A New Short-Bar Method for 4TP Admittance Standards Calibration by Using a Modified Z-Matrix Expression to Improve Signal-to-Noise Ratio $(S/N)$ for Higher Impedances

This paper describes how to calibrate four-terminal-pair (4TP) admittance standards using a new short-bar method with a modified Z-matrix expression containing a coefficient C ₁ . The short-bar method is an effective way of measuring of a signal to the standard with better signal-to-noise ratio (S/N) for higher impedance standards, particularly 1 pF. This allows a 1-pF capacitor to be calibrated using direct measurement at frequencies reported for calibrations. As this method does not require the equivalent circuit for interpolation using measurements at frequencies beyond the reported frequencies, it can be applied to 4TP admittance calibration, where the 4TP sections have the same mechanical structure as lower impedance standards.