Electromagnetic self-adaptive surfaces with shielded external support system

Abstract

We analyse the electromagnetic (EM) characteristics of a self-adaptive material (SAM) surface whose support system is shielded from the SAM array by a perfectly conducting ground plane. This configuration enables subarrays consisting of EM sensors and actuators to be completely separated from the control unit, active components, beamformers, power hybrids and wiring harness. The radiation characteristics, spectral-domain Green dyadic function and array impedance are obtained in closed form, based on image theory. It is shown that the performance of a previously studied free-standing implementation can be achieved with the present implementation in a more practical manner. Numerical examples are given to illustrate the analytical results. An equivalent circuit representation is developed for a single sensor/actuator pair that takes all conductive and radiated EM interactions in this pair into account. The results find application in the design and operation of fully EM ‘intelligent’ surfaces, ‘smart’ antennas, and as novel active absorbing EM boundary conditions in computational electromagnetics.