阅读说明：本技术 射频前端综合电磁防护电路 (Radio frequency front end integrated electromagnetic protection circuit ) 是由 王玉明 陈亚洲 孟兆祥 马立云 毕军建 谭志良 宋培姣 于 2020-05-28 设计创作，主要内容包括：本发明涉及射频前端综合电磁防护电路,包括输入匹配电路、扩容防护电路、开关防护电路、限幅防护电路、级间匹配电路、输出匹配电路和耦合检波电路,级间匹配电路为第一至第四级间匹配电路；输入匹配电路第一端作为输入端、第二端与扩容防护电路第一端相连；扩容防护电路至少包括两个扩容分支；开关防护电路包括一个以上的导通单元；限幅防护电路包括一个以上的限幅单元；耦合检波电路包括定向耦合器、检波二极管、第三电感及扼流电感。本装置同时具有连续波及瞬态强电磁脉冲综合防护能力,提升了射频前端的大信号在强场连续波及强电磁脉冲下的功率容量及通流能力。(The invention relates to a radio frequency front end comprehensive electromagnetic protection circuit, which comprises an input matching circuit, an expansion protection circuit, a switch protection circuit, an amplitude limiting protection circuit, an interstage matching circuit, an output matching circuit and a coupling detection circuit, wherein the interstage matching circuit is a first to fourth interstage matching circuit; the first end of the input matching circuit is used as an input end, and the second end of the input matching circuit is connected with the first end of the capacity expansion protection circuit; the capacity expansion protection circuit at least comprises two capacity expansion branches; the switch protection circuit comprises more than one conducting unit; the amplitude limiting protection circuit comprises more than one amplitude limiting unit; the coupling detection circuit comprises a directional coupler, a detection diode, a third inductor and a choke inductor. The device has the comprehensive protection capability of continuous wave and transient strong electromagnetic pulse, and the power capacity and the through-current capability of a large signal at the front end of the radio frequency under the conditions of strong field continuous wave and strong electromagnetic pulse are improved.)

1. The utility model provides a radio frequency front end synthesizes electromagnetic protection circuit which characterized in that: the device comprises an input matching circuit, a capacity expansion protection circuit, a switch protection circuit, an amplitude limiting protection circuit, an interstage matching circuit, an output matching circuit and a coupling detection circuit;

the first end of the input matching circuit is used as the input end of the radio frequency front end comprehensive electromagnetic protection circuit, and the second end of the input matching circuit is connected with the first end of the capacity expansion protection circuit;

the number of the interstage matching circuits is more than two, the interstage matching circuits are connected between the capacity expansion protection circuit and the switch protection circuit and between the switch protection circuit and the amplitude limiting protection circuit, and the two interstage matching circuits are respectively a first interstage matching circuit and a third interstage matching circuit;

the capacity expansion protection circuit comprises at least two capacity expansion branches, the capacity expansion branches are connected in parallel based on a power division principle, first ends of all the capacity expansion branches are connected together to serve as a first end of the capacity expansion protection circuit, and the first end of the capacity expansion protection circuit is connected with a first end of the first inter-stage matching circuit;

the second ends of all the capacity expansion branches are connected together to be used as the second end of the capacity expansion protection circuit, and the second end of the capacity expansion protection circuit is grounded;

the switch protection circuit comprises more than one conducting unit, and the second ends of all the conducting units are grounded; if the number of the conduction units is one, the first end of the conduction unit is respectively connected with the second end of the first inter-stage matching circuit and the first end of the third inter-stage matching circuit; if the number of the conduction units is more than two, the first ends of the adjacent conduction units are connected by an inter-stage matching circuit, the first end of the first conduction unit is connected with the second end of the first inter-stage matching circuit, the first end of the last conduction unit is connected with the first end of the third inter-stage matching circuit, and meanwhile, the starting powers of the capacity expansion protection circuit, the switch protection circuit and the amplitude limiting protection circuit are sequentially equal or gradually reduced according to the electromagnetic energy propagation direction;

the amplitude limiting protection circuit comprises more than one amplitude limiting unit, and the second ends of all the amplitude limiting units are grounded; if the number of the amplitude limiting units is one, the first end of the amplitude limiting unit is respectively connected with the second end of the third inter-stage matching circuit and the first end of the output matching circuit; if the number of the amplitude limiting units is more than two, the first ends of the adjacent amplitude limiting units are connected through an interstage matching circuit, the first end of the first amplitude limiting unit is connected with the second end of a third interstage matching circuit, the first end of the last amplitude limiting unit is connected with the first end of an output matching circuit, and meanwhile the starting powers of the capacity expansion protection circuit, the switch protection circuit and the amplitude limiting protection circuit are sequentially equal or gradually reduced according to the electromagnetic energy propagation direction;

the second end of the output matching circuit is used as the output end of the radio frequency front end comprehensive electromagnetic protection circuit;

the input end and the output end of the coupling detection circuit are respectively connected with different interstage matching circuits, and the input end of the coupling detection circuit is closer to the input end of the radio frequency front end comprehensive electromagnetic protection circuit than the output end of the coupling detection circuit.

