Millimeter-wave Low-noise Three-channel Receiver Front-end Development

In microwave and millimeter-wave communication, receiver systems play critical roles in the whole system performance. The role of the receiver is through the antenna to collect weak electromagnetic signal sent by the transmitter and select needed signal from a large number of electromagnetic signals within the channel. The received signal is amplified by LNAs and down-converted by Mixers, in order to recover original signal. However, the receiver front-end is a very important part of the receiver system, so, it is important to design and manufacture high-integrated, light-weighted and high-reliable receiver front-end.Based on the analysis and study of previous researchers and characteristics of receiver performance and structure from user's request, in this paper, a superheterodyne receiver front-end with double-conversion solution is put forward and improved. And at last a Ka-band low noise three-channel receiver front-end is developed. From the test results, we know that the noise figure is less than 4dB, the gain is approximately equal 30dB, receive-transmit isolation is greater than 35dB, isolation between channels is greater than 35dB and image-frequency rejection is greater than 25dB.The receiver front-end in this paper include waveguide-probe-microstrip transition, receive-transmit isolation switch, two stage low noise amplifier, microstrip image-frequency rejection filter, sub-harmonically pumped mixer, microstrip power divider, IF amplifier and power supplier. From the noise figure formula of the cascade system, we know that NF of the waveguide-to-microstrip transiton affects the NF of the whole system most. In this paper, an improved waveguide-probe-microstrip transition is analysed and designed. The result of the experiment show that the insertion loss is less than 0.7dB and the return loss is greater than 25dB.In this paper, HMIC–MMIC combined design method is used to develop Ka-band low noise three-channel receiver front-end.