I. Awai et T. Yamashita, 2-STAGE BANDPASS-FILTERS BASED ON ROTATED EXCITATION OF CIRCULAR DUAL-MODE RESONATORS, IEEE microwave and guided wave letters, 7(8), 1997, pp. 212-213
A new excitation method for dual-mode circular resonators is studied.
The bandwidth and the frequency of attenuation poles of the resulting
two-stage bandpass filter (BPF) are determined by the angle between I/
O ports. Addition of a shunt susceptance at the I/O ports gives an ind
ependent control of the bandwidth.