A radio frequency burn-out protection circuit and a high-power radio frequency switch

Abstract

This invention relates to the field of radio frequency (RF) microwave communication, and particularly to an RF burn-out protection circuit and a high-power RF switch. The RF burn-out protection circuit of this invention includes a first 3dB coupler, a second 3dB coupler, a first parallel unit, a second parallel unit, a first matched load, a second matched load, a first RF circuit, and a second RF circuit. The RF burn-out protection circuit and high-power RF switch of this invention have high power capacity, low insertion loss, high isolation, stable VSWR performance, and are flexible in application and low in cost, possessing broad application prospects and value.

Description

Technical Field

[0001] This invention relates to the field of radio frequency microwave communication, and in particular to a radio frequency burn-out protection circuit and a high-power radio frequency switch. Background Technology

[0002] With the development of communication technology, radio frequency (RF) circuits in communication systems are becoming increasingly susceptible to burn-out, making the improvement of RF circuit burn-out protection a crucial aspect of design. Taking a base station system as an example, the RF receiver typically features a high-sensitivity low-noise amplifier (LNO). High-power leakage of transmitted signals within the system and nearby high-power interference signals can both cause the burn-out of core semiconductor devices in the LNO, leading to system failure. Furthermore, with the rise of 5G (5th Generation) mobile communication standards, the complexity of communication systems has increased dramatically, and the power that systems need to handle has also increased significantly. For widely used macro base stations and small base stations, the average transmit power of the power amplifier in the base station system is relatively high. For example, in a micro base station, the average transmit power of the power amplifier is >10W, and considering the requirement of at least 9dB peak-to-average power ratio (PAR), the receiver needs to handle a maximum power of 80W. Therefore, improving the burn-out resistance of RF circuits plays a vital role in the overall system design.

[0003] Traditional radio frequency burn-out protection circuits, such as Figure 1a As shown, the RF burn-out protection circuit mainly consists of a single-pole double-throw (SPDT) switch and a load resistor. The SPDT switch has three ports: P1, P2, and P3. When the switching path is from P1 to P2, the signal can pass through with low insertion loss. When an abnormal high-power signal arrives, the switching path switches to P1 to P3, and most of the power is absorbed by the load, thus providing burn-out protection. The basic structure of the SPDT switch is as follows: Figure 1b As shown, the single-pole double-throw switch mainly consists of series units 101 and 102 and parallel units 103 and 104. Series units 102 and 103 are controlled by control signal VC, while series units 101 and 104 are controlled by control signal VCF. Control signals VC and VCF are a pair of inverted control signals. When control signal VC is high, series units 102 and 103 are turned on, while series units 101 and 104 are turned off, and the radio frequency (RF) signal flows from RF port P1 to RF port P3. When control signal VC is low, series units 102 and 103 are turned off, while series units 101 and 104 are turned on, and the RF signal flows from RF port P1 to RF port P2.

[0004] This radio frequency burn-out protection circuit structure has the following disadvantages:

[0005] (1) Low power handling capacity. When the series unit is turned on, the radio frequency signal acts directly on the parallel unit, and when the parallel unit is turned on, the radio frequency signal acts directly on the series unit. When the input power increases, the voltage swing will quickly reach the breakdown voltage swing of the parallel / series unit, limiting the power handling capacity of the radio frequency burnout protection circuit;

[0006] (2) Unstable standing wave performance. The single-pole double-throw switch in the traditional radio frequency burn-out protection circuit structure is a reflective switch. The standing wave characteristics of this type of switch are different in the on and off states, especially the standing wave is poor in the off state, which affects the stability and reliability of the system.

[0007] (3) Large insertion loss. Series units introduce large insertion loss, which affects the overall performance of the system.

[0008] Therefore, a novel radio frequency burn-out protection circuit is needed. Summary of the Invention

[0009] The purpose of this invention is to provide a radio frequency burn-out protection circuit and a high-power radio frequency switch, which has a large power capacity, low insertion loss, high isolation, stable VSWR performance, flexible application, and low cost, and has broad application prospects and value.

[0010] This invention discloses a radio frequency burn-out protection circuit, including a first 3dB coupler, a second 3dB coupler, a first parallel unit, a second parallel unit, a first matched load, a second matched load, a first radio frequency circuit, and a second radio frequency circuit;

[0011] The input terminal of the first 3dB coupler is connected to the RF input port. The coupling terminal of the first 3dB coupler is connected to one end of the first parallel unit and the input terminal of the first RF circuit, respectively. The through terminal of the first 3dB coupler is connected to one end of the second parallel unit and the input terminal of the second RF circuit, respectively. The isolation terminal of the first 3dB coupler is connected to one end of the first matched load.

[0012] The input terminal of the second 3dB coupler is connected to the RF output port, the coupling terminal of the second 3dB coupler is connected to the output terminal of the second RF circuit, the through terminal of the second 3dB coupler is connected to the output terminal of the first RF circuit, and the isolation terminal of the second 3dB coupler is connected to one end of the second matched load.

[0013] The other ends of the first parallel unit and the second parallel unit are respectively grounded, and the control ports of the first parallel unit and the second parallel unit are respectively connected to the control signal;

[0014] The other ends of the first and second matched loads are respectively grounded.

[0015] Optionally, each of the first parallel unit and the second parallel unit includes a transistor and a high-resistance device; the first electrode of the transistor is connected to one end of the high-resistance device; and the other end of the high-resistance device is connected to the control port of the parallel unit.

[0016] Optionally, each of the first and second 3dB couplers includes a Lange coupler or a hybrid 3dB coupler.

