Broadband characterization of the total active reflection coefficient of multiport antennas

This paper focuses on the broadband characterization of multiport antennas, and introduces the TARC (total active reflection coefficient) method. A method for calculating the TARC is detailed for different port excitations directly from the scattering matrix of the antenna and independent of the feeding network. As an example, the cavity backed annular patch antenna (CABAPA) is analyzed as a multiport antenna and the TARC is calculated for this antenna for different polarizations. The calculated results, when compared to the measured results, show good agreement.