Microwave amplitude limiting device capable of removing peak leakage

Abstract

The invention belongs to the technical field of radio and microwaves, and discloses a microwave amplitude limiting device capable of removing peak leakage. According to the invention, through skillfully combining the coupling and resonance principles, quick response can be realized at the moment when a strong signal arrives, and the time window of energy leakage is obviously reduced. Compared with a traditional microwave amplitude limiter, the microwave amplitude limiter has the advantages that the response speed is higher, the response to strong signals can be made in an extremely short time, and therefore the risk of sharp point leakage is greatly reduced; the device provided by the invention is high in design flexibility, and can be optimized and adjusted according to different working frequency bands and signal characteristics so as to adapt to diversified application scenes; the device is compact in structure and can be easily integrated into an existing receiving link, large-scale transformation of the system is not needed, and the overall reliability and stability of the receiving link are further guaranteed.

Description

Technical Field

[0001] The present invention mainly relates to the field of radio and microwave technologies, and particularly to a microwave limiting device capable of removing spike leakage. Background Art

[0002] A microwave limiter is a key protective device widely used in radio receiving systems, usually located between the receiving antenna and the front-end high-gain amplifier of the receiver. The front-end high-gain amplifier of the receiver is a highly sensitive weak-signal amplification device, so it is very fragile. Once the input signal exceeds a certain value, it is easily saturated, blocked, or completely burned out. The main function of the microwave limiter is to prevent the front end of the receiver from being damaged by excessive signals by limiting the amplitude of the input signal.

[0003] The working principle of the microwave limiter is to connect a discharge tube filled with a special gas or a semiconductor limiting diode in parallel in the signal path. When the signal passing through it is less than its breakdown (or conduction) threshold, it presents a high-resistance state, and the loss of the passing signal can be ignored; when the signal passing through it is greater than its breakdown (or conduction) threshold, it presents a low-resistance state, and the passing signal is greatly attenuated. In this way, under normal circumstances, the weak signal received by the antenna system can almost pass through the limiter without loss, while the strong signal that accidentally or unexpectedly enters the receiving antenna can be greatly attenuated, thereby protecting the vulnerable front-end equipment of the receiver behind it. The microwave limiter is a typical non-linear device, and its characteristics make it play a crucial role in signal processing.

[0004] However, the microwave limiters of the prior art generally have certain defects, and the existing spike leakage phenomenon still poses a risk to the front-end equipment of the receiver. Because whether it is the breakdown of the gas discharge tube or the conduction of the crystal limiting diode, a certain amount of energy is required, and energy is the product of power and time. Therefore, when a strong signal suddenly comes, it takes a certain amount of time to accumulate enough energy to break down or conduct the limiting device. Therefore, its action inevitably has a delayed start, resulting in the generation of spike leakage similar to impact signals and reducing the limiting effect. Summary of the Invention

[0005] The purpose of the present invention is to provide a microwave limiting device capable of removing spike leakage. The microwave limiters of the prior art generally have certain defects, and the existing spike leakage phenomenon still poses a risk to the front-end equipment of the receiver. In view of this defect, the present invention aims to provide a novel coupling and resonance combination device, which can effectively eliminate or weaken the energy of spike leakage, make the limiting protection effect more perfect, and thus ensure the reliable operation of the overall performance of the receiving link.

[0006] To achieve the above object, the present invention provides a microwave limiting device capable of removing spike leakage, comprising a limiting element, an impedance matching network, a signal transmission path, a resonant structure, and a coupling structure; The signal output port of the signal transmission path is connected to a plurality of resonant structures; A plurality of coupling structures are inserted before the first resonant structure, after the last resonant structure, and between adjacent two resonant structures.

[0007] Furthermore, the coupling structure includes self-inductive coupling, mutual-inductive coupling, capacitive coupling, electric field coupling, magnetic field coupling, transmission line coupling, and space coupling of an equivalent circuit.

[0008] Furthermore, in the microstrip application mode, a microwave dielectric double-sided copper-clad substrate is used, and the copper foil is entirely reserved on the back of the microwave dielectric double-sided copper-clad substrate; The limiting element can be a microwave limiting diode or a PIN diode. The signal transmission path includes a signal input port, a signal output port, and a grounding end. The resonant structure is a plurality of equivalent capacitors and a plurality of equivalent inductors; The limiting element, the signal transmission path, the resonant structure, and the coupling structure are arranged on the front side of the microwave dielectric double-sided copper-clad substrate, and the copper foil is only reserved on the part of the front side of the microwave dielectric double-sided copper-clad substrate where the signal transmission path, the resonant structure, and the coupling structure are arranged.

[0009] Furthermore, a plurality of equivalent capacitors and a plurality of equivalent inductors are connected in series one by one to form a series resonant structure, and the signal output port of the signal transmission path is connected in series with a plurality of series resonant structures.

[0010] Furthermore, a plurality of equivalent capacitors and a plurality of equivalent inductors are connected in parallel one by one to form a parallel resonant structure, and the signal output port of the signal transmission path is connected in parallel with a plurality of parallel resonant structures.

