Waveguide amplitude limiting filter structure and radar system

Abstract

The present application relates to a kind of waveguide amplitude limiting filter structure and radar system, the structure includes waveguide body, first pin and second pin.First pin and second pin are inserted in the waveguide H face center of waveguide body, first pin and second pin are arranged along the waveguide H face center line, and the distance between two pins is set distance.First pin penetrates waveguide body and the pin diameter is first set diameter, and the depth of second pin inserted into waveguide body is set depth and the pin diameter is second set diameter.First set diameter is greater than second set diameter.First pin is divided into three sections and is connected by diode between every two sections, first pin is provided with cylindrical encapsulation layer for pin structure support, and second pin is cylindrical pin.Greatly improves waveguide filtering and strong electromagnetic protection performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of microelectronics, in particular to a waveguide amplitude limiting filter structure and a radar system. BACKGROUND

[0002] With the rapid development of microelectronics technology, the circuit integration degree is greatly improved, the device function and performance are greatly improved, which brings the performance of various electronic systems such as radar, communication, navigation, control and guidance. However, the increase of circuit integration degree and the reduction of system size will bring the increase of sensitivity and the decrease of anti-interference ability. As a new type of directional energy weapon, high power microwave (HPM) has been successfully applied in actual combat. HPM generally refers to narrow spectrum HPM, and sometimes UWB strong electromagnetic pulse is also classified as HPM. By comprehensively analyzing the current situation and development prospect of high power microwave technology and microelectronics technology, there is still a large space for improvement in the output power and conversion efficiency of microwave source. In the strong electromagnetic transient pulse environment, various electronic systems are likely to be disturbed or even damaged, and their protection ability is greatly challenged.

[0003] In the high-tech information age, radar has been practically applied in many fields, and its role is often very important, and it is extremely easy to become a high power microwave (HPM) attack object, especially the early warning and guidance radar working in the gigahertz frequency band. Rectangular waveguide is an important channel for transmitting microwave signals in radar system, which has the characteristics of single-mode transmission, small insertion loss, filter implementation and simple structure, and is widely used in radar system. Therefore, it is of great significance to study the rectangular waveguide protection device. However, the traditional waveguide amplitude limiting filter structure still has the technical problem of poor protection performance. SUMMARY

[0004] Therefore, it is necessary to provide a waveguide amplitude limiting filter structure and a radar system, which can greatly improve the waveguide filtering and strong electromagnetic protection performance.

[0005] In order to achieve the above purpose, the technical scheme adopted by the embodiments of the present application is as follows:

[0006] On the one hand, a waveguide amplitude limiting filter structure is provided, which comprises a waveguide body, a first pin and a second pin. The first pin and the second pin are inserted into the center of the waveguide H plane of the waveguide body, the first pin and the second pin are arranged along the center line of the waveguide H plane, and the distance between the two pins is a set distance. The first pin penetrates the waveguide body and the pin diameter is a first set diameter, the second pin is inserted into the waveguide body to a depth of a set depth and the pin diameter is a second set diameter; the first set diameter is greater than the second set diameter.

[0007] The first pin is divided into three sections and each two sections are connected by a diode, the first pin is provided with a cylindrical packaging layer for supporting the pin structure, and the second pin is a cylindrical pin.

[0008] In another aspect, a radar system is also provided, which comprises a system body, a waveguide body, a first pin and a second pin, the first pin and the second pin are inserted into the center of the waveguide H surface of the waveguide body, the first pin and the second pin are arranged along the center line of the waveguide H surface, and the distance between the two pins is a set distance, the first pin penetrates the waveguide body and the pin diameter is a first set diameter, the second pin is inserted into the waveguide body to a depth of a set depth and the pin diameter is a second set diameter; the first set diameter is greater than the second set diameter.

[0009] The first pin is divided into three sections and each two sections are connected by a diode, the first pin is provided with a cylindrical packaging layer for supporting the pin structure, and the second pin is a cylindrical pin.

