CN109103596B

CN109103596B - Dual-polarized high-isolation antenna and satellite-borne synthetic aperture radar active scaler

Info

Publication number: CN109103596B
Application number: CN201810946733.2A
Authority: CN
Inventors: 李亮; 洪峻; 明峰; 孙巍; 王宇; 朱勇涛
Original assignee: Institute of Electronics of CAS
Current assignee: Institute of Electronics of CAS
Priority date: 2018-08-17
Filing date: 2018-08-17
Publication date: 2020-10-30
Anticipated expiration: 2038-08-17
Also published as: CN109103596A

Abstract

A dual-polarized high isolation antenna, comprising: the conical horn is used as a transmitting end or a receiving end of a signal; and the orthogonal mode coupler is connected with the conical horn and used for realizing waveguide conversion, and the dual-polarized high-isolation antenna can receive both horizontally polarized signals and vertically polarized signals. Another aspect of the present invention provides an active scaler for scaling of a space-borne synthetic aperture radar, comprising the dual-polarized high-isolation antenna described above. The scheme provided by the invention can flexibly provide various calibration scattering matrixes required by the active calibrator, reduces the complexity of the system and greatly improves the convenience in use.

Description

Dual-polarized high-isolation antenna and satellite-borne synthetic aperture radar active scaler

Technical Field

The invention relates to the technical field of radar detection, in particular to a dual-polarized high-isolation antenna and an active scaler for scaling a satellite-borne synthetic aperture radar, wherein the active scaler comprises the dual-polarized high-isolation antenna.

Background

The active scaler of the satellite-borne Synthetic Aperture Radar (SAR) is a key device for the on-orbit scaling of the satellite-borne polarized SAR, is an important component of a satellite ground system, and can be used for the polarization scaling of the satellite-borne SAR, the measurement of an antenna directional diagram, the measurement of a scaling constant, the evaluation of image quality and the like. The active scaler-based polarimetric calibration of the satellite-borne SAR is a main technical support for acquiring satellite load on-orbit distortion matrix parameters, is a basic link for realizing high-precision data processing and application of the satellite-borne SAR system, and is a key for improving the full-polarimetric application level of the satellite-borne SAR. At present, corresponding active scalers are almost developed for the all-polarization satellite-borne SAR system transmitted at home and abroad for on-orbit calibration. The antenna is a main component of the active scaler and is mainly used for receiving and transmitting satellite-borne SAR signals, and the structural form and the implementation mode of the antenna are directly related to the overall structure and the use convenience of the active scaler system.

The existing satellite-borne SAR active scaler adopts four single-polarized antennas, namely a horizontal polarized receiving antenna, a vertical polarized receiving antenna, a horizontal polarized transmitting antenna and a vertical polarized transmitting antenna, and is used for receiving and transmitting horizontal polarized signals and vertical polarized signals; some single-polarized antenna 45-degree rotation modes are adopted to realize the receiving and transmitting of horizontal polarized signals and vertical polarized signals. Although the former four-antenna form can realize all functions of the polarized active scaler, the active scaler system is very heavy due to the large number of antennas, and the use convenience of the system is greatly reduced. The latter realizes the scattering matrix of the polarized active scaler by means of 45-degree rotation, resulting in single scattering matrix, and the polarization state is very sensitive to the rotation angle, thus it is difficult to flexibly provide various scattering matrices required by the active scaler.

Disclosure of Invention

In order to avoid the problems caused by the two antenna forms, an embodiment of the present invention provides, on one hand, a dual-polarized high-isolation antenna, which is characterized in that the dual-polarized high-isolation antenna includes:

the conical horn is used as a transmitting end or a receiving end of a signal;

an orthogonal mode coupler connected with the conical horn for realizing waveguide conversion,

the dual-polarized high-isolation antenna can receive both horizontally polarized signals and vertically polarized signals.

In some embodiments, the inner wall of the conical horn comprises a corrugated structure.

In some embodiments, the conical horn is excited in operation using a mixed mode.

In some embodiments, the orthogonal mode coupler is fed using a square waveguide.

In some embodiments, the square waveguide comprises a multi-step structure to enable the conversion of the square wave guided rectangular waveguide.

Another aspect of the present invention provides an active scaler for scaling a space-borne synthetic aperture radar, comprising:

a transmitting antenna for transmitting the calibration signal;

the receiving antenna is used for receiving signals sent by the synthetic aperture radar; and

a radio frequency module, which is respectively connected with the receiving antenna and the transmitting antenna, and is used for processing the signals received by the receiving antenna and transmitting the processed signals through the transmitting antenna,

the antenna is characterized in that the receiving antenna and the transmitting antenna are both the dual-polarized high-isolation antenna.

Based on the technical scheme, the invention at least obtains the following beneficial effects:

the satellite-borne SAR active scaler and the dual-polarized high-isolation antenna provided by the invention can effectively avoid the problems caused by two forms of active scalers in the background technology, can flexibly provide various scaling scattering matrixes required by the active scaler, reduces the complexity of a system and greatly improves the use convenience.

Drawings

Fig. 1 is a schematic diagram of a dual polarized high isolation antenna in an embodiment of the present invention;

FIG. 2 is a schematic diagram of an active sealer of a satellite-borne synthetic aperture radar in an embodiment of the invention;

fig. 3 is a schematic diagram of a conical horn of the dual polarized high isolation antenna of fig. 1;

fig. 4 is a schematic diagram of an orthogonal mode coupler of the dual polarized high isolation antenna of fig. 1;

fig. 5a and 5b are graphs showing the results of the isolation measurement of the dual-polarized high-isolation antenna of fig. 1 in the horizontal polarization and the vertical polarization, respectively.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention without any inventive step, are within the scope of protection of the invention.

Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs.

Fig. 1 is a schematic diagram of a dual-polarized high-isolation antenna in an embodiment of the present invention, which includes a conical horn 1 and an orthogonal-mode coupler 2. The conical horn 1 is used as a transmitting end or a receiving end of a signal. One end of the orthogonal mode coupler 2 is connected with the small end of the conical horn 1; when the dual-polarized high-isolation antenna is applied to the active scaler shown in fig. 2, the other end of the orthogonal mode coupler 2 is connected with the radio frequency module 3, and the orthogonal mode coupler 2 is used for realizing waveguide conversion.

The dual-polarization high-isolation antenna provided by the embodiment of the invention is suitable for a satellite-borne SAR active scaler, and overcomes the defects of inconvenient use or incomplete function of the satellite-borne SAR active scaler caused by the adoption of the conventional antenna implementation mode.

Preferably, with further reference to fig. 3, the inner wall of the conical horn 1 comprises a corrugated structure; when the dual-polarization high-isolation antenna works, the hybrid mode is adopted to excite the conical horn 1. According to the embodiment of the invention, the conical horn 1 is excited by adopting the mixed mode, so that excellent low cross polarization performance can be obtained, and polarization isolation is provided; the conical horn 1 adopts a corrugated design method, so that the good performance of the hybrid die in a large bandwidth is ensured, and the high polarization isolation degree of the antenna in a large bandwidth is ensured.

Preferably, with further reference to fig. 4, the orthogonal mode coupler 2 is fed with a square waveguide 21, and the square waveguide 21 comprises a multi-step ladder structure 22 to achieve the conversion of a square wave guided rectangular waveguide 24; the quadrature mode coupler 2 may also comprise a connection port 23. The orthogonal mode coupler 2 in the embodiment of the invention adopts the square waveguide 21 and adopts the multistage stepped structure 22 to realize the conversion from the square waveguide 21 to the rectangular waveguide 24, so that the cross component is not easy to generate, the higher polarization isolation degree can be realized, and the voltage standing wave ratio and the port isolation degree of the port are effectively improved.

Further referring to fig. 2, which is a schematic diagram of an active scaler for spaceborne SAR in an embodiment of the present invention, as shown in fig. 2, the active scaler includes a transmitting antenna 4, a receiving antenna 5 and a radio frequency module 3, the transmitting antenna 4 is used for transmitting a scaling signal; the receiving antenna 5 is used for receiving signals sent by the satellite-borne SAR; the radio frequency module 3 is respectively connected with the transmitting antenna 4 and the receiving antenna 5, processes the signal received by the receiving antenna 5, and transmits the processed signal through the transmitting antenna 4. The transmitting antenna 4 and the receiving antenna 5 are each a dual-polarized high-isolation antenna as described above, which is configured to receive both horizontally and vertically polarized signals. In fig. 2, H denotes a horizontally polarized signal, and V denotes a vertically polarized signal.

The embodiment of the invention realizes the satellite-borne SAR active scaler by adopting the form of the dual-polarized high-isolation antenna, and can flexibly provide various scaling scattering matrixes required by the polarization active scaler; and provides a portable, fully functional active scaler for spaceborne SAR.

Further referring to fig. 5a and 5b, an embodiment of the present invention provides a C-band dual-polarized high-isolation antenna, where actual test results of the dual-polarized high-isolation antenna in the embodiment of the present invention are shown in the figure, and antenna directional diagrams of the same polarization and cross polarization are shown in the figure, respectively, and it can be seen from the directional diagrams that the dual-polarized antenna of the present invention has very high polarization isolation (close to 50dB), and completely meets the requirements of a satellite-borne SAR polarization active scaler.

In summary, the active scaler for the satellite-borne SAR and the dual-polarized high-isolation antenna provided by the embodiment of the invention overcome the defects of heavy system and inconvenient use caused by a four-antenna mode, greatly reduce the overall weight and structural complexity of the system, and improve the use convenience of the system; and the defect that the scattering matrix of the polarized active scaler is single due to the 45-degree rotation form of the antenna is overcome, and each device can flexibly provide various scattering matrices required by satellite-borne SAR scaling. The scheme provided by the invention adopts a plurality of key technologies, greatly improves the polarization degree of the antenna and provides a basis for high-precision polarization calibration of the satellite-borne SAR.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An active sealer for on-board synthetic aperture radar scaling, comprising:

a transmitting antenna for transmitting the calibration signal;

characterized in that, the receiving antenna with transmitting antenna is dual polarization high isolation antenna, wherein, dual polarization high isolation antenna includes:

the inner wall of the conical horn comprises a corrugated structure and is used as a transmitting end or a receiving end of a signal;

the orthogonal mode coupler is connected with the conical horn and used for realizing waveguide conversion, the orthogonal mode coupler adopts square waveguide for feeding, and the square waveguide comprises a multistage stepped structure so as to realize conversion of the square wave guide rectangular waveguide;

2. The active sealer for calibration of a space-borne synthetic aperture radar according to claim 1, wherein said conical horn is excited in a mixed mode in operation.