Title :
Compact microstrip coupled-line bandpass filter with four transmission zeros
Author :
Wu, Chao-Huang ; Lin, Yo-Shen ; Wang, Chi-Hsueh ; Hsiung Chen, Chun C.
Author_Institution :
Dept. of Electr. Eng., Nat. Taiwan Univ., Taipei, Taiwan
Abstract :
A compact coupled-line bandpass filter with multiple capacitive cross-couplings to create four transmission zeros is proposed. The locations of transmission zeros can be adjusted by varying the values of cross-coupled capacitances so as to improve the filter selectivity. The proposed filter is based on one-eighth-wavelength (λ/8) coupled-line sections and quarter-wavelength (λ/4) resonators, thus it occupies only half of the circuit area comparing with the conventional coupled-line bandpass filters. Specifically, a fourth-order microstrip coupled-line bandpass filter centered at 2.46GHz with a 3-dB bandwidth of 10.2% and four transmission zeros is implemented and examined.
Keywords :
UHF filters; band-pass filters; microstrip couplers; microstrip filters; poles and zeros; 2.46 GHz; 3 dB; capacitive cross-couplings; coupled-line sections; cross-coupled capacitances; filter selectivity; microstrip coupled-line bandpass filter; quarter-wavelength resonators; transmission zeros; Band pass filters; Capacitance; Capacitors; Coupling circuits; Filtering theory; Frequency; Microstrip filters; Microstrip resonators; Passband; Resonator filters; Bandpass filter; coupled-line; microstrip; multiple cross-couplings;
Journal_Title :
Microwave and Wireless Components Letters, IEEE
DOI :
10.1109/LMWC.2005.855375
