Publications

The Advanced Technology Demonstrator (ATD) is an active, S-band, dual-polarization phased array radar developed for weather sensing. The ATD is an active electronically scanned array (AESA) with a 4-m aperture comprised of 4,864 individual transmit/receive (T/R) modules. The antenna was calibrated at the element, subarray, and array levels. Calibration, validation, and verification testing was completed in two main stages, first in an anechoic chamber and second after it was installed on site in its permanent location. This paper describes the procedure used to collect antenna patterns at each stage and compares three key performance metrics: beamwidth, mean-squared sidelobe level (MSSL), and integrated sidelobe level (ISL).

An active S-band dual-polarized multifunction phased array radar (MPAR), the Advanced Technology Demonstrator (ATD), has recently been developed for weather sensing and aircraft surveillance. The ATD is an active electronically scanned array (AESA) with 4864 transmit/receive (T/R) modules and was installed in a spherical radome. Simulations and a novel phased array measurement technique have been explored to assess the impact of high reflectivity from a wet radome during rain that can potentially induce voltages exceeding the transmit amplifier breakdown voltage. The measurement technique uses array elements radiating one at a time to illuminate the radome, and uses superposition to quantify the received signal power in a reference antenna on the face of the array. It is shown that when the radome surface is wet and highly reflective, certain electronic steering angles sum to a large reflected signal focused on the array face. This measurement technique can be used prior to high-power phased array radar operation to monitor the magnitude of reflections and help avoid element transmit amplifier failures.