A New Compact Dual-Band Filter Using SIR

Abstract

A narrowband dual-band bandpass filter based on step impedance resonator (SIR) is proposed in this paper to realize high performance with a compact size. The center frequencies of the designed filter are 2.4 and 5.8GHz, where it is suitable for wireless communication system. The absolute bandwidth approaches 200MHz with 8.3% fractional bandwidth at -3dB, and the simulations show that the return loss of the first and the second band is lower than -20dB. Between the two passbands, there is a transmission zero which can achieve a high out-band isolation. For demonstration, the filter has been fabricated and the measurement results show the excellent agreement with the theoretical simulation results