A Novel Serpentine Online Calibration Network for Printed Dipole Phased Array Antenna at Ku-Band

This paper presents a novel serpentine-shaped online calibration network for printed dipole Active Electrically Scanned Array (AESA) antenna at Ku-band. When AESA antennas are deployed in the field, online calibration network is essential to correct imbalances in amplitude and phase excitations of antenna elements without bringing the array back to test range. A passive serpentine-shaped microstrip network is designed to couple power from calibration network to all antenna elements uniformly. One serpentine line couples power from the cal line to nearby two linear arrays of printed dipoles. All cal lines are combined onto a single port to excite the network with a common source. Simulation results show coupling amplitudes from calibration network to antenna elements are about $- 40 \pm 5$ dB. Calibration network has been realized and coupling amplitudes are measured from calibration network to all antenna elements. Measured results show a good correlation with the simulation results. Design of a serpentine-shaped passive online calibration network to couple power strongly and uniformly onto all printed dipole elements is a novel contribution of this work.