volume | PIER Journals

Abstract

This paper presents a new type of wideband bandpass filter (BPF) with quasi-elliptic frequency response by using proposed stubs loaded anti-parallel coupled-line. With different loads, the proposed stubs loaded anti-parallel coupled-line has different numbers of transmission zeros (TZs). These TZs are symmetrical along the designing frequency f₀. By using a quarter-wavelength parallel coupled-line to connect two proposed stubs loaded anti-parallel coupled-line, three wideband BPFs centered at f₀ = 1.575 GHz with quasi-elliptic frequency response are successfully designed. Good agreements between the simulations and measurements can be observed. The measured results also exhibits that the fabricated BPFs have the merits of low in-band insertion loss, good in-band return loss, sharp passband selectivity and high out-of-band rejection.

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Prof. Xin Xu

Dr. Wen Wu