[0017] Optionally, the radio frequency burn-out protection circuit can be monolithically integrated using RF CMOS, GaAs, BiCMOS, or RF SOI processes.

[0018] Alternatively, discrete components can be used to build the radio frequency burn-out protection circuit.

[0019] This invention discloses a high-power radio frequency switch, including a first 3dB coupler, a second 3dB coupler, a first parallel unit, a second parallel unit, a first matched load, and a second matched load;

[0020] The input terminal of the first 3dB coupler is connected to the first RF port. The coupling terminal of the first 3dB coupler is connected to one end of the first parallel unit and the through terminal of the second 3dB coupler, respectively. The through terminal of the first 3dB coupler is connected to one end of the second parallel unit and the coupling terminal of the second 3dB coupler, respectively. The isolation terminal of the first 3dB coupler is connected to one end of the first matched load.

[0021] The input terminal of the second 3dB coupler is connected to the second RF port. The coupling terminal of the second 3dB coupler is connected to one end of the second parallel unit and the through terminal of the first 3dB coupler, respectively. The through terminal of the second 3dB coupler is connected to one end of the first parallel unit and the coupling terminal of the first 3dB coupler, respectively. The isolation terminal of the second 3dB coupler is connected to one end of the second matched load.

[0022] The other ends of the first parallel unit and the second parallel unit are respectively grounded, and the control ports of the first parallel unit and the second parallel unit are respectively connected to the control signal;

[0023] The other ends of the first and second matched loads are respectively grounded.

[0024] Optionally, each of the first parallel unit and the second parallel unit includes a transistor and a high-resistance device; the first electrode of the transistor is connected to one end of the high-resistance device; and the other end of the high-resistance device is connected to the control port of the parallel unit.

[0025] Optionally, each of the first and second 3dB couplers includes a Lange coupler or a hybrid 3dB coupler.

[0026] Optionally, the high-power RF switch can be monolithically integrated using RF CMOS, GaAs, BiCMOS, or RF SOI processes.

[0027] Alternatively, discrete components can be used to build the high-power radio frequency switch.

[0028] The main differences and effects of this invention compared to existing technologies are as follows:

[0029] (1) High power capacity. This invention employs a first 3dB coupler and a second 3dB coupler. The 3dB coupler can split the input power in two, so theoretically, compared with the traditional RF burn-out protection circuit, the power capacity of the RF burn-out protection circuit of this invention can be doubled. In addition, this invention uses a parallel unit with series transistors, which further improves the maximum power handling capacity of the RF burn-out protection circuit.

[0030] (2) Low insertion loss. Compared with the traditional RF burn-out protection circuit, the RF burn-out protection circuit of the present invention omits the series unit. Although the 3dB coupler will also introduce insertion loss, the overall insertion loss of the RF burn-out protection circuit will still be reduced.

[0031] (3) High isolation. When the RF signal is an abnormally high-power signal, only a small portion of the RF signal leaks into the RF circuit, thus preventing the RF circuit from burning out and improving the isolation of the RF burn-out protection circuit. In addition, the present invention uses a parallel unit with parallel transistors, which further improves the isolation of the RF burn-out protection circuit, and the power of the signal leaking into the RF circuit will also be smaller.

[0032] (4) Stable VSWR performance. This invention employs a first matched load and a second matched load. When the RF signal is an abnormally high-power signal, most of the RF signal is reflected to the isolation terminal of the 3dB coupler and absorbed by the matched load. Therefore, compared to traditional RF burn-out protection circuits, the RF burn-out protection circuit of this invention is an absorption type. Regardless of the state of the RF burn-out protection circuit of this invention, no signal is reflected to the input terminal, and the VSWR characteristics of the RF burn-out protection circuit remain stable. Therefore, the system stability can be maintained, improving the system reliability.

[0033] (5) The radio frequency burn-out protection circuit of the present invention can be implemented by single-chip integration using various processes such as RF CMOS, GaAs, BiCMOS, and RF SOI, or it can be built using discrete devices. It is flexible in application, low in cost, and has broad application prospects and value. Attached Figure Description

[0034] Figure 1a This is the schematic diagram of a traditional radio frequency burn-out protection circuit;

[0035] Figure 1b This is the schematic diagram of a single-pole double-throw switch in a traditional radio frequency burn-out protection circuit;

[0036] Figure 2 According to some embodiments of this application, a schematic diagram of a radio frequency burn-out protection circuit is disclosed;

[0037] Figure 3 According to some embodiments of this application, a schematic diagram of a radio frequency burn-out protection circuit including a parallel unit having transistors and high-impedance devices is disclosed.

[0038] Figure 4 According to some embodiments of this application, a schematic diagram of a radio frequency burn-out protection circuit including a parallel unit with series transistors is disclosed.

[0039] Figure 5 According to some embodiments of this application, a schematic diagram of a radio frequency burn-out protection circuit including a parallel unit with parallel transistors is disclosed.

[0040] Figure 6 According to some embodiments of this application, a schematic diagram of a radio frequency burn-out protection circuit including a parallel unit having a set of parallel transistors is disclosed.

[0041] Figure 7 According to some embodiments of this application, a schematic diagram of a high-power radio frequency switch is disclosed;

[0042] Figure 8According to some embodiments of this application, a schematic diagram of a high-power radio frequency switch including a parallel unit having transistors and high-impedance devices is disclosed.

[0043] Figure 9 According to some embodiments of this application, a schematic diagram of a high-power radio frequency switch including a parallel unit with series transistors is disclosed;

[0044] Figure 10 According to some embodiments of this application, a schematic diagram of a high-power radio frequency switch including a parallel unit with parallel transistors is disclosed;

[0045] Figure 11 According to some embodiments of this application, a schematic diagram of a high-power radio frequency switch including a parallel unit having a set of parallel transistors is disclosed. Detailed Implementation

[0046] To make the objectives and technical solutions of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0047] According to some embodiments of this application, a radio frequency burn-out protection circuit is disclosed. Figure 2 This is the schematic diagram of the radio frequency burn-out protection circuit.

