Fabrication and evaluation of a compact rat-race circuit using lumped parameter elements

This paper proposes a compact rat-race circuit using LC lumped parameter elements. The circuit, which converted transmission lines into pi-type phase shifters, consists of six lumped parameter elements. Therefore, the circuit can be the size of 1/267, while having a conventional performance. The prototype for use in 1GHz band is fabricated on a substrate, and the propagation characteristics and reflection characteristics of each port are measured. The measurement results agreed well with those of the simulation. The dimensions of the circuit are approximately 5.5 mm×5.5mm. © 2015 The Institute of Electrical Engineers of Japan..