[0011] Furthermore, the coupling structure can be a microstrip line segment with copper foil covered between each resonant structure.

[0012] Furthermore, in the waveguide application mode, the limiting element is a gas discharge device or a semiconductor limiting diode. The signal transmission path includes an input waveguide flange and fixing holes, and an output waveguide flange and fixing holes. The resonant structure is a plurality of waveguide resonant windows.

[0013] Furthermore, the waveguide application mode is applicable to the lowest-order mode TE10 mode of a rectangular waveguide.

[0014] Furthermore, the coupling structure is a waveguide section between adjacent two waveguide resonant windows.

[0015] Beneficial effects: The present invention proposes a microwave limiting device capable of removing spike leakage. By cleverly combining the principles of coupling and resonance, it can quickly respond at the moment when a strong signal arrives, significantly reducing the time window of energy leakage. Specifically, the coupling device can guide part of the signal energy into the resonant structure, and the resonant structure, through its inherent frequency selectivity characteristics, absorbs or reflects the spike energy in a specific frequency band, thereby effectively suppressing the leakage signal.

[0016] Compared with traditional microwave limiters, the microwave limiting device capable of removing spike leakage of the present invention has the following significant advantages: First, its response speed is faster, and it can respond to strong signals in an extremely short time, thereby greatly reducing the risk of spike leakage; Second, the device has strong design flexibility and can be optimized and adjusted according to different operating frequency bands and signal characteristics to adapt to diverse application scenarios; Finally, its structure is compact and easy to integrate into the existing receiving link without large-scale modification of the system, further ensuring the overall reliability and stability of the receiving link. Description of the Drawings

[0017] Figure 1 is the microstrip application mode structure diagram of the microwave limiting device capable of removing spike leakage involved in the embodiment of the present invention; Figure 2 is the waveguide application mode structure diagram of the microwave limiting device capable of removing spike leakage involved in the embodiment of the present invention.

[0018] Description of the Reference Numerals: Among them: 11 is a microwave dielectric double-sided copper-clad substrate; 21 is a signal input port; 22 is a signal output port; 23 is a grounding end; 31, 32, and 33 are three equivalent capacitors connected in parallel in the path; 41, 42, and 43 are three equivalent inductors connected in parallel in the path; 51 is a limiting diode; 31 and 41 form a parallel resonance link; 32 and 42 form a parallel resonance link; 33 and 43 form a parallel resonance link; 61 is an input waveguide flange and fixing holes; 62 is an output waveguide flange and fixing holes; 71 is a gas discharge device or a limiting diode; 81, 82, 83, and 84 are four waveguide resonance windows. Detailed Embodiments

[0019] The following further describes the preferred mechanisms and implementation methods of the present invention in conjunction with the drawings and specific embodiments.

[0020] As Figures 1 to 2 shown, the embodiment of the present invention discloses a technical solution of a microwave limiting device capable of removing spike leakage. Among them Figure 1 is an embodiment implemented on a microstrip transmission line platform, Figure 2 is an embodiment implemented on a waveguide transmission line platform. Embodiment 1

[0021] In Figure 1 except for the semiconductor limiter diode 51, all components constituting this embodiment are implemented in the form of distributed parameters on a microwave dielectric double-sided copper-clad substrate 11. The diode 51 that plays the limiter role can be a dedicated microwave limiter diode, or a PIN-type or other type of microwave diode. The difference from an ordinary diode is that an ordinary diode exhibits a unidirectional conduction characteristic under low-frequency applications and is often used in the fields of detection and rectification; while the diode selected in this embodiment is equivalent to a capacitor with an extremely small capacitance and a very large capacitive reactance (often estimated as infinite in qualitative analysis) under microwave low-power conditions, and does not conduct in both directions, but under microwave high-power conditions, it is equivalent to a resistor with an extremely small resistance without any bias and has the characteristic of bidirectional conduction. It is precisely by utilizing this characteristic that small-power microwave signals can pass through approximately without loss, while high-power microwave signals will be greatly attenuated when passing through, thereby playing a role in protecting the subsequent equipment. The sharp spikes leaked by the limiter diode are eliminated by the subsequent devices (equivalent capacitors 31 - 33, equivalent inductors 41 - 43, etc.), where 31 and 41 form a parallel resonance link, 32 and 42 form a parallel resonance link, 33 and 43 form a parallel resonance link, and the microstrip segments before and after each resonance link can be regarded as coupling links. For simplicity and clarity, the coupling devices between non-adjacent resonance links are not drawn in the figure, and if needed, coupling devices can be bridged between any two resonance links. In the figure, 21 is the signal input port, 22 is the signal output port, and 23 is the ground terminal (short-circuited to the copper foil on the back of the microwave dielectric double-sided copper-clad substrate 11). 31, 32, and 33 are planar capacitors formed between the copper foil reserved on the front and the ground-potential copper foil on the back, and their capacitances can be obtained by calculation using existing technologies or can be replaced by finished lumped-parameter capacitors. 41, 42, and 43 are high-impedance microstrip transmission lines less than a quarter wavelength and grounded at the end, equivalent to inductors, and their inductances can be obtained by calculation using existing technologies or can be replaced by wound coils. Figure 1 Taking three resonance links as an example, in the specific design, the resonance links can be any number more than one. Embodiment 2

