Broadband continuously variable microwave phase shifter employing a distributed Schottky contact on silicon

Fabrication details and microwave measurements are presented for the first realisation of a silicon, broadband, voltage-controlled, microwave phase shifter comprising a coplanar, slow-wave, Schottky-contact transmission line. This structure exhibits very little dispersion over the measured frequency range of 1¿20 GHz. A voltage-dependent `wave compression¿ factor is observed that can be varied from 11.7 to 17.0 by varying the bias between ¿6 and +0.1 V. Even though the device is fabricated on a `true¿ (lossy) semiconducting substrate, the attenuation per unit length is smaller than that reported for a similar structure fabricated on semi-insulating GaAs.