HIGH POWER CO-AXIAL DUAL DIRECTIONAL COUPLER

摘要

In any high power transmitter, on-line monitoring of forward and reflected power is a must. It serves two purposes; firstly, it gives instantaneous transmitted power, which is required for other processing details in a Radar. Secondly, in case of abnormal behavior and high load reflection, the transmitter is interlocked for automatic switching off. The high power directional couplers are used extensively for on-line measurements of transmitted and reflected power. Sometimes, because of malfunctioning of load (it is antenna for Radar application), power transmitted from and reflected towards the transmitter changes. The reflected power needs to be minimized for longer life of the high power devices such as triode, tetrode, klystron etc. This optimization (maximization) of transmitted power is achieved by use of a dual directional coupler along with a tuner. A high power co-axial dual directional coupler has been designed and developed for the on line measurements/monitoring of the high power transmitter in UHF frequency range. The experimental design curves are also generated which can be used to develop these couplers. This coupler has been successfully used for power measurement, monitoring and control circuits of a 20 kW transmitter used in a wind profiler system operating at 404.37MHz.