Title :
Asymmetric bandpass filter using a ceramic structure
Author :
Field, P.L. ; Hunter, I.C. ; Gardiner, J.G.
Author_Institution :
Dept. of Electr. Eng., Bradford Univ., UK
Abstract :
A ceramic bandpass filter with increased selectivity on the lower side of the passband is presented. One application is the receive filter of a mobile radio transceiver operating in the 1.8-GHz bands. Finite transmission zeros have been introduced by using a network with additional cross couplings. The circuit was constructed with four coaxial ceramic resonators capacitively coupled using a microstrip PCB. For a 75-MHz passband filter, a stopband attenuation of 37 dB was attained at 20-MHz offset from the passband. A midband insertion loss of 1.2 dB and bandedge loss of 3 dB were achieved.<>
Keywords :
band-pass filters; equivalent circuits; microwave filters; passive filters; poles and zeros; radiofrequency filters; resonators; strip line components; 1.8 GHz; 75 MHz; UHF; bandedge loss; bandpass filter; ceramic structure; coaxial ceramic resonators capacitively coupled; cross couplings; finite transmission zeros; microstrip PCB; midband insertion loss; mobile radio transceiver; receive filter; Band pass filters; Ceramics; Coaxial components; Coupling circuits; Filtering theory; Land mobile radio; Microstrip resonators; Passband; Resonator filters; Transceivers;
Journal_Title :
Microwave and Guided Wave Letters, IEEE
