A high-Q factor resonator includes a solenoid having an embedded capacitor assembled in a machinable high-frequency dielectric printed circuit board (PCB), or other substrate. The solenoid comprises a plurality of surface conductors positioned on upper and lower surfaces of the PCB. The solenoid further comprises a plurality of conductive vias extending through the PCB between the surface conductors, and at least two aligned vias are separated by a capacitive gap. A liquid crystal dielectric is embedded within the capacitive gap in order to control the capacitance. Accordingly, a tunable capacitive filter is achieved by changing the dielectric permittivity of the liquid crystal. In one example, a nematic liquid crystal is sealed in the capacitive gap and has its permittivity changed with a low frequency bias to tune the capacitor.

A high-Q factor resonator includes a solenoid having an embedded capacitor assembled in a machinable high-frequency dielectric printed circuit board (PCB), or other substrate. The solenoid comprises a plurality of surface conductors positioned on upper and lower surfaces of the PCB. The solenoid further comprises a plurality of conductive vias extending through the PCB between the surface conductors, and at least two aligned vias are separated by a capacitive gap. A liquid crystal dielectric is embedded within the capacitive gap in order to control the capacitance. Accordingly, a tunable capacitive filter is achieved by changing the dielectric permittivity of the liquid crystal. In one example, a nematic liquid crystal is sealed in the capacitive gap and has its permittivity changed with a low frequency bias to tune the capacitor.