A Lattice-Based Equivalent Circuit Model for Frequency Selective Surfaces
MetadataShow full item record
This work introduces a novel analytical framework for designing and synthesizing frequency selective surfaces (FSSs). In this framework, referred to as the “lattice model”, a periodic FSS is represented as an infinite lattice of interconnected admittances arranged in a multiport network. The model provides a compromise between traditional full-wave numerical analyses and simplistic aggregated circuit models, effectively dividing the analysis into two parts: a “circuit domain”, in which the periodicity of the FSS is accounted for using a discrete lattice of admittances; and an “electromagnetic domain”, in which the admittances of the lattice are calculated using classic full-wave techniques. The bulk of this dissertation provides the mathematical theory underlying the lattice model. The details of the model are initially developed for single-element, single-layer FSSs under uniform normal plane wave incidence. The theory is then extended to several additional cases: multi-element and multilayer topologies; non-uniform incidence, with particular emphasis on oblique plane wave incidence; and impedance analysis of integrated structures combining FSSs with antennas. Next, the model is applied to the task of FSS synthesis - specifically in the form of constrained optimization problems. For illustration, the lattice model is applied to a variety of specific FSS designs comprising rectangular aperture resonators. Several of these designs are fabricated, and the measured performance is compared to lattice model and simulation results. The most general result of the various avenues of investigation in this work is the verification of the lattice model as a legitimate and accurate tool for FSS analysis. Beyond this, two important features of the model are established that set it apart from other analysis techniques. First, changes in an incident field can be accounted for entirely in the circuit domain by changing the input currents to the multiport network; the admittances of the lattice remained unchanged, allowing for versatility under different scenarios of FSS illumination. Second, decomposition of an FSS into such a lattice provides an opportunity to approximate the lattice admittances as multidimensional polynomial functions of the FSS dimensions. A novel class of computationally-tractable optimization problems for FSS synthesis can be formulated using this polynomial-based scheme.
Rolando, David (2014). A Lattice-Based Equivalent Circuit Model for Frequency Selective Surfaces. Doctoral dissertation, Texas A & M University. Available electronically from