A low impedance and short-guided wavelength microstrip line employing a periodically perforated ground metal and its application to miniaturized and low impedance ratrace on GaAs MMIC

In this work, in order to realize highly miniaturized and low impedance ratrace on GaAs MMIC, novel microstrip line structure employing PPGM (Periodically Perforated Ground Metal) was proposed. The novel microstrip line structure exhibited much lower characteristic impedance and shorter guided-wavelength than conventional one. Using the novel microstrip line, a highly miniaturized ratrace with a low port impedance of 10.6 Q was developed for KMa band MMIC applications. It was fabricated on GaAs substrate with a height of 100 pm, and its size was 0.375 mm´, which was 9.3 % of the one fabricated by conventional microstrip line. The ratrace exhibited good RF performances from 20 to 30 GHz.