Geometrically Conformal Multi-Layer Selective Frequency Shielding Materials

ABSTRACT: The objective of this program is to develop structurally conformal materials with frequency-selective radio frequency (RF) transmission and shielding properties for military aircraft. Materials that allow RF transmission at sensing/communication frequencies while enabling broadband electromagnetic shielding outside of these frequencies are useful for both RF operations and survivability. NanoSonic will design, fabricate and experimentally measure the selective RF transmission properties of multi-layer materials with spatially-structured electromagnetic properties. Early NanoSonic research has demonstrated frequency-selective notch RF filter and resonant frequency filtering behaviors in such multi-layer materials. We will build on those initial experimental demonstrations to design, fabricate and test materials with arbitrary frequency-selective passband and stopband properties. This will allow us to establish the design relationship between the physical structure and the material properties of such materials, and their frequency-dependent RF shielding behaviors. We will also consider methods whereby the passband of the material may be actively"opened"to allow communication and sensing, and then"closed"to reduce RCS to as low a value as possible. During Phase I NanoSonic would work with the current supplier of custom RF shielding materials, and the RF system group at a major U.S. aircraft manufacturer to evaluate and test developed materials. BENEFIT: EMI shielding materials are used to block unwanted electromagnetic fields from interfering with the operation of electrical and electromagnetic systems. Most EMI shielding materials exhibit uniform shielding as a function of frequency. Materials developed through this program would provide selective EMI shielding versus frequency, and would thus be useful to block specific sources of RF noise or permit low-loss transmission at specific frequencies to permit communication. Such materials would be of use in military and non-military communication systems, consumer and industrial RF and electronic systems, and personal portable communication electronic devices such as cell phones, pads and platforms. Examples include shielding paints and coatings, gaskets, tape, cable and connector shielding, windows, enclosures and radomes.