Figure 2 shows a schematic diagram of the parallel feedback oscillator using a transmission-type high-Q resonator
and a GaAs FET low noise amplifier.
Consequently, high-Q resonators
provide huge enhancement to other characteristics of devices exploiting the resonance effects, e.
This idea is being pursued in a class of novel high-temperature-superconducting tunable microwave devices such as microstrip line phase shifters, high-Q resonators
and tunable filters.