Fiber-Coupled Array Calibration System for On-Site Tx/Rx-Mode Calibration of Large-Scale Phased Antenna Arrays

The goal of this SBIR project is the development, assembly, and functional test of a prototype fiber-coupled diagnostic system for the comprehensive calibration and performance monitoring of large scale phased-antenna arrays. In the proposed calibration system, innovative electro-optic (EO) field sensors will noninvasively monitor the near-field amplitude and phase emanating from an array under observation during transmit-mode calibration. In addition, compact, optically-activated RF emitters will provide reference incident fields to the array in order to perform receive-mode calibration. The pure optical signals that either interrogate or drive the EO sensors and RF emitters will be immune from electromagnetic interference, and the EO sensors/RF emitters can be arranged into their own array geometry and safely positioned within close proximity to the aperture of the antenna elements. The exceptional flexibility of the optical fiber, onto whose ends the very small EO sensors/RF emitters are attached, makes the proposed calibration approach a viable solution for the characterization of collapsible/deployable arrays, as well as other conventional arrays. The fiber-coupled array-calibration system will open a new paradigm of array operation and maintenance, from accurate on-site calibration and real-time detection of malfunctioning cells, to the evaluation of the overall array operating condition.