A port element for p-adaptive S-parameter calculation

A new element is proposed for the treatment of ports in p-adaptive finite-element analysis of microwave devices. The element consists of a number of segments, on each of which the field is represented by high-order, hierarchical polynomials that match those used in the interior. As the p-adaption proceeds, the number of waveguide modes taken into account on the port increases, and so does the accuracy of the port boundary condition. Results for several H-plane problems in rectangular waveguide demonstrate that, with the new element, adaptive convergence to the same scattering parameters can be achieved no matter how closely the ports are placed.