[Under construction]2016 AFOSR MURIUniversal Electromagnetic Surface: Exploiting active electronics and active origami to generate a programmable electromagnetic responsePO: Dr. Ken Goretta, Ghz-THz Electronics and Materials PI: Dr. Kaushik Bhattacharya, California Institute of TechnologyWebsite: TBD
We propose a program integrating electromagnetics, mechanics, and materials with the vision of exploiting controlled origami structures and active electromagnetic (EM) circuits to create universal EM surfaces that emulate the far field pattern of any EM structure possible within a given aperture. Our program advances the state-of-the-art in this field through fundamental research in electromagnetics and integrated circuits, origami design/control, objective structures, new concepts for actuation, and conductive soft skins.
Mathematically, the concept of a universal electromagnetic surface relies on the surface and its electromagnetic and mechanical properties not being fixed. With complete control of surface EM fields, arbitrary near field patterns are possible, and large-scale manipulation of the surface itself gives added functionality. We will develop electromagnetically active structures and integrated circuit architectures that enable operation of a large number of EM active sources on scales much smaller than the wavelength to generate a broad range of near and far field patterns.
We will exploit the concept of objective structures to simplify control routines and phasing. The motion paths for our reconfigurable antenna will be sampled using fast algorithms for path planning, to find actuation sequences that allow smooth changes in the EM properties of an antenna. Our research addresses a critical need for active EM surfaces: robust lightweight actuators that match the remarkable flexibility of the surfaces themselves. We will explore the use of active materials – shape-memory alloys (SMAs) and liquid crystal elastomers (LCEs) – as actuation mechanisms. SMAs exhibit the largest work output per volume of any actuator system, but have been plagued by reversibility issues, which were recently addressed by materials design strategies proposed by a team member. LCEs have a similar remarkable recent achievement in terms of work output and also are high-k dielectric materials. To support reversible folding and collapse, the proposed origami requires highly deformable wiring, sensors, and insulating film.
An initial demonstration of our self-actuating universal EM surface will be achieved by designing, building and testing an origami surface consisting of mechanically actuated panels, each with an active EM surface capable of synthesizing the local EM field necessary for the far field response. Further evolution of this concept will lead to prototypes built from continuous sheets, with flexible electronics and interconnects, and emerging active materials.
The proposed universal EM surfaces have the potential to make game changing impact on applications such as conformal active EM structures for mono- and poly-static radar, cloaking shrouds, and active and reactive electronic countermeasures in a broad range of ground and airborne systems.
This project will be carried out by 6 researchers, 8 graduate students and 4 post-doctoral researchers located at 4 different academic institutions, and a part-time origami consultant.