[0048] Specifically, such as Figure 2 As shown, the radio frequency burn-out protection circuit 200 includes a first 3dB coupler 201, a second 3dB coupler 202, a first parallel unit 203, a second parallel unit 204, a first matching load 205, a second matching load 206, a first radio frequency circuit 207, and a second radio frequency circuit 208.

[0049] The input terminal 201a of the first 3dB coupler 201 is connected to the RF input port RFin. The coupling terminal 201b of the first 3dB coupler 201 is connected to one end of the first parallel unit 203 and the input terminal of the first RF circuit 207, respectively. The through terminal 201c of the first 3dB coupler 201 is connected to one end of the second parallel unit 204 and the input terminal of the second RF circuit 208, respectively. The isolation terminal 201d of the first 3dB coupler 201 is connected to one end of the first matched load 205.

[0050] The input terminal 202a of the second 3dB coupler 202 is connected to the RF output port RFout, the coupling terminal 202b of the second 3dB coupler 202 is connected to the output terminal of the second RF circuit 208, the through terminal 202c of the second 3dB coupler 202 is connected to the output terminal of the first RF circuit 207, and the isolation terminal 202d of the second 3dB coupler 202 is connected to one end of the second matched load 206.

[0051] One end of the first parallel unit 203 is connected to the coupling terminal 201b of the first 3dB coupler 201 and the input terminal of the first radio frequency circuit 207, respectively. The other end of the first parallel unit 203 is grounded, and the control port of the first parallel unit 203 is connected to the control signal VC.

[0052] One end of the second parallel unit 204 is connected to the through terminal 201c of the first 3dB coupler 201 and the input terminal of the second RF circuit 208, respectively. The other end of the second parallel unit 204 is grounded, and the control port of the second parallel unit 204 is connected to the control signal VC.

[0053] One end of the first matched load 205 is connected to the isolation terminal 201d of the first 3dB coupler 201, and the other end of the first matched load 205 is grounded.

[0054] One end of the second matched load 206 is connected to the isolation terminal 202d of the second 3dB coupler 202, and the other end of the second matched load 206 is grounded.

[0055] In some embodiments, the control ports of the first parallel unit 203 and the second parallel unit 204 can be connected to the same control signal VC. When the control signal VC is low, the first parallel unit 203 and the second parallel unit 204 are disconnected. When the control signal VC is high, the first parallel unit 203 and the second parallel unit 204 are turned on.

[0056] Now assume that the radio frequency (RF) signal is input from the RF input port RFin of the RF burn-out protection circuit 200, and is split into two signals after passing through the first 3dB coupler 201, with the two signals having a 90° phase difference. When the RF signal is a normal small signal, the control signal VC is at a low level, the first parallel unit 203 and the second parallel unit 204 are disconnected, presenting a high impedance state, which basically does not affect the signal transmission. The two signals pass through the first RF circuit 207 and the second RF circuit 208 respectively, and are then combined into one signal by the second 3dB coupler 202, and output from the RF output port RFout of the RF burn-out protection circuit 200. When the radio frequency signal is an abnormally high-power signal, the control signal VC is at a high level, and the first parallel unit 203 and the second parallel unit 204 are turned on, presenting a low-impedance state. They are equivalent to a small resistor connected in parallel to ground. Part of the high-power radio frequency signal goes to ground through this resistor, while most of it is reflected to the isolation terminal 201d of the first 3dB coupler 201 and absorbed by the first matched load 205. Only a very small part of the signal leaks into the first radio frequency circuit 207 and the second radio frequency circuit 208, and will not burn out the first radio frequency circuit 207 and the second radio frequency circuit 208.

[0057] The present invention employs a first 3dB coupler 201 and a second 3dB coupler 202. The 3dB coupler can split the input power into two, so theoretically, the power capacity of the radio frequency anti-burn-out protection circuit 200 of the present invention can be doubled compared with the traditional structure of the radio frequency anti-burn-out protection circuit.

[0058] Compared to traditional RF burn-out protection circuits, the RF burn-out protection circuit 200 of this invention omits the series unit. Although the 3dB coupler will also introduce insertion loss, the overall insertion loss of the RF burn-out protection circuit 200 will still be reduced.

[0059] When the radio frequency signal is an abnormally high-power signal, only a small portion of the radio frequency signal leaks into the radio frequency circuit, thus preventing the radio frequency circuit from burning out and improving the isolation of the radio frequency anti-burnout protection circuit 200.

[0060] This invention employs a first matched load 205 and a second matched load 206. When the RF signal is an abnormally high-power signal, most of the RF signal is reflected to the isolation terminal of the 3dB coupler and absorbed by the matched load. Therefore, compared to the traditional RF burn-out protection circuit, the RF burn-out protection circuit 200 of this invention is an absorption type. Regardless of the state of the RF burn-out protection circuit 200, no signal is reflected to the input terminal, and the standing wave ratio of the RF burn-out protection circuit 200 remains stable. Therefore, the system stability can be maintained, and the system reliability is improved.

[0061] In some embodiments, the radio frequency burn-out protection circuit 200 can be monolithically integrated using various processes such as RF CMOS, GaAs, BiCMOS, and RF SOI.

[0062] In some embodiments, discrete components can be used to build the radio frequency burn-out protection circuit 200.

[0063] The radio frequency burn-out protection circuit 200 of the present invention is flexible in application, low in cost, and has broad application prospects and value.