2. The rf front-end integrated electromagnetic protection circuit of claim 1, wherein each of the capacitive-amplifying branches includes a first diode unit, a second diode unit, and a first inductor;

the first diode unit comprises more than one diode which is connected in series in the forward direction, and the positive electrode direction is the first end of the first diode unit; the second diode unit is the reverse series connection of the first diode unit, and the negative pole direction is the first end of the second diode unit; the number of diodes of the second diode unit is equal to that of the diodes of the first diode unit;

the first end of the first diode unit, the first end of the second diode unit and the first end of the first inductor are connected and jointly used as the first end of the capacity expansion branch; and the second end of the first diode unit, the second end of the second diode unit and the second end of the first inductor are connected together and are used as the second end of the capacitance-expanding branch to be grounded.

3. The rf front-end integrated electromagnetic protection circuit of claim 1, wherein the number of the inter-stage matching circuits is four, and the inter-stage matching circuits include a second inter-stage matching circuit and a fourth inter-stage matching circuit in addition to the first inter-stage matching circuit and the third inter-stage matching circuit;

the switch protection circuit comprises two conduction units, namely a first conduction unit and a second conduction unit, the first conduction unit is connected with the second conduction unit through a second inter-stage matching circuit, and the first end of the first conduction unit is connected with the second end of the first inter-stage matching circuit and is also connected with the first end of the second inter-stage matching circuit; the first end of the second conduction unit is connected with the second end of the second inter-stage matching circuit and is simultaneously connected with the first end of the third inter-stage matching circuit; the second end of the first conduction unit and the second end of the second conduction unit are grounded;

the amplitude limiting protection circuit comprises two amplitude limiting units, namely a first amplitude limiting unit and a second amplitude limiting unit, the first amplitude limiting unit and the second amplitude limiting unit are connected through a fourth stage matching circuit, the first end of the first amplitude limiting unit is connected with the second end of the third stage matching circuit and is connected with the first end of the fourth stage matching circuit, and the first end of the second amplitude limiting unit is connected with the second end of the fourth stage matching circuit and is connected with the first end of the output matching circuit; the second end of the first amplitude limiting unit and the second end of the second amplitude limiting unit are both grounded.

4. The rf front-end integrated electromagnetic protection circuit of claim 3, wherein the first conduction unit is a pair-transistor structure formed by two first switching diodes connected end-to-end, one end of the pair-transistor structure being used as a first end of the first conduction unit, the other end being used as a second end of the first conduction unit and grounded; the second conduction unit is a pair tube structure formed by connecting two second switching diodes end to end, one end of the pair tube structure is used as a first end of the second conduction unit, and the other end of the pair tube structure is used as a second end of the second conduction unit and is grounded;

the starting power of the first diode unit, the first switch diode and the second switch diode is equal or decreased gradually in sequence.

5. The rf front-end integrated electromagnetic protection circuit of claim 3, wherein the first clipping unit is a pair-transistor structure formed by two first clipping diodes connected end to end, one end of the pair-transistor structure being used as the first end of the first clipping unit, the other end being used as the second end of the first clipping unit and grounded; the second amplitude limiting unit is a pair tube structure formed by connecting two second amplitude limiting diodes end to end, one end of the pair tube structure is used as the first end of the second amplitude limiting unit, and the other end of the pair tube structure is used as the second end of the second amplitude limiting unit and is grounded;

the opening power of the second switch diode, the first amplitude limiting diode and the second amplitude limiting diode is equal or decreased gradually in sequence.

6. The rf front-end integrated electromagnetic protection circuit of claim 1, wherein the coupling detection circuit includes a directional coupler, a detection diode, a third inductor, and a choke inductor;

the directional coupler is used as the input end of the coupling detection circuit, and a straight line of the directional coupler is a microstrip line in the interstage matching circuit; the power output end of a coupling line of the directional coupler is connected with the anode of a detection diode, the cathode of the detection diode is connected with the first end of a choke inductor, and the second end of the choke inductor is used as the output end of the coupling detection circuit; the non-power output end of a coupling line of the directional coupler is connected with the first end of a third inductor, and the second end of the third inductor is grounded;

the input end of the coupling detection circuit is connected with the first stage matching circuit, and the output end of the coupling detection circuit is connected with the third stage matching circuit.

