A new type NRD-guide receiving front-end in Ka-band

A new type millimeter-wave receiving frond-end using NRD-guide as internal transmission line is presented in this paper. The receiving frond-end consists of a NRD-guide crossbar balanced mixer, a NRD-guide LSE mode local oscillator and two impedance-converters at two input ports of the mixer circuit. Firstly, the propagation characteristics of some transmission modes often used in NRD-guide are given, and the conditions which these modes are applied as the operating modes are discussed. Secondly, the principle of the balanced mixed which is regarded as the key circuit unit in the receiving frond-end is analysed by using vector Green's function, and the conversion loss of the mixer is computed with an equivalent circuit in Ka-band. And then, from the view of obtaining the optimum performances of the whole receiving frond-end, some methods of designing local oscillator are expound. Some experimental results of the receiving frond-end at Kaband are given in the paper lastly. Because the frond-end have the impedance matching and converting circuits, it possesses better electrical performance. The integrated frond-end which have compact size and excellent shock strength is suitable for varied millimeter-wave system.