A dual-polarized multifunctional active reflect-transmitter for microwave radiometer jamming

Abstract

The application relates to a dual-polarized multifunctional active reflect-transmitter for microwave radiometer interference, which comprises a plurality of periodically arrayed basic units, the basic unit comprises a dielectric layer and a top metal patch and a bottom metal patch arranged on the upper and lower surfaces of the dielectric layer respectively; the top metal patch comprises four metal branches, the metal branch comprises at least two parallel metal sheets and a vertical metal sheet, one end of the vertical metal sheet is arranged on the outermost metal sheet, and the other end is a free end and protrudes from the innermost metal sheet; the end of the free end of the top metal patch and the end of the corresponding free end of the bottom metal patch are connected through a connecting rod; a PIN diode is connected between a pair of oppositely arranged free ends of the top metal patch, and a PIN diode is connected between a pair of oppositely arranged free ends of the bottom metal patch; the application can well meet the performance requirements of identifying the interference microwave radiometer.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electromagnetic metamaterials, and particularly relates to a dual-polarized multifunctional active reflect-transmitter for microwave radiometer interference. BACKGROUND

[0002] Passive microwave thermal radiation detection is not sensitive to light conditions and visibility, has good cloud, fog, rain and snow penetration capability and environmental adaptability, and can stably obtain radiation contrast information of a target and a background under day and night and complex weather conditions, and is gradually becoming an important development direction of target detection. Under this trend, the traditional interference / stealth scheme only facing radar or infrared systems has been difficult to meet the new type of countermeasure demand, and it is necessary to study the intrinsic regulation of the target "radiation characteristics", which is an inevitable choice to improve the stealth protection level of ground high-value targets and build a new type of detection countermeasure system.

[0003] At present, existing target electromagnetic characteristic regulation technologies mainly focus on the regulation of scattering characteristics to reduce the radar detectability of the target in a specific wave band. Traditional scattering characteristic regulation methods include geometric shape design and coating of wave-absorbing materials, but they generally have problems such as complex design, limited frequency band, strong angle dependence and poor environmental adaptability, and are difficult to meet the stealth requirements under complex conditions. In recent years, metamaterials have gradually become an important research direction of target scattering characteristic regulation due to their strong designability, flexible spectral response and strong adaptability to complex electromagnetic environments. Related research has proposed various target scattering characteristic regulation methods based on metamaterials, such as metamaterial wave absorbers, frequency selective surfaces, liquid-based metamaterials and coded metamaterials, which have shown significant advantages in reducing the radar scattering cross section of the target. However, although metamaterials have great potential in target scattering characteristic regulation, research on their application in target microwave radiation characteristic regulation has not been carried out.

[0004] Once a common passive metamaterial is designed and manufactured, its working frequency, working bandwidth and other parameters are fixed, however, the electromagnetic field in the environment is mostly in a changing state, so the passive metamaterial cannot meet the dynamic electromagnetic environment many times. Multifunctional active reflect / transmitter has a broader application prospect in the fields of electromagnetic interference, electromagnetic shielding, electronic countermeasures and the like. Therefore, designing a dual-polarized multifunctional active reflect / transmitter for microwave radiometer interference is of great significance to improve the protection capability of the target. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a dual-polarized multifunctional active reflect / transmitter for microwave radiometer interference. The present application has polarization insensitivity, a relatively wide bandwidth meeting the requirements in two polarization cases, and two working states of reflection and transmission, and can well meet the performance requirements of interfering with the identification of a microwave radiometer.

[0006] The embodiment of the present application provides a dual-polarized multifunctional active reflect-transmitter for microwave radiometer interference, which comprises a plurality of periodically arrayed basic units, the basic unit comprises a dielectric layer and a top metal patch and a bottom metal patch arranged on the upper and lower surfaces of the dielectric layer respectively, the top metal patch and the bottom metal patch are of the same shape and are symmetrically arranged with respect to the dielectric layer.

[0007] The top metal patch comprises four metal branches symmetrically distributed around the center of the basic unit, the metal branch comprises at least two parallel metal sheets and a vertical metal sheet perpendicular to the metal sheet and located in the middle of the metal sheet, from the outside to the inside of the dielectric layer (the outside is the edge direction of the dielectric layer, and the inside is the center direction of the dielectric layer), the length of the metal sheet is sequentially shortened, one end of the vertical metal sheet is arranged at the outermost metal sheet, and the other end is a free end protruding from the innermost metal sheet.

