It can be understood that due to the design of the resonators and the impedance matching, the distribution of the interference signal in the first branch resonator 211 and the second branch resonator 212 is equal in amplitude.

[0070] The first branch resonator 211 and the second branch resonator 212 are designed so that the signal generates a preset phase difference when passing through them, and the phase difference generated by the signal between the two is 180 degrees (i.e., anti-phase). The signal after phase adjustment continues to flow to the second output port 540, but because the two signals are of equal amplitude and anti-phase, when they are superimposed at the second output port 540, they will cancel each other, resulting in an output signal of zero or close to zero.

[0071] Likewise, when the interference signal at the in-phase input port 510 flows to the inverting input port 520 , or when the interference signal at the inverting input port 520 flows to the in-phase input port 510 , mutual cancellation will also be achieved.

[0072] This design can reduce or eliminate interference signals, thereby achieving signal isolation between the first output port 530 and the second output port 540 and between the in-phase input port 510 and the inverting input port 520 .

[0073] In this way, the present application can achieve good port matching and port isolation in various states. For example, in dual-band operation, the in-band isolation between the in-phase input port 510 and the inverting input port 520 is good (e.g., greater than 28dB, 33dB, etc.), and the return loss between the first output port 530 and the second output port 540 is good (e.g., greater than 14dB, 18dB, etc.). Good port characteristics help reduce signal reflection and crosstalk, and improve the performance of the communication system.

[0074] In some embodiments, in combination Figure 1 The four center-loaded branch resonators 210 each include a main body section 210a and a branch section 210b. It can be understood that each center-loaded branch resonator 210 is composed of a main body section 210a and a branch section 210b. This design helps to achieve preset electromagnetic performance and signal processing capabilities.

[0075] The main body sections 210a of the first branch resonator 211, the third branch resonator 213, and the fourth branch resonator 214 all extend in a straight line, and the branch sections 210b are located inside the corresponding main body sections 210a and vertically connected to the main body sections 210a. Among them, the straight line design of the main body sections 210a of the above three helps to maintain the continuity and stability of the signal, and is also convenient for connection with other circuit elements, while the layout design of the branch sections 210b helps to achieve local control and phase fine-tuning of the signal, ensuring that each branch signal maintains an accurate phase relationship during transmission, thereby improving the performance and reliability of the overall system.

[0076] The branch section 210b of the second branch resonator 212 is located outside the corresponding main section 210a. This design is used to achieve a specific phase relationship or signal distribution requirement. For example, when the signal passes through the second branch resonator 212, the outer layout of the branch section 210b can effectively adjust the signal phase to ensure that it forms an anti-phase effect with the branch signal generated by the first branch resonator 211.

[0077] For example, when the interference signal is transmitted to the second branch resonator 212 and the first branch resonator 211, the signal will be divided into two equal-amplitude and opposite-direction components, thereby canceling each other out, effectively reducing the impact of the interference signal and improving the overall performance. Through the layout design of the center-loaded branch resonator 210, not only the efficient transmission of the signal and the precise phase control are achieved, but also the anti-interference ability is significantly improved.

[0078] In addition, the synergistic effect of each branch resonator further optimizes the signal transmission efficiency and ensures stable operation in a high-frequency environment.

[0079] In some embodiments, in combination Figure 1 Each main segment 210a has two ends formed with bending portions 210c parallel to the diagonal lines of the square.

[0080] This design increases the electrical length of the main section 210a, which helps to adjust the resonant frequency of the resonator. In addition, the bend 210c can also affect the phase response of the signal. By adjusting the position and shape of the bend 210c, the phase balance and phase stability of the coupler can be optimized.

[0081] Specifically, in actual operation, the parameters of the bending portion 210c can be adjusted to achieve precise control of performance indicators such as the resonant frequency, bandwidth, and phase response, thereby improving the flexibility of the tunable cavity filter coupler.

[0082] In some embodiments, in combination Figure 1 The varactor diode 400 includes a first varactor diode 410. The first varactor diode 410 may be a branch-loaded varactor diode. Optionally, the model of the first varactor diode 410 may be SMV1413.

[0083] The first varactor diode 410 is disposed at one end of the branch segment 210b away from the main segment 210a, and a current limiting resistor 600 and a DC blocking capacitor 700 are further disposed between the first varactor diode 410 and the bias circuit 300. Optionally, the resistance value of the current limiting resistor 600 may be 100 kilo-ohms. Optionally, the capacitance value of the DC blocking capacitor 700 may be 100 pF.

[0084] The designed capacitance diode changes the capacitance value by adjusting the bias voltage, thereby accurately controlling the resonant frequency and phase response, and further optimizing the performance of the bias circuit 300 by adjusting the parameters of the current limiting resistor 600 and the DC blocking capacitor 700.

