A compact broadband switching circuit and radio frequency front end

Abstract

The present invention relates to a compact broadband switching circuit and a radio frequency front end, comprising: a first radio frequency end, a plurality of inductors, a plurality of dual-gate switch modules, a second radio frequency end, and a control unit; wherein the first radio frequency end, the plurality of inductors, and the second radio frequency end are connected in sequence; a dual-gate switch module is provided between two adjacent inductors of the plurality of inductors, a first dual-gate switch module of the plurality of dual-gate switch modules is provided between the first radio frequency end and a first inductor of the plurality of inductors, and a last dual-gate switch module of the plurality of dual-gate switch modules is provided between the second radio frequency end and a last inductor of the plurality of inductors; the plurality of dual-gate switch modules are further electrically connected to the control unit to synchronously turn on or off in response to a control signal sent by the control unit to switch the passage path of the radio frequency signal flowing in from the first radio frequency end. The present invention can ensure signal transmission quality, reduce the degree of leakage of high-frequency signals, and reduce chip manufacturing costs.

Description

Technical Field

[0001] The present invention belongs to the technical field of radio frequency microwave integrated circuits, and in particular relates to a compact broadband switching circuit and a radio frequency front end. Background Art

[0002] In recent years, wireless communication technology has made significant progress. With the multifunctionalization of communication terminals, a single device often needs to support multiple communication standards. At the same time, the miniaturization trend of communication equipment has led to the widespread use of RF front-end modules in mobile communication equipment. As a key part of phased array radar and 5G communication systems, RF front-end modules have received widespread attention and research. As a key circuit module in the RF front-end module, the RF switch is mainly used to realize the mutual switching of information between channels. It plays a vital role in the functional realization of the RF front-end module and the entire communication system. As the most basic control unit, the insertion loss of the switch directly affects the noise figure of the receiving end and the efficiency of the transmitting end, and the isolation affects the degree of interference between channels. With the development of communication technologies such as 5G, the switch also needs to meet many requirements of miniaturization and high power.

[0003] However, existing RF switching circuits have difficulty in meeting the requirements of reducing switch insertion loss, wide bandwidth, and small size. Summary of the Invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a compact broadband switching circuit and radio frequency front end. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0005] In a first aspect, the present invention provides a compact broadband switching circuit, comprising: a first RF terminal, a plurality of inductors, a plurality of dual-gate switch modules, a second RF terminal, and a control unit; wherein the first RF terminal, the plurality of inductors, and the second RF terminal are connected in sequence; a dual-gate switch module is disposed between two adjacent inductors of the plurality of inductors, and a first dual-gate switch module of the plurality of dual-gate switch modules is disposed between the first RF terminal and a first inductor of the plurality of inductors, and a last dual-gate switch module of the plurality of dual-gate switch modules is disposed between the second RF terminal and a last inductor of the plurality of inductors; one end of each dual-gate switch module is grounded; the plurality of dual-gate switch modules are further electrically connected to the control unit and configured to be synchronously turned on or off in response to a control signal sent by the control unit, so that RF signals within a preset frequency range flowing from the first RF terminal pass through the plurality of dual-gate switch modules or through the second RF terminal; wherein when the plurality of dual-gate switch modules are in the off state, the plurality of inductors and the plurality of dual-gate switch modules form a multi-order low-pass filter network.

[0006] In some embodiments, each dual-gate switch module includes: Q dual-gate switch tubes and an RC resonant network, where Q is a positive integer; a bias resistor is connected between each of the Q dual-gate switch tubes and an output end of the control unit; the source and drain of adjacent dual-gate switch tubes in the Q dual-gate switch tubes are connected in sequence, wherein the drain of the first dual-gate switch tube in the Q dual-gate switch tubes is connected to the output end of the first RF end or the output ends of the several inductors, the source of the Qth dual-gate switch tube in the Q dual-gate switch tubes is connected to the first end of the RC resonant network, and the second end of the RC resonant network is grounded.