[0008] The end of the free end of the top metal patch and the end of the corresponding free end of the bottom metal patch are connected by a connecting rod.

[0009] A pair of oppositely arranged free ends of the top metal patch are connected by a PIN diode, a pair of oppositely arranged free ends of the bottom metal patch are connected by a PIN diode, and the arrangement directions of the two PIN diodes intersect.

[0010] The pair of oppositely arranged free ends, i.e. two oppositely arranged free ends, so that only one PIN diode is arranged on the top metal patch, and only one PIN diode is arranged on the bottom metal patch, and the arrangement directions of the two PIN diodes intersect, that is, the pair of oppositely arranged free ends of the top metal patch and the pair of oppositely arranged free ends of the bottom metal patch are not in the same direction.

[0011] Preferably, the basic unit is square; in the same metal patch, one metal branch is rotated by 90°, 180° and 270° to obtain other three metal branches.

[0012] Preferably, the metal sheet is parallel to the side length of the basic unit.

[0013] Preferably, the number of metal sheets is three, and the outermost metal sheet is attached to the side of the basic unit.

[0014] Preferably, the metal sheet is rectangular, the side length of the basic unit is 5.5 mm, the length of the outermost metal sheet is 4.5 mm, and the length of the innermost metal sheet is 1.5 mm.

[0015] Preferably, the width of the metal sheet is 0.4 mm, and the distance between two adjacent metal sheets is 0.35 mm.

[0016] Preferably, the distance between the free ends of the two oppositely arranged vertical metal sheets is 0.8mm.

[0017] Preferably, the radius of the connecting rod is 0.1-0.15mm.

[0018] Preferably, the material of the medium layer is FR4, the relative dielectric constant is 4.3, the loss tangent is 0.025, and the thickness is 1-2mm.

[0019] The beneficial effects of the present application are that the four metal branches are combined to form a metal patch with a symmetrical geometric structure, and relatively stable dual-polarization characteristics can be obtained. In the present application, the active frequency selective surface does not need to be designed with an additional feeding network, and the metal structure is used as a bias line to feed the PIN diode, and the bias lines in the horizontal and vertical directions are separated from each other, and by controlling the switching state of the PIN diode loaded in different directions respectively, the state switching can be realized independently and controllably. The present application has independently switchable transmission state and reflection state, changes the radiation characteristics of the target, and can well simulate the environment high brightness temperature and the metal low brightness temperature, and interfere with the identification of the microwave radiometer.

[0020] The resonance point of the present application is at 6.75GHz, which is near an "atmospheric window", at this time, the influence of clouds, water vapor and rainfall on the microwave radiometer is relatively small, and the radiometer can "see through" most of the atmosphere and directly detect the ground information, therefore, the present application can greatly interfere with the detection of the microwave radiometer. In addition, the present application has polarization insensitivity and a relatively wide bandwidth that meets the requirements in two polarization cases, and can well meet the performance requirements of interfering with the identification of the microwave radiometer. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a schematic view of the overall structure of embodiment 1 of the present application.

[0022] Figure 2 It is a top view of embodiment 1 of the present application.

[0023] Figure 3 It is a side view of embodiment 1 of the present application.

[0024] Figure 4 It is a transmission coefficient curve graph when all the PIN diodes loaded on the top layer and the bottom layer in embodiment 1 of the present application are closed.

[0025] Figure 5 It is a transmission coefficient curve graph when all the PIN diodes loaded on the top layer and the bottom layer in embodiment 1 of the present application are opened.

[0026] Figure 6 It is a transmission coefficient curve graph when the diodes on the top layer and the bottom layer in comparative example 1 are closed.

[0027] Figure 7 This is a transmission coefficient curve for Comparative Example 2 where both the top and bottom diodes are turned on.

[0028] In the diagram, 1 is the dielectric layer, 2 is the top metal patch, 3 is the bottom metal patch, 4 is the first metal branch, 5 is the second metal branch, 6 is the third metal branch, 7 is the fourth metal branch, 8 is the inner metal sheet, 9 is the middle metal sheet, 10 is the outer metal sheet, 11 is the vertical metal sheet, 12 is the connecting rod, and 13 is the PIN diode. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention.