[0085] Exemplarily, when the first varactor diode 410 is adjusted, the upper passband will be mainly affected, such as making the upper passband frequency range wider, thereby improving the overall frequency band utilization.

[0086] It is understandable that the main purpose of providing the current limiting resistor 600 between the first varactor diode 410 and the bias circuit 300 is to protect the first varactor diode 410 from the impact of excessive current. When the bias voltage changes, the current limiting resistor 600 can limit the current passing through the first varactor diode 410 to prevent it from being damaged due to overheating.

[0087] The function of the DC blocking capacitor 700 is to isolate the AC signal (i.e., the RF signal) from the DC bias voltage, allowing the RF signal to pass smoothly while preventing the DC bias voltage from interfering with the RF circuit. In this way, it can be ensured that the first varactor diode 410 can maintain its tuning function without affecting the RF performance of the tunable cavity filter coupler.

[0088] Thus, by changing the bias voltage, the capacitance value of the first varactor diode 410 can be changed, thereby adjusting the resonant frequency of the coupler, and the tuning function can enable the tunable cavity filter coupler to adapt to different frequency bands and bandwidth requirements. In addition, the design of the current limiting resistor 600 and the DC blocking capacitor 700 protects the first varactor diode 410 from damage, and also ensures that the RF performance of the tunable cavity filter coupler is not interfered by the DC bias voltage.

[0089] In some examples, the DC voltage first passes through the current limiting resistor 600 and then is grounded through a reverse-connected varactor diode 400 . Meanwhile, a DC blocking capacitor 700 is provided on one side of the varactor diode 400 to prevent the DC signal from entering the bias circuit 300 .

[0090] When the varactor diode 400 operates in the reverse breakdown region, it can be equivalent to an adjustable capacitor. When the bias voltage increases, the equivalent capacitance decreases. Based on this principle, the equivalent capacitance can be changed by changing the bias voltage, thereby changing the electrical structure of the entire circuit.

[0091] In some embodiments, in combination Figure 1 The varactor diode 400 further includes a second varactor diode 420. The second varactor diode 420 may be a varactor diode loaded at both ends. Optionally, the model of the second varactor diode 420 may be SMV1237.

[0092] The second varactor diode 420 is disposed at the free end of the bent portion 210c of the main body segment 210a. This layout design enables the second varactor diode 420 to directly affect the electromagnetic performance of the main body segment 210a, thereby further adjusting the resonant frequency and phase response of the coupler. By accurately adjusting the bias voltage of the second varactor diode 420, more precise resonant frequency and phase control can be achieved.

[0093] Exemplarily, when the second varactor diode 420 is adjusted, both the upper passband and the lower passband are greatly affected, thereby optimizing the overall frequency band performance.

[0094] By introducing the second varactor diode 420, the tuning capability of the coupler is further enhanced, and more precise control of the resonant frequency and phase response of the tunable cavity filter coupler can be achieved by simultaneously adjusting the capacitance values ​​of the first varactor diode 410 and the second varactor diode 420.

[0095] Optionally, similar to the first varactor diode 410, a current limiting resistor 600 and a DC blocking capacitor 700 are also provided between the second varactor diode 420 and the bias circuit 300, thereby protecting the second varactor diode 420 from damage and ensuring that the RF performance of the tunable cavity filter coupler is not interfered by the DC bias voltage.

[0096] In some embodiments, in combination Figure 1 The varactor diode 400 includes a third varactor diode 430. The third varactor diode 430 may be a middle-loaded varactor diode. Optionally, the model of the third varactor diode 430 may be SMV1413.

[0097] The third varactor diode 430 is disposed between two circumferentially adjacent feeding ports 500. This layout design enables the third varactor diode 430 to directly affect the electromagnetic coupling between the two feeding ports 500 to further adjust the performance of the coupler. By introducing the third varactor diode 430, the coupling strength between the feeding ports 500 can be more accurately controlled. In addition, it is also helpful to optimize the bandwidth and frequency response of the tunable cavity filter coupler. By adjusting its capacitance value, fine adjustment of the operating frequency band of the tunable cavity filter coupler can be achieved.

[0098] Exemplarily, when the third varactor diode 430 is adjusted, the lower passband will be mainly affected, such as making the lower passband frequency range wider, thereby improving the overall frequency band utilization.

[0099] Optionally, similar to the first varactor diode 410 and the second varactor diode 420, a current limiting resistor 600 and a DC blocking capacitor 700 may be provided between the third varactor diode 430 and the bias circuit 300. In this way, the varactor diode 400 is protected from damage and the RF performance of the tunable cavity filter coupler is ensured not to be interfered by the DC bias voltage.

