CN110221131B - A terahertz compact field test system based on electronically scanned antenna - Google Patents

Abstract

The invention discloses a terahertz compact field test system based on an electric scanning antenna, which comprises the following components: the device comprises a darkroom, a target to be tested, a fixing device, a vector network analyzer, a terahertz vector network expansion module, a computer, an electric scanning antenna and a feed module, wherein the electric scanning antenna and the feed module are both positioned in the darkroom, and the electric scanning antenna is in control connection with the terahertz vector network expansion module through the feed module. By the mode, the radar reflection section of the target to be tested or the far-field pattern data of the antenna to be tested can be obtained through the small-sized, quick and convenient terahertz compact field, and the brand-new active electric scanning antenna is adopted to replace the original emitting surface or holographic grating, so that the system cost is reduced, the use space is reduced, and meanwhile, the capability of quickly testing the small-sized compact field is provided.

Description

A terahertz compact field test system based on electronically scanned antenna

Technical Field

The present invention relates to the fields of industrial detection, scientific experiments, testing and measurement, and in particular to a terahertz compact field testing system based on an electrically scanned antenna.

Background Art

Radio technology equipment such as communication, radar, navigation, remote sensing, broadcasting, and television all transmit information through radio waves and require the radiation and reception of radio waves. In radio technology equipment, the device used to radiate and receive electromagnetic waves is called an antenna. Antennas are an indispensable and important part of radio information transmission systems. Using vector network analyzers and vector network extension modules, core parameters such as the directivity diagram of microwave to terahertz antennas can be tested to obtain the main performance parameter indicators of antennas.

There are currently three main methods for obtaining antenna parameter indicators: far-field method, near-field method and compact field method. The far-field method is very expensive, takes several months and often requires testing at a distance of tens of kilometers. The near-field method requires converting near-field data into far-field data, which has a certain error.

The compact field measurement system is an antenna measurement system that can provide a quasi-plane wave test area with excellent performance at close range. In the past, it used precise reflective surfaces or holographic gratings to transform the spherical waves generated by the feed source into plane waves at close range, thus meeting the far-field test requirements. The compact field measurement system simulates the far-field plane wave electromagnetic environment in a smaller microwave darkroom, and uses conventional far-field test equipment and methods to perform multiple measurements and studies, such as antenna pattern measurement, gain comparison, radar cross-section measurement, imaging, etc.

Traditional compact field measurement systems generally use reflective surfaces or holographic gratings to transform spherical waves into plane waves at close range. As the operating frequency increases, compact field measurement systems face many challenges:

In the terahertz frequency band, the compact field system requires higher processing accuracy of the reflective surface (accuracy <5um) and that the reflective surface is large enough to ensure sufficient quiet area. Traditional mechanical processing methods can no longer meet the requirements of high-precision and large-size reflective surface processing, and the processing cost is also increasing.

Traditional compact field systems are complex in design, occupy a large area, require time-consuming and labor-intensive installation and debugging of reflective surfaces, and have high overall operating costs.

Traditional compact field systems use mechanical turntable steering functions to achieve multi-angle scanning of targets. Traditional mechanical turntables are limited by the characteristics of mechanical physical movement, and are slow and large in size. They cannot simulate a variety of application scenarios in 5G/6G communications, nor can they provide fast and convenient compact field testing functions.

Summary of the invention

The main technical problem solved by the present invention is how to provide a terahertz compact field test system which can obtain the radar reflection cross section of a target to be tested or the far-field radiation pattern data of an antenna to be tested.

In order to solve the above technical problems, the technical solution adopted by the present invention is: to provide a terahertz compact field test system based on an electronically scanned antenna, comprising: a darkroom, a target to be measured, a fixture, a vector network analyzer, a terahertz vector network expansion module and a computer. The darkroom is a terahertz darkroom and has an internal space, the target to be measured and the fixture are both located inside the darkroom, and the target to be measured is located above the top plane of the fixture.

The computers are electrically connected to each other, and are also connected to the vector network analyzer and the terahertz vector network expansion module in sequence.

The terahertz compact field test system based on the electrically scanned antenna also includes an electrically scanned antenna and a feeding module. The electrically scanned antenna and the feeding module are both located inside the darkroom. The electrically scanned antenna and the terahertz vector network expansion module are controlled and connected via the feeding module.

Among them, after the vector network analyzer sends out a millimeter wave signal, it is amplified and frequency-multiplied to the terahertz frequency band by a terahertz vector network extension module to obtain a terahertz signal, and the terahertz signal is converted into a free space plane wave after passing through an electrically scanned antenna; the free space plane wave irradiates the target to be measured, and after being reflected by the target to be measured, it returns to the electrically scanned antenna along the original path, and after being received by the electrically scanned antenna, it is restored to a current signal, and the current signal is down-converted into a millimeter wave signal by the terahertz vector network extension module, and the millimeter wave signal returns to the vector network analyzer, and the vector network analyzer calculates parameters and stores them in a computer.