7. The rf front-end integrated electromagnetic protection circuit of claim 1, wherein the input matching circuit, the output matching circuit, and the inter-stage matching circuit are designed using microstrip transmission lines in combination with lumped elements.

8. The rf front-end integrated electromagnetic protection circuit of claim 1, wherein the input matching circuit includes at least one isolation capacitor connected in series; the output matching circuit includes at least one isolation capacitor connected in series.

Technical Field

The invention relates to the field of electromagnetic protection, in particular to a radio frequency front-end continuous wave and transient strong electromagnetic pulse comprehensive protection circuit.

Background

Along with the competition of electric and electronic equipment for frequency spectrum resources, the electromagnetic environment is more and more severe, and the electromagnetic environment is represented by high frequency spectrum density, large energy intensity and multiple signal patterns. In addition to the various continuous wave signals, there are also various intentional and unintentional electromagnetic pulses in space. Particularly, strong electromagnetic pulse weapons become targets of competitive development of various countries, and a large number of foreign advanced strong electromagnetic pulse weapons are developed over decades, thereby bringing great threats to power, communication, finance, energy, traffic and the like of China.

Most of the electric and electronic equipment is frequency-using equipment, and electromagnetic waves influencing the electric and electronic equipment comprise continuous waves and electromagnetic pulses due to the existence of a radio frequency front end. When electromagnetic waves enter the radio frequency front end with a certain power, information interference is caused if the electromagnetic waves are light, and hardware damage is caused if the electromagnetic waves are heavy. The intentional strong electromagnetic pulse comprises nuclear electromagnetic pulse, high-power microwave and the like, and has extremely fast pulse rising edge and extremely high pulse peak power, so that the frequency domain range of the striking with frequency equipment is large, and the energy intensity is high.

The protection to the radio frequency front end includes the protection to the continuous wave and the protection to electromagnetic pulse, in the current protectiveness design, mostly is the protection to the continuous wave, receives technical maturity and test condition restriction, and most protection circuit is limited to the protective capacities of strong electromagnetic pulse, and especially the amplitude limiting response speed is less than 1ns, and the protection circuit that can be used to high power microwave is rare, and its degree of difficulty lies in that protection circuit needs to have response speed concurrently fast, current capacity is strong, insertion loss is low, the little these four characteristics of spike leakage.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a radio frequency front end integrated electromagnetic protection circuit, which is used to solve the problem of having continuous wave and strong electromagnetic pulse protection capability, especially having high power microwave protection capability.

In order to solve the problems, the technical scheme adopted by the invention is as follows:

a radio frequency front end integrated electromagnetic protection circuit, comprising: the circuit comprises an input matching circuit, a capacity expansion protection circuit, a switch protection circuit, an amplitude limiting protection circuit, an interstage matching circuit, an output matching circuit and a coupling detection circuit;

the first end of the input matching circuit is used as the input end of the radio frequency front end comprehensive electromagnetic protection circuit, and the second end of the input matching circuit is connected with the first end of the capacity expansion protection circuit;

the number of the interstage matching circuits is more than two, the interstage matching circuits are connected between the capacity expansion protection circuit and the switch protection circuit and between the switch protection circuit and the amplitude limiting protection circuit, and the two interstage matching circuits are respectively a first interstage matching circuit and a third interstage matching circuit;

the capacity expansion protection circuit at least comprises two capacity expansion branches, the capacity expansion branches are connected in parallel based on a power division principle, first ends of all the capacity expansion branches are connected together to serve as a first end of the capacity expansion protection circuit, and the first end of the capacity expansion protection circuit is connected with a first end of the first inter-stage matching circuit;

the second ends of all the capacity expansion branches are connected together to be used as the second end of the capacity expansion protection circuit, and the second end of the capacity expansion protection circuit is grounded;

the switch protection circuit comprises more than one conducting unit, and the second ends of all the conducting units are grounded; if the number of the conduction units is one, the first end of the conduction unit is respectively connected with the second end of the first inter-stage matching circuit and the first end of the third inter-stage matching circuit; if the number of the conduction units is more than two, the first ends of the adjacent conduction units are also connected by an inter-stage matching circuit, the first end of the first conduction unit is connected with the second end of the first inter-stage matching circuit, the first end of the last conduction unit is connected with the first end of the third inter-stage matching circuit, and meanwhile, the starting powers of the capacity expansion protection circuit, the switch protection circuit and the amplitude limiting protection circuit are sequentially equal or gradually reduced according to the electromagnetic energy propagation direction;