[0010] One of the above technical solutions has the following advantages and beneficial effects:

[0011] The waveguide limiting amplitude filter structure and the radar system described above, by inserting two pins of different specifications from the waveguide H surface along the center line of the waveguide H surface and at a certain distance into the center of the waveguide H surface, one of the pins is divided into three sections, each two sections of the pin are connected using a cylindrical diode, which is equivalent to a series circuit of a capacitor and an inductor; the other pin is equivalent to a series circuit of a capacitor and an inductor. After the pins are inserted, the entire limiting amplitude filter structure is equivalent to a parallel connection of two capacitors and inductors. When the signal frequency is within the passband of the waveguide filter structure and the signal energy is small, the field strength is not enough to turn on the diode, the signal transmitted in the waveguide can penetrate the waveguide limiting amplitude filter structure with low loss; when the signal frequency is within the passband of the waveguide filter structure and the transmitted signal energy is large, the field strength is enough to turn on the diode, the passband of the waveguide limiting amplitude filter structure is closed, and the energy transmitted in the waveguide is reflected; when the signal frequency is outside the passband of the waveguide filter structure, the signal transmitted in the waveguide cannot pass through the waveguide limiting amplitude filter structure, thereby having the characteristics of low loss for low field strength signals within the passband, reflection of strong field signals, and reflection of signals outside the passband. In this way, the filtering and limiting amplitude functions are integrated inside the waveguide, effectively improving the protection effect of strong electromagnetic coupling energy, achieving the effect of greatly improving the waveguide filtering and strong electromagnetic protection performance, and compared with the traditional technology, the pin and nonlinear device loading structure are used, the processing and manufacturing process is simpler and more efficient, and it is more convenient for production and implementation. BRIEF DESCRIPTION OF DRAWINGS

[0012] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated in and constitute a part of this application. The embodiments of the application illustrated in the drawings, and their description, are presented to add generic structure and an understanding of the application. They are intended to be not an undue limitation on the scope of the application.

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0014] Figure 1 A schematic diagram of the overall structure of the waveguide limiting filter structure in one embodiment;

[0015] Figure 2 A schematic diagram of the cross-sectional structure of the waveguide limiting filter structure in one embodiment;

[0016] Figure 3 An equivalent circuit diagram of the waveguide limiting filter structure in one embodiment;

[0017] Figure 4 A transmission characteristic diagram of the waveguide limiting filter structure in one embodiment under different states. DETAILED DESCRIPTION

[0018] In order to make the above-mentioned purposes, features and advantages of the present application more apparent and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings. In the following description, many specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the scope of the present application, so the present application is not limited to the specific embodiments disclosed below.

[0019] Currently, there are research subjects that have proposed a waveguide limiter design scheme, which involves plasma and loaded circuits, etc., but no waveguide filter structure related design with similar protective function to the design structure of the present application has been found. The existing waveguide limiter design ideas mainly include three schemes: the first scheme is to put a circuit board loaded with a nonlinear device into the waveguide, which utilizes the characteristics of the nonlinear device that presents high impedance when weak field is incident and presents low impedance when strong field is incident, so that the impedance in the waveguide changes with the energy of the electromagnetic wave transmitted inside, showing the characteristics of weak field transmission and strong field reflection or absorption. However, the position of the circuit board loaded into the waveguide is difficult to fix, and once the position of the circuit board deviates, the electromagnetic wave transmission characteristics will also change. The second scheme is to load an external waveguide box, and to realize the waveguide limiting effect by loading a complex detection and limiting structure outside the waveguide. However, such a waveguide limiter structure is complex, has high processing cost and is difficult to manufacture. The third scheme is to seal plasma in the waveguide, which utilizes the strong field ionization characteristics of the plasma to realize the characteristics of strong field reflection and weak field low loss transmission. However, the plasma ionization threshold is high, and the transmitted electromagnetic energy may exceed the threshold of the backend sensitive device.

[0020] The embodiments of the present application will be described in detail below with reference to the drawings.

