Waveguide Unit Of Phased Array Antenna Analysis And Design

At the present time, phased array antennas have already become the main develop- ment direction of radar antennas. This thesis in combination with the actual engineering demand, analyzes and designs a horizontally polarized triangular-grid planar phased array antenna, which composed of open-ended rectangular waveguide, the main steps of analyzing and designing are as follows:1. At first, taking no account of mutual coupling among the array elements, classical electromagnetic theory is used to establish analyzing model for finite array, and initial value parameters of the array structure which basic satisfy the design index are got, these parameters provide reference for subsequent analyzing and design.2. Under the condition of taking account of mutual coupling among the array elements, mode coupling method is used to establish analyzing model for finite array, and parameters of the array structure satisfying the design index are got. And, with these parameters, the mutual coupling and scan blindness of the array are analyzed, which are normal phenomena for the phased arrays.3. After the parameters of the array structure are got, simulation software, such as CST Microwave Studio, CTS Design Studio and Ansoft Hfss, are used to design the power dividers for the radiation units in the horizontally polarized direction of the array. These power dividers adopt structure of coupling slots in the narrow side of main rectangular waveguides, in which the narrow side of the main waveguide and the broadside of secondary waveguides are crossed at locations of each slot. In order to make the apertures distribution of the power dividers satisfy the Taylor distribution of the horizontally polarized direction of the array, the rake angle and depth of cut of each slot should be adjusted. Due to the existence of error of amplitude distribution and phase distribution in power dividers, the side lobe of azimuth pattern for this planar waveguide array is influenced, thus, the power dividers should be optimized.