[0022] Figure 2 is another embodiment of the present invention, which realizes the specific implementation of the present invention under the waveguide platform, and its basic principle is the same as that of Figure 1 completely the same. 61 is the input waveguide flange and fixing holes, 62 is the input waveguide flange and fixing holes, 71 is usually a discharge tube (gas discharge device) filled with special gas. When a small-power microwave signal passes through, the discharge tube does not break down and is equivalent to an open circuit, and the signal can pass through smoothly without obstruction. When the amplitude of the input signal is greater than the breakdown threshold of the discharge tube, the discharge tube discharges and breaks down, and the equivalent impedance approaches zero, and the passing signal is greatly attenuated. This is the same as Figure 1The limiting principle is completely consistent, so the semiconductor diode in Example 1 can also be used to replace the gas discharge device. Figure 2 Each waveguide resonant window (81, 82, 83, 84) is an independent resonant link, and the waveguide section between two adjacent resonant windows can be regarded as a coupling link. In the figure, four resonant windows are taken as an example, and in a specific design, the number of resonant windows can be any number of more than one. The rectangular waveguide of this embodiment must work in the TE10 mode.

[0023] In the above two embodiments, in order to ensure that the loss of low-power microwave signals is as small as possible when passing through the limiter, the limiter must be adjusted to reduce its standing wave coefficient. The relevant adjustment method is an existing mature technology. Although Embodiment 1 and Embodiment 2 only introduce the microstrip application mode and waveguide application mode of the present invention, the application mode in engineering is far from limited to these two. Coaxial transmission lines, plate-shaped transmission lines and concentrated parameter components can all be used to realize the concept of the present invention.

[0024] The present invention proposes a microwave limiting device that can remove peak leakage. By cleverly combining the coupling and resonance principles, it can respond quickly at the moment of strong signal arrival and significantly reduce the time window of energy leakage. Specifically, the coupling device can guide part of the signal energy into the resonant structure, and the resonant structure absorbs or reflects the peak energy in a specific frequency band through its inherent frequency selectivity, thereby effectively suppressing the leakage signal.

[0025] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. However, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A microwave limiting device capable of removing peak leakage, characterized in that: Including limiting elements, impedance matching network, signal transmission path, resonant structure, coupling structure; The signal output port of the signal transmission path is connected to a plurality of resonant structures; A plurality of coupling structures are inserted before the first resonant structure, after the last resonant structure and between two adjacent resonant structures.

2. The microwave amplitude limiting device capable of removing peak leakage according to claim 1, characterized in that: The coupling structure includes self-inductance coupling, mutual inductance coupling, capacitive coupling, electric field coupling, magnetic field coupling, transmission line coupling, and spatial coupling of the equivalent circuit.

3. The microwave amplitude limiting device capable of removing peak leakage according to claim 1, characterized in that: In the microstrip application mode, a microwave dielectric double-sided copper-clad substrate is used, and the copper foil is completely retained on the back of the microwave dielectric double-sided copper-clad substrate; The limiting element may be a microwave limiting diode or a PIN diode, the signal transmission path includes a signal input port, a signal output port and a ground terminal, and the resonant structure includes a plurality of equivalent capacitors and a plurality of equivalent inductors; The limiting element, signal transmission path, resonant structure and coupling structure are arranged on the front side of the microwave dielectric double-sided copper-clad substrate, and the copper foil is retained only in the part where the signal transmission path, resonant structure and coupling structure are arranged on the front side of the microwave dielectric double-sided copper-clad substrate.

4. The microwave limiting device capable of removing peak leakage according to claim 3, characterized in that: A plurality of equivalent capacitors and a plurality of equivalent inductors are connected in series one by one to form a series resonant structure, and a signal output port of a signal transmission path is connected in series with the plurality of series resonant structures.

5. The microwave amplitude limiting device capable of removing peak leakage according to claim 3, characterized in that: A plurality of equivalent capacitors and a plurality of equivalent inductors are connected in parallel in a one-to-one correspondence to form a parallel resonant structure, and a signal output port of the signal transmission path is connected in parallel with the plurality of parallel resonant structures.

6. The microwave limiting device capable of removing peak leakage according to claim 4 or 5, characterized in that: The coupling structure may be a microstrip line segment covered with copper foil between the resonant structures.

7. The microwave amplitude limiting device capable of removing peak leakage according to claim 1, characterized in that: In the waveguide application mode, the limiting element is a gas discharge device or a semiconductor limiting diode, the signal transmission path includes an input end waveguide flange and a fixing hole, an output end waveguide flange and a fixing hole, and the resonant structure is a plurality of waveguide resonant windows.

8. The microwave limiting device capable of removing peak leakage according to claim 7, characterized in that: The waveguide application model is applicable to the lowest-order mode TE10 of a rectangular waveguide.

9. The microwave amplitude limiting device capable of removing peak leakage according to claim 7, characterized in that: The coupling structure is a waveguide section between two adjacent waveguide resonance windows.

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