Optionally, the electronically scanned antenna is an active electronically scanned antenna, which is configured as a phased array antenna or a metamaterial electronically scanned antenna.

Optionally, the phased array antenna includes a plurality of antenna elements, and the antenna elements are arranged to form an antenna array plane.

Optionally, the antenna element includes a radio frequency signal module, a phase shifter and an amplifier, and the radio frequency signal module, the phase shifter and the amplifier are controlled and connected in sequence.

Optionally, the metamaterial electronically scanned antenna includes a plurality of metamaterial units, and the metamaterial units form a metamaterial scanning array.

Optionally, each metamaterial unit includes a varactor diode or a MEMS switch.

Optionally, the vector network analyzer is replaced by a signal source and a spectrum analyzer.

Optionally, absorbing materials of corresponding working frequency band are arranged in the terahertz darkroom.

The beneficial effects of the present invention are as follows: a miniaturized, fast, convenient, low-cost terahertz compact field can obtain the radar reflection cross section of the target to be tested or the far-field radiation pattern data of the antenna to be tested, and a new active electronically scanned antenna is used to replace the original emitting surface or holographic grating, which reduces the system cost and the usage space while providing the ability of fast testing in a miniaturized compact field.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

FIG1 is a schematic diagram of a specific embodiment of a conventional reflective surface compact field test system in the prior art;

FIG2 is a schematic diagram of a specific embodiment of a terahertz compact field test system based on an electronically scanned antenna according to the present invention;

3 is a schematic diagram of a phased array electronically scanned antenna in a specific embodiment of a terahertz compact field test system based on an electronically scanned antenna according to the present invention;

FIG4 is a schematic diagram of a metamaterial electrically scanned antenna in a terahertz compact field test system based on an electrically scanned antenna according to a specific embodiment of the present invention;

Among them, the correspondence between the reference numerals and component names in the figure is as follows: 1. darkroom; 2. target to be measured; 3. electronically scanned antenna; 31. antenna element; 311. radio frequency signal module; 312. phase shifter; 313. amplifier; 32. metamaterial unit; 4. feeding module; 5. terahertz vector network extension module; 6. vector network analyzer; 7. computer; 8. fixture.

DETAILED DESCRIPTION

The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Please refer to the accompanying drawings. In a specific embodiment of the present invention, a terahertz compact field test system based on an electronically scanned antenna is provided, comprising: a darkroom 1, a target 2 to be measured, a fixture 8, a vector network analyzer 6, a terahertz vector network expansion module 5 and a computer 8. The darkroom 1 is a terahertz darkroom and has an internal space. The target 2 to be measured and the fixture 8 are both located inside the darkroom 1. The target 2 to be measured is located above the top plane of the fixture 8. The fixture 8 is used to support and fix the target 2 to be measured. During the implementation process, absorbing materials of the corresponding working frequency band are arranged in the terahertz darkroom. The target 2 to be measured may also need to be specifically configured with a turntable or a robotic arm to achieve 1, 2, or 3-dimensional steering.

During the implementation process, the vector network analyzer 6 can emit millimeter wave signals, and the computer 7, the vector network analyzer 6, and the terahertz vector network extension module 5 are all located outside the darkroom 1. The computer 7 is electrically connected to each other. The computer 7 is also connected to the vector network analyzer 6 and the terahertz vector network extension module 5 in sequence.

In the present invention, the terahertz compact field test system based on the electronically scanned antenna also includes an electronically scanned antenna 3 and a feeding module 4. The electronically scanned antenna 3 and the feeding module 4 are both located inside the darkroom 1. The electronically scanned antenna 3 and the terahertz vector network expansion module 5 are controlled and connected via the feeding module 4.

Among them, in the specific implementation process, after the vector network analyzer 6 sends out a millimeter wave signal, it is amplified and frequency-multiplied to the terahertz frequency band by the terahertz vector network extension module 5 to obtain a terahertz signal, and the terahertz signal is converted into a free space plane wave after passing through the electronic scanning antenna 3; the free space plane wave irradiates the target 2 to be measured, and after being reflected by the target 2 to be measured, it returns to the electronic scanning antenna 3 along the original path, and the electronic scanning antenna 3 receives it and restores it to a current signal, and the current signal is down-converted into a millimeter wave signal by the terahertz vector network extension module 5, and the millimeter wave signal returns to the vector network analyzer 6, and the vector network analyzer 6 calculates the parameters and stores them in the computer 7. Thereafter, the computer 7 controls the electronic scanning antenna beam to turn to the next position, and repeats the above actions to obtain the radar reflection cross section of the target to be measured or the far-field pattern data of the antenna to be measured.

In a specific embodiment, the electronically-steered antenna 3 is an active electronically-steered antenna; the active electronically-steered antenna is configured as a phased array antenna or a metamaterial electronically-steered antenna.

Furthermore, the phased array antenna includes a plurality of antenna elements 31, and the antenna elements 31 are arranged to form an antenna array plane.