[0007] In some embodiments, the compact broadband switching circuit further includes: a plurality of inductors; each inductor is disposed between adjacent dual-gate switch modules among the plurality of dual-gate switch modules.

[0008] In some embodiments, the control signal includes: a high-level signal and a low-level signal; when the control signal is the high-level signal, the plurality of dual-gate switch modules are synchronously turned on, and the RF signal is grounded via the first RF end, the plurality of inductors, and the plurality of dual-gate switch modules; when the control signal is the low-level signal, the plurality of dual-gate switch modules are synchronously turned off, and the RF signal flows out via the first RF end, the plurality of inductors, and the second RF end.

[0009] In some embodiments, each RC resonant network includes: a capacitor and a resistor in parallel, the first end of the capacitor and the first end of the resistor are connected to the source of the Qth dual-gate switch tube, and the second end of the capacitor and the second end of the resistor are grounded.

[0010] In some embodiments, the plurality of dual-gate switch modules include: a first dual-gate switch module, a second dual-gate switch module, and a third dual-gate switch module; the plurality of inductors include: an inductor L1 and an inductor L2; one end of the first dual-gate switch module is connected between the first RF terminal and the inductor L1, one end of the second dual-gate switch module is connected between the inductor L1 and the inductor L2, and one end of the third dual-gate switch module is connected between the inductor L2 and the second RF terminal; the other end of the first dual-gate switch module, the other end of the second dual-gate switch module, and the other end of the third dual-gate switch module are grounded.

[0011] In some embodiments, the dual-gate switch tubes in the first dual-gate switch module and the third dual-gate switch module have the same size, and the dual-gate switch tube in the second dual-gate switch module has a larger size than the dual-gate switch tube in the first dual-gate switch module.

[0012] In some embodiments, the RC resonant network in the first dual-gate switch module and the third dual-gate switch module is the same.

[0013] In some embodiments, each of the plurality of inductors is a microstrip inductor, a stripline inductor, or a spiral inductor.

[0014] In some embodiments, the Q dual-gate switch transistors in each dual-gate switch module are one of field effect transistors, high electron mobility transistors, mHEMTs, and pHEMT transistors.

[0015] In a second aspect, the present invention further provides a radio frequency front end, which includes a radio frequency switching circuit, and the radio frequency switching circuit is the compact broadband switching circuit described in the first aspect above.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] In response to the problem that existing RF switching circuits are difficult to balance the requirements of reducing the insertion loss of the switch and small size, the present invention proposes a compact broadband switching circuit and RF front-end. By setting a number of dual-gate switch modules between two RF ends, the circuit can improve chip space utilization and realize a compact circuit design; and the number of dual-gate switch modules can be synchronously turned on or off in response to a control signal. When the number of dual-gate switch modules are synchronously turned off in response to the control signal sent by the control unit, the multiple dual-gate switch modules are equivalent to capacitors, which form a multi-order low-pass filter network with multiple inductors connected in series between the two RF ends. The low-pass filter network can process RF signals in an ultra-wideband range while ensuring the overall power capacity of the circuit and reducing the insertion loss of the switch, thereby ensuring signal transmission quality, reducing the leakage of high-frequency signals, having smaller insertion loss and better on-state standing wave, and reducing chip manufacturing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 1 is a schematic structural diagram of a compact broadband switching circuit provided by an embodiment of the present invention;

[0019] Figure 2 is a circuit connection example diagram of a compact broadband switching circuit provided by an embodiment of the present invention;

[0020] Figure 3 is an example diagram of a compact broadband switching circuit provided by an embodiment of the present invention;

[0021] Figure 4 yes Figure 3 A simulation example diagram showing how the circuit power compression of multiple dual-gate switch modules in the on-state varies with input power;

[0022] Figure 5 yes Figure 3 Simulation example diagram of the change of S21 parameters and S11 parameters of multiple dual-gate switch modules in the on state with the frequency of the input signal;

