Implementation of Slow-Wave Thin-Film Microstrip Transmission Lines in a 35nm InGaAs Technology

This paper presents the implementation of slow-wave thin-film microstrip lines (TFMSL) and a comparison to conventional TFMSLs in the frequency ranges of 0-150 GHz and in H-band from 220-320 GHz fabricated in a 35nm InGaAs metamorphic high electron mobility (mHEMT) technology, whereby the implementation at lower THz frequencies represents a novelty. The use of slow-wave transmission lines has two positive effects. First, the insertion losses are reduced by the deplacement of the magnetic field under the signal line and second the phase velocity of the signal is reduced by implementing a slotted ground plane below the signal line. Both effects combined lead to a loss reduction per quarter wavelength up to 54 % at 110 GHz and up to 47 % in H-band in comparison to conventional TFMSLs.