Opto-electronic control of coplanar transmission lines up to 110 GHz

Lumped circuit and 3D-electromagnetic models are presented for a photo-induced plasma that induces local changes in the dielectric properties of a coplanar waveguide transmission line to switch millimeter waves, propagating along transmission lines on BCB coated high resistive silicon substrates. Measurements up to 110 GHz are compared with the various developed models. The insertion loss of these transmission lines was only 1 dB/mm at 100 GHz. The modulation of S21 was about 40 dB at 110 GHz for an optical power of 60 mW focused on one slot between signal and ground. S11 could only be fitted with a lumped circuit model when introducing a frequency dependent impedance was introduced