[0021] In one embodiment, referring to Figure 1 , there is provided a waveguide amplitude limiting filter structure 100, comprising a waveguide body 11, a first pin 12 and a second pin 13. The first pin 12 and the second pin 13 are inserted in the center of the waveguide H surface of the waveguide body 11, the first pin 12 and the second pin 13 are arranged along the center line of the waveguide H surface, and the distance between the two pins is a set distance. The first pin 12 penetrates the waveguide body 11 and the pin diameter is a first set diameter. The second pin 13 is inserted into the waveguide body 11 to a depth of a set depth and has a pin diameter of a second set diameter; the first set diameter is greater than the second set diameter. The first pin 12 is divided into three sections, and each two sections are connected by a diode. The first pin 12 is provided with a cylindrical packaging layer for supporting the pin structure, and the second pin 13 is a cylindrical pin.

[0022] It can be understood that in the design process of the waveguide amplitude limiting filter structure 100, the waveguide amplitude limiting filter structure 100 loaded with pins and diodes fully utilizes the characteristics that the equivalent inductance and capacitance of the pin loaded with diodes change with the on-off state of the diode, achieving the purpose of small signal filtering and large signal protection. The diode can be a PIN diode in the art, or a Schottky diode. If a Schottky diode is used, only two Schottky diodes in parallel connection are needed between each two sections of the first pin 12 to achieve better amplitude limiting protection effect. The overall shape of the two pins is a common cylindrical shape, which can make it easier to adjust the depth of insertion into the waveguide during the design process of the waveguide amplitude limiting filter structure 100. The depth adjustment method can be, but is not limited to, screw adjustment or sliding adjustment. In addition, if the convenience of adjusting the insertion depth of the pin during the design process is not considered, the pin can also be designed as a cylindrical pin with other geometric shapes, which can theoretically achieve the required amplitude limiting protection effect, but the depth adjustment of the pin inserted into the waveguide is more difficult.

[0023] The waveguide body 11 is a rectangular waveguide, which is a main structure for loading the two pins described above. The waveguide is a waveguide structure for transmitting electromagnetic waves, which is defined by a conductor boundary. In the waveguide, electromagnetic waves propagate in space through reflection and refraction. The waveguide can be divided into TE mode (Transverse Electric Field Mode) and TM mode (Transverse Magnetic Field Mode). The H-plane refers to a propagation mode in the waveguide, which is the Transverse Magnetic Mode, also known as H mode. In the H-plane mode, the magnetic field lines of the magnetic field are perpendicular to the propagation direction of the waveguide, and the electric field exists in the cross-sectional plane of the waveguide. This means that the electric field is perpendicular to the width direction of the waveguide, and the magnetic field is perpendicular to the height direction of the waveguide. The magnetic field of the H-plane mode is perpendicular to the propagation direction of the waveguide. Arranging along the H-plane center line of the waveguide means arranging the pins on the center line of the waveguide cross section, such as the AA' center line shown in Figure 2 where r0 represents the first specified diameter, l1 represents the specified distance, r1 represents the second specified diameter, and h1 represents the specified depth. This arrangement is commonly used in the design and arrangement of components in waveguide systems to achieve optimal propagation characteristics, minimum loss, and maximum efficiency. By arranging the elements along the H-plane center line of the waveguide, the symmetry of the electromagnetic field distribution can be ensured, and the cross-coupling and loss of the electromagnetic mode can be reduced. This is very important for many waveguide applications, such as microwave circuits, antennas, and optical fiber communication. The H-plane center of the waveguide refers to the position of the two pins near the H-plane center of the waveguide body 11, which is centered on the midpoint of the H-plane center line of the waveguide, for example, symmetrically arranged with the midpoint of the H-plane center line of the waveguide as the center, and the sum of the distances from the two pins to the midpoint is the specified distance. The specific dimensions of the specified distance, pin diameter, and insertion depth can be determined by fitting calculation using existing numerical methods in the field, or can be selected by experimental comparison and testing, as long as the amplitude limiting and filtering protection effect required by the actual application can be obtained.

