Nonlinear characteristics and RF losses of CPW and TFMS lines over a wide temperature range

This paper analyzes RF losses and non-linear behavior from room temperature up to 175°C of coplanar waveguide (CPW) and thin film microstrip (TFMS) lines fabricated on both High Resistivity (HR) and Standard resistivity (STD) Silicon-on-Insulator (SOI) substrates. Through measurements it is shown that CPW topology exhibits larger 2nd harmonic distortion level, more than 25 dB higher compared with TFMS counterpart at 25°C, whereas the later shows larger insertion losses. At higher temperature, RF losses increase for both transmission line topologies whereas the 2nd and 3rd harmonic levels are almost not affected by the temperature increase.