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

Abstract

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 Padé 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.

Sensitivity analysis of network parameters with electromagnetic frequency-domain simulators

“…Then, the analysis with (4) and (6) applies. We first write (7) in terms of the field of the surface elements of the th port as -- (10) where has been already defined in (7). Making use of (9), we have - (11) From (11), we find the derivatives of with respect to the edge field components of the element at the th port…”

Transient Adjoint Sensitivities for Discontinuities With Gaussian Material Distributions

“…Several AVM techniques have been developed for sensitivity analysis with different numerical approaches [8][9][10][11][12][13][14][15][16][17][18][19][20][21]. These include the Finite-Element-Time-Domain (FETD) [8], Finite-Element-FrequencyDomain (FEFD) [9], Method of Moments (MoM) [20,21], FiniteDifference-Time-Domain (FDTD) [15], Frequency Domain TLM (FD-TLM) [11], and TD-TLM [13,14,18]. It was assumed in all these techniques that the material properties are constants within the discontinuity of interest.…”

“…Recently, the use of AVM has been extended to sensitivity analysis with numerical electromagnetic techniques [8][9][10][11]. Using only one extra electromagnetic (EM) simulation, the sensitivities of the desired response can be estimated with respect to all parameters.…”

An Impulse Sampling Approach for Efficient 3d TLM-Based Adjoint Sensitivity Analysis

“…The updated numbering scheme ensures simple and direct factorization of the scattering matrix according to the associated polarization. For example, in (11)…”

“…The AVM approach has been successfully developed for both time and frequency domain numerical techniques, including the finite difference time domain (FDTD) [8], the time-domain transmission line modeling (TLM) [7], the frequency domain transmission line modeling (FDTLM) [9], the method of moments (MOM) [10], and the finite element method (FEM) [11]. An efficient self AVM (SAVM) approach is developed for network parameter sensitivity analysis where the sensitivities are calculated without any extra simulations [12].…”