PROBLEM TO BE SOLVED: To provide a
voltage controlled oscillator providing a strip line
resonator in the inside layer of a multilayer substrate and less in the dispersion of oscillation frequency by
humidity. SOLUTION:
Polytetrafluoroethylene is used as the core material of the multilayer substrate. Since the
polytetrafluoroethylene has smaller water absorptivity than
glass epoxy, the change of dielectricity to the change of
humidity. As a result, also the change of the resonant frequency of the strip line
resonator formed in the inside layer of the multilayer substrate is small, as a result, also the change of oscillation frequency becomes small. Then, since the change of the oscillation frequency is small, control
voltage sensitivity can be reduced, and thus, C / N characteristics is improved. Then, since also the property of the
polytetrafluoroethylene material itself is small in
dielectric loss comparing with the
glass epoxy and also specific dielectricity is small, the Q of resonant
system is improved, and thereby, the C / N characteristics is improved too.