[0024] The waveguide amplitude limiting filter structure 100 is obtained by inserting two kinds of pins from the waveguide H surface along the waveguide H surface center line and at a certain distance in the waveguide H surface center, one of the pins is divided into three sections, and the two sections of the pin are connected by using a cylindrical diode, which is equivalent to a capacitor and an inductor in series; the other pin is equivalent to a capacitor and an inductor in series. After the pins are inserted, the whole amplitude limiting filter structure is equivalent to two capacitors and inductors in parallel. When the signal frequency is in the passband of the waveguide filter structure, and the signal energy is small, and the field strength is not enough to make the diode conduct, the signal transmitted in the waveguide can penetrate the waveguide amplitude limiting filter structure with low loss; when the signal frequency is in the passband of the waveguide filter structure, and the transmission signal energy is large, and the field strength is enough to make the diode conduct, the passband of the waveguide amplitude limiting filter structure is closed, and the energy transmitted in the waveguide is reflected; when the signal frequency is out of the passband of the waveguide filter structure, the signal transmitted in the waveguide cannot pass through the waveguide amplitude limiting filter structure, thereby having the characteristics of low loss of low field strength signal in the passband, reflection of strong field signal, and reflection of signal out of the passband. In this way, the filtering and limiting functions are integrated in the waveguide, which effectively and greatly improves the protection effect of strong electromagnetic coupling energy, and achieves the effect of greatly improving the waveguide filtering and strong electromagnetic protection performance. Moreover, compared with the traditional technology, the pin and nonlinear device loading structure are used, the processing and manufacturing process is simpler and more efficient, and the production is more convenient.

[0025] It should be noted that in the design process of the waveguide amplitude limiting filter structure 100, the insertion of the pin in the waveguide H surface can be regarded as connecting a reactance in parallel in a two-port network. With different insertion depths of the pin, different reactance sizes are shown. When the diode is forward biased, its resistance is very small, close to short circuit, and when it is reverse biased, its resistance is very large, close to open circuit, and it is commonly used as a radio frequency switch and a radio frequency protection circuit.

[0026] The cylindrical packaged diode is introduced into the waveguide filter design, and two kinds of pins are inserted into the waveguide to form the initial structure of the filter structure. In order to fix the PIN diode, the first pin 12 is inserted into the bottom surface and the top surface of the rectangular resonant cavity, and the pin is divided into three sections from the bottom to the top. The cylindrical diode is connected between the two adjacent sections of the pin. The size of the first pin 12 loaded with the diode is optimized through experiments to realize the filtering function of the waveguide structure. When the electromagnetic energy intensity propagating in the rectangular waveguide is not enough to make the diode conduct, i.e. it does not exceed the threshold and the signal frequency is in the filtering passband, the signal passes through the waveguide filter with low loss; when the signal frequency is in the passband, and the signal energy intensity makes the diode conduct, i.e. it exceeds the threshold, the passband is closed, and the signal is reflected and cannot pass through the designed structure; when the signal frequency propagating in the rectangular waveguide is out of the passband, the signal is reflected.

[0027] Two kinds of pin structures with different specifications are inserted from the H plane and arranged along the center line of the rectangular waveguide. The two kinds of pin structures are separated by a certain distance. The equivalent circuit of the designed structure is shown in Figure 3 The metal part of the first pin structure (i.e., the first pin 12) is equivalent to an inductor L1. After loading a cylindrical diode, the equivalent circuit of the pin structure is a series circuit of the inductor L1 and the diode D. The second pin 13 is equivalent to a series structure of an inductor L2 and a capacitor C. The size of the inductor can be adjusted by changing the size of the pin and the depth of insertion into the waveguide. The waveguide part between the two pins is equivalent to a transmission line with a length of l1 and a characteristic impedance of Z0.

