Proposals for extending traceable impedance measurements to higher frequencies

Geometrical constructions are proposed which minimize residual impedances of four terminal-pair (4 T-P) capacitance, resistance and inductance standards together with adaptors to other terminal systems. Some standards whose measured frequency dependence is small (up to 10 MHz) have been made using surface-mounting electronic capacitors. These standards facilitate the traceable calibration of 4 T-P impedance-measuring instruments. A 4 T-P to single-port adaptor having small, measurable residual impedances bridges the gap in calibration traceability between low and microwave frequencies. The resistance standards usually used for ac/dc transfer up to 1 MHz can also be converted to a 4 T-P definition with another adaptor.