[0023] Figure 6 yes Figure 3 An example diagram of the simulation of the change of S21 parameters of multiple dual-gate switch modules in the off state with the frequency of the input signal. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0025] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0026] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0027] A compact broadband switching circuit and a radio frequency front end proposed in an embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[0028] Figure 1 FIG is a schematic diagram of the structure of a compact broadband switching circuit provided by an embodiment of the present invention. Figure 1As shown, the compact broadband switching circuit includes: a first radio frequency terminal RF1, a plurality of inductors, a plurality of dual-gate switch modules, a second radio frequency terminal RF2, and a control unit; wherein the first radio frequency terminal RF1, the plurality of inductors, and the second radio frequency terminal RF2 are connected in sequence; a dual-gate switch module is disposed between two adjacent inductors among the plurality of inductors, and a first dual-gate switch module among the plurality of dual-gate switch modules is disposed between the first radio frequency terminal RF1 and a first inductor among the plurality of inductors, and a last dual-gate switch module among the plurality of dual-gate switch modules is disposed between the second radio frequency terminal RF2 and a last inductor among the plurality of inductors; one end of each dual-gate switch module is grounded; the plurality of dual-gate switch modules are further electrically connected to the control unit and configured to be synchronously turned on or off in response to a control signal sent by the control unit, so that radio frequency signals within a preset frequency range flowing from the first radio frequency terminal RF1 pass through the plurality of dual-gate switch modules or through the second radio frequency terminal RF2; wherein, when the plurality of dual-gate switch modules are in the off state, the plurality of inductors and the plurality of dual-gate switch modules form a multi-order low-pass filter network.

[0029] Exemplarily, the number of dual-gate switch modules is N, the number of inductors is N-1, the first RF terminal RF1, N-1 inductors and the second RF terminal RF2 are connected in series, N dual-gate switch modules are connected in parallel between the first RF terminal RF1 and the second RF terminal RF2, and a dual-gate switch module is arranged between two adjacent inductors, and one end of each dual-gate switch module is grounded.

[0030] By connecting several dual-gate switch modules in parallel between the two RF ends, broadband characteristics can be achieved. Compared with the traditional series-parallel structure, the parasitic capacitance introduced by several dual-gate switch modules in the off state is smaller, which can effectively reduce the insertion loss of the switching circuit.

[0031] Figure 2 FIG. 1 is a circuit connection diagram of a compact broadband switching circuit provided by an embodiment of the present invention. Figure 2As shown, in a possible implementation, the plurality of dual-gate switch modules include: a first dual-gate switch module, a second dual-gate switch module, and a third dual-gate switch module; the plurality of inductors include: an inductor L1 and an inductor L2; one end of the first dual-gate switch module is connected between the first radio frequency terminal RF1 and the inductor L1, one end of the second dual-gate switch module is connected between the inductor L1 and the inductor L2, and one end of the third dual-gate switch module is connected between the inductor L2 and the second radio frequency terminal RF2; the other end of the first dual-gate switch module, the other end of the second dual-gate switch module, and the other end of the third dual-gate switch module are grounded. Furthermore, each dual-gate switch module includes: Q dual-gate switches and an RC resonant network, where Q is a positive integer; a bias resistor is connected between each of the Q dual-gate switches and an output terminal of a control unit; the source and drain of adjacent dual-gate switches in the Q dual-gate switches are connected in sequence, wherein the drain of a first dual-gate switch in the Q dual-gate switches is connected to the output terminal of a first radio frequency terminal RF1 or the output terminals of several inductors, the source of a Qth dual-gate switch in the Q dual-gate switches is connected to the first terminal of the RC resonant network, and the second terminal of the RC resonant network is grounded. By connecting the RC resonant network to the source of the Qth dual-gate switch, the source impedance can be reduced, thereby improving isolation.