the amplitude limiting protection circuit comprises more than one amplitude limiting unit, and the second ends of all the amplitude limiting units are grounded; if the number of the amplitude limiting units is one, the first end of the amplitude limiting unit is respectively connected with the second end of the third inter-stage matching circuit and the first end of the output matching circuit; if the number of the amplitude limiting units is more than two, the first ends of the adjacent amplitude limiting units are connected through an interstage matching circuit, the first end of the first amplitude limiting unit is connected with the second end of a third interstage matching circuit, the first end of the last amplitude limiting unit is connected with the first end of an output matching circuit, and meanwhile the starting powers of the capacity expansion protection circuit, the switch protection circuit and the amplitude limiting protection circuit are sequentially equal or gradually reduced according to the electromagnetic energy propagation direction;

the second end of the output matching circuit is used as the output end of the radio frequency front end comprehensive electromagnetic protection circuit;

the input end and the output end of the coupling detection circuit are respectively connected with different interstage matching circuits, and the input end of the coupling detection circuit is closer to the input end of the radio frequency front end comprehensive electromagnetic protection circuit than the output end of the coupling detection circuit.

Preferably, each of the capacity-extending branches includes a first diode unit, a second diode unit and a first inductor;

the first diode unit comprises more than one diode which is connected in series in the forward direction, and the positive electrode direction is the first end of the first diode unit; the second diode unit is the reverse series connection of the first diode unit, and the negative pole direction is the first end of the second diode unit; the number of diodes of the second diode unit is equal to that of the diodes of the first diode unit;

the first end of the first diode unit, the first end of the second diode unit and the first end of the first inductor are connected and jointly used as the first end of the capacity expansion branch; the second end of the first diode unit, the second end of the second diode unit and the second end of the first inductor are connected and are used as the second ends of the capacitance-expanding branches to be grounded; specifically, as shown in fig. 2, the first terminals of the capacity expansion protection circuit are connected to each other on the circuit, and play a role of sharing power together, which is also a point that the design of the present invention wants to protect, and all the first terminals have equal potentials.

Preferably, in an embodiment of the present invention, the inter-stage matching circuit includes four stages, and the inter-stage matching circuit includes a second inter-stage matching circuit and a fourth inter-stage matching circuit in addition to the first inter-stage matching circuit and the third inter-stage matching circuit;

the switch protection circuit comprises two conduction units, namely a first conduction unit and a second conduction unit, the first conduction unit is connected with the second conduction unit through a second inter-stage matching circuit, and the first end of the first conduction unit is connected with the second end of the first inter-stage matching circuit and is also connected with the first end of the second inter-stage matching circuit; the first end of the second conduction unit is connected with the second end of the second inter-stage matching circuit and is simultaneously connected with the first end of the third inter-stage matching circuit; the second end of the first conduction unit and the second end of the second conduction unit are grounded;

the amplitude limiting protection circuit comprises two amplitude limiting units, namely a first amplitude limiting unit and a second amplitude limiting unit, the first amplitude limiting unit and the second amplitude limiting unit are connected through a fourth stage matching circuit, the first end of the first amplitude limiting unit is connected with the second end of the third stage matching circuit and is connected with the first end of the fourth stage matching circuit, and the first end of the second amplitude limiting unit is connected with the second end of the fourth stage matching circuit and is connected with the first end of the output matching circuit; the second end of the first amplitude limiting unit and the second end of the second amplitude limiting unit are grounded;

preferably, in an embodiment of the present invention, the first diode unit and the second diode unit are in a form of a pair tube formed by the same type and number of switching diodes, and the first inductor is removed;

the first conduction unit is a pair tube structure formed by connecting two first switch diodes end to end, one end of the pair tube structure is used as a first end of the first conduction unit, and the other end of the pair tube structure is used as a second end of the first conduction unit and is grounded; the second conduction unit is a pair tube structure formed by two second switching diodes, one end of the pair tube structure is used as a first end of the second conduction unit, and the other end of the pair tube structure is used as a second end of the second conduction unit and is grounded;

the starting power of the first diode unit, the first switch diode and the second switch diode is equal or decreased gradually in sequence; since the second diode unit is the inverse series connection of the first diode unit, and the cathode direction is the first end of the second diode unit, the turn-on power of the second diode unit is practically the same as that of the first diode.

In one embodiment of the invention, the switch protection circuit only comprises a first conduction unit, and does not comprise a second stage matching circuit and a second conduction unit; the starting power of the first diode unit and the first switch diode is equal or decreased gradually.

