A 94 GHz solid state FM-CW-Doppler radar profiler

Describes a millimetre radar system for the measurement of clouds. The 94 GHz cloud profiler is a bistatic system with an average transmitted power of 1.6 W and it is built up using only semiconductor devices. Due to the modular design power upgrade is possible. It´s size without antenna is approx. 65cm×42cm×22cm. The weight of the system is about 25 kg. The initial signal is generated by a voltage controlled CW Gunn oscillator. This signal synchronizes a 500 mW IMPATT oscillator by injection locking. The heart of the system is a power combiner consisting of four 500 mW IMPATT oscillators. A fraction ofthe transmitted signal is used as a local oscillator of the mixer which converts the received signal to IF-level. The mixer used for deriving the IF signal from transmitted and received signals has a noise temperature of T=625K at a operation temperature of 300K. The diameter of the antenna used for the first tests is 157 mm