All-dielectric miniature wideband rf receive antenna

An integrated Mach-Zehnder interferometer made of electro- optic (EO) polymers with a dimension of 331.2 cm was fabricated as a wideband rf receive antenna. When an electric field is applied to the interferometer arm(s) made of EO material, a phase delay is generated that results in a net imbalance in the interferometer, and thus a change in the output intensity. This output intensity change, which contains electric field strength and temporal profile information, is then read by a photo- detector and processed. This antenna was tested in a m-strip traveling wave electromagnetic cell at frequencies from 100 MHz to 1.04 GHz. The test results show the antenna had a good linear response over a 70-dB power range. The lowest possible measured Emin was about 4 mV/m (or 2.1 pW/cm 2 ) at 1-kHz resolution bandwidth with a laser power of 0.4 mW (24 dBm) measured after the sensor. The measured E-field signal increases with increasing laser power, which indicates that signifi- cant sensitivity improvement can be easily obtained by lowering passive losses. The antenna sensitivity can be further improved by lowering the device insertion loss, optimizing the photodetector and detection cir- cuitry, and using EO polymers with higher EO coefficients.