[0032] Here, the dual-gate switching transistors in the first and third dual-gate switch modules are of the same size, while the dual-gate switching transistors in the second dual-gate switch module are larger than those in the first dual-gate switch module. Furthermore, the RC resonant networks in the first and third dual-gate switch modules are identical. This configuration significantly expands bandwidth while maintaining a certain power capacity.

[0033] Exemplarily, the first dual-gate switch module includes: Q dual-gate switch tubes M1 to M2 in cascade connection of source and drain. Q , and the capacitor C1 and resistor R1 in parallel, one end of the capacitor C1 is connected to M Q The second dual-gate switch module includes: Q source-drain cascaded dual-gate switch tubes M Q+1 ~M 2Q , and the capacitor C2 and resistor R2 in parallel, one end of the capacitor C2 is connected to M 2Q The source of the third dual-gate switch module includes: Q source-drain cascaded dual-gate switch tubes M 2Q+1 ~M 3Q , and the capacitor C3 and resistor R3 in parallel, one end of the capacitor C3 is connected to M 3Q The three dual-gate switch modules include bias resistors R4 to R 6Q .

[0034] In one possible implementation, each of the multiple inductors is a microstrip inductor, a stripline inductor, or a spiral inductor. Compared to quarter-wavelength transmission lines, which are large and difficult to miniaturize, using microstrip, stripline, or spiral inductors can reduce the required circuit area while maintaining the circuit's power capacity, effectively improving space utilization and reducing chip costs.

[0035] It should be noted that in Figure 2 When each dual-gate switch module includes Q dual-gate switches, the number of bias resistors corresponding to 3Q dual-gate switches is 6Q. The value and size of each bias resistor are equal, and the resistance range of each bias resistor is 5k-10k ohms. By setting a relatively large value for the bias resistor, the probability of RF signal leakage from the gate can be reduced, thereby reducing the loss of the entire circuit.

[0036] Here, the Q dual-gate switch tubes in each dual-gate switch module are all one of field effect transistors, high electron mobility transistors, mHEMTs, and pHEMT transistors. Compared with the effect of a single-gate transistor being equivalent to only one capacitor in the off state, the dual-gate switch tube can be equivalent to two series-connected off capacitors C in the off state. ds,off1 and C ds,off2 , and based on the off capacitor C ds,off1 and C ds,off2 The overall off-state capacitance of the device is significantly reduced, thereby making each dual-gate switch module equivalent to an equivalent capacitor. This equivalent capacitor can, together with multiple inductors connected between the first RF terminal RF1 and the second RF terminal RF2, form a CLC-...-C low-pass filter network. This low-pass filter network can process RF signals in an ultra-wideband range, reduce the degree of leakage of high-frequency signals, and have lower insertion loss and better on-state standing wave.

[0037] like Figure 2 As shown, each RC resonant network includes: a capacitor and a resistor connected in parallel, the first end of the capacitor and the first end of the resistor are connected to the source of the Qth dual-gate switch tube, and the second end of the capacitor and the second end of the resistor are grounded. In one possible implementation, the capacitor of the RC resonant network in each dual-gate switch module is one of a microstrip line capacitor, a metal-insulator-metal capacitor, a metal-oxide-metal capacitor, a flat plate capacitor, and an interdigital capacitor. By using the above capacitors, the introduced parasitic capacitance and parasitic inductance can be effectively reduced.

[0038] Here, the control signal generated by the control unit includes: a high-level signal and a low-level signal; when the control signal is a high-level signal, several dual-gate switch modules are turned on synchronously, and the RF signal is grounded through the first RF terminal RF1, several inductors and several dual-gate switch modules; when the control signal is a low-level signal, several dual-gate switch modules are turned off synchronously, and the RF signal flows out through the first RF terminal RF1, several inductors and the second RF terminal RF2.

[0039] In one possible implementation, the equivalent impedance Z corresponding to each RC resonant network is RC Expressed as:

[0040]

[0041] Where R is the resistance of the resistor in the RC resonant network, j is the imaginary unit, ω is the angular frequency, and C is the capacitance of the capacitor in the RC resonant network.

