The Design of Four Channel Equalization Amplifier Module for Radio Astronomy Receiver

IF system of radio astronomy receiver is an important part of the receiver. The left circular polarization and right circular polarization signals of L, S, C and K bands in the receiver become IF signals through down conversion in the high frequency bin. IF signals are transmitted to the observation chamber by coaxial cable. The observation chamber is far from the radio telescope's high frequency chamber, so the line loss is large, and the signal loss at different frequencies is different. The higher the frequency is, the greater the loss is, resulting in the lower power of intermediate frequency signal and the decrease of gain flatness with the increase of frequency. A four-channel equalization amplifier module is designed to improve the gain of IF signal and compensate the gain flatness. The equalizer of this module adopts the combination of lumped element and microstrip line, which has the advantages of compact structure, easy integration and low cost. The test results show that the equalization amplifying module can meet the requirements of intermediate frequency system of radio astronomy receiver with equalization measure ≥8 dB, power flatness ≤3.5 dBm and return loss ≤-15 dB within 6x frequency band width.