Error analysis of radiation directivity of TE11 main mode of circular waveguide

This paper presents the simulation of the radiation from both the pure mode of TE11 and the mixed modes of TE11 and TM01 with different power proportion for circular wave-guides of different diameters. The directivities of E plane and of H plane are calculated, with the hypothesis of axially symmetric radiation patterns, which is usually used in the power measurement of HPM in far-field zones. The calculated directivities are compared with the simulated ones of the real radiation patterns. The results show that in the case of the pure mode and of the mixed modes with TM01 power proportion of 5% and 10%, the maximum difference between the calculated directivities and the simulated ones is less than 0.8 dB at H plane, while the minimum difference between the two kinds of directivities is lar