Extended stop-band band pass filter using new spurious suppression technique.

A spurious suppression method by using the “T” feeders is proposed and investigated. A novel band pass filter using “T” feeders is implemented. The measured results of the filter demonstrate good spurious suppression. The experimental results of the filter operating at the center frequency f0= 1.87 GHz are the fractional bandwidth of 9%, the insertion loss of 1.7 dB, the return loss better than 25 dB. The spurious frequency with rejection larger than 25 dB is up to 5f0. Below 1 GHz, the stop-band rejection is larger than 51.5 dB, and the largest stop-band rejection is 54 dB in the upper stop-band. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 706–709, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24179 [ABSTRACT FROM AUTHOR]