Abstract: The present invention relates to an oscillator having a first substrate on which a resonator circuit and an amplifier circuit are arranged. The resonator circuit has a first set of components and the amplifier circuit has an amplifier transistor and a second set of components. The first substrate includes at least two additional substrates: a second substantially insulating substrate and a third substantially semiconducting substrate. At least the amplifier transistor is arranged on the third substrate and the first and second sets of components are arranged on the second substantially insulating substrate.

Abstract: The invention relates to a resonator (200,300) with variable resonance frequency, intended for connection to an amplifier, thus forming an oscillator, said resonator comprising a resonator circuit (205,305) for deciding the resonance frequency of the resonator and the oscillator, said resonator circuit comprising an inductance (L), a variable capacitance (Cj), and means (Vtune) for varying the capacitance. The resonator also comprises connection means (C1, Ck; C1, Ck, C2) for connecting the resonator to an amplifier. The resonator is provided with means (Vtune) for varying the capacitance of the connection means in proportion to the variation of the capacitance (Cj) of the resonator circuit. Preferably, the means (Vtune) for varying the capacitance (Ck) of the connection means are arranged such that an essentially constant relationship (Ck/Cj) is maintained between the capacitance (Ck) of the connection means and the first capacitance (Cj) of the resonator across all resonance frequencies.