An Active Resonator Using Defected Ground Structure with Islands

A new resonator using active device and defected ground structure with islands (DGSI) is proposed. The active device is used for supplying the negative resistance which is one of key factors of the proposed active resonator. The negative resistance is realized by the series active device. The electrical characteristics of the proposed resonator with DGSI are improved by combining the negative resistance and the microstrip line with DGSI where the electric field is the most strong. It is shown that the measured improvement in S21 and Sll of the proposed active resonator with DGSI are 4.55 dB and 0.32 dB, respectively, at the resonant frequency compared to the previous DGSI resonator without active device.