Design of a 16-Port Shared-Arm Dipole Array for Monostatic Imaging Radar

A 16-port shared-arm dipole array (SADA) is designed and its performance verified. When constructing a 2D physical array to image a target, arranging the antenna elements in a longitudinal direction becomes problematic due to the element spacing constraint for alias-free sampling. Therefore, the proposed structure is designed such that the two dipole elements share a single arm, which leads to alias-free sampling in the aperture domain. In order to improve the performance of the SADA, each antenna arm is loaded with a constant resistive profile. The resistive loading allows each element to operate over a broad-band and radiate a temporally short pulse, while correcting the distorted beam pattern of the SADA. The resultant 16-port SADA with resistive loading is manufactured by printing the arms on an FR-4 substrate and loading them with equally spaced chip resistors. The performance of the 16-port SADA as a sensor array for an imaging radar is then verified by an experiment.