[0028] When the transmitted signal frequency is within the passband of the waveguide limiting filter structure and the intensity is small, the diode is not turned on, and the transmitted signal passes through the waveguide limiting filter structure with low loss. When the transmitted signal frequency is outside the passband of the waveguide limiting filter structure and the intensity is large enough to turn on the diode, the passband of the waveguide limiting filter structure is closed, and the signal is reflected. When the signal frequency is not within the passband of the waveguide limiting filter structure, the signal is reflected regardless of the signal intensity, thereby realizing the required waveguide filtering and strong electromagnetic protection performance.

[0029] In an embodiment, further, the diode is a PIN diode. It can be understood that, in this embodiment, the PIN diode is used as the connecting element between every two sections of the first pin 12. The PIN diode is loaded to realize the variable impedance function. The on-off characteristics of the PIN diode can be used to more conveniently and efficiently realize the required limiting filter effect, and the structure is simple and has higher reliability.

[0030] In an embodiment, further, the cylindrical packaging layer is a PMI foam layer. It can be understood that, in this embodiment, the three-section structure of the first pin 12 is wrapped with a high-strength and high-temperature-resistant PMI foam layer, which is used to support the sectional pin structure and fully ensure the structural reliability and performance stability of the pin.

[0031] In an embodiment, further, the distance is 36 mm. The first pin 12 has a first specified diameter of 8 mm, and the second pin 13 has a second specified diameter of 4 mm. The specified depth of the second pin 13 is 36 mm. It can be understood that, in this embodiment, one kind of design structure with better effect is selected. The two ends of the rectangular waveguide are energy input ports, the port face length a is 98.06 mm, and the width b is 49.03 mm. The specified distance between the two pin structures is 36 mm. The second pin 13 without a loaded PIN diode is a cylindrical structure with a radius of 2 mm, and the depth of insertion into the rectangular waveguide is 36 mm. The first pin 12 with a three-section structure and a loaded PIN diode is a cylindrical structure with a radius of 4 mm. The loaded PIN diode model can be, but is not limited to, MA4L021-120. The electromagnetic simulation verification is as follows:Figure 4 As shown, it has better performance in relative to other dimensions, such as lower loss of low field signal in passband, more sufficient reflection of strong field signal, and better reflection of signals out of passband.

[0032] In one embodiment, a radar system is also provided, which comprises a system body, a waveguide body 11, a first pin 12 and a second pin 13. The first pin 12 and the second pin 13 are inserted in the center of the waveguide H surface of the waveguide body 11, the first pin 12 and the second pin 13 are arranged along the center line of the waveguide H surface, and the distance between the two pins is a set distance. The first pin 12 penetrates the waveguide body 11 and the pin diameter is a first set diameter. The second pin 13 is inserted into the waveguide body 11 to a depth of a set depth and has a pin diameter of a second set diameter. The first set diameter is greater than the second set diameter. The first pin 12 is divided into three sections, and each two sections are connected by a diode. The first pin 12 is provided with a cylindrical packaging layer for supporting the pin structure, and the second pin 13 is a cylindrical pin.

[0033] It can be understood that the explanations and descriptions of the above components can be understood in the same way as the corresponding features of the waveguide limiting amplitude filter structure 100 described above. In this embodiment, the system body refers to the remaining system structure body of the radar system except for the improved waveguide limiting amplitude filter structure described above. Those skilled in the art can understand that the above radar system can also include other additional components in addition to the above components. The specific structure can be understood in the same way as the existing structure of different radar systems, and this specification will not be expanded and described in detail.

