Miniaturized wideband bandstop filter using an air-bridge capacitor via gallium-arsenide based integrated passive device technology

摘要

This letter reports a new implementation of miniaturized wideband bandstop (WBBS) filter using a gallium-arsenide (GaAs)-based integrated passive device technology (IPD). The implementation of an air-bridge capacitor explores the possibility of frequency selectivity from 8.15 to 9.20 GHz. The WBBS filter generates a return loss of -0.50 dB with a rejection depth of -38.01 dB at the resonance frequency of 9.20 GHz. The size of the filter was drastically reduced by implementing a microfabrication (IPD) with folded meandered-line, featuring the length equal to 0.38 times the guided wavelength ((g)) that occupies only 0.22 (g) x 0.13 (g) of the die area. The selectivity of the filter was reflected by the higher value of return loss with sufficient suppression of out-of-band signals close to the resonance frequency. Experimental verification of the filter response demonstrates its potential as a WBBS filter operating in the X-band frequency spectrum. (c) 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:980-985, 2016