Electromagnetic scattering from a two-state phase switched screen using a control impedance

Much research has been conducted lately in order to understand the electromagnetic scattering characteristics of phase switched screens (PSS). Motivation arose from an interest in exploiting the capabilities of structures with variable impedances that might be used as tunable or reconfigurable radar absorbers. Further encouragement was provided by the advent of seemingly practical dynamically adaptive radar absorbing materials. Such devices have been shown, both analytically and empirically, to exhibit interesting and desirable scattering properties. Perhaps most notable of these is the versatility in terms of adjustable or increased bandwidth over purely passive conventions. The paper presents a method for deriving control impedance values to produce a desired time-averaged scattered electric field for a two-state system. The problem is characterized by normal incidence energy impingement upon a planar interface, and the system is characterized by an equivalent linear network, two load impedance values and a duty cycle. Given parameters for one of the two states, a desired outcome can be realized by varying either the duty cycle or second impedance condition or both, and selecting the most practical values.