In one embodiment of the invention, the switch protection circuit comprises two or more conducting units, the first ends of the adjacent conducting units are connected by an inter-stage matching circuit, and the turn-on power of the switch diodes is equal or decreased in sequence according to the electromagnetic energy propagation direction.

Preferably, the first amplitude limiting unit is a pair tube structure formed by connecting two first amplitude limiting diodes end to end, one end of the pair tube structure is used as the first end of the first amplitude limiting unit, and the other end of the pair tube structure is used as the second end of the first amplitude limiting unit and is grounded; the second amplitude limiting unit is a pair tube structure formed by connecting two second amplitude limiting diodes end to end, one end of the pair tube structure is used as the first end of the second amplitude limiting unit, and the other end of the pair tube structure is used as the second end of the second amplitude limiting unit and is grounded;

the opening power of the second switch diode, the first amplitude limiting diode and the second amplitude limiting diode is equal or decreased gradually in sequence.

In one embodiment of the present invention, the slice protection circuit only includes the first slice unit, and does not include the fourth inter-stage matching circuit and the second slice unit; the starting power of the second switch diode and the first limiting diode is equal or decreased;

in one embodiment of the invention, the amplitude limiting protection circuit comprises two or more amplitude limiting units, the first ends of the adjacent amplitude limiting units are connected by an inter-stage matching circuit, and the opening power of the amplitude limiting diodes is equal or decreased in sequence according to the electromagnetic energy propagation direction.

Preferably, the coupling detection circuit comprises a directional coupler, a detection diode, a third inductor and a choke inductor;

the directional coupler is used as the input end of the coupling detection circuit, and a straight line of the directional coupler is a microstrip line in the interstage matching circuit; the power output end of a coupling line of the directional coupler is connected with the anode of a detection diode, the cathode of the detection diode is connected with the first end of a choke inductor, and the second end of the choke inductor is used as the output end of the coupling detection circuit; the non-power output end of the coupling line of the directional coupler is connected with the first end of the third inductor, and the second end of the third inductor is grounded.

Specifically, the input end of the coupling detection circuit is connected with the first stage matching circuit, and the output end of the coupling detection circuit is connected with the third stage matching circuit.

Preferably, the input matching circuit, the output matching circuit and the interstage matching circuit are designed by combining a microstrip transmission line and a lumped element, and the radio frequency front end comprehensive electromagnetic protection circuit presents low-pass filter characteristics under small signals.

The input matching network ensures that the standing waves at the input end of the radio frequency front-end comprehensive electromagnetic protection circuit are well matched, and the output matching network ensures that the standing waves at the output end of the radio frequency front-end comprehensive electromagnetic protection circuit are well matched; the interstage matching network realizes impedance matching among all stages of protection circuits, is matched with the coupling detection circuit to realize response speed matching among all stages of protection circuits, and is matched with the through-current capacity of all stages of protection circuits to realize power capacity matching among all stages of protection circuits;

preferably, under the condition of determining lumped parameters and distributed parameters of the radio frequency front end comprehensive electromagnetic protection circuit, the matching network is adjusted to enable the radio frequency front end comprehensive electromagnetic protection circuit to present low-pass filter characteristics under small signals.

The input matching circuit at least comprises an isolation capacitor connected in series; the output matching circuit at least comprises an isolation capacitor connected in series; and the second end of the output matching circuit is used as the output end of the radio frequency front-end comprehensive electromagnetic protection circuit.

Due to the adoption of the technical scheme, the invention has the beneficial effects that:

1. meanwhile, the device has the comprehensive protection capability of continuous wave and transient strong electromagnetic pulse.

2. The capacity-expansion protection circuit is provided with capacity-expansion branches according to the power division principle, so that the power capacity and the through-current capacity of the radio frequency front-end integrated electromagnetic protection circuit under large signals (strong field continuous waves and strong electromagnetic pulses) are improved.

3. The capacity expansion protection circuit, the interstage matching circuit and the coupling detection circuit are matched with each other, so that the phenomenon that protection devices are burnt down due to unmatched response speed and unmatched power capacity of each stage of protection circuit units under the impact of transient strong electromagnetic pulses is avoided, and the beneficial effects of high response speed, high power capacity and strong through-current capacity are achieved.

4. The combination design of the distributed parameters and the lumped parameters is favorable for obtaining an accurate calculation result of the radio frequency circuit, further favorable for optimizing the matching network to form the characteristic of a low-pass filter under a small signal (normal working signal) of the radio frequency front-end comprehensive electromagnetic protection circuit, and the beneficial effects of low insertion loss and small influence on normal working of the radio frequency front end are obtained.

