A simple but feasible method for the large and high frequency antenna patterns measurement is proposed in this paper.The computational electromagnetics method physical optics(PO) analysis based on targets data obtained by optical tests and finite element methods(FEM) is used to simulate the far field patterns and gains of the antenna.Because the optical testing systems have the accuracy well above the need for the microwave and terahertz(THz).Therefore the measurement data outline the real surface instead of ideal curve of the antenna.The PO simulations of currents integration of the real surface fitted by the sample spots represent the actual antenna radiation pattern.This method can also be used to evaluate the antenna radiation under special condition such as high and low temperature vacuum chamber test

THz antenna radiation test

deployable and inflatable antenna test(that are easily affected by gravity

wind and other environment etc.).The good agreement of the antenna patterns between direct test and simulations verifies the effectiveness and accuracy of this method.