Short Course: Intelligent Antenna Design Using Characteristic Mode Analysis

Presented by

Martin Vogel, Gopinath Gampala, and C.J. Reddy
EM Software & Systems (USA) Inc.

Abstract

The theory of Characteristic Mode Analysis (CMA) is a well-known method that allows for the analysis of arbitrary structures by solving a generalized eigenvalue equation derived from the Method of Moments (MoM) impedance matrix. The resulting eigenvalues and eigenvectors give insight into the resonating behavior of structures such as antennas. This helps designers to follow a systematic, intelligent approach rather than a brute force method, by looking at the eigenvalue spectrum and the eigenvector distribution. The approach is based on insight in the fundamental resonance characteristics of antenna geometries and of the structures on which they are mounted. This insight aids in choosing the locations of the excitations on the antenna and of the antennas on the platform. Furthermore, knowledge of the coupling between excitations and modes enables the design engineer to synthesize the desired antenna pattern by exciting a linear combination of modal patterns. This is a deterministic approach, based on insight in physics. It contrasts with an approach in which an optimization routine is used to explore a large many-dimensional design space with few constraints. This short course will present a refresher on the theory of characteristic modes and practical examples illustrating use of CMA for variety of antenna designs. In this course attendees will learn

  • computation of characteristic modes for arbitrary geometries
  • visualization of character currents and radiation patterns
  • use of modal significance and mode tracking for antenna design
  • use of CMA for antenna placement on structures
  • antenna design process for using CMA
  • practical antenna design examples