Design of Quarter-Wave-Like Transformers (QWLTs) Implemented Using ConjugatelyCharacteristic-Impedance Transmission Lines (CCITLs)

摘要

A quarter-wave transformer (QWT) is a simple anduseful circuit component in microwave engineering. Itsability to match arbitrary real load impedances toarbitrary lossless transmission-lines (TLs) has beenemployed in various applications from basic ones likematching networks, power dividers, and directionalcouplers [1]-[5] to more advanced ones like microwavefilters and antennas [6]-[9]. Due to the physicalrequirement of having a fixed electrical length at anoperating frequency [1]-[3], standard QWTs arerelatively large, especially at lower frequencies.