5. It can obtain high-power microwave protection ability from the above 2, 3 and 4 strips.

6. The design of optimally selecting the protection circuit unit device and the microstrip circuit can reduce the volume of the radio frequency front end comprehensive electromagnetic protection circuit, and is convenient to assemble and use.

Drawings

FIG. 1 is a schematic diagram of the circuit configuration of the present invention;

FIG. 2 is a schematic diagram of the principle of the present invention;

FIG. 3 is a first schematic diagram of the structure of the invention;

FIG. 4 is a schematic diagram of the second embodiment of the present invention;

FIG. 5 is a graph of loss simulation characteristics without access to the present invention;

FIG. 6 is a graph of loss simulation characteristics for access to the present invention;

wherein: 1. input matching circuit, 2, expansion protection circuit, 21, expansion branch, L1, first inductance, 211, switch diode, 3, first stage matching circuit, 4, switch protection circuit, 41, first conduction unit, 42, second conduction unit, 411, first switch diode, 421, second switch diode, 5, second stage matching circuit, 6, third stage matching circuit, 7, amplitude limiting protection circuit, 71, first amplitude limiting unit, 72, second amplitude limiting unit, 711, first amplitude limiting diode, 721, second amplitude limiting diode, 8, fourth stage matching circuit, 9, output matching circuit, 10, coupling detection circuit.

Detailed Description

The present invention will be described in further detail with reference to examples.

As shown in fig. 1, an embodiment of the present invention provides a schematic structural diagram of a radio frequency front-end integrated electromagnetic protection circuit, which includes an input matching circuit 1, a capacity expansion protection circuit 2, a first inter-stage matching circuit 3, a switch protection circuit 4, a third inter-stage matching circuit 6, an amplitude limiting protection circuit 7, an output matching circuit 9, and a coupling detection circuit 10.

In this embodiment 1, the rf front end integrated electromagnetic protection circuit is designed to be bidirectional, and can be directly applied between the antenna and the rf front end without affecting normal transceiving communication.

In another embodiment 2, the rf front end integrated electromagnetic protection circuit is designed to be unidirectional and is connected between the receiving antenna and the rf front end receiving end. The antenna is only used for a radio frequency front end receiving end, is bidirectional, can be directly applied between the antenna and the radio frequency front end, and does not influence normal receiving and transmitting communication.

In this embodiment 1, the input matching circuit 1 and the transceiving antenna implement standing wave matching for normally transmitting the transceiving signal at the rf front end; one end of the input matching circuit 1 connected with the antenna is used as a first end, and one end connected with the capacity expansion protection circuit 2 is used as a second end.

In this embodiment 1, the capacity expansion protection circuit 2 includes two capacity expansion branches 21, and the two capacity expansion branches 21 are connected in parallel based on the power division principle, as shown in fig. 2. The first ends of all the capacity expansion branches 21 are connected together to be used as the first end of the capacity expansion protection circuit 2, and the first end of the capacity expansion protection circuit 2 is simultaneously connected with the first end of the first inter-stage matching circuit 3; the second ends of all the capacity expansion branches 21 are connected together to be used as the second end of the capacity expansion protection circuit 2, and the second end of the capacity expansion protection circuit 2 is grounded.

Each capacity expansion branch 21 comprises a first diode unit, a second diode unit and a first inductor L1; the first diode unit comprises more than one diode which is connected in series in the forward direction, and the positive electrode direction is the first end of the first diode unit; the second diode unit is the reverse series connection of the first diode unit, and the negative pole direction is the first end of the second diode unit; the number of diodes of the second diode unit is equal to that of the diodes of the first diode unit;

the first end of the first diode unit, the first end of the second diode unit and the first end of the first inductor are connected and jointly used as the first end of the capacity expansion branch; the second ends of the first diode unit and the second diode unit are connected with the second end of the first inductor L1, and are used as the second ends of the capacitance-expanding branch to be grounded.

In this embodiment, the first diode unit and the second diode unit are respectively composed of a switching diode 211, the types are the same, the connection directions are opposite, and a pair tube structure is formed; one end of the pair tube structure is used as the first end of the expansion branch 21, and the other end is used as the second end of the expansion branch 21 and is grounded; the first end of the capacity expansion branch 21 is connected to the first end of the first inductor L1, and the second end of the first inductor L1 is grounded.

