Title :
Varactor-tuned dual-mode bandpass filter for wireless applications
Author :
Djoumessi, E.E. ; Chaker, M. ; Wu, Ke
Author_Institution :
Dept. of Electr. Eng., Ecole Polytech., Montreal, QC
Abstract :
A tunable dual-mode microstrip bandpass filter for mobile GSM and ISM bands (2000 MHz to 2.45 GHz) is proposed and characterized. The structure is composed of a meander loop dual-mode resonator and four loading capacitances. Perturbation of the degenerate modes is achieved by combination of a small square patch and an additional meander line resonator. Frequency tuning is made possible by modifying the electrical length of orthogonal quarter-wavelength meander arms with four varactor-diode capacitors. The measured insertion loss of a filter prototype realized on alumina substrate is between 3.5 dB to 7 dB over the tuning frequency range, with a constant 3-dB bandwidth of about 5.75%. The filter exhibits a center-frequency tunability of 20%.
Keywords :
UHF filters; band-pass filters; cellular radio; circuit tuning; resonators; varactors; ISM bands; alumina substrate; frequency 2000 MHz to 2.45 GHz; frequency tuning; insertion loss measurement; meander line resonator; meander loop dual-mode resonator; mobile GSM band; perturbation modes; square patch resonator; varactor-diode capacitors; varactor-tuned dual-mode bandpass filter; wireless applications; Arm; Band pass filters; Capacitance; Capacitors; Frequency measurement; GSM; Loss measurement; Microstrip filters; Resonant frequency; Tuning; Tunability; alumina; dual-mode; filter; varactor diode; wireless bands;
Conference_Titel :
Radio and Wireless Symposium, 2009. RWS '09. IEEE
Conference_Location :
San Diego, CA
Print_ISBN :
978-1-4244-2698-0
Electronic_ISBN :
978-1-4244-2699-7
DOI :
10.1109/RWS.2009.4957434