In a specific implementation process, the antenna element 31 includes a radio frequency signal module 311, a phase shifter 312 and an amplifier 313, and the radio frequency signal module 311, the phase shifter 312 and the amplifier 313 are controlled and connected in sequence.

Phased array electronically scanned antennas mainly use a large number of small antenna elements arranged into an antenna array. Each antenna unit is controlled by an independent switch. Based on the Huygens principle, by controlling the phase difference of each antenna element, it can synthesize main beams with different directions. The technology is mature and can be divided into passive phased array and active phased array according to different structures.

In another specific implementation process, the metamaterial electronically scanned antenna includes a plurality of metamaterial units 32, and the metamaterial units 32 form a metamaterial scanning array. Each metamaterial unit 32 includes a varactor diode or a MEMS switch.

The metamaterial electrically scanned antenna mainly uses metamaterials to form a new type of antenna called a leaky wave antenna. When electromagnetic waves propagate along the traveling wave structure, the electromagnetic waves will continuously radiate leaky waves outward along the traveling wave structure. This structure that generates leaky waves is a leaky wave antenna. The leaky wave antenna made of metamaterials has a "backfire-endfire" frequency scanning feature, which can widen the antenna's scanning angle to -90° to +90°. If a varactor diode is introduced into the metamaterial unit structure, scanning within a range of 180° can be achieved.

In a preferred embodiment, the terahertz standard antenna and the antenna to be tested may also be millimeter wave antennas. The vector network analyzer may work independently or in conjunction with a vector network extension module according to the operating frequency requirements. In a preferred embodiment, the vector network analyzer 6 is replaced by a signal source and a spectrum analyzer, and the vector network analyzer 6 is replaced by a spectrum analyzer and a signal source for use in conjunction with each other.

Therefore, the present invention has the following advantages: a miniaturized, fast, convenient, low-cost terahertz compact field can obtain the radar reflection cross section of the target to be tested or the far-field radiation pattern data of the antenna to be tested, and adopts a new active electronically scanned antenna to replace the original emitting surface or holographic grating, which reduces the system cost and the usage space while providing the ability of fast testing in a miniaturized compact field.

The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims (4)

1. A terahertz compact field test system based on an electronically scanned antenna, comprising: a darkroom (1), a target to be measured (2), a fixture (8), a vector network analyzer (6), a terahertz vector network extension module (5) and a computer (7), wherein the darkroom (1) is a terahertz darkroom and has an internal space, the target to be measured (2) and the fixture (8) are both located inside the darkroom (1), the target to be measured (2) is located above the top plane of the fixture (8), the vector network analyzer (6) emits a millimeter wave signal, the computer (7), the vector network analyzer (6) and the terahertz vector network extension module (5) are all located outside the darkroom (1), the computer (7) is electrically connected to each other, and the computer (7) is also connected to the vector network analyzer (6) and the terahertz vector network extension module (5) in sequence; characterized in that the terahertz compact field test system based on an electronically scanned antenna The invention also comprises an electric scanning antenna (3) and a feeding module (4), wherein the electric scanning antenna (3) and the feeding module (4) are both located inside the darkroom (1), and the electric scanning antenna (3) is connected to the terahertz vector network extension module (5) through the feeding module (4), wherein after the vector network analyzer (6) emits a millimeter wave signal, the signal is amplified and frequency-multiplied to the terahertz frequency band by the terahertz vector network extension module (5) to obtain a terahertz signal, and the terahertz signal is converted into a free space plane wave after passing through the electric scanning antenna (3); the free space plane wave irradiates the target to be measured (2), and after being reflected by the target to be measured (2), it returns to the electric scanning antenna (3) along the original path, and after being received by the electric scanning antenna (3), it is restored to a current signal, and the current signal is down-converted into a millimeter wave signal by the terahertz vector network extension module (5), and the millimeter wave signal returns to the vector network analyzer (6), and the vector network analyzer (6) calculates parameters and stores them in a computer (7); The electronically scanned antenna (3) is an active electronically scanned antenna; the active electronically scanned antenna is configured as a phased array antenna or a metamaterial electronically scanned antenna; the phased array antenna comprises a plurality of antenna elements (31), and the antenna elements (31) are arranged to form an antenna array surface; and a wave absorbing material is provided in the terahertz darkroom. 2. According to claim 1, the terahertz compact field test system based on the electronically scanned antenna is characterized in that the antenna element (31) includes a radio frequency signal module (311), a phase shifter (312) and an amplifier (313), and the radio frequency signal module (311), the phase shifter (312) and the amplifier (313) are controlled and connected in sequence. 3. The terahertz compact field test system based on the electronically scanned antenna according to claim 1 is characterized in that the metamaterial electronically scanned antenna comprises a plurality of metamaterial units (32), and the metamaterial units (32) form a metamaterial scanning array. 4. The terahertz compact field test system based on electronically scanned antenna according to claim 3, characterized in that each metamaterial unit (32) comprises a varactor diode or a MEMS switch.