Characterization of Optically Sensitive Polymer and Application to Microwave Antenna

Due to the rapid growth in wireless networks in recent years, there is a need for a tunable microwave device to be able to effectively switch between different networks and wireless technologies. This thesis investigates the use of a photoconductive polymer to optically tune a microwave device or antenna.;The properties of the novel photoconductive polymer were used in the theoretical design of an optically tunable dipole antenna. The antenna was designed for GSM band (1900MHz to 2100MHz). The tunability in the antenna was achieved by applying the characterized polymer along a slotted segment of the dipole arm, and effectively changing the dipole length by optical illumination.;The dielectric properties of a hybrid (Polymer + Cadmium Sulphide) photoconductive polymer are extracted using microwave reflection measurements on a coplanar waveguide test structure. The material under test was overlaid on an interdigitated capacitor that was fabricated on a transparent glass substrate. The material characterization was done with and without broadband optical illumination. The material parameters were obtained by fitting measured reflection coefficient data to an equivalent lumped element circuit or HFSS model in ADS. The results obtained from the characterization show that the polymer was photoconductive. The extracted dielectric constant (epsilon r) of 4 and loss tangent (tan delta) of 0.004 were obtained without illumination, while the loss tangent increased to 0.11 with illumination but the epsilon r value had no measureable change.