[0064] In some embodiments, each of the first 3dB couplers 201 and the second 3dB coupler 202 may include a Lange coupler or a hybrid 3dB coupler.

[0065] Furthermore, it is understood that in other embodiments, the 3dB coupler may also include various other 3dB directional couplers, without limitation herein.

[0066] In some embodiments, the first matching load 205 and the second matching load 206 can be designed to be 50Ω matched, and can be various matching networks with a resistance or impedance of 50Ω.

[0067] In some embodiments, the first radio frequency circuit 207 and the second radio frequency circuit 208 may be the same and may include amplifiers, oscillators, filters, etc.

[0068] According to some embodiments of this application, a schematic diagram of a radio frequency burn-out protection circuit including a parallel unit having transistors and high-impedance devices is disclosed. Figure 3 This is the schematic diagram of the radio frequency burn-out protection circuit.

[0069] Specifically, such as Figure 3 As shown, the radio frequency burn-out protection circuit 300 includes a first 3dB coupler 201, a second 3dB coupler 202, a first parallel unit 303, a second parallel unit 304, a first matching load 205, a second matching load 206, a first radio frequency circuit 207, and a second radio frequency circuit 208.

[0070] Each parallel unit in the first parallel unit 303 and the second parallel unit 304 includes a transistor M1 and a high-resistance device Zg.

[0071] The first electrode of transistor M1 is connected to one end of the high-resistivity device Zg, the second electrode of transistor M1 is connected to one end of the parallel unit, and the third electrode of transistor M1 is connected to the other end of the parallel unit, thus grounding.

[0072] One end of the high-resistivity device Zg is connected to the first electrode of the transistor M1, and the other end of the high-resistivity device Zg is connected to the control port of the parallel unit, thereby being controlled by the control signal VC.

[0073] In some embodiments, a high-resistance device may include a resistor, an inductor, or a combination of a resistor and an inductor.

[0074] In some embodiments, such as Figure 3 As shown, the impedance of the high-impedance device Zg is generally much greater than the impedance of the parasitic capacitance between nodes ① and ②, and the impedance of the parasitic capacitance between nodes ② and ③, so that the voltage amplitude at node ① is proportional to the voltage amplitude at node ②. At the same time, the impedance of the high-impedance device Zg is sufficiently large to prevent radio frequency signals from leaking through it.

[0075] In some embodiments, the transistor can be implemented by a field-effect transistor (FET), specifically including a junction field-effect transistor (JFET), a high electron mobility transistor (HEMT), a metal-semiconductor field-effect transistor (MESFET), and a metal-oxide-semiconductor field-effect transistor (MOSFET).

[0076] In some embodiments, the transistors described above are implemented using an N-type field-effect transistor (NMOS FET) or a P-type field-effect transistor (PMOS FET).

[0077] In some embodiments, such as Figure 3 As shown, transistor M1 can be an NMOS transistor, and the first electrode of transistor M1 can be the gate, the second electrode of transistor M1 can be the drain, and the third electrode of transistor M1 can be the source.

[0078] Furthermore, it is understood that in other embodiments, transistor M1 may also be implemented by other transistors, and no limitation is made here.

[0079] According to some embodiments of this application, a schematic diagram of a radio frequency burn-out protection circuit including a parallel unit with series transistors is disclosed. Figure 4 This is the schematic diagram of the radio frequency burn-out protection circuit.

[0080] Specifically, such as Figure 4 As shown, the radio frequency burn-out protection circuit 400 includes a first 3dB coupler 201, a second 3dB coupler 202, a first parallel unit 403, a second parallel unit 404, a first matched load 205, a second matched load 206, a first radio frequency circuit 207, and a second radio frequency circuit 208.

[0081] Each parallel unit in the first parallel unit 403 and the second parallel unit 404 includes multiple transistors M1,1-M1,n and multiple high-resistivity devices Zg,1-Zg,n.

[0082] Multiple transistors M1,1-M1,n are connected in series. The first electrode of each transistor is connected to one end of a high-impedance device. The second electrode of the first transistor M1,1 is connected to one end of the parallel unit. The third electrode of the first transistor M1,1 is connected to the second electrode of the second transistor M1,2. The third electrode of the second transistor M1,2 is connected to the second electrode of the third transistor M1,3, and so on. The third electrode of the last transistor M1,n is connected to the other end of the parallel unit, thus grounding it.

[0083] One end of each high-impedance device is connected to the first electrode of a transistor, and the other ends of multiple high-impedance devices Zg,1-Zg,n are interconnected and connected to the control port of the parallel unit, so that they are all controlled by the control signal VC.

[0084] This invention employs a parallel unit with series-connected transistors, further improving the maximum power handling capacity of the RF burn-out protection circuit 400. For example, if the maximum voltage that a single transistor can withstand from physical damage is Vmax, then with n transistors connected in series, the ideal maximum voltage that can withstand from physical damage increases to n×Vmax, thus increasing the maximum power handling capacity of the RF burn-out protection circuit 400 by n×Vmax. 2 times.

[0085] According to some embodiments of this application, a schematic diagram of a radio frequency burn-out protection circuit including a parallel unit with parallel transistors is disclosed. Figure 5 This is the schematic diagram of the radio frequency burn-out protection circuit.

[0086] Specifically, such as Figure 5 As shown, the radio frequency burn-out protection circuit 500 includes a first 3dB coupler 201, a second 3dB coupler 202, a first parallel unit 503, a second parallel unit 504, a first matching load 205, a second matching load 206, a first radio frequency circuit 207, and a second radio frequency circuit 208.

