Compact broadband switch circuit and radio frequency front end

Abstract

The invention relates to a compact broadband switch circuit and a radio frequency front end. The compact broadband switch circuit comprises a first radio frequency end, a plurality of inductors, a plurality of double-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 double-gate switch module is arranged between two adjacent inductors in the plurality of inductors, and a first double-gate switch module in the plurality of double-gate switch modules is arranged between the first radio frequency end and a first inductor in the plurality of inductors. The last double-gate switch module in the plurality of double-gate switch modules is arranged between the second radio frequency end and the last inductor in the plurality of inductors; and the plurality of double-gate switch modules are also electrically connected with the control unit so as to respond to a control signal sent by the control unit to be synchronously switched on or switched off so as to switch a passing path of a radio frequency signal flowing in from the first radio frequency end. According to the invention, the signal transmission quality can be ensured, the leakage degree of a high-frequency signal is reduced, and the chip manufacturing cost is reduced.

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 application 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, which 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 coefficient 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 switch circuits have difficulty in meeting the requirements of reducing switch insertion loss, large 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 a radio frequency front end. The technical problem to be solved by the present invention is achieved by the following technical solutions:

[0005] In a first aspect, the present invention provides a compact broadband switching circuit, comprising: a first RF end, a plurality of inductors, a plurality of dual-gate switch modules, a second RF end and a control unit; wherein the first RF end, the plurality of inductors and the second RF end are connected in sequence; a dual-gate switch module is arranged 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 arranged between the first RF end and the first inductor among the plurality of inductors, and a last dual-gate switch module among the plurality of dual-gate switch modules is arranged between the second RF end and the 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 also electrically connected to the control unit, and are used to be synchronously turned on or off in response to a control signal sent by the control unit, so that the RF signal within a preset frequency range flowing from the first RF end passes through the plurality of dual-gate switch modules or through the second RF end, 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 constitute 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 switch 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 sizes of the dual-gate switch tubes in the first dual-gate switch module and the third dual-gate switch module are the same, and the size of the dual-gate switch tube in the second dual-gate switch module is larger than the size of the dual-gate switch tube in the first dual-gate switch module.

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

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

[0014] In some embodiments, 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.

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

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

[0017] In view of the problem that it is difficult for existing radio frequency switching circuits to take into account both the reduction of switch insertion loss and the need for small size, the present invention proposes a compact broadband switching circuit and a radio frequency front end. The circuit can improve chip space utilization and achieve a compact circuit design by setting a plurality of dual-gate switch modules between two radio frequency ends; and the plurality of dual-gate switch modules can be synchronously turned on or off in response to a control signal. When the plurality of dual-gate switch modules are synchronously turned off in response to a control signal sent by a control unit, the plurality of dual-gate switch modules are equivalent to capacitors, so as to form a multi-order low-pass filter network with a plurality of inductors connected in series between the two radio frequency ends. The low-pass filter network can process radio frequency 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 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 switch circuit provided by an embodiment of the present invention;

[0020] Figure 3 is an exemplary 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 the variation of circuit power compression of multiple dual-gate switch modules in the on state with input power;

[0022] Figure 5 yes Figure 3 A 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 is further described in detail below with reference to specific embodiments, 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 as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0026] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means 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 may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may 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 Schematic diagram of the structure of a compact broadband switch circuit provided by an embodiment of the present invention. Figure 1As shown, the compact broadband switch 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 arranged 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 arranged between the first radio frequency terminal RF1 and the first inductor among the plurality of inductors, and a last dual-gate switch module among the plurality of dual-gate switch modules is arranged between the second radio frequency terminal RF2 and the 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 also electrically connected to the control unit, and are used to synchronously turn on or off in response to a control signal sent by the control unit, so that the radio frequency signal within a preset frequency range flowing from the first radio frequency terminal RF1 passes through the plurality of dual-gate switch modules or passes 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 constitute 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 switch 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. In addition, 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 radio frequency terminal RF1 or the output ends of 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. By connecting the RC resonant network at the source of the Qth dual-gate switch tube, the source impedance can be reduced, thereby improving the isolation.

[0032] Here, the size of the dual-gate switch tubes in the first dual-gate switch module and the third dual-gate switch module is the same, and the size of the dual-gate switch tube in the second dual-gate switch module is larger than the size of the dual-gate switch tube in the first dual-gate switch module. In addition, the RC resonant network in the first dual-gate switch module and the third dual-gate switch module is the same. This setting method can greatly expand the bandwidth while ensuring 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 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 a possible implementation, each of the plurality of inductors is a microstrip inductor, a stripline inductor, or a spiral inductor. Compared with the large size of a quarter-wavelength transmission line, which is difficult to meet the requirements of miniaturization, by using a microstrip inductor, a stripline inductor, or a spiral inductor, the area required for the circuit can be reduced while ensuring the power capacity of the circuit, 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 switch tubes, the number of bias resistors corresponding to 3Q dual-gate switch tubes is 6Q. The value and size of each bias resistor are equal, and the resistance value of each bias resistor ranges from 5k to 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 that a single-gate transistor can only be equivalent to 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 off-state capacitance of the device as a whole is greatly reduced, so that each dual-gate switch module is equivalent to an equivalent capacitance. The equivalent capacitance can be combined with a plurality of inductors connected between the first RF terminal RF1 and the second RF terminal RF2 to form a low-pass filter network in the form of CLC-…-C. The low-pass filter network can process RF signals in an ultra-wideband range, reduce the degree of leakage of high-frequency signals, and have smaller insertion loss and better on-state standing wave.

