An ultracompact CRLH‐TL bandpass filter for VHF applications

Abstract

ABSTRACTThis article proposes a new design approach to an ultracompact composite right‐/left‐handed transmission line (CRLH‐TL) bandpass filter with good passband and very broad stopband performances. In order to reduce the size, a series connection of the interdigital capacitor and shorted spiral inductor for realizing CRLH‐TL is adopted and optimized to create the target Terrestrial‐Digital Multimedia Broadcasting (T‐DMB, 174–216 MHz) bandpass filtering. T‐DMB was developed in South Korea. The results of a Bloch impedance analysis suggest that the proposed approach generates good impedance matching. The proposed filter has overall dimensions of λg/19 by λg/34 in terms of a center frequency of 180 MHz, a 3 dB fractional bandwidth of over 28%, an insertion loss of much lower than 2 dB, and a good return loss performance in the predicted and measured results. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:694–697, 2016