Spatial Power Combining In Antenna Array Applications

Because high-power microwave source have power bound which is introduced by physical restriction and fabrication difficulties. It's important to study the technique of spatial power combination(SPC) in free space by antenna array. As a complex system, spatial power combination have a lot of directions waiting for investigate deeply. In this thesis, we focus on the theorem of SPC and the arraying technique. This thesis contain: some classical array configuration's characteristics are listed and analyzed; the sparse spatial array's synthesis method is studied under multiple restrictions; spatial power combination realized by cross beam method is studied; and the law of electric strength distribution in target area is investigated, too.When target is located in array's far-field, the array theory can be used to analyze spatial power combination. Because narrow-band high-power microwave often operate in short pulse mode, the array's transition time exist which influence the choice of array's maximum aperture. Based on spatial power combination's application background, this thesis study the sparse spatial array's synthesis method under multiple constraints. In the application of spatial power combination, antenna array can be used to improve the efficiency of finite power and control the beam's shape. In this thesis, four kinds of fitness function are constructed. By adjusting each element's location and control corresponding feeding phase, elevating array's directivity, improving spatial solid angle's power ratio, suppressing grating lobes level and sidelobe levels, azimuth symmetry and low sidelobe level when beam steered were realized. When the array's sparse ratio is about 11%, the results were compared between uniform spacing rectangular array and synthesized array with the same aperture and element numbers. The simulation results conform the method's efficiency.When target located in array's near field and in each element's far field, the pattern multiplication theorem failed and the cross beam method should be used to compute the electric strength in target area. Comparing with parallel beam, cross beam will generate energy's strip in target domain. Because antenna's main beam's direction is different, the electric field's polarization direction in target radiated from each element was different, too. In this thesis, the target area's electric strength was computed by using the conformal array's method. Assuming the electric field's polarization direction radiated from each element was identical, the law of electric field distribution in target domain is analyzed and deduced. Then, the effects introduced by different electric polarization to electric field distribution are studied.