The equivalent circuit of air capacitor in high frequency range

The air capacitor has a very good frequency response and is suitable to act as an impedance standard for the frequency range of several MHz. In this paper, the determination of capacitance at high frequency is discussed. It should be noted that the result depends on the form of equivalent circuit used. An ordinary simple circuit of lumped parameters gives an inaccurate result and a distributed parameter circuit gives a better result for capacitance at high frequency. This work is important when an air capacitor is intended for use as an a reference standard.