부산대학교 도서관

In this paper, a dual-mode bandpass filter that operates in two different bands is proposed. A circular patch with a small circular hole is set as the basic resonator, and, as the circular hole moves, the linewidth of the ring resonator becomes non-uniform. Consequently, the ring resonator is structurally asymmetric and exhibits a dual-mode characteristic. A gap is formed in the middle of the resonator, a pair of inductors and capacitors is applied to the gap, and the proposed dual-mode structure operates as a dual-band filter. The first resonant frequency f1 is determined by the inductor and capacitor values, and the second resonant frequency f2 is determined by the capacitor values. In addition, the frequency ratio (f2/f1) can be adjusted by an appropriate combination of inductor and capacitor values.