Demonstration and Performance Appraisal of Calibration Network for Multi-Element Calibration in Active Phased Array

In active phased arrays, T/R module performance drifts due to active components’ aging and thermal effect. Hence periodic online field calibration is required during the deployment of a radar system. This paper presents an innovative design of a precise and consistent calibration network consisting of a buried leaky coaxial cable (LCX) and a calibration switch network (CSN) for fast periodic field calibration of an active phased array. In the antenna plate, the leaky coaxial cables are buried within the wall of the cavity-backed antenna to realize calibration lines. A calibration switching network is realized using a 1: 30 way Wilkinson power divider/combiner for simultaneous excitation of multiple calibration lines to characterize multiple radiating elements in the active array. An S-band (3.3 GHz ± 200 MHz) experimental active array with 64 T/R modules is configured and tested in the near-field test range (NFTR) to demonstrate the performance of the proposed calibration network. The presented scheme of simultaneous calibration of multiple radiating elements significantly reduces array calibration time and provides more flexibility to other multifunction radar functions. The availability of multiple receivers and non-overlapping RF beam forming networks in the radar system limits the improvement factor in array calibration time mentioned in this paper. © 2022, Electromagnetics Academy. All rights reserved.