Reduction of the antenna coupling in a bi-static, FM-CW radar system

[摘要] ENGLISH ABSTRACT: A well-known problem with FM-CW radar systems is the leakage of transmitter power into the receiver which leads to the making of close-in targets, and can severely limit the system dynamic range performance. This thesis considers two solutions to this radar system problem for a low frequency radar operating in the VHF band.The first method to suppress coupling is using separate transmit and receive antennas designed in such a way as to reduce coupling between them. The second is to design a negative feedback loop as part of the radar receiver where the feedback loop adaptively reduces the amount of transmitter leakage through to the receiver.This project details the realisation of these two solutions. A number of antenna designs are modelled in software and simulated to determine their characteristics of which the transmit-to-receive coupling is the key parameter. As no low coupling configuration could be found a simple configuration is chosen and practical measurements are taken. These antennas are then used in the radar system that is to be built.An FM-CW radar system is designed and simulated using software with a negative feedback loop being designed and implemented into the radar simulation.A practical radar system is then made inclusive of the feedback loop. Measurements are then taken to determine the efficacy of the feedback loop.

[发布机构] Stellenbosch University