[0087] Each parallel unit in the first parallel unit 503 and the second parallel unit 504 includes multiple transistors M1,1-M1,n and multiple high-resistivity devices Zg,1-Zg,n.

[0088] Multiple transistors M1,1-M1,n are connected in parallel. The first electrode of each transistor is connected to one end of a high-impedance device, the second electrode of each transistor is connected to one end of the parallel unit, and the third electrode of each transistor is connected to the other end of the parallel unit, thereby grounding.

[0089] One end of each high-impedance device is connected to the first electrode of a transistor, and the other ends of multiple high-impedance devices Zg,1-Zg,n are interconnected and connected to the control port of the parallel unit, so that they are all controlled by the control signal VC.

[0090] This invention employs a parallel unit with parallel transistors, which improves the bandwidth of the RF burn-out protection circuit 500 and further enhances its isolation. Multiple transistors are connected in parallel, and with the addition of inductors or transmission lines for matching, when the parallel unit is disconnected, the parasitic capacitance of a single transistor can be distributed across multiple transistors, facilitating distributed matching and increasing bandwidth. When the parallel unit is on, each transistor is equivalent to a small resistor connected in parallel to ground. The RF signal passes through this resistor to ground. Through proper design, the isolation of the RF burn-out protection circuit 500 can be further improved, and the signal power leaking into the RF circuit will be reduced.

[0091] According to some embodiments of this application, a schematic diagram of a radio frequency burn-out protection circuit including a parallel unit having a set of parallel transistors is disclosed. Figure 6 This is the schematic diagram of the radio frequency burn-out protection circuit.

[0092] Specifically, such as Figure 6 As shown, the radio frequency burn-out protection circuit 600 includes a first 3dB coupler 201, a second 3dB coupler 202, a first parallel unit 603, a second parallel unit 604, a first matching load 205, a second matching load 206, a first radio frequency circuit 207, and a second radio frequency circuit 208.

[0093] Each parallel unit in the first parallel unit 603 and the second parallel unit 604 includes multiple transistor sets and multiple high-resistivity devices Zg,11-Zg,ij.

[0094] Multiple transistor sets are connected in parallel. Each transistor set includes multiple transistors M1,1-M1,j; ...; Mi,1-Mi,j. Multiple transistors M1,1-M1,j; ...; Mi,1-Mi,j are connected in series. The first electrode of each transistor is connected to one end of a high-impedance device. The second electrode of the first transistor M1,1-Mi,1 is connected to one end of the parallel unit. The third electrode of the first transistor M1,1-Mi,1 is connected to the second electrode of the second transistor M1,2-Mi,2. The third electrode of the second transistor M1,2-Mi,2 is connected to the second electrode of the third transistor M1,3-Mi,3, and so on. The third electrode of the last transistor M1,j-Mi,j is connected to the other end of the parallel unit, thus grounding it.

[0095] One end of each high-impedance device is connected to the first electrode of a transistor, and the other ends of multiple high-impedance devices Zg,11-Zg,ij are interconnected and connected to the control port of the parallel unit, so that they are all controlled by the control signal VC.

[0096] The present invention employs a parallel unit with a set of parallel transistors, which can simultaneously possess the advantages of both series transistors and parallel transistors.

[0097] According to some embodiments of this application, a high-power radio frequency switch is disclosed. Figure 7 This is the schematic diagram of the high-power RF switch. When the RF circuit in the RF burn-out protection circuit described above is short-circuited, or when a transmission line is used as the RF circuit in the RF burn-out protection circuit described above, the RF burn-out protection circuit can be transformed into a high-power RF switch.

[0098] Specifically, such as Figure 7 As shown, the high-power radio frequency switch 700 includes a first 3dB coupler 701, a second 3dB coupler 702, a first parallel unit 703, a second parallel unit 704, a first matched load 705, and a second matched load 706.

[0099] The input terminal 701a of the first 3dB coupler 701 is connected to the first radio frequency port RF1. The coupling terminal 701b of the first 3dB coupler 701 is connected to one end of the first parallel unit 703 and the through terminal 702c of the second 3dB coupler 702. The through terminal 701c of the first 3dB coupler 701 is connected to one end of the second parallel unit 704 and the coupling terminal 702b of the second 3dB coupler 702. The isolation terminal 701d of the first 3dB coupler 701 is connected to one end of the first matched load 705.

[0100] The input terminal 702a of the second 3dB coupler 702 is connected to the second RF port RF2. The coupling terminal 702b of the second 3dB coupler 702 is connected to one end of the second parallel unit 704 and the through terminal 701c of the first 3dB coupler 701. The through terminal 702c of the second 3dB coupler 702 is connected to one end of the first parallel unit 703 and the coupling terminal 701b of the first 3dB coupler 701. The isolation terminal 702d of the second 3dB coupler 702 is connected to one end of the second matched load 706.

[0101] One end of the first parallel unit 703 is connected to the coupling end 701b of the first 3dB coupler 701 and the through end 702c of the second 3dB coupler 702, respectively. The other end of the first parallel unit 703 is grounded, and the control port of the first parallel unit 703 is connected to the control signal VC.

[0102] One end of the second parallel unit 704 is connected to the through end 701c of the first 3dB coupler 701 and the coupling end 702b of the second 3dB coupler 702, respectively. The other end of the second parallel unit 704 is grounded, and the control port of the second parallel unit 704 is connected to the control signal VC.

[0103] One end of the first matched load 705 is connected to the isolation terminal 701d of the first 3dB coupler 701, and the other end of the first matched load 705 is grounded.

[0104] One end of the second matching load 706 is connected to the isolation terminal 702d of the second 3dB coupler 702, and the other end of the second matching load 706 is grounded.

