Topology Optimization of a Wideband Planar Phased Array Element Using Periodic Level Set Functions

Adding complexity to the radiating surface of a planar phased array has the potential to extend the bandwidth of economical array designs, while allowing relative trade-offs between broadside gain, scan volume, and polarization purity to be more fully explored. This work introduces the use of the periodic level set function (p- Lsf)for antenna arrays, an approach which can describe complex material distributions through only a few continuously variable parameters, and applies it to the optimization of a broadband, single polarization, and unbalanced phased array element. The optimization and resulting element are compared against similar prior optimizations of a fragmented aperture antenna with equivalent bandwidth requirements. Finally, the scan performance of an 18x18 finite array (16x16 driven) with the optimized element is modeled and shown.