1. A planar bandpass filter design with wide stopband using double split-end stepped-impedance resonators
- Author
-
U-yen, Kongpop, Wollack, Edward J., Doiron, Terence A., Papapolymerou, John, and Laskar, Joy
- Subjects
Electric filters, Bandpass -- Design and construction ,Electric filters, Bandpass -- Analysis ,Resonators -- Usage ,Business ,Computers ,Electronics ,Electronics and electrical industries - Abstract
In this paper, we propose a compact planar bandpass filter design with wide stopband. The double split-end quarter-wave-length ([lambda]/4) resonator is introduced to reduce the resonator size while providing additional transmission zeros. Optimal split-end length is determined to provide transmission zeros that attenuate the two lowest spurious resonance frequencies. The singly loaded quality factor ([Q.sub.si]) of the optimal-length [lambda]/4 s tepped-impedance resonator (SIR) is also analytically derived. Using the proposed technique to design an Nth-order filter, N + 1 controllable transmission zeros are generated and used to suppress spurious frequency responses. The experimental design shows that the sixth-order filter can provide a very broad stopband of 8.5 times the fundamental frequency with at least 37.8 dB of attenuation using the SIRs with a stepped-impedance ratio (R) of 0.528. Index Terms--Microstrip, microwave filter, spurious response, stepped-impedance resonator (SIR), transmission zero.
- Published
- 2006