[0034] The radar system is characterized in that two kinds of pins are inserted into the center of the waveguide H plane along the center line of the waveguide H plane and at a certain distance, one of which is divided into three sections, and the two sections are connected by a cylindrical diode, which is equivalent to a series circuit of a capacitor and an inductor; the other pin is equivalent to a series circuit of a capacitor and an inductor. After the pins are inserted, the entire amplitude limiting filter structure is equivalent to two parallel circuits of a capacitor and an inductor. When the signal frequency is within the passband of the waveguide filter structure, and the signal energy is small, the field strength is not enough to turn on the diode, the signal transmitted in the waveguide can penetrate the waveguide amplitude limiting filter structure with low loss; when the signal frequency is within the passband of the waveguide filter structure, and the transmitted signal energy is large, the field strength is enough to turn on the diode, the passband of the waveguide amplitude limiting filter structure is closed, and the energy transmitted in the waveguide is reflected; when the signal frequency is outside the passband of the waveguide filter structure, the signal transmitted in the waveguide cannot pass through the waveguide amplitude limiting filter structure, thereby having the characteristics of low field strength signal low loss in the passband, strong field signal reflection, and all signal reflection outside the passband. In this way, the filtering and limiting functions are integrated in the waveguide, effectively improving the protection effect of strong electromagnetic coupling energy, and achieving the effect of greatly improving the waveguide filtering and strong electromagnetic protection performance. Moreover, compared with the traditional technology, the pin and nonlinear device loading structure are used, the processing and manufacturing process is simpler and more efficient, and the production is more convenient to realize.

[0035] In one embodiment, the diode is a PIN diode.

[0036] In one embodiment, the cylindrical packaging layer is a PMI foam layer.

[0037] In one embodiment, the set distance is 36 mm. The first set diameter of the first pin 12 is 8 mm, and the second set diameter of the second pin 13 is 4 mm. The set depth of the second pin 13 is 36 mm.

[0038] It can be understood that the explanation and description of the above radar system can be understood in the same way as the explanation and description of the corresponding embodiments of the waveguide amplitude limiting filter structure 100, which will not be repeated here.

[0039] The technical features of the above embodiments can be combined in any way. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not exist, they should be considered as the scope of the description.

[0040] The above embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be pointed out that for ordinary skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

[0041] In addition, the terms "first", "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly specified and limited.

[0042] In the present application, unless otherwise explicitly specified and limited, the terms "connected", "connected" and other terms should be understood in a broad sense, for example, it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

Claims

1. A waveguide amplitude limiting filter structure, characterized by, The application relates to a waveguide body, a first pin and a second pin, the first pin and the second pin are inserted in the waveguide H plane center of the waveguide body, the first pin and the second pin are arranged along the waveguide H plane center line, the distance between the two pins is a set distance, the first pin penetrates the waveguide body and has a first set diameter, the second pin is inserted into the waveguide body to a set depth and has a second set diameter; the first set diameter is larger than the second set diameter. The first pin is divided into three sections and connected by a diode between each two sections, the first pin is provided with a cylindrical packaging layer for supporting the pin structure, and the second pin is a cylindrical pin.

2. The waveguide amplitude limiting filter structure of claim 1, wherein, The diode is a PIN diode.

3. The waveguide amplitude limiting filter structure of claim 1 or 2, wherein, The cylindrical packaging layer is a PMI foam layer.

4. The waveguide amplitude limiting filter structure of claim 3, wherein, The set distance is 36 mm, the first set diameter of the first pin is 8 mm, the second set diameter of the second pin is 4 mm, and the set depth of the second pin is 36 mm.

5. A radar system, characterized by The application relates to a waveguide body, a first pin and a second pin, the first pin and the second pin are inserted in the waveguide H plane center of the waveguide body, the first pin and the second pin are arranged along the waveguide H plane center line, the distance between the two pins is a set distance, the first pin penetrates the waveguide body and has a first set diameter, the second pin is inserted into the waveguide body to a set depth and has a second set diameter; the first set diameter is larger than the second set diameter. The first pin is divided into three sections and connected by a diode between each two sections, the first pin is provided with a cylindrical packaging layer for supporting the pin structure, and the second pin is a cylindrical pin.

6. The radar system of claim 5, wherein, The diode is a PIN diode.

7. The radar system of claim 5 or 6, characterized in that, The cylindrical packaging layer is a PMI foam layer.

8. The radar system of claim 7, wherein, The set distance is 36 mm, the first set diameter of the first pin is 8 mm, the second set diameter of the second pin is 4 mm, and the set depth of the second pin is 36 mm.

Images