Efficient Constrained Optimization Method for In-Situ Antenna Performance Restoration

In-situ antenna measurements are often impractical or too costly, since they require the fabrication of the antenna and structural modifications of the platform for antenna installation. As the forward EM problems can be numerically solved ever more efficiently, it is possible to perform antenna-platform optimizations in a reasonable time. They provide allow the investigation of alternative antenna sites, material treatments, or antenna modifications to mitigate the platform or nearby structure effects in order to satisfy the performance requirements. In this proposal, it is assumed that the installed antenna is near optimum and only small adjustments or modifications are required to regain its performance characteristics. As such, the limited-memory BFGS with simple bound constraints is chosen to solve the large scale mutli-objective optimization problem. In this approach, the gradient of the vector functional is computed by the adjoint method and the explicit storage of the approximate Hessian computed based on a recursive equation is not required. The function evaluation will be performed by the method-of-moment solver in the commercial FEKO.