Novel Compact Single Pole Three Throw Switch by using Slow Wave Microstrip Structure

Slow wave structures have been being widely and deeply investigated up to now, and extensively used in integrated circuits with various applications, such as microwave tubes and miniature components. This paper presents a novel compact single pole three throw (SP3T) switch, and the proposed SP3T involves some sections of novel slow wave microstrip structures, which is constructed by microsrip lines periodically loaded with radial stubs. The periodically loaded microstrip line (PLML) structure is analysed in details. It is revealed that the PLML possesses low insertion loss and good return loss in the pass-band, along with slow wave features, and with good controllable wide bandgap characteristics by tuning its structure parameters. On the basis of the analysis of PLML, the SP3T switch in shunt configuration utilizing PLML structure is designed and manufactured. We obtain good performances and compact size of the SP3T in the experiments. Comparisons of measurements are presented between the conventional and the proposed structures, which verify the validity of this proposed method.