Contact effects on HF loss of CPW high resistivity silicon lines

This paper shows that the HF losses of CPW lines realized on 5-10 K/spl Omega/cm HRS (High Resistivity Silicon) substrates are strongly affected by the derivative of the I-V curves, ie. HF losses are higher where the I-V characteristic changes most rapidly. As a result the excess HF loss due to choice of quiescent bias voltage can be as high as 0.3-0.4 dB/cm. The implication of the effect is that by proper dc biasing of a CPW line on HRS substrate minimum HF loss can be achieved. This is of importance when active devices are to be biased through line interconnects.