[0042] In a possible implementation, when each dual-gate switch module is turned on, the input impedance Z of the non-grounded terminal of each dual-gate switch module is on Expressed as:

[0043]

[0044] Among them, R on is the equivalent on-resistance of Q dual-gate transistors, R is the resistance of the resistor in the RC resonant network, j is the imaginary unit, ω is the angular frequency, and C is the capacitance of the capacitor in the RC resonant network.

[0045] In a possible implementation, when each dual-gate switch module is turned off, the input impedance Z of the non-grounded terminal of each dual-gate switch module is off Expressed as:

[0046]

[0047] Among them, R off is the equivalent off-resistance of Q dual-gate transistors, R is the resistance of the resistor in the RC resonant network, j is the imaginary unit, ω is the angular frequency, and C is the capacitance of the capacitor in the RC resonant network.

[0048] It should be understood that the non-grounded end of each dual-gate switch module can also be understood as the input impedance at the drain of the first dual-gate switch tube among the Q dual-gate switch tubes in a dual-gate switch module, or in other words, one end of each dual-gate switch module connected to the first RF end RF1 or the second RF end RF2.

[0049] By the equivalent impedance Z on and equivalent impedance Z off It can be seen from the expression that when several dual-gate switch modules are turned on, the equivalent impedance Zon The increase in the real part of the impedance can be ignored, and the imaginary part of the impedance is reduced, that is, the corresponding equivalent parasitic inductance is reduced, thereby increasing the off-state isolation of the switching circuit. When several dual-gate switch modules are turned off, the equivalent impedance Z off The increase in the real part of the impedance can be ignored, and the imaginary part of the impedance increases, that is, the corresponding equivalent parasitic capacitance decreases, and it is more difficult for high-frequency signals to leak from the dual-gate switch tube, effectively reducing the insertion loss of the switching circuit.

[0050] Figure 3 FIG is an example diagram of a compact broadband switching circuit provided by an embodiment of the present invention. Figure 3 As shown, in one possible implementation, the number of dual-gate switches in the first, second, or third dual-gate switch modules is one. The first dual-gate switch module includes a dual-gate switch module M1, the second dual-gate switch module includes a dual-gate switch module M2, and the third dual-gate switch module includes a dual-gate switch module M3. The dual-gate switch modules M1 and M3 have the same size, and the dual-gate switch module M2 is larger than both the dual-gate switch module M1 and the dual-gate switch module M3.

[0051] like Figure 3 As shown, the control signals generated by the control unit include signals Vctrl1, Vctrl2, and Vctrl3. Signal Vctrl1 controls the on / off state of the dual-gate switch module M1, signal Vctrl2 controls the on / off state of the dual-gate switch module M2, and control the on / off state of the dual-gate switch module M3. When signals Vctrl1, Vctrl2, and Vctrl3 are all high-level signals, the dual-gate switch modules M1, M2, and M3 are turned on. When signals Vctrl1, Vctrl2, and Vctrl3 are all low-level signals, the dual-gate switch modules M1, M2, and M3 are turned off. Among them, when the dual-gate switch module M1, the dual-gate switch module M2 and the dual-gate switch module M3 are turned off, they are equivalent to equivalent capacitors C11, equivalent capacitors C22 and equivalent capacitors C33. The three equivalent capacitors and the inductor L1 and the inductor L2 together form a fifth-order low-pass filter network in the form of CLCLC, which greatly expands the bandwidth and realizes the passband characteristics of the low-pass filter.

[0052] Corresponding to the compact broadband switching circuit proposed in the present invention, the present invention also provides a radio frequency front end, which includes a radio frequency switching circuit, which is the compact broadband switching circuit proposed in the present invention. The compact broadband switching circuit proposed in the present invention can switch the path of radio frequency signals. It should be noted that this radio frequency front end is an radio frequency front end for use in wireless communication systems. The embodiments of the present invention do not limit the type of radio frequency front end.