The first ends of all the capacity expansion branches 21 are used as the first ends of the capacity expansion protection circuit 2, and the first ends of the capacity expansion protection circuit 2 are connected with the input matching circuit 1 and the first inter-stage matching circuit 3. The first end of the self capacity expansion protection circuit 2 is connected without input and output ends. As for the first end of the capacity expansion branch 21, in fig. 2, the intermediate node of the two pair tube structure and the node connected to the input matching circuit 1 and the first inter-stage matching circuit 3 are both the first end of the capacity expansion protection circuit 2.

In another embodiment 3, the first conducting unit 41 of the switch protection circuit 4 has sufficient power tolerance to the strong electromagnetic pulse, and the capacity expansion protection circuit 2 and the first inter-stage matching circuit 3 are omitted.

In this embodiment 1, the switch protection circuit 4 includes a first conducting unit 41 and a second conducting unit 42, a first end of the first conducting unit 41 is connected to a second end of the first inter-stage matching circuit 3, and is connected to a first end of the second inter-stage matching circuit 5; a first end of the second conduction unit 42 is connected with a second end of the second inter-stage matching circuit 5, and is also connected with a first end of the third inter-stage matching circuit 6; the second terminals of the first conducting unit 41 and the second conducting unit 42 are grounded.

The first conduction unit 41 is a pair tube structure formed by a first switching diode 411, one end of the pair tube structure is used as a first end of the first conduction unit 41, and the other end is used as a second end of the first conduction unit 41 and is grounded; the second conduction unit 42 is a pair-transistor structure formed by the second switching diode 421, and one end of the pair-transistor structure is used as the first end of the second conduction unit 42, and the other end is used as the second end of the second conduction unit 42 and is grounded.

The switching diodes 211, 411 and 421 of the first diode unit have the same or decreasing power.

In embodiment 1, the switching diodes 211 and 411 of the first diode unit are each a switching diode capable of withstanding a pulse power of 60dBm, and the second switching diode 421 is a switching diode capable of withstanding a pulse power of 45 dBm. Specifically, in order to reduce the influence of the distribution parameters of the packaging structure and reduce the volume, a bare chip is directly used in the circuit.

In another embodiment 4, the switch protection circuit 4 includes only the first conducting unit 41, and does not include the second inter-stage matching circuit 5 and the second conducting unit 42; the switching diode 211 of the first diode unit and the first switching diode 411 are turned on with equal power or decreased power.

In another embodiment 5, the switch protection circuit 4 includes more than two conducting units, the first terminals of adjacent conducting units are connected by an inter-stage matching circuit, and the turn-on power of each diode is equal or decreased sequentially according to the electromagnetic energy propagation direction.

In this embodiment 1, the amplitude limiting protection circuit 7 includes a first amplitude limiting unit 71 and a second amplitude limiting unit 72, a first end of the first amplitude limiting unit 71 is connected to a second end of the third inter-stage matching circuit 6, and is simultaneously connected to a first end of the fourth inter-stage matching circuit 8, a first end of the second amplitude limiting unit 72 is connected to a second end of the fourth inter-stage matching circuit 8, and is simultaneously connected to a first end of the output matching circuit 9; and the second ends of the first amplitude limiting unit and the second amplitude limiting unit are grounded.

The first amplitude limiting unit 71 is a pair tube structure formed by a first amplitude limiting diode 711, one end of the first amplitude limiting unit 71 is used as a first end, and the other end of the first amplitude limiting unit 71 is used as a second end of the first amplitude limiting unit 71 and is grounded; the second amplitude limiting unit 72 is a pair tube structure formed by a second amplitude limiting diode 721, one end of the second amplitude limiting unit 72 is used as the first end of the second amplitude limiting unit 72, and the other end of the second amplitude limiting unit 72 is used as the second end of the second amplitude limiting unit 72 and is grounded;

the turn-on power of the second switching diode 421, the first limiting diode 711 and the second limiting diode 721 is equal or decreased in sequence;

in this embodiment 1, the first limiter diode 711 is a limiter diode capable of withstanding a pulse power of 35dBm, the second limiter diode 721 is a schottky diode capable of withstanding a pulse power of 25dBm, and the final output of the rf front-end integrated electromagnetic protection circuit is limited to 20dBm or less, i.e., the power strength that can be withstood by the rf front-end low noise amplifier.

Specifically, in order to reduce the distribution parameters of the packaging structure and reduce the volume, a bare chip is directly used in the circuit.

In another embodiment 6, the clipping prevention circuit 7 includes only the first clipping unit 71, and does not include the fourth inter-stage matching circuit 8 and the second clipping unit 72; the second switching diode 421 and the first limiting diode 711 turn on the same power or decrease the power;

in another embodiment 7, the clipping protection circuit 7 includes more than two clipping units, the first terminals of the adjacent clipping units are connected by an inter-stage matching circuit, and the turn-on powers of the clipping diodes are sequentially equal or decreased according to the electromagnetic energy propagation direction.

