Finite-element Analysis Of Microwave Devices Research Articles

An Efficient Perturbative Approach for Finite-Element Analysis of Microwave Devices Exhibiting Small Geometrical Variations

An innovative method for fast analysis of geometrical variations in electromagnetic wave problems is proposed. The method is based on a perturbative approach applied to the solution of the linear integro-differential operator of the electromagnetic problem in presence of small domain modifications. This approach has been embedded in a classical finite-element framework to achieve a very fast technique for field evaluation in synthesis or tolerance investigation of microwave passive devices. The proposed technique can handle geometrical variations without the need of re-meshing the domain and without any deformation of the original mesh of the problem.

Hierarchical multilevel potential preconditioner for fast finite-element analysis of microwave devices

A robust hierarchical multilevel preconditioning technique is presented for the fast finite-element analysis of microwave devices. The proposed preconditioner is based on a hierarchical multilevel scheme for the vector-scalar potential finite-element formulation of electromagnetic problems. Numerical experiments from the application of the new preconditioner to the finite-element analysis of microwave devices are used to demonstrate its superior numerical convergence and efficient memory usage.

Hybrid multilevel/multigrid potential preconditioner for fast finite element modeling

A robust hybrid multilevel/multigrid potential preconditioner is introduced for the fast and robust finite-element modeling of electromagnetic structures. The proposed preconditioning process combines the advantages of the hierarchical multilevel preconditioner and the nested multigrid potential preconditioner into a novel preconditioner with superior computational versatility. Numerical experiments from the application of the new preconditioner to the finite-element analysis of microwave devices demonstrate its superior numerical convergence and efficient memory usage.

An Error Estimator for Design Sensitivities of Microwave Device Parameters

A new error estimator for design sensitivities is proposed for finite-element analysis of microwave devices. A function of scattering parameters, C, varies with parameter g. By the adjoint method, the sensitivity dC/dg can be found. A new estimate of the error in dC/dg is based on derivatives of C with respect to position for internal nodes in the mesh (not on any parameterized boundaries or interfaces). It is shown that these estimates of the error are close to the actual errors for a variety of test cases. The estimator is tested using a p-adaptive finite-element method.

Design sensitivity of frequency response in 3-D finite-element analysis of microwave devices

The finite-element method is an established computational tool for analyzing three-dimensional microwave devices. It can also provide, at little additional cost, the sensitivities of the device's scattering parameters to changes in design variables. This paper describes a method for computing these sensitivities over a whole range of frequencies in an efficient way, by solving at just one frequency and employing a Pade expansion in the complex frequency. The sensitivity of the reflection coefficient of a piece of empty waveguide to change in its length is computed with the new approach, and there is excellent agreement with the exact values available in this case. The insertion loss of a partial-height metallic post in a waveguide is also computed. The sensitivity to change in the post height found with the new method closely matches values obtained by direct analysis of the perturbed post at a number of discrete frequencies.

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.