Measurement, simulation, and theory of a non-Foster unit cell with parasitic resistance

Measured, simulated, and theoretical results are presented for a unit cell loaded by a non-Foster circuit element comprising a negative capacitor. The unit cell is suspended in the electromagnetic field of a coaxial line for characterization, rather than being directly wired to the transmission line. Relative dielectric constant less than unity was observed over a 5:1 bandwidth, and supporting theory is presented showing that bandwidth can be improved by reducing parasitic resistance of the non-Foster element. Theoretical, simulated, and measured results show similar bandwidth and permittivity characteristics.