Power Pattern Synthesis With Peripherally Excited Phased Arrays

Peripherally excited (PEX) phased arrays have been demonstrated as an effective way to realize some aspects of phased array performance with a simple design and reduced cost. This work develops a method to realize shaped beams with PEX arrays by controlling the relative magnitude and phase of the antenna's peripheral sources. Through a simple model of fields in a parallel-plate waveguide, a linear system of equations can be defined and solved to find the peripheral source excitations that best approximate a desired field pattern. This model is used to solve for a uniform broadside beam and yields a higher aperture illumination efficiency than a broadside beam obtained from an equal-amplitude excitation. A cosecant beam is also synthesized, showing good agreement with the goal beam pattern. The linear system of equations can be easily integrated into other beam synthesis techniques for increased design flexibility. A particle swarm optimization (PSO) is used to solve for controlled sidelobe levels, flat-top, and multibeam patterns. Beams realized with full-wave simulation show good agreement with the ideal and predicted beams.