DESIGN AND IMPLEMENTATION OF MICROWAVE PARTS OF AIRBORNE-RADAR-WARNING RECEIVERS

The radar warning receiver (RWR) is the heart of the self protection system of modern aircraft. The most important receiver structures that can be used as RWR are the crystal video receiver (CVR) and the instantaneous frequency measurement (IFM) receiver. This paper presents a complete design and implementation of the microwave part of the CVR. This CVR is designed to cover a frequency ranging from 1.5 up to 4 GHz. The CVR is implemented using the recently developed microstrip technology. The designed receiver was successfully tested and the results in terms of the output voltage and the voltage standing wave ratio (VSWR) were very good. This paper presents also a complete design and implementation of the critical components of the IFM receiver. These components are the phase correlator, the power dividers, the delay line, the square law detectors preceded by broadband matching circuits, and the low pass filter. They are implemented using the microstrip technology. The input to the correlator is the threatening radar signal and the output comprises four video signals that can be processed to obtain the signal frequency instantaneously. A new design procedure is proposed to overcome the problems, usually encountered when trying to design and implement phase correlators. The designed correlator was successfully tested and found to operate adequately in the whole S-band.