Compact ultra-wideband bandpass filter based on composite right/left-handed transmission line with improved out-of-band performance.

This paper presents a novel compact ultra-wideband (UWB) bandpass filter (BPF). It consists of two composite right/left-handed transmission line (CRLH-TL) unit cells and an anti-coupled line structure. The CRLH-TL unit exhibits good passband performance with a compact size. By cascading the anti-coupled line structure, a wide upper stopband is obtained. The measured fractional bandwidth and insertion loss are 113.9% and 0.52 dB, respectively. Moreover, a broad stopband from 14 to 30 GHz with a high rejection level of 20 dB is obtained. The whole size is 14.4 mm × 10.2 mm. The simulated and measured results agree well. [ABSTRACT FROM AUTHOR]