A transmisrion-line theory approach that includes the comp1e.x propagal i o n constant of ihe micron,ai.e electrodes and the impedance match between the electrode and the rfsource and load is used to analyze the handnidth of polyamide optical modulators. The analysis is then applied to an electro-optic modulator that ha.5 microstrip transmission lines placed directly owr an optical wareguide buned in the po!vatnide ntbstrate. The modulator i s designed with coplanar war.eguide (CPW) input and output contacts for $characterization. 7he transition between * Also with Department of Electrical Engineering & Applied Physics. Case Western Reserve University. Cleveland, Ohio the microstrip electrode and the CPW lines is presented. In addition, the processing techniques that yield polyamide side-wall profiles that are highly suited for trunsitioning from the CPW and the microstrip are presented. Finally, rf measurements of the complete microwave electrode are presented. 0 ABSTRACT A n e~' esperiinmtul discoi'ery in electrostatics is first reported: The capticitarm of (1 inidticonductor ~s t e t i i maintuitis the same value for all possible configrrmtions, procided the geometric centers of the conductors iirc /?xed irrtleperidrntlv. 0 1996 John Wiley & Som, lrrc.