Image Number 12 for United States Patent #4619001.
A tuning system employs a specific resonant circuit which includes two electrodes confronting each other through a dielectric interposed therebetween. Each of the two electrodes has at least one bent portion to present a lumped-constant inductance and has a desired equivalent electrical length. The two electrodes respectively have common terminals located out of mutually confronting positions so that voltage signals induced by mutual inductance between the electrodes will be opposite in phase so as to thereby produce a parasitic distributed-constant capacitance. The two electrodes form a two-terminal circuit network having a first terminal disposed at a desired position on one of the two electrodes and the common terminals as a second terminal. The first terminal of the resonant circuit is connected to a feedback amplifier, an amplifier, or a mixer so as to form a tuning oscillator, a tuning amplifier or a mixer.