3-4 GHz bandpass filters using dielectric-filled stepped impedance resonators

The authors describe the principle of the /spl lambda//sub g//2 dielectric-filled stepped impedance resonator and the design formulae are derived. The filters of the 3-4 GHz band using /spl lambda//sub g//2 dielectric-filled stepped impedance resonators provide low insertion loss (3.5 dB) small passband ripple (/spl plusmn/0.5), high stop-band (27 dB), small size, light weight and high stability.