We propose and analyze an organization for a field-programmable gate array structure that operates using a balanced ternary logic system where the logic set {±1, 0} maps directly to equivalent voltage levels {±1.0V, 0.0V}. Circuits for basic components such as a ternary buffer, flip-flop and LUT are described based on the characteristics of a commercial silicon-on-sapphire process that offers multiple simultaneous transistor thresholds. A simple example of a balanced ternary FIR filter is mapped to the FPGA and some preliminary estimates made of its performance and area.