Formation structure and the series resonance circuit null of the distribution capacitor in substrate

摘要

PURPOSE: To facilitate and adjustment of the capacitance by adopting a distributed capacitor comprising a distributed constant for a capacitor of an electronic circuit such as a series resonance circuit and making a hole in a base plate in the vicinity of the distributed constant capacitor so as to avoid dispersion in the capacitance of the distributed capacitor. ;CONSTITUTION: A hole surrounding one terminal of a coil L is made in a base plate in the vicinity of the one terminal of the coil L. Since the base plate has a larger dielectric constant than that of air, the hole is made to remove the base plate in existence between the coil L and a copper foil provided to the lower side of the base plate and connecting to ground. Thus, the capacitance of a distributed capacitor in existence between the coil L and the copper foil forming a ground plane and connecting to ground is reduced. Furthermore, a conductor 1 is provided and its both ends are connected to the copper foil on the rear side of the base plate and to ground. The distance between the conductor 1 and the coil L is changed by tilting the conductor 1 with respect to the base plate. The capacitance of the distributed constant capacitor C₃ comprising the distributed circuit constant is the sum of the distributed capacitance between the coil L and the conductor 1 and the distributed capacitance between the coil L and the copper foil on the base plate. The distance between the coil L and the conductor 1 is changed by tilting the conductor 1 with respect to the base plate to change the capacitance of the capacitor C₃.;COPYRIGHT: (C)1996,JPO