A 62 GHz compact low-loss bandpass filter in integrated passive devices technology

This paper presents a low insertion-loss millimeter-wave bandpass filters in an integrated passive device (IPD) technology. The designed IPD bandpass filter is composed of a stepped-impedance resonator with stepped-impedance stubs for transmission zero generation. The defected-ground three-line coupler was used for input/output feeding to alleviate the line-spacing layout restriction in the IPD. An implemented IPD filter has the measured insertion loss of 2.3 dB and the return loss better than 20 dB at 64.7 GHz. Two transmission zeros, located at 49 and 88 GHz, improve the stopband suppression. The measured performance is better than the same structure in CMOS technology.