Passive Microwave Equalizers for Radar Receiver Design

Receiver design for digital radar and optical communication involves optimization and realization of an equalizing filter to provide a suitable signal at the input of the decision circuit. This is a frequently encountered problem in filter design, where one needs to realize a network capable of having an arbitrary response in a given frequency band. This chapter approaches to approximate the target frequency response for a single equalizer using the real frequency technique (RFT). Since the RFT optimizes equalizer functions that are realizable, it can also directly synthesize the elements of the equalizing filter. The solution uses a Levenberg-Marquardt-More optimization technique. The optimization produces realizable functions without an a priori choice of equalizer topology and does not require an analytic form of the system transfer function to be assumed. The chapter also gives examples of microwave equalizers for radar applications in the 8 GHz range.