[0031] Example 1

[0032] like Figures 1-3 As shown, a dual-polarized multifunctional active reflector-transmitter for microwave radiometer interference includes multiple periodically arrayed basic units. Each basic unit includes a dielectric layer 1 and a top metal patch 2 and a bottom metal patch 3 respectively disposed on the upper and lower surfaces of the dielectric layer 1. The top metal patch 2 and the bottom metal patch 3 have the same shape and are symmetrically arranged relative to the dielectric layer 1, i.e., mirror symmetry.

[0033] The top metal patch 2 includes four metal branches symmetrically distributed around the center of the base unit (namely, the first metal branch 4, the second metal branch 5, the third metal branch 6, and the fourth metal branch 7). Each metal branch includes at least two parallel metal sheets (three in Embodiment 1, namely, the outer metal sheet 10, the middle metal sheet 9, and the inner metal sheet 8) and a vertical metal sheet 11 perpendicular to the metal sheets and located in the middle of the metal sheets. From the outside to the inside of the dielectric layer 1, the length of the metal sheets decreases sequentially. One end of the vertical metal sheet 11 is located on the outermost metal sheet (in Embodiment 1, the outer metal sheet 10 is attached to the edge of the base unit, and the end of the vertical metal sheet 11 is located on the outer metal sheet 10 and does not protrude from the outer metal sheet 10), and the other end is a free end that protrudes from the innermost metal sheet (i.e., the inner metal sheet 8).

[0034] The end of the free end of the top layer metal patch 2 and the end of the free end of the corresponding bottom layer metal patch 3 are connected by a connecting rod 12; the "corresponding free end" refers to the free ends of the two metal branches symmetrical to the dielectric layer 1, such as the end of the free end of the vertical metal sheet 11 on the first metal branch 4 of the top layer metal patch 2 and the end of the free end of the corresponding vertical metal sheet 11 on the bottom layer metal patch 3 are connected by the connecting rod 12, the connecting rod 12 is made of conductive material, such as metal material, a through hole is formed on the dielectric layer 1, and the connecting rod 12 passes through the through hole to connect the free end.

[0035] The top layer metal patch 2 has a PIN diode 13 connected between a pair of oppositely arranged free ends, and the bottom layer metal patch 3 has a PIN diode 13 connected between a pair of oppositely arranged free ends, and the setting directions of the two PIN diodes 13 intersect, such as in example 1, the top layer metal patch 2 has a PIN diode 13 arranged between the free ends of the second metal branch 5 and the fourth metal branch 7, and in the bottom layer metal patch 3, the PIN diode 13 is arranged between the corresponding metal branches of the first metal branch 4 and the third metal branch 6, therefore, the two PIN diodes 13 intersect when they are in the same projection plane, as shown in example 1, they are orthogonal, and the PIN diode 13 can be an SMP1321 series low-capacitance plastic package diode, packaged as SC-79.

[0036] In this way, in combination with the arrangement of the connecting rod 12, the second metal branch 5 and the fourth metal branch 7 on the top layer metal patch 2 and the bottom layer metal patch 3 are connected as a whole, and the first metal branch 4 and the third metal branch 6 on the top layer metal patch 2 and the bottom layer metal patch 3 are connected as a whole.

[0037] As shown in Figure 1 The base unit is square; in the same metal patch, one metal branch is rotated by 90°, 180°, and 270° to obtain another three metal branches, i.e., the first metal branch 4, the second metal branch 5, the third metal branch 6, and the fourth metal branch 7, the first metal branch 4 and the third metal branch 6 are oppositely arranged, and the second metal branch 5 and the fourth metal branch 7 are oppositely arranged.

[0038] As shown in Figure 1 The number of metal sheets is three, and from the edge of the base unit to the center direction, they are outer metal sheet 10, middle metal sheet 9, and inner metal sheet 8, and the length is shortened in turn. The metal sheet is parallel to the side length of the base unit. The outermost metal sheet (i.e., the outer metal sheet 10) is attached to the side of the base unit.

[0039] The metal sheet is rectangular, and the radius of the connecting rod is 0.1-0.15mm, and in example 1, it is 0.13mm.

