An oscillator has a feedback loop with a signal output, a multi-pole resonator, and a gain block. The gain block applies a gain sufficient to generate a stable oscillation signal at the signal output; and the multi-pole resonator is tunable between two or more resonance modes.

Systems and methods for forming a mm wave resonant filter include a lithographically fabricated high Q resonant structure. The resonant structure may include a plurality of cavities, each cavity having a characteristic frequency that defines its passband. A filter may include a plurality of resonant structures, and each resonant structure may include a plurality of cavities. These cavities and filters may be fabricated lithographically.

Systems and methods for forming a mm wave resonant filter include a lithographically fabricated high Q resonant structure. The resonant structure may include a plurality of cavities, each cavity having a characteristic frequency that defines its passband. A filter may include a plurality of resonant structures, and each resonant structure may include a plurality of cavities. These cavities and filters may be fabricated lithographically.

Systems and methods for forming a compact gas sensor include using a lithographically fabricated high Q resonator coupled to at least one of a Gunn diode and an IMPATT diode. The resonator may include a plurality of cavities filled with a sample gas. A detector coupled to the resonator may measure the amplitude of the emitted mm wave radiation.

An oscillator includes a resonator and a first loop circuit. The first loop circuit includes an amplifier and a first coupler. That first loop circuit is electrically coupled to the resonator. The oscillator is configured to produce negative feedback for the amplifier in a cavity mode relative to short circuit terminations or open circuit terminations of a cavity modelling the oscillator at frequencies offset from a carrier frequency. The oscillator has a loss of less than 4.00 dB for a bidirectional trip through the cavity at the frequencies offset from the carrier frequency.

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.

Systems and methods for forming a compact gas sensor include using a lithographically fabricated high Q resonator coupled to at least one of a Gunn diode and an IMPATT diode. The resonator may include a plurality of cavities filled with a sample gas. A detector coupled to the resonator may measure the amplitude of the emitted mm wave radiation.

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.

Vibration compensation is provided for Interferometric Noise Suppressed Oscillators (INSOs). In an INSO the error signal at the mixer output responds linearly to changes in carrier frequency. A vibration compensation signal is summed with the error signal at the input to the feedback amplifier to provide the control signal to the loop phase shifter to suppress close-in phase noise near the carrier frequency and to reduce the effects of mechanical vibrations on oscillator phase noise. The addition of the vibration compensation signal does degrade carrier suppression, hence increases the flicker noise contributed by the INSO's LNA but does so without degrading overall oscillator phase noise. In a frequency tuned configuration, the vibration compensation signal reduces the effects of mechanical vibrations on oscillator phase noise independent of the tuning voltage applied to the phase shifter.