Characteristics of TCAS circular phased array antennas for moment method

The authors present an analysis of the top-loaded, low-profile TCAS (traffic alert and collision avoidance system) antenna, a disk-loaded folded-type monopole antenna. Particular emphasis is placed on the input impedance and the pattern when eight elements are arranged in circular form. The analysis is based on the wire-grid moment method. The results are compared with measured values and agree fairly well.<>