Highly miniaturized on-chip passive components fabricated by microstrip lines with periodically perforated ground metal on GaAs MMIC

In this work, using the novel microstrip line structure with PPGM (periodically perforated ground metal), highly miniaturized and low impedance on-chip passive components were realized on GaAs MMIC. The size of highly miniaturized branch-line coupler with a low port impedance of 24 Ω was 0.25 mm² on GaAs MMIC, which was 10% of the one fabricated by conventional microstrip line. The branch-line coupler exhibited good RF performances from 20 to 30 GHz. In addition, in this work, highly miniaturized on-chip filter and impedance transformer were also realized using the microstrip line structure with PPGM, and they exhibited good RF performances in Ku-Ka band. The length of the open stub filter was reduced to 39% of the one fabricated by conventional microstrip line, and the size of impedance transformer was about 1% of the one fabricated by conventional microstrip line. According to the theoretical analysis, the passband of the microstrip line with PPGM was estimated to reach up to 600 GHz.