[0037] like Figure 2 As shown, 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. In a 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 It is expressed as:

[0040]

[0041] Among them, 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 end of each dual-gate switch module is on It is 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 It is 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 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 terminal RF1 or the second RF terminal RF2.

[0049] By the equivalent impedance Z on And the 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 switch 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 is an example diagram of a compact broadband switching circuit provided by an embodiment of the present invention. Figure 3 As shown, in a possible implementation, the number of double-gate switches in the first double-gate switch module, the second double-gate switch module or the third double-gate switch module is 1, the first double-gate switch module includes a double-gate switch module M1, the second double-gate switch module includes a double-gate switch module M2, and the third double-gate switch module includes a double-gate switch module M3. The double-gate switch module M1 and the double-gate switch module M3 have the same size, and the double-gate switch module M2 is larger than the size of the double-gate switch module M1 and the size of the double-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 and off of the dual-gate switch module M1, and signal Vctrl2 controls the on and off of the dual-gate switch module M2, and controls the on and off of the dual-gate switch module M3. When the signals Vctrl1, Vctrl2 and Vctrl3 are all high-level signals, the dual-gate switch modules M1, M2 and M3 are turned on. When the 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 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 proposed in the present invention. The compact broadband switching circuit proposed in the present invention can switch the passage path of the radio frequency signal. It should be noted that the radio frequency front end is a radio frequency front end applied to a wireless communication system. The model type of the radio frequency front end is not limited in the embodiments of the present invention.

[0053] In view of the problem that it is difficult for existing radio frequency switch circuits to take into account both the reduction of switch insertion loss and the requirement for small size, the present invention proposes a compact broadband switch circuit. By setting a plurality of dual-gate switch modules between two radio frequency ends, the circuit can improve chip space utilization and realize a compact circuit design; and the plurality of dual-gate switch modules can be synchronously turned on or off in response to a control signal. When the plurality of dual-gate switch modules are synchronously turned off in response to a control signal sent by a control unit, the plurality of dual-gate switch modules are equivalent to capacitors, so as to form a multi-order low-pass filter network with a plurality of inductors connected in series between the two radio frequency ends. The low-pass filter network can process radio frequency 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 degree 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 the present invention, ADS software is used to Figure 3 The compact broadband switch circuit in the simulation is simulated. The core circuit size of the compact broadband switch circuit is less than 0.3 square millimeters. Specifically, the simulation frequency is set to 40GHz, the input power scanning range is 0dBm~50dBm, the S parameter frequency scanning range is 0GHz~60GHz, and the DC bias voltage is -28V. Figure 4 The embodiment of the present invention provides Figure 3 A simulation example diagram showing the circuit power compression of multiple dual-gate switch modules in the on state following the change of input power. Figure 5 The embodiment of the present invention provides Figure 3 An example diagram of the simulation of the changes in the S21 parameters 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 diagram of a simulation of the change in the S21 parameter of multiple dual-gate switch modules in the off state following the frequency of the input signal.

[0055] like Figure 4 As shown, the circuit power compression is expressed as P01db, in dB; the input power is expressed as Pin, in dBm; when Pin is 46.5dBm, P01db only increases to 0.123dB. When processing a large input power for a radio frequency switch, only a small loss is generated, indicating that the compact broadband switch circuit proposed in the present invention has a significant power advantage.

[0056] like Figure 5As shown, 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, and 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] Combination 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 contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling 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 arranged 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 arranged between the first RF terminal and the first inductor among the plurality of inductors, and a last dual-gate switch module among the plurality of dual-gate switch modules is arranged between the second RF terminal and the 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 also electrically connected to the control unit, and are used to be synchronously turned on or off in response to a control signal sent by the control unit, so that the RF signal within a preset frequency range flowing from the first RF terminal passes 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 constitute a multi-order low-pass filter network.

2. The compact broadband switching circuit according to claim 1, characterized in that: Each of the dual-gate switch modules 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 double-gate switch tubes and an output terminal of the control unit; The sources and drains of adjacent dual-gate switch tubes among the Q dual-gate switch tubes are connected in sequence, wherein the drain of the first dual-gate switch tube among 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 among 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.

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 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 through the first RF terminal, the plurality of inductors and the second RF terminal.

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 end 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 end; 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 sizes of the dual-gate switch tubes in the first dual-gate switch module and the third dual-gate switch module are the same, and the size of the dual-gate switch tube in the second dual-gate switch module is larger 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 one of a microstrip line 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 as described in any one of claims 1 to 9.

Images