L-band Transceiver

According to the target, we present a design scheme which achieves transmission and receiving signal of center frequency 1GHz, band width 85MHz and the local oscillation signal of 9GHz. In order to filter other spur, we design a hairpin band-pass filter, which has the center frequency of 8.9 GHz, the band width of 380 MHz and rejection greater than 40 dBc at 8 GHz and 10 GHz. In the Quadrature demodulator chip, we set the base-band filter's "floating" ground to 1 V to reduce the noise.The transceiver comprises three parts: local oscillation circuit, transmitting circuit and receiving circuit. In the local oscillation circuit, we use phase-locked loop and frequency multiplication chain to generate the 9GHz local oscillation signal with power of 18.85dBm and phase noise of -72.58dBc/Hz@1kHz, -79.29dBc/Hz@10kHz. In the transmitting circuit, we choose the appropriate chip to realize transmitting signal of center frequency 1GHz, band width 85MHz and power of -2dBm. In order to reach the design requirements, there are the two-cascade amplifying technologies, zero-if receiver and automatic gain controls in receiving circuit. This study realize the maximum receive gain of 51dB, most greatly dynamic range >45dB and the signal I/Q demodulation.The transceiver has been measured and some improving advice is presented based on experiment. All of these can provide important experience for later research on this area.