[0053] In response to the problem that existing RF switching circuits are difficult to balance the requirements of reducing the insertion loss of the switch and small size, the present invention proposes a compact broadband switching circuit. By setting a number of dual-gate switch modules between two RF ends, the circuit can improve chip space utilization and realize a compact circuit design; and the number of dual-gate switch modules can be synchronously turned on or off in response to a control signal. When the number of dual-gate switch modules are synchronously turned off in response to the control signal sent by the control unit, the multiple dual-gate switch modules are equivalent to capacitors, which form a multi-order low-pass filter network with multiple inductors connected in series between the two RF ends. The low-pass filter network can process RF signals in an ultra-wideband range while ensuring the overall power capacity of the circuit and reducing the insertion loss of the switch, thereby ensuring signal transmission quality, reducing the leakage of high-frequency signals, having smaller insertion loss and better on-state standing wave, and reducing chip manufacturing costs.

[0054] In order to verify the technical effect of the compact broadband switching circuit proposed in this invention, ADS software is used to Figure 3 The compact broadband switching circuit in the simulation was simulated. The core circuit size of this compact broadband switching circuit is less than 0.3 square millimeters. Specifically, the simulation frequency was set to 40 GHz, the input power sweep range was 0 dBm to 50 dBm, the S-parameter frequency sweep range was 0 GHz to 60 GHz, and the DC bias voltage was -28 V. Figure 4 The embodiment of the present invention provides Figure 3 A simulation example diagram showing how the circuit power compression of multiple dual-gate switch modules in the on-state changes with input power. Figure 5 The embodiment of the present invention provides Figure 3 An example of a simulation of the changes in the S21 and S11 parameters of multiple dual-gate switch modules in the on state following the frequency of the input signal. Figure 6 The embodiment of the present invention provides Figure 3 An example simulation diagram of the S21 parameters of multiple dual-gate switch modules in the off state changing with the frequency of the input signal.

[0055] like Figure 4 As shown, the circuit power compression is expressed as P01db in dB, while the input power is expressed as Pin in dBm. When Pin is 46.5dBm, P01db increases by only 0.123dB. This minimal loss is achieved when handling input powers that are very high for RF switches, demonstrating the significant power advantages of the compact broadband switching circuit proposed in this invention.

[0056] like Figure 5As shown in the figure, in the on state, when the frequency (freq) of the input signal is 1 GHz, the corresponding insertion loss (S21 parameter) is 0.105, and the input return loss (S11 parameter) is 38.947. Moreover, in the frequency range of 0 GHz-40 GHz, the S21 parameter is greater than -1.218 dB, and the S11 parameter is less than -25.689 dB, indicating that the compact broadband switching circuit proposed in the present invention has extremely small insertion loss and on-state return loss, which can ensure the transmission quality of the signal.

[0057] like Figure 6 As shown, in the off state, when the frequency of the input signal is 1 GHz, the corresponding S21 parameter is 20.266; when the frequency of the input signal is 24.3 GHz, the corresponding S21 parameter is 30.152; when the frequency of the input signal is 40 GHz, the corresponding S21 parameter is 28.44, and, in the frequency range of 0 GHz-40 GHz, the S21 parameter is less than 20.266, indicating that the compact broadband switching circuit proposed in the present invention can effectively improve the circuit isolation.

[0058] Combine Figures 4 to 6 It can be seen that the compact broadband switching circuit proposed in the present invention not only occupies a very small chip area, but also achieves low loss, high power, high isolation and excellent on-state standing wave characteristics in the frequency range of 0GHz-40GHz, and is suitable for high-efficiency, high-power, ultra-wideband RF front-end systems.