[0040] The material of the medium layer 1 is FR4, the relative dielectric constant is 4.3, the loss tangent is 0.025, and the thickness is 1-2 mm, and the specific embodiment of the embodiment 1 is h=1.4 mm. The side length of the basic unit is 5.5 mm, the length L1 of the outermost metal sheet (i.e. the outer metal sheet 10) is 4.5 mm, the length L2 of the middle metal sheet 9 is 3.0 mm, the length L3 of the innermost metal sheet (i.e. the inner metal sheet 8) is 1.5 mm, the width w of the metal sheet is 0.4 mm, the distance g between two adjacent metal sheets is 0.35 mm, and the distance L4 between the free ends of two oppositely arranged vertical metal sheets 11 is 0.8 mm.

[0041] Embodiment 2

[0042] The simulation results of the transmission coefficient S21 of the structure of the embodiment 1 in the frequency range of 4-10 GHz are obtained by simulation with the commercial electromagnetic simulation software CST Studio Suite.

[0043] Figures 4-5 The simulation results of the transmission coefficient S21 of the two independently switchable working states of the microwave radiometer interference-oriented dual-polarized multifunctional active reflectance / transmittance device of the embodiment when the PIN diode switch state changes in the horizontal direction and the vertical direction are given. Among them Figure 4 is the transmission coefficient S21 when all the PIN diodes 13 loaded in the top metal patch 2 and the bottom metal patch 3 of the microwave radiometer interference-oriented dual-polarized multifunctional active reflectance / transmittance device are closed, Figure 5 is the transmission coefficient S21 when all the PIN diodes 13 loaded in the top metal patch 2 and the bottom metal patch 3 of the microwave radiometer interference-oriented dual-polarized multifunctional active reflectance / transmittance device are opened.

[0044] When all the PIN diodes 13 loaded in the top metal patch 2 and the bottom metal patch 3 are closed, the microwave radiometer interference-oriented dual-polarized multifunctional active reflectance / transmittance device can simultaneously reflect TE polarized incident electromagnetic waves and TM polarized incident electromagnetic waves, the-10 dB bandwidth of the transmission coefficient in the TE polarization case is 4.03 GHz (4.03-8.00 GHz), the-10 dB bandwidth of the transmission coefficient in the TM polarization case is 4.07 GHz (4.03-8.10 GHz), and both polarizations show reflection characteristics. When all the PIN diodes 13 loaded in the top metal patch 2 and the bottom metal patch 3 are opened, the microwave radiometer interference-oriented dual-polarized multifunctional active reflectance / transmittance device can simultaneously transmit TE polarized incident electromagnetic waves and TM polarized incident electromagnetic waves, the transmission coefficient at 6.75 GHz in the TE polarization case is-0.77 dB, the transmission coefficient at 6.75 GHz in the TM polarization case is-0.83 dB, and both polarizations of the incident electromagnetic waves show a wave-transparent state.

[0045] Comparative Example 1

[0046] Based on Example 1, the middle metal sheet 9 and the inner metal sheet 8 are removed, and the outer metal sheet 10 is retained. Everything else is the same as in Example 1.

[0047] The structure of Comparative Example 1 was tested using the simulation method described in Example 2, and the results were as follows: Figure 6 The transmission coefficient S21 curves are shown when all PIN diodes 13 loaded on the top metal patch 2 and the bottom metal patch 3 are turned off. The resonant points of the TE-polarized incident electromagnetic waves and the TM-polarized incident electromagnetic waves are shifted down to 6.55 GHz, deviating from the "atmospheric window" frequency of the microwave radiometer operation. Therefore, the shape of the metal plates in the dual-polarized multifunctional active reflector / transmitter of this invention, configured as in Example 1, represents the optimal structure for performance.

[0048] Comparative Example 2

[0049] Based on Example 1, the length of the outer metal sheet 10 is reduced to 1.5 mm, and everything else is the same as in Example 1.

[0050] The structure of Comparative Example 2 was tested using the simulation method described in Example 2, and the results were as follows: Figure 7 The transmission coefficient S21 curves shown are displayed when all PIN diodes 13 loaded on the top metal patch 2 and the bottom metal patch 3 are turned on. The transmission coefficient at TE-polarized incident electromagnetic wave 6.75 GHz decreases from -0.77 dB to -2.14 dB, and the transmission coefficient at TM-polarized incident electromagnetic wave 6.75 GHz decreases from -0.83 dB to -2.29 dB, indicating a deterioration in transmission performance. Therefore, the shape of the metal sheets in the dual-polarized multifunctional active reflector / transmitter of this invention, configured as in Example 1, represents the optimal structure for performance.