[0105] In some embodiments, the control ports of the first parallel unit 703 and the second parallel unit 704 can be connected to the same control signal VC. When the control signal VC is low, the first parallel unit 703 and the second parallel unit 704 are disconnected. When the control signal VC is high, the first parallel unit 703 and the second parallel unit 704 are turned on.

[0106] In some embodiments, the high-power radio frequency switch 700 may be designed to operate bidirectionally, while in other embodiments, the high-power radio frequency switch 700 may be designed to operate unidirectionally.

[0107] When the high-power RF switch 700 is designed to operate bidirectionally, both the first RF port RF1 and the second RF port RF2 are input / output ports. RF signals can be input from the first RF port RF1 and output from the second RF port RF2, or vice versa.

[0108] When the high-power RF switch 700 is designed for unidirectional operation, the first RF port RF1 is the input port and the second RF port RF2 is the output port, or the first RF port RF1 is the output port and the second RF port RF2 is the input port. RF signals can only be input from the first RF port RF1 and output from the second RF port RF2, or vice versa.

[0109] Now, assume the radio frequency (RF) signal is input from the first RF port RF1, and after passing through the first 3dB coupler 701, it is split into two signals with a 90° phase difference. When the control signal VC is low, the first parallel unit 703 and the second parallel unit 704 are disconnected, exhibiting a high-impedance state, which has virtually no impact on signal transmission. The two signals are then combined into one signal by the second 3dB coupler 702 and output from the second RF port RF2. At this time, the high-power RF switch 700 is equivalent to being in a conducting state. When the control signal VC is high, the first parallel unit 703 and the second parallel unit 704 are turned on, exhibiting a low-impedance state, each equivalent to a small resistor connected in parallel to ground. Part of the RF signal passes through this resistor to ground, while most of it is reflected to the isolation terminal 701d of the first 3dB coupler 701 and absorbed by the first matched load 705. Only a very small portion of the signal leaks to the output terminal. The two signals are then combined into one signal by the second 3dB coupler 702 and output from the second RF port RF2. At this time, the high-power RF switch 700 is equivalent to being in the off state.

[0110] The present invention employs a first 3dB coupler 701 and a second 3dB coupler 702. The 3dB coupler can split the input power into two, so theoretically, the power capacity of the high-power RF switch 700 of the present invention can be doubled compared with the traditional switching circuit.

[0111] Compared to traditional switching circuits, the high-power RF switch 700 of this invention omits the series unit. Although the 3dB coupler also introduces insertion loss, the overall insertion loss of the high-power RF switch 700 is still reduced.

[0112] When the high-power RF switch 700 of the present invention is equivalent to the off state, only a small portion of the RF signal leaks to the output terminal, thus greatly reducing the output signal power and improving the isolation between the two RF ports.

[0113] This invention employs a first matched load 705 and a second matched load 706. When the high-power RF switch 700 of this invention is equivalent to the off state, most of the RF signal is reflected to the isolation terminal of the 3dB coupler and absorbed by the matched load. Therefore, compared to the traditional reflective switch circuit, the high-power RF switch 700 of this invention is an absorptive type. Regardless of whether the high-power RF switch 700 of this invention is in the on or off state, no signal is reflected to the input terminal, and the standing wave ratio (VSWR) of the high-power RF switch 700 remains stable. Therefore, the system stability can be maintained, and the system reliability is improved.

[0114] In some embodiments, a variety of processes such as RF CMOS, GaAs, BiCMOS, and RF SOI can be used to monolithically integrate the high-power RF switch 700.

[0115] In some embodiments, discrete components can be used to build the high-power radio frequency switch 700.

[0116] The high-power radio frequency switch 700 of this invention is flexible in application, low in cost, and has broad application prospects and value.

[0117] In some embodiments, each of the first 3dB coupler 701 and the second 3dB coupler 702 may include a Lange coupler or a hybrid 3dB coupler.

[0118] Furthermore, it is understood that in other embodiments, the 3dB coupler may also include various other 3dB directional couplers, without limitation herein.

[0119] The first 3dB coupler 701 and the second 3dB coupler 702 can be designed to be identical or separate. Generally, when the high-power RF switch 700 is designed to operate bidirectionally, the first 3dB coupler 701 and the second 3dB coupler 702 can be designed to be identical. However, when the high-power RF switch 700 is designed to operate unidirectionally, the first 3dB coupler 701 and the second 3dB coupler 702 can be designed separately.

[0120] For example, if the high-power RF switch 700 is designed to operate unidirectionally, with the first RF port RF1 as the input port and the second RF port RF2 as the output port, then the design of the first 3dB coupler 701 mainly considers power handling. However, when the high-power RF switch 700 operates normally in unidirectional mode, the output does not need to handle high power; therefore, the design of the second 3dB coupler 702 mainly considers insertion loss, amplitude imbalance, phase error, and area.

[0121] In some embodiments, the first matching load 705 and the second matching load 706 can be designed to be 50Ω matched, and can be various matching networks with a resistance or impedance of 50Ω.

[0122] The first matched load 705 and the second matched load 706 can be designed to be the same or separate. Generally, when the high-power RF switch 700 is designed to operate bidirectionally, the first matched load 705 and the second matched load 706 can be designed to be the same. However, when the high-power RF switch 700 is designed to operate unidirectionally, the first matched load 705 and the second matched load 706 can be designed separately.

[0123] For example, if the high-power RF switch 700 is designed to operate unidirectionally, and the first RF port RF1 is the input port and the second RF port RF2 is the output port, then the design of the first matched load 705 mainly considers matching characteristics and power handling. However, when the high-power RF switch 700 operates normally in unidirectional mode, the output does not need to handle high power; therefore, the design of the second matched load 706 mainly considers matching characteristics.

