Method for Radiation Center Position Measurements of a Combined Antenna in the Pulsed Mode

This paper proposes a method for measuring the position of radiation centers for an ultra-wideband combined antenna (CA) in the pulsed mode. The radiation centers for E- and H-planes of the antenna are determined. Antenna rotation in these planes, with respect to an arbitrary axis, results in the time delays (advances) of the recorded receiving pulses for various angles. The purpose of the measurements is to find the rotation axes providing minimum time delays of the radiated pulse registration at the receiving antenna for the largest possible range of observation angles. These rotation axes pass through local areas (radiation centers) in the antenna volume. Simple analytic formulas refining the position of the radiation center from an arbitrary measurement are proposed. In the simulations, a code based on the FDTD method was used. The CA has at least two radiation centers. Radiation center of the H-plane is located at 1/3-1/2 of the antenna length counting from its rear wall, slightly below the antenna's half height. Radiation center of the E-plane is located near the aperture plane of the antenna, also slightly below the antenna's half height.