[0059] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A compact broadband switching circuit, characterized in that: include: A first RF terminal, a plurality of inductors, a plurality of dual-gate switch modules, a second RF terminal, and a control unit; wherein the first RF terminal, the plurality of inductors, and the second RF terminal are connected in sequence; a dual-gate switch module is disposed between two adjacent inductors of the plurality of inductors, and a first dual-gate switch module of the plurality of dual-gate switch modules is disposed between the first RF terminal and a first inductor of the plurality of inductors, and a last dual-gate switch module of the plurality of dual-gate switch modules is disposed between the second RF terminal and a last inductor of the plurality of inductors; one end of each dual-gate switch module is grounded; the plurality of dual-gate switch modules are further electrically connected to the control unit and configured to be synchronously turned on or off in response to a control signal sent by the control unit, so that RF signals within a preset frequency range flowing from the first RF terminal pass through the plurality of dual-gate switch modules or through the second RF terminal; wherein when the plurality of dual-gate switch modules are in the off state, the plurality of inductors and the plurality of dual-gate switch modules form a multi-order low-pass filter network.

2. The compact broadband switching circuit according to claim 1, characterized in that: Each dual-gate switch module includes: Q dual-gate switch tubes and an RC resonant network, where Q is a positive integer; A bias resistor is connected between each of the Q dual-gate switching tubes and an output terminal of the control unit; The sources and drains of adjacent dual-gate switching tubes in the Q dual-gate switching tubes are connected in sequence, wherein the drain of the first dual-gate switching tube in the Q dual-gate switching tubes is connected to the output end of the first RF end or the output ends of the several inductors, the source of the Qth dual-gate switching tube in the Q dual-gate switching tubes is connected to the first end of the RC resonant network, and the second end of the RC resonant network is grounded.

3. The compact broadband switching circuit according to claim 1, characterized in that: The control signal includes: a high level signal and a low level signal; When the control signal is the high level signal, the plurality of dual-gate switch modules are synchronously turned on, and the radio frequency signal is grounded via the first radio frequency terminal, the plurality of inductors, and the plurality of dual-gate switch modules; When the control signal is the low-level signal, the plurality of dual-gate switch modules are synchronously turned off, and the radio frequency signal flows out through the first radio frequency end, the plurality of inductors, and the second radio frequency end.

4. The compact broadband switching circuit according to claim 2, characterized in that: Each RC resonant network includes: a capacitor and a resistor connected in parallel, the first end of the capacitor and the first end of the resistor are connected to the source of the Qth dual-gate switch tube, and the second end of the capacitor and the second end of the resistor are grounded.

5. The compact broadband switching circuit according to claim 2, characterized in that: The plurality of dual-gate switch modules include: a first dual-gate switch module, a second dual-gate switch module and a third dual-gate switch module; the plurality of inductors include: an inductor L1 and an inductor L2; one end of the first dual-gate switch module is connected between the first RF terminal and the inductor L1, one end of the second dual-gate switch module is connected between the inductor L1 and the inductor L2, and one end of the third dual-gate switch module is connected between the inductor L2 and the second RF terminal; the other end of the first dual-gate switch module, the other end of the second dual-gate switch module and the other end of the third dual-gate switch module are grounded.

6. The compact broadband switching circuit according to claim 5, characterized in that: The dual-gate switch tubes in the first and third dual-gate switch modules have the same size, and the dual-gate switch tube in the second dual-gate switch module has a larger size than that of the dual-gate switch tube in the first dual-gate switch module.

7. The compact broadband switching circuit according to claim 5, characterized in that: The RC resonant network in the first double-gate switch module and the third double-gate switch module is the same.

8. The compact broadband switching circuit according to claim 1, characterized in that: Each of the plurality of inductors is a microstrip inductor, a stripline inductor or a spiral inductor.

9. The compact broadband switching circuit according to claim 2, characterized in that: The Q dual-gate switch tubes in each dual-gate switch module are one of field effect transistors, high electron mobility transistors, mHEMTs and pHEMT transistors.

10. A radio frequency front end, characterized in that: The RF front end includes a RF switching circuit, and the RF switching circuit is a compact broadband switching circuit according to any one of claims 1 to 9.

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