[0051] In this invention, symmetrically distributed metal patch structures are loaded on the upper and lower surfaces of the dielectric layer 1. The metal branches consist of three horizontal rectangular metal strips and one vertical rectangular metal strip. The switching between a transmitter and a reflector is achieved by controlling the on / off state of the PIN diodes 13 in the top metal patch 2 and the bottom metal patch 3. For some metallic targets, due to the extremely low emissivity of metal in the microwave band, they only reflect cold background radiation from the sky, exhibiting a low brightness temperature. When the dual-polarized multifunctional active reflector / transmitter operates as a reflector, it exhibits low brightness temperature characteristics very similar to those of metal. When the dual-polarized multifunctional active reflector / transmitter operates as a transmitter, its brightness temperature matches that of the surrounding environment. Therefore, by loading dual-polarized multifunctional active reflectors / transmitters in different states, the radiation characteristics of the target can be altered, thereby interfering with the microwave radiometer's identification and detection of the target.

[0052] Those skilled in the art should understand that the above discussion of any embodiment is only intended to be illustrative and is not intended to be limiting to the scope of the present application; the above embodiments or technical features among different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes to different aspects of one or more embodiments of the present application as described above, which are not provided in details for the sake of brevity.

[0053] One or more embodiments of the present application are intended to cover all such alternatives, modifications, and variations as falling within the broad scope of the application. Accordingly, any omission, modification, equivalent replacement, improvement, etc. made within the spirit and principle of one or more embodiments of the present application should be included in the scope of the present application.

Claims

1. A dual-polarization multifunctional active reflector-transmitter for microwave radiometer interference, characterized in that, The base unit includes multiple periodically arrayed basic units, each including a dielectric layer (1) and a top metal patch (2) and a bottom metal patch (3) respectively disposed on the upper and lower surfaces of the dielectric layer (1). The top metal patch (2) and the bottom metal patch (3) have the same shape and are symmetrically disposed relative to the dielectric layer (1). The top metal patch (2) includes four metal branches symmetrically distributed around the center of the base unit. Each metal branch includes at least two parallel metal sheets and a vertical metal sheet (11) perpendicular to the metal sheets and located in the middle of the metal sheets. From the outside to the inside of the dielectric layer (1), the length of the metal sheets decreases sequentially. One end of the vertical metal sheet (11) is located on the outermost metal sheet, and the other end is a free end that protrudes from the innermost metal sheet. The free ends of the top metal patch (2) and the corresponding free ends of the bottom metal patch (3) are connected by a connecting rod (12). A PIN diode (13) is connected between one pair of oppositely arranged free ends of the top metal patch (2), and a PIN diode (13) is connected between one pair of oppositely arranged free ends of the bottom metal patch (3). The arrangement directions of the two PIN diodes (13) intersect. The basic unit is a square; within the same metal patch, one metal branch is rotated by 90°, 180°, and 270° respectively to obtain three other metal branches; The metal sheet is parallel to the side length of the basic unit; The number of metal sheets is 3, and the outermost metal sheet is attached to the edge of the base unit; The metal sheet is rectangular, with a side length of 5.5mm for the basic unit, a length of 4.5mm for the outermost metal sheet, and a length of 1.5mm for the innermost metal sheet. The width of the metal sheet is 0.4 mm, and the distance between two adjacent metal sheets is 0.35 mm.

2. The dual-polarization multifunctional active reflector-transmitter as described in claim 1, characterized in that, The distance between the free ends of the two opposing vertical metal plates (11) is 0.8 mm.

3. The dual-polarization multifunctional active reflector-transmitter as described in claim 1, characterized in that, The radius of the connecting rod (12) is 0.1-0.15 mm.

4. The dual-polarization multifunctional active reflector-transmitter as described in claim 1, characterized in that, The dielectric layer (1) is made of FR4, with a relative permittivity of 4.3, a loss tangent of 0.025, and a thickness of 1-2 mm.

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