An oscillator circuit includes an oscillator transistor (Q1) having respective first, second, and control terminals, the oscillator transistor being arranged to generate a microwave oscillating signal at the first terminal. A surface integrated waveguide resonator (Y1) is connected to the second terminal of the oscillator transistor (Q1). An active bias circuit portion (202) including a negative feedback arrangement is between the first terminal of the oscillator transistor (Q1) and the control terminal of the oscillator transistor (Q1), the active bias circuit portion being arranged to supply a bias current to the control terminal of the oscillator transistor (Q1). The bias current is dependent on a voltage at the first terminal of the oscillator transistor (Q1) multiplied by a negative gain.

An oscillator circuit includes an oscillator transistor (Q1) having respective first, second, and control terminals, the oscillator transistor being arranged to generate a microwave oscillating signal at the first terminal. A surface integrated waveguide resonator (Y1) is connected to the second terminal of the oscillator transistor (Q1). An active bias circuit portion (202) including a negative feedback arrangement is between the first terminal of the oscillator transistor (Q1) and the control terminal of the oscillator transistor (Q1), the active bias circuit portion being arranged to supply a bias current to the control terminal of the oscillator transistor (Q1). The bias current is dependent on a voltage at the first terminal of the oscillator transistor (Q1) multiplied by a negative gain.

Methods, systems, and apparatuses, including computer programs encoded on computer-readable media, for a microwave cavity resonator stabilized oscillator, are described. The oscillator can include a cavity resonator configured to resonate at least at one predetermined resonant frequency in a GHz frequency range. The oscillator can include circuitry including a microwave amplifier, a low pass filter and a phase shifter. The circuitry may be arranged in a feedback loop configuration, and may be at least partially mounted above a first surface of the cavity resonator. The circuitry may be electrically coupled to the cavity resonator to form an oscillator. The circuitry can include a first delay line segment that is selected instead of at least one other delay line segments for wire-bond connection to complete the feedback loop configuration at zero degree phase.

Methods, systems, and apparatuses, including computer programs encoded on computer-readable media, for a microwave cavity resonator stabilized oscillator, are described. The oscillator can include a cavity resonator configured to resonate at least at one predetermined resonant frequency in a GHz frequency range. The oscillator can include circuitry including a microwave amplifier, a low pass filter and a phase shifter. The circuitry may be arranged in a feedback loop configuration, and may be at least partially mounted above a first surface of the cavity resonator. The circuitry may be electrically coupled to the cavity resonator to form an oscillator. The circuitry can include a first delay line segment that is selected instead of at least one other delay line segments for wire-bond connection to complete the feedback loop configuration at zero degree phase.

A semiconductor device includes: an MMIC having a DC pad; a bias substrate; a plurality of MIM capacitors mounted on the bias substrate; a plurality of pads provided on the bias substrate and respectively connected to overlying electrodes of the MIM capacitors; and a wire connecting the DC pad to any one of the plurality of pads, wherein the plurality of pads are arranged between the DC pad and the plurality of MIM capacitors in a planar view, and extend parallel to a row of the plurality of MIM capacitors laterally arranged side by side.