Tunable Band-Pass Filters Employing Stretchable Electronic Components

This paper describes some of the recent results of an ongoing U.S. Army research program examining the electronic behavior of hyperelastic stretchable capacitor, resistor, and inductor networks for which the conductor material employed is stretchable. As with traditional rigid analog components, stretchable electronic components exhibit frequency-dependant behavior. Unlike their rigid counterparts, stretchable electronic components may also exhibit dramatic strain-dependent behavior. In this way stretchable circuit networks may be viewed as controllable spatio-temporal filters. Resistance, capacitance, and inductance all change to varying degrees depending on the specific set of spatio-temporal inputs. These variations may be harnessed to create an adaptive circuit element that is controllable. This paper describes the results of integrating stretchable components into a tunable band-pass filter. Center frequency, bandwidth, and gain can be varied in a controllable way by varying the capacitance or resistance of specific circuit elements by stretching them. Biaxially stretchable components are described that are subjected to equibiaxial strain-states as high as 100% area strain. We examine the influence that the type of compliant conductor has on tunable circuit properties and on control authority.