[0100] In some embodiments, in combination Figure 1 The varactor diode 400 further includes: a tap varactor diode 440, which is disposed at the feeding port 500; and a grounding varactor diode 450, which is disposed at the feeding port 500 and is used for grounding.

[0101] Optionally, the model of the tap varactor diode 440 may be SMV1255. Optionally, the model of the grounding varactor diode 450 may be SMV1247.

[0102] The tapped varactor diode 440 and the grounded varactor diode 450 are connected in series, one of the tapped varactor diode 440 and the grounded varactor diode 450 is arranged along a first direction, and the other is arranged along a second direction.

[0103] It can be understood that the tapped varactor diode 440 can change the electromagnetic characteristics at the feeding port 500 by adjusting the capacitance value, thereby affecting the overall performance of the coupler. The grounded varactor diode 450 is mainly used for grounding. By adjusting its capacitance value, the coupling to the ground can be adjusted, which further affects the performance of the tunable cavity filter coupler.

[0104] Optionally, the tapped varactor diode 440 and the grounded varactor diode 450 may be arranged vertically. This design improves the utilization of the installation space, increases the compactness, and can also reduce the electromagnetic interference between the two, thereby ensuring the stable performance of the tunable cavity filter coupler.

[0105] It can be seen that the synergistic effect of the tapped varactor diode 440 and the grounded varactor diode 450 enables the two to act together on the feeding port 500 to independently adjust the external coupling of the upper passband or the lower passband.

[0106] As described above, by properly designing the first varactor diode 410 , the second varactor diode 420 , the third varactor diode 430 , the tap varactor diode 440 , and the grounded varactor diode 450 , the upper passband and the lower passband are independently adjustable.

[0107] In some examples, combined Figure 2 and Figure 3 , Figure 2 This is a schematic diagram of the change state of the center frequency of the low frequency band in this application. Figure 3 Schematic diagram of the change of the center frequency of the higher frequency band in this application. Among them, S11 is the return loss of the filter coupler, and S21 and S31 are the insertion losses.

[0108] It can be seen that the present application realizes that the center frequency of the low frequency band can be varied in the range of 0.3-0.5 GHz, and the center frequency of the higher frequency band can be varied in the range of 0.82-1.04 GHz, and during the tuning process, the two frequency bands can be tuned independently, as shown in reference Figure 2 , the lower passband can be tuned in the range of 0.3-0.5GHz, and the upper passband can be tuned in the range of 0.82-1.04GHz.

[0109] Optionally, a grounding hole 900 is further provided on the dielectric substrate 100 to achieve grounding and improve the safety factor.

[0110] In addition, the second aspect of the present application also provides an antenna device, including the tunable cavity filter coupler in any of the above embodiments.

[0111] The third aspect of the present application also provides a communication device, including the antenna device in the above embodiment.

[0112] The antenna device and communication equipment provided by the present application, by setting the above-mentioned tunable cavity filter coupler, introduce a varactor diode 400 and a bias circuit 300, so that the coupler has high flexibility and can be optimized for different application scenarios. The response characteristics of the coupler can also be changed in real time by adjusting the bias voltage, so that it can adapt to different frequency bands, bandwidths, phase shifts or power distribution requirements. In addition, through precise design and optimization, the coupler can achieve high performance indicators such as low loss, high isolation and good phase balance. In this way, by introducing the varactor diode 400 and the bias circuit 300, the problem of fixed filter coupler response in the traditional Rat-Race coupler is solved, and the high performance, reconfigurability and high flexibility design of the antenna device and communication equipment are achieved.

[0113] The present application can obtain good port matching and port isolation in multiple states. For example, in dual-band operation, the in-band isolation between the in-phase input port 520 and the inverting input port 520 is good (e.g., greater than 28dB, 33dB, etc.), and the return loss between the first output port 530 and the second output port 540 is good (e.g., greater than 14dB, 18dB, etc.). Compared with the prior art, good port characteristics help to reduce signal reflections and crosstalk, and improve the performance of the communication system.

[0114] In addition, there are multiple transmission zeros between the two passbands and outside the passbands, which brings high frequency selectivity. Compared with some filter couplers with poor frequency selectivity in the prior art, this high frequency selectivity helps to better filter out unnecessary frequency components and improve signal purity and communication quality.

[0115] It can be seen that the present application realizes a good reconfigurable filtering power allocation response, has the advantages of flexible and adjustable center frequency, good phase and amplitude characteristics, high in-band isolation, and can be expanded to other orders of multi-mode or multi-frequency situations, and is expected to be widely used in the field of mobile communications.

