June 22, 2024
Abbas Rezaei

Abbas Rezaei

Academic rank: Assistant professor
Education: Ph.D in Electrical engineering
Phone: 083-38305001
Faculty: Faculty ofٍٍ Electrical Engineering


Design of microstrip wide stopband quad-band bandpass filters for multi-service communication systems
Type Article
Multi-channel Wide stopband Microstrip Circular Close channels
Researchers leila noori، Abbas Rezaei


This paper presents two planar high performance quad-channel bandpass filters, which are designed based on a novel circular multi-mode resonator. In this paper and for the first time, the proposed resonator is utilized to achieve quad passbands. It consists of diverged feeding lines that are coupled to etched circular cells. The first filter has quite close channels at 2.62, 2.88, 4.34 and 4.67 GHz, which make it appropriate for frequency division duplex (FDD) scheme. Meanwhile, the second filter is designed for WCDMA and WiMAX applications. Both filters are able to attenuate the harmonics up to 19 GHz with a maximum harmonic level of 20 dB. The insertion losses and return losses of both filters at all channels are better than 1.2 dB and 17.5 dB, respectively. The harmonic attenuation method is presented employing a LC equivalent circuit of the proposed resonator. In order to verify the designing methodology, the proposed filters are fabricated and measured where there are good agreements between the simulation and measurement results