Using electro-optic field mapping for design of dual-band circularly polarized active phased arrays

Electro-optic (EO) probes provide an ultrawideband, high-resolution, non-invasive technique for polarimetric near-field scanning of antennas and phased array systems. Unlike conventional near field scanning systems which typically involve metallic components, the small footprint alldielectric EO probes can get extremely close to an RF device under test (DUT) without perturbing its fields. In this paper, we discuss and present measurement results for EO field mapping of a dualband circularly polarized active phased array that operates at two different S and C bands: 2.1GHz and 4.8GHz. The array uses probe-fed, cross-shaped, patch antenna elements at the S-band and dual-slot-fed rectangular patch elements at the C-band. At each frequency band, the active phased array works both as transmitting and receiving antennas. The antenna elements have been configured as scalable array tiles that are arranged together to create larger apertures.