[0116] It should be noted that the plate model of the dielectric substrate 100 and the model of each varactor diode 400 mentioned above are all implementable examples and can also be replaced with other models. However, it should be noted that in actual operation, after replacing the plate model or the model of each varactor diode 400, the structural parameters of each device need to be readjusted to meet the required tuning range and application requirements.

[0117] Finally, it should be noted that those skilled in the art will readily conceive of other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses or adaptations of the present invention, which follow the general principles of the present invention and include common knowledge or customary technical means in the art not disclosed by the present invention, are not limited to the precise structure described above and shown in the drawings, and may be modified and changed in various ways without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A tunable cavity filter coupler, characterized in that: include: A dielectric substrate (100) comprising a base layer (110) and a metal layer provided on at least one surface of the base layer (110), the metal layer being provided with an annular coupler (200) and a bias circuit (300), wherein the annular coupler (200) comprises four center-loaded branch resonators (210) sequentially distributed along a circumferential direction, each of the center-loaded branch resonators (210) being connected to a variable capacitance diode (400), and the metal layer further comprising a feeding port (500) corresponding to and connected to the center-loaded branch resonators (210) in a one-to-one manner; The bias circuit (300) is arranged around the outer periphery of the annular coupler (200), and the bias circuit (300) is electrically connected to the varactor diode (400).

2. The tunable cavity filter coupler according to claim 1, characterized in that: The four center-loaded branch resonators (210) include a first branch resonator (211) and a second branch resonator (212) arranged opposite to each other along a first direction, and a third branch resonator (213) and a fourth branch resonator (214) arranged opposite to each other along a second direction. The feeding port (500) connected to the first branch resonator (211) is an in-phase input port (510), and the feeding port (500) connected to the second branch resonator (212) is an in-phase input port (520). The third branch resonator (213) and the fourth branch resonator (214) are configured to split a signal input from the in-phase input port (510) into equal-amplitude and in-phase sub-signals, and to split a signal input from the inverting input port (520) into equal-amplitude and inverted sub-signals.

3. The tunable cavity filter coupler according to claim 2, characterized in that: The feeding port (500) comprises a first output port (530) and a second output port (540), wherein the first output port (530) and the second output port (540) are respectively connected to a third branch resonator (213) and a fourth branch resonator (214), The first branch resonator (211) and the second branch resonator (212) are constructed to split the signal flowing from the first output port (530) to the second output port (540) into equal-amplitude and inverted sub-signals, and to split the signal flowing from the in-phase input port (510) to the inverted input port (520) into equal-amplitude and inverted sub-signals.

4. The tunable cavity filter coupler according to claim 2, characterized in that: The four center-loaded branch resonators (210) each comprise a main body section (210a) and a branch section (210b); the main body sections (210a) of the first branch resonator (211), the third branch resonator (213), and the fourth branch resonator (214) each extend in a straight line, and the branch sections (210b) are located inside the corresponding main body sections (210a) and are vertically connected to the main body sections (210a). The branch section (210b) of the second branch resonator (212) is located outside the corresponding main section (210a).

5. The tunable cavity filter coupler according to claim 4, characterized in that: Both ends of each main body segment (210a) are respectively formed with a bending portion (210c) parallel to the diagonal line of the square.

6. The tunable cavity filter coupler according to claim 5, characterized in that: The varactor diode (400) comprises a first varactor diode (410), the first varactor diode (410) being arranged at an end of the branch segment (210b) away from the main segment (210a), and a current limiting resistor (600) and a DC blocking capacitor (700) being arranged between the first varactor diode (410) and the bias circuit (300).

7. The tunable cavity filter coupler according to claim 6, characterized in that: The varactor diode (400) further comprises a second varactor diode (420), wherein the second varactor diode (420) is arranged at the free end of the bent portion of the main body section (210a).

8. The tunable cavity filter coupler according to claim 6, characterized in that: The varactor diode (400) comprises a third varactor diode (430), wherein the third varactor diode (430) is arranged between two circumferentially adjacent feeding ports (500).

9. The tunable cavity filter coupler according to claim 8, characterized in that: The varactor diode (400) further comprises: A tapped varactor diode (440), arranged at the feeding port (500); A grounding varactor diode (450), provided at the feeding port (500) and used for grounding; The tapped varactor diode (440) and the grounded varactor diode (450) are connected in series; one of the tapped varactor diode (440) and the grounded varactor diode (450) is arranged along a first direction, and the other is arranged along a second direction.

10. An antenna device, characterized in that: include: The tunable cavity filter coupler according to any one of claims 1 to 9.

11. A communication device, characterized in that: The invention comprises the antenna device as claimed in claim 10.

Images