Highly stabilized circuit for measuring very low impedance (Rx, Cx) and their small changes (δRx, δCx) at high frequencies with some applications

A circuit is described for the accurate, measurement of the equivalent parallel capacitance C_x, resistance R_x of high-loss materials, and also their small changes ΔC_x, ΔR_x. The capacitance measurement is not affected by the specimen´s resistance when the value of R_x is greater than 10 Ω. The important characteristic of the new circuit is its ability to measure accurately the value of C_x, R_x, and also ΔC_x, ΔR_x of very high-loss materials at high frequencies.