Tuning system on dielectric substrates

Claim 1

A tuning system characterised by: a dielectric; a pair of first and second electrodes (29,30) confronting each other with said dielectric interposed therebetween, each of said first and second electrodes having at least one bent portion to present primarily a lumped-constant inductance and having a desired equivalent electrical length; said first and second electrodes having ground or common terminals located out of mutually confronting positions so that voltage signals induced by mutual induction between the electrodes will be opposite in phase with respect to each other, thereby producing a parasitic distributed-constant capacitance due to a potential difference between the electrodes and a dielectric constant of the dielectric; one of said first and second electrodes having a first terminal (27) at a desired position thereof, the electrodes forming a two-terminal circuit network having the first terminal with the ground or common terminals serving as a second terminal, the two-terminal circuit network forming an equivalent parallel resonant circuit composed of a lumped-constant inductance formed by said one electrode and a parasitic distributed-constant capacitance between the first and second electrodes; and one or more of the following items:- a) a feedback amplifier (26) connected to said parallel resonant circuit for generating an inherent voltage vibration to produce a tuning oscillating signal; b) an amplifier (40) connected to said parallel resonant circuit for generating a tuning amplifying action to produce a selective tuning amplified signal; c) a mixer (68) connected to said parallel resonant circuit and responsive to frequency signals to be mixed for generating a frequency converting action to produce an intermediate frequency tuning signal.