A Transceiver Shared Antenna Structure to Improve Radar System Transceiver Signal Isolation

Abstract

The invention discloses a sending-receiving shared type antenna structure capable of increasing a signal sending-receiving isolation degree of a radar system. The structure comprises a first coupler, a second coupler, an electric bridge and an antenna, wherein an input end of the first coupler is connected to a sending port of the radar system, and a direct-connection end is connected to an input port of the electric bridge; and an input end of the second coupler is connected to a receiving port of the radar system, the direct-connection end is connected to another input port of the electric bridge, and a coupling port of the first coupler is connected to an isolation port of the second coupler by a transmission line. Sent signals are partially taken out by the first coupler; the partial signals are treated by phase shifting of the transmission line and then coupled into a receiving chain line by the second coupler; and these signals are offset by signals which are leaked by the sent signals into the receiving chain line via the electric bridge and other routes, so that the isolation degree between the sent signals and the received signals as well as the isolation degree bandwidth can be increased. The structure disclosed by the invention satisfies a requirement for the sending and receiving isolation degree and effectively solves the problems that integration and miniaturization of a radar can hardly be implemented.

Description

technical field [0001] The invention relates to the technical field of radar, in particular to a transmitting and receiving common antenna structure for improving the isolation degree of transmitting and receiving signals of a radar system. Background technique [0002] FM continuous wave radar has the advantages of small distance blind zone, high precision, large bandwidth, low power, simple and compact, etc., and has been widely used in the field of small radars. However, in the FM CW radar system, the frequency bands of the sending and receiving signals are the same and used simultaneously, so a high requirement is placed on the isolation between the receiving and transmitting systems. If the isolation between transceivers is not enough, the signal strength of the transmitted signal leaking into the receiving system is too high, which will lead to an increase in the noise floor of the receiving system, system saturation, performance degradation, etc., and may even cause d...

AI Technical Summary

Problems solved by technology

[0006] From the point of view of the principle of the circulator, ferrite material is needed as the medium, and a constant magnetic field is added, so it can be seen that the production is more complicated, it is difficult to miniaturize, and it is not easy to integrate

On the other hand, as the frequency of radar is getting higher and higher, the requirements for the precision of the ferrite material manufacturing process are getting higher and higher, and the isolation is also difficult to achieve.

[0007] It can be seen that the existing circulator-based structure for transmitting and receiving to share an antenna cannot meet the requirements of radar integration, and it is difficult to meet the requirements of transmitting and receiving isolation as the radar frequency becomes higher and higher.

[0008] (2) Use the bridge to isolate the transceiver system, connect the transmit signal and the receive signal to a pair of isolated ports of the bridge, and connect one or both of the other pair of isolated ports of the bridge to the antenna. The isolation of the transceiver system in this solution is only achieved by the isolation of the bridge. Although it can meet the requirements of high-frequency miniaturization, the bandwidth of a simple bridge is relatively narrow, and it is easy to deviate from the set frequency. It is subject to many applications. limit

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