Compact UWB bandpass filter using folded-T-shaped resonator with a notch-band

Abstract

This paper presents a compact ultra-wideband bandpass filter based on a folded-T-shaped resonator with a notch-band. Characterized by theoretical analysis, the T-shaped resonator makes it easier to control resonant modes, and two transmission zeros appear in the lower and upper stopbands to improve skirt selectivity. A narrow slot is embedded within the resonator, in order to produce a bandstop characteristic. In this way, a notched band is introduced around 5.75 GHz, and the bandwidth and coupling strength of the notch-band could be tuned easily. Finally, a filter is fabricated and measured, and the measured results are in good agreement with simulation, demonstrating good insertion/return losses as well as a notch-band application.

Acknowledgment

This work is supported by the National Natural Science Foundation of China (61,101,017) and the Fundamental Research Funds for the Central Universities (2012ZM0024).