Method of admittance matrix measurement of an antenna array

A method is described for measuring the admittance matrix of an antenna array considered as an N-port network. The method utilizes the properties of hybrid junctions to apply at the antenna ports, taken two at a time, with all other ports short-circuited, two pairs of incident voltages of known amplitudes and phases. Measurements are obtained of the reflections coefficients (\Gamma) and of the input admittances (Y_{in}) at the pair of antenna ports under test for both modes of excitations. The desired admittance parameters are then easily determined from the measured quantities as shown in the formulation given below. The proposed method applies to arbitrary arrays and is gererally easier to implement than those that are now available [1-4].