Sapphire microwave oscillator with low phase noise

Abstract

The invention discloses a sapphire microwave oscillator with low phase noise. The sapphire microwave oscillator comprises a mixer, a low pass filter, a power detector, a integral circuit, a voltage controlled phase shifter, a manual phase shifter, a microwave amplifier, a power coupler, a microwave circulator, a sapphire filter and a temperature control circuit, wherein the sapphire filter comprises an evacuated enclosure, a heating wire 13, a metallic shield chamber, a sapphire crystal and a vacuum maintaining subassembly. The microwave oscillator of the invention could obtain a stable high-frequency microwave signal with low phase noise under room temperature, and the phase noise of the microwave signal at the far-end is far higher than the index reached by crystal oscillator frequency doubling.

Description

Technical field [0001] The invention relates to a microwave oscillator. More specifically, it relates to a low phase noise sapphire microwave oscillator. Background technique [0002] Microwave frequency sources with low phase noise and high stability are widely used in radar, communication measurement and other fields. The traditional microwave source is generally obtained by multiple frequency multiplications of the crystal oscillator, but as the number of frequency multiplications increases, the phase noise (short-term stability) will become larger and larger, which means that the phase noise will increase with the carrier frequency. And increase. The low temperature (4k) sapphire microwave frequency source has extremely low phase noise (in the X band, <-160dBc / Hz10kHz) and excellent short-term stability ( <1E-151s). The microwave source formed by the sapphire high-Q filter can generate extremely low phase noise at high frequencies, which has a higher index than the h...

AI Technical Summary

Problems solved by technology

However, the disadvantage of sapphire resonator is that the dielectric constant of sapphire crystal changes with temperature, which makes the temperature coefficient of sapphire resonator very high, and the drift of sapphire dielectric constant with temperature is relatively large. Therefore, the temperature drift coefficient of resonator Relatively large (50KHz-70KHz), these