Electrical Matching of Unidirectional Surface Wave Devices

Recent advances in surface wave device (SWD) technology have made it possible to obtain bandpass filters with insertion losses as low as 0.65 dB by implementing 3-phase unidirectional transducers. This paper discusses the techniques used for electrically matching unidirectional SWD´s and shows recent experimental results obtained by using these techniques. Also included are discussions on electrical measurements of 3-phase transducer terminals, different methods of phase splitting and transducer interface, component value calculations for phase splitting and matching, and a review of sources of filter insertion loss.