In the present embodiment 1, the coupling detector circuit 10 includes a directional coupler, a detector diode D1, a third inductor L3, and a choke inductor L2;

the directional coupler is used as the input end of the coupling detection circuit 10; a through line of the directional coupler is a microstrip line in the interstage matching circuit and is connected with the first interstage matching circuit 3; the coupled line power output end of the directional coupler is connected with the anode of a detection diode D1, the cathode of the detection diode D1 is connected with the first end of a choke inductor L2, and the second end of the choke inductor L2 is used as the coupled detection circuit output end; the non-power output end of the coupling line of the directional coupler is connected with the first end of a third inductor L3, and the second end of the third inductor L3 is grounded;

the input end and the output end of the coupling detection circuit 10 are respectively connected to different interstage matching circuits, and the input end of the coupling detection circuit is closer to the input end of the radio frequency front end comprehensive electromagnetic protection circuit than the output end of the coupling detection circuit.

Specifically, a direct line of a directional coupler in the coupling detection circuit 10 is a microstrip line in the first inter-stage matching circuit 3, a power output end of the coupled line of the directional coupler is connected with the schottky detection diode D1, and is rectified and output through the L2 and then connected with the first limiter diode 711 of the limiter protection circuit 7 through the third inter-stage matching circuit 6, so as to ensure that a direct current rectified and output by the coupling detection circuit can accelerate the starting speed of the first limiter diode 711, and improve the power bearing capacity of the first limiter diode 711. In order to reduce the influence of the distribution parameters of the packaging structure and reduce the volume, a bare chip is directly used in the circuit.

In this embodiment 1, the input matching circuit 1, the output matching circuit 9, and the inter-stage matching circuit are all designed by combining microstrip transmission lines and lumped elements.

Specifically, the interstage matching circuit realizes impedance matching among all stages of protection circuits, is matched with the coupling detection circuit 10 to realize response speed matching among all stages of protection circuits, and is matched with the through-current capacity of all stages of protection circuits to realize power capacity matching among all stages of protection circuits.

In this embodiment 1, under the condition that the lumped parameter and the distributed parameter of the rf front-end integrated electromagnetic protection circuit are obtained through calculation, the matching network is adjusted, so that the rf front-end integrated electromagnetic protection circuit exhibits the characteristic of a low-pass filter under a small signal.

In an embodiment of the present invention, the rf front-end integrated electromagnetic protection circuit provided in this embodiment adopts a monolithic integration manner, so as to reduce the volume; fig. 3 to fig. 4 show a physical diagram provided in this embodiment, where the left side in the diagram is the rf input direction and the right side in the diagram is the rf output direction.

In an embodiment of the present invention, the continuous wave withstand capability of the rf front-end integrated electromagnetic protection circuit provided in this embodiment is about 53dBm, the withstand capability of the strong electromagnetic pulse is about 55dBm under a pulse width of 3ms and a duty ratio of 10%, the amplitude limiting response speed for the strong electromagnetic pulse is less than 1ns, and the insertion loss is less than 1 dB.

Fig. 5 and 6 are comparative graphs of the measured effect. In fig. 5 and 6, the upper curve is an ultra-wide spectrum high-power microwave strong electromagnetic pulse, and the lower curve is an induced voltage waveform received by the antenna, that is, the upper curve is an original signal curve, and the lower curve is an effect curve. The raw signal curves in fig. 5 and 6 are the same, with the difference being the effect curve below.

Fig. 5 shows that the left side pulse is not accessed to the embodiment of the present invention, when the ultra-wide spectrum high-power microwave strong electromagnetic pulse radiation field intensity is 75.8kV/m, the peak pulse voltage is 2009V for the induced voltage waveform received by a certain antenna; the right side is an ultra-wide spectrum high-power microwave monitoring waveform. Fig. 6 shows that after the embodiment of the present invention is connected, the induced voltage waveform is suppressed to a peak voltage not exceeding 242V, the right side pulse is still an ultra-wide spectrum high-power microwave monitoring waveform, and the rising edge of the pulse of the ultra-wide spectrum high-power microwave source is less than 1 ns. Therefore, the protective circuit has obvious effect, has the comprehensive protective capability of continuous wave and transient strong electromagnetic pulse, and improves the power capacity and the current capacity of the large signal of the radio frequency front-end comprehensive electromagnetic protective circuit under the condition of strong field continuous wave and strong electromagnetic pulse.