Modal analysis of radiation and energy storage mechanisms on conducting scatterers
The manifestation of radiation and stored energy by electric currents on conducting bodies is studied via modal expansions. The novel modal expansions are based on the quadratic operators which map a current distribution to each quantity. Adaptations of the continuous forms of these operators into the Method of Moments is reviewed. The discrete modal expansions are studied on several example objects, leading to conclusions regarding the sparsity of the radiation mode spectrum. Analytic forms for the sparse radiation modes on electrically small objects are derived. Negative energy current distributions are studied using the energy storage modal expansions. The role of ground plane radiation on the determination of an embedded antenna's Q factor is studied using radiation modes, giving a new perspective on the convergence behavior of this parameter with respect to ground plane size. Leveraging the invariance of radiation modes on small objects, an example procedure for the design of an embedded antenna array using radiation modes is presented.
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign