Frequency reconfigurable quasi-Yagi antenna using variable-length transmission line resonator

This paper presents a frequency reconfigurable wideband quasi-Yagi antenna. This antenna is fed by a microstrip line to slot line transition structure and two parasitic strips as directors. The transition feed consists of a microstrip circular stub and a slot circular stub, with different Radius to achieve wideband impedance matching. The reconfigurability of this antenna can be achieved by tuning the length of the transmission line resonator placed on the bottom of slot line transition. Ideal switches were used to control the length of the resonators. Simulated results of the antenna, demonstrate a good performances of the proposed designs such ass compactness, radiation patterns and diversity gain.