Wave Radiometer Developed Waveguide Slot Array

Slot antennas have important role in modern antenna design. As the most widely used type of slot antennas, waveguide slots arrays have the advantage of tight structure, easily controlled aperture distribution, and wide band for the nonresonant waveguide slots antennas, which make it be one of the preferred form in antenna domain of high efficiency and low side-lobe. Because of the complex structure of slot, especially for inclined narrow-wall slot, theoretical analysis is very difficult and most of the slot designs are depend on the experimental data. It takes long design circle and great expense. In this dissertation, an exact numerical analysis of the inclined narrow-wall slot is studied at first. In this part we start form the magnetic field integral equations (MFIE) and then establish the matrix equations for the unknown magnetic currents on the surface of slot aperture. To solve this problem, piece-wise sinusoidal basis and Galerkin's method are used. After these manipulations, the key point turned to solve the dyadic Green functions for the interior domain, the slot domain and the exterior domain. All calculations are in the hypothesis of 'ideal slot', that is the slots are so narrow that longitudinal field along the slots can be ignored and all fields are independent about the z-coordinate. A convergence acceleration technique, boundary element method (BEM), spectrum of two-dimension solutions (S2DS) method are used separately in solving dyadic Green function of the three domain. Next, waveguide narrow-wall slots array's is introduced in this paper. We use approximate method to fit the accurate results and find a fast and rather accurate way to design waveguide narrow-wall slots array. To prove the validity of this approximate, characteristics of a seven units waveguide narrow-wall slots array emulated by Ansoft HFSS8.0 are given in the paper. In the last part, the millimeter wave radiometer's waveguide narrow-wall slots array's testing result is also listed in this dissertation; good accordance is shown between theory and practice.