Microfluidic systems for reconfigurable RF surfaces and systems

Abstract

Adaptive control of electromagnetic (EM) properties across the surface of a platform can enhance its operational capabilities and survivability. Microfluidic systems may be an enabling technology for such EM control. Communication links use portions of the surface and other EM sensors may provide information about the environment or gather signal intelligence (SIGINT). At the surface, light or radar signals are reflected or scattered and provide the primary means of detection by an adversary's sensor systems such as radar. An electronically reconfigurable surface (ERS) would adaptively control these EM processes. An ERS is based on the distributed and adaptive control of the RF (radio frequencies) surface properties. For an ERS system the RF control would be accomplished by embedding in the surface region microwave circuits containing devices with controllable impedance characteristics. A microfluidic system that uses colloidal particle control and local circulation could provide a means of implementing the distributed impedance control needed for ERS systems. This paper provides a systems level overview of the application of microfluidic devices and systems as an enabling technology for ERS systems. A feedback and control subsystem would provide control signals to adaptively alter microfluidic device impedance characteristics, which would be the basis of the RF control. OVERVIEW -MICROFLUIDIC SYSTEMS FOR ELECTRONICALLY RECONFIGURABLE SURFACESMany important functions and processes occur at or near the outer surface of a platform (land, sea, air, or space) where it interacts electromagnetically with its surroundings. These include the RF transmission or reception of communication signals; sensor systems that provide information about the environment or gather signal intelligence (SIGINT); and the reflection or scattering of light or radar signals that provide the primary means of detection by an adversary's sensor systems such as radar. An electronically reconfigurable surface (ERS) is based on the distributed and adaptive control of the RF (radio frequencies) surface properties. In this paper we nominally use RF to refer to transmission frequencies ranging from about 30 MHz to 300 GHz. For an ERS system the RF control would be accomplished by embedding microwave circuits containing devices with controllable impedance characteristics in the surface region. An ERS can provide new capabilities for military and commercial vehicles, such as enhanced communication links, while reducing observable signatures. Ideally, the subsystem that provides the impedance control should require little volume or added weight. A microfluidic system that uses colloidal particle control and local circulation could provide distributed impedance control needed for ERS systems. Under DARPA and AFOSR sponsorship a team consisting of Toyon Research Corporation and Texas A&M University College of Engineering is investigating the feasibility of this application of microfluidics.In electromagnetics, boundary conditions are of fundamental import...