[0124] According to some embodiments of this application, a schematic diagram of a high-power radio frequency switch including a parallel unit having transistors and high-impedance devices is disclosed. Figure 8 This is the schematic diagram of the high-power radio frequency switch.

[0125] Specifically, such as Figure 8 As shown, the high-power radio frequency switch 800 includes a first 3dB coupler 701, a second 3dB coupler 702, a first parallel unit 803, a second parallel unit 804, a first matched load 705, and a second matched load 706.

[0126] Each parallel unit in the first parallel unit 803 and the second parallel unit 804 includes a transistor M1 and a high-resistivity device Zg.

[0127] The first electrode of transistor M1 is connected to one end of the high-resistivity device Zg, the second electrode of transistor M1 is connected to one end of the parallel unit, and the third electrode of transistor M1 is connected to the other end of the parallel unit, thus grounding.

[0128] One end of the high-resistivity device Zg is connected to the first electrode of the transistor M1, and the other end of the high-resistivity device Zg is connected to the control port of the parallel unit, thereby being controlled by the control signal VC.

[0129] In some embodiments, a high-resistance device may include a resistor, an inductor, or a combination of a resistor and an inductor.

[0130] In some embodiments, such as Figure 8As shown, the impedance of the high-impedance device Zg is generally much greater than the impedance of the parasitic capacitance between nodes ① and ②, and the impedance of the parasitic capacitance between nodes ② and ③, so that the voltage amplitude at node ① is proportional to the voltage amplitude at node ②. At the same time, the impedance of the high-impedance device Zg is sufficiently large to prevent radio frequency signals from leaking through it.

[0131] In some embodiments, the transistor can be implemented by a field-effect transistor (FET), specifically including a junction field-effect transistor (JFET), a high electron mobility transistor (HEMT), a metal-semiconductor field-effect transistor (MESFET), and a metal-oxide-semiconductor field-effect transistor (MOSFET).

[0132] In some embodiments, the transistors described above are implemented using an N-type field-effect transistor (NMOS FET) or a P-type field-effect transistor (PMOS FET).

[0133] In some embodiments, such as Figure 8 As shown, transistor M1 can be an NMOS transistor, and the first electrode of transistor M1 can be the gate, the second electrode of transistor M1 can be the drain, and the third electrode of transistor M1 can be the source.

[0134] Furthermore, it is understood that in other embodiments, transistor M1 may also be implemented by other transistors, and no limitation is made here.

[0135] According to some embodiments of this application, a schematic diagram of a high-power radio frequency switch including a parallel unit with series transistors is disclosed. Figure 9 This is the schematic diagram of the high-power radio frequency switch.

[0136] Specifically, such as Figure 9 As shown, the high-power radio frequency switch 900 includes a first 3dB coupler 701, a second 3dB coupler 702, a first parallel unit 903, a second parallel unit 904, a first matched load 705, and a second matched load 706.

[0137] Each parallel unit in the first parallel unit 903 and the second parallel unit 904 includes multiple transistors M1,1-M1,n and multiple high-resistivity devices Zg,1-Zg,n.

[0138] Multiple transistors M1,1-M1,n are connected in series. The first electrode of each transistor is connected to one end of a high-impedance device. The second electrode of the first transistor M1,1 is connected to one end of the parallel unit. The third electrode of the first transistor M1,1 is connected to the second electrode of the second transistor M1,2. The third electrode of the second transistor M1,2 is connected to the second electrode of the third transistor M1,3, and so on. The third electrode of the last transistor M1,n is connected to the other end of the parallel unit, thus grounding it.

[0139] One end of each high-impedance device is connected to the first electrode of a transistor, and the other ends of multiple high-impedance devices Zg,1-Zg,n are interconnected and connected to the control port of the parallel unit, so that they are all controlled by the control signal VC.

[0140] This invention employs a parallel unit with series-connected transistors, further increasing the maximum power handling capacity of the high-power RF switch 900. For example, if the maximum voltage a single transistor can withstand from physical failure is Vmax, then with n transistors connected in series, the ideal maximum voltage that can withstand from physical failure increases to n × Vmax, thus increasing the maximum power handling capacity of the high-power RF switch 900 by n. 2 times.

[0141] According to some embodiments of this application, a schematic diagram of a high-power radio frequency switch including a parallel unit with parallel transistors is disclosed. Figure 10 This is the schematic diagram of the high-power radio frequency switch.

[0142] Specifically, such as Figure 10 As shown, the high-power radio frequency switch 1000 includes a first 3dB coupler 701, a second 3dB coupler 702, a first parallel unit 1003, a second parallel unit 1004, a first matched load 705, and a second matched load 706.

[0143] Each parallel unit in the first parallel unit 1003 and the second parallel unit 1004 includes multiple transistors M1,1-M1,n and multiple high-resistivity devices Zg,1-Zg,n.

[0144] Multiple transistors M1,1-M1,n are connected in parallel. The first electrode of each transistor is connected to one end of a high-impedance device, the second electrode of each transistor is connected to one end of the parallel unit, and the third electrode of each transistor is connected to the other end of the parallel unit, thereby grounding.

[0145] One end of each high-impedance device is connected to the first electrode of a transistor, and the other ends of multiple high-impedance devices Zg,1-Zg,n are interconnected and connected to the control port of the parallel unit, so that they are all controlled by the control signal VC.

[0146] This invention employs a parallel unit with parallel transistors, which improves the bandwidth of the high-power RF switch 1000 and further enhances the isolation between the two RF ports. Multiple transistors are connected in parallel, along with some inductors or transmission lines for matching. When the parallel unit is open, the parasitic capacitance of a single transistor can be distributed across multiple transistors, facilitating distributed matching and improving bandwidth. When the parallel unit is on, each transistor is equivalent to a small resistor connected in parallel to ground. The RF signal passes through this resistor to ground. With proper design, the isolation between the two RF ports can be further improved.

[0147] According to some embodiments of this application, a schematic diagram of a high-power radio frequency switch including a parallel unit having a set of parallel transistors is disclosed. Figure 11 This is the schematic diagram of the high-power radio frequency switch.

[0148] Specifically, such as Figure 11 As shown, the high-power radio frequency switch 1100 includes a first 3dB coupler 701, a second 3dB coupler 702, a first parallel unit 1103, a second parallel unit 1104, a first matched load 705, and a second matched load 706.

[0149] Each parallel unit in the first parallel unit 1103 and the second parallel unit 1104 includes multiple transistor sets and multiple high-resistivity devices Zg,11-Zg,ij.

[0150] Multiple transistor sets are connected in parallel. Each transistor set includes multiple transistors M1,1-M1,j; ...; Mi,1-Mi,j. Multiple transistors M1,1-M1,j; ...; Mi,1-Mi,j are connected in series. The first electrode of each transistor is connected to one end of a high-impedance device. The second electrode of the first transistor M1,1-Mi,1 is connected to one end of the parallel unit. The third electrode of the first transistor M1,1-Mi,1 is connected to the second electrode of the second transistor M1,2-Mi,2. The third electrode of the second transistor M1,2-Mi,2 is connected to the second electrode of the third transistor M1,3-Mi,3, and so on. The third electrode of the last transistor M1,j-Mi,j is connected to the other end of the parallel unit, thus grounding it.

[0151] One end of each high-impedance device is connected to the first electrode of a transistor, and the other ends of multiple high-impedance devices Zg,11-Zg,ij are interconnected and connected to the control port of the parallel unit, so that they are all controlled by the control signal VC.

[0152] The present invention employs a parallel unit with a set of parallel transistors, which can simultaneously possess the advantages of both series transistors and parallel transistors.

[0153] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes made within the scope of knowledge possessed by those skilled in the art without departing from the spirit and purpose of the present invention should be included within the scope of the present invention patent.

[0154] In the accompanying drawings, some structural or methodological features may be shown in a specific arrangement and / or order. However, it should be understood that such a specific arrangement and / or order may not be necessary. Rather, in some embodiments, these features may be arranged in a manner and / or order different from that shown in the illustrative drawings. Furthermore, the inclusion of structural or methodological features in a particular figure does not imply that such features are required in all embodiments, and in some embodiments, these features may be omitted or may be combined with other features.

[0155] It should be noted that in the examples and description of this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0156] Although this application has been illustrated and described with reference to certain preferred embodiments thereof, those skilled in the art should understand that various changes in form and detail may be made thereto without departing from the spirit and scope of this application.

Claims

1. A high-power radio frequency switch, characterized in that, The system includes a first 3dB coupler, a second 3dB coupler, a first parallel unit, a second parallel unit, a first matched load, and a second matched load. Each parallel unit in the first and second parallel units includes a transistor and a high-impedance device. The first electrode of the transistor is connected to one end of the high-impedance device, and the other end of the high-impedance device is connected to the control port of the parallel unit. The second electrode of the transistor is connected to one end of the parallel unit, and the third electrode of the transistor is connected to the other end of the parallel unit. The input terminal of the first 3dB coupler is connected to the first RF port. The coupling terminal of the first 3dB coupler is connected to one end of the first parallel unit and the through terminal of the second 3dB coupler, respectively. The through terminal of the first 3dB coupler is connected to one end of the second parallel unit and the coupling terminal of the second 3dB coupler, respectively. The isolation terminal of the first 3dB coupler is connected to one end of the first matched load. The input terminal of the second 3dB coupler is connected to the second RF port. The coupling terminal of the second 3dB coupler is connected to one end of the second parallel unit and the through terminal of the first 3dB coupler, respectively. The through terminal of the second 3dB coupler is connected to one end of the first parallel unit and the coupling terminal of the first 3dB coupler, respectively. The isolation terminal of the second 3dB coupler is connected to one end of the second matched load. The other ends of the first parallel unit and the second parallel unit are respectively grounded. The control ports of the first parallel unit and the second parallel unit are respectively connected to the same control signal. The control signal is used to simultaneously control the conduction or disconnection of both the first parallel unit and the second parallel unit to realize the switching state of the high-power radio frequency switch. When the control signal is at the first level, the first parallel unit and the second parallel unit are disconnected, and the high-power radio frequency switch is equivalent to the conduction state. When the control signal is at the second level, the first parallel unit and the second parallel unit are conducted, and the high-power radio frequency switch is equivalent to the off state. The other ends of the first and second matched loads are respectively grounded.

2. The high-power radio frequency switch according to claim 1, characterized in that, Each of the first and second 3dB couplers includes a Lange coupler or a hybrid 3dB coupler.

3. The high-power radio frequency switch according to claim 1, characterized in that, The first 3dB coupler and the second 3dB coupler are designed to be identical.

4. The high-power radio frequency switch according to claim 1, characterized in that, The first matched load and the second matched load are designed to be identical.

5. The high-power radio frequency switch according to any one of claims 1 to 4, characterized in that, The high-power radio frequency switch is monolithically integrated using RF CMOS, GaAs, BiCMOS, and RF SOI processes.

6. The high-power radio frequency switch according to any one of claims 1 to 4, characterized in that, The high-power radio frequency switch is constructed using discrete components.

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