A Multi-band Sar Radar P-band Broadband Sub-transmitters

The Wideband Synthetic Aperture Radar (WB-SAR) is a new radar system which developed at the end of the last century, also, it is a investigative hotspot in the radar technologies nowadays. The SAR offer a greatness distinction of target character on different frequency band, and it has a strong penetrating performance can detect the concealed targets which under foliage or under the earth's surface when it operates on VHF/UHF band, so, many people show considerable interest in the radar imaging technology on the band. As a main part of multi frequency band SAR on the middle or low frequency band, P band Wideband transmitter's capability has a direct influence on the performance of the whole system, so the research of the transmitter has important practical value and can get more experience for the work in the future.The article shows a certain airplane carried SAR system which operates on multi frequency bands as a base first, then detailed discuss the P band Wideband sub-transmitter design and debug technology. First, the article introduce the principle of transistor amplifier, the matching technology of microwave power amplifier, the primary concept of Balun impedance transform, then, the article shows some advisement and choice of design the transmit system which works in the airtight suspend cabin's space with the complex electromagnetism environment of several high-power transmitters work in double harness. The article introduce the basic design of monitor and control, protect circuit of transmitter also. The article discuss the analysis of computer emulator and the use of software for design the matching circuit of microwave power amplifier, and give some examination result. The article shows the design and debug technology of the P band Wideband sub-transmitter which works on hundreds watt successfully. The transmitter achieve the performance of instantaneous relative work band over than 50%, gain over than 47dB, flatness inner band less than 1dB(R.M.S), secondary harmonic/base wave less than -50dBc etc, and it get the relevant experiment validate. The practice proved the performance of the transmitter can entirely meet the apply requirement of the test system.