Moment Method Analysis Of Inclined Slots In The Narrow Wall Of A Rectangular Waveguide

The array of slots in the narrow wall of rectangular waveguides has been widely used in phased array antennas. Because of its compact, easy processing, easy to control the distribution of the array aperture and wide-band characteristics, the array of slots has become a modern low-sidelobe and even ultra-low-sidelobe antennas's priority options. This paper studies the basic unit, a inclined slot in the narrow wall of a rectangular waveguide, of the slots array in a waveguide.Based on the analysis of slots'structural characteristics, a integral equation of the magnetic field was established and piecewise-sinusoidal functions and the Galerkin moment method were used to solve the equation in this thesis. The traditional dyadic Green's function and moment method were used to solve the admittance of inner waveguide. When I was calculating the admittance of slot cavity, I made reasonable assumuptions and used the boundary element method to solve the Green's function. I selected the 90 wedge Green's function as the external dyadic Green's function and simplified the function to make it fit the boundary condition, so the external admittance was gotten. Generalized input current was calculated by using the distribution of waveguide's electromagnetic field. Then, by solving the complex linear equations, coefficient vector of the basic function was obtained and the network parameters of the slot were calculated easily.After the correctness of this theory was verified, the contact between the admittance and the slot parameters was analysed and some useful conclusions were obtained.