Interdigital Capacitors for Use in Lumped-Element Microwave Integrated Circuits

An analysis of the frequency response of interdigital capacitors is given along with an equation for their design. The capacitor Q is given in terms of its geometry which consists of a planar interdigital conductor deposited on the surface of a substrate. Capacitance values ranging from 0.1 to 10 pF at L band with measured Q's in excess of 400 are realizable.