Bandwidth-enhanced lumped-element absorptive bandstop filter topology and its application to LTCC bandstop filter design
- 27 August 2014
- journal article
- research article
- Published by Cambridge University Press (CUP) in International Journal of Microwave and Wireless Technologies
- Vol. 7 (6), 691-698
- https://doi.org/10.1017/s1759078714001147
Abstract
In this paper, we show a second-order (four-resonator) absorptive bandstop filter circuit topology which gives a larger bandwidth compared to a first-order topology. Due to the absorptive characteristic, it creates a large attenuation at the center frequency using low-Q resonators. Since low-Q resonators can be used in generating a large attenuation, small-size resonators can be employed in bandstop filter design. Analytic design equations are provided so that a higher-order absorptive bandstop filter can be designed analytically. It is also shown that the second-order filter topology exhibits a better frequency selectivity having a same bandwidth. The proposed filter topology has been applied to a design of a miniaturized low-temperature co-fired ceramic bandstop filter with low-Q resonators. The Q-factor of the lumped-element resonators has been chosen to be 5 for demonstration.Keywords
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