Abstract This specification discloses variable capacitance devices which vary their capacitances under the influence of DC bias voltages or radiations. One embodiment comprises a PN junction diode, a dielectric thin film deposited on the surface of said junction diode at which the junction terminates and a conducting electrode deposited on the dielectric thin film, in which the area of an equivalent plate electrode formed in said junction diode is varied by changing the thickness of a depletion region. In another embodiment, a nonlinear resistance layer deposited on the dielectric thin film is employed. As a DC voltage as applied to the nonlinear resistance layer is increased, the lateral conductivity of the nonlinear resistance layer increases and the area of the equivalent plate electrode facing the conducting electrode is increased. A further embodiment employs a thin film transistor or a MIS transistor to vary the area of the equivalent plate electrode provided therein.
A variable capacitor having a variable capacitance between two terminals, which comprises: a thin film of insulating dielectric material; a conducting plate electrode disposed on one surface of said film and ohmically connected only to one of said two terminals; a semiconductor substrate disposed on the other surface of said thin film and containing at least two adjacent and alternate layers of p-type and n-type which forms a p-n junction therebetween and are ohmically connected to the other of said two terminals, said junction being substantially perpendicular to and lying directly under said conducting plate electrode; and means for applying a d-c bias voltage across said junction and ohmically connected to the other of said two terminals.
Claim 2
Dependent Claim
117 words
A variable capacitor having a variable capacitance between two terminals, which comprises: a thin film of insulating dielectric material; a conducting plate electrode disposed on one surface of said film and ohmically connected only to one of said two terminals; a semiconductor substrate disposed on the other surface of said thin film and containing at least two adjacent and alternate layers of p-type and n-type which forms a p-n junction therebetween and are ohmically connected to the other of said two terminals, said junction being substantially perpendicular to and lying directly under said conducting plate electrode; and means for applying a d-c bias voltage across said junction and ohmically connected to the other of said two terminals.
Claim 3
Dependent Claim
40 words
A variable capacitor according to claim 1 in which said thin film is provided with at least two apertures, and said layers of p-type and n-type are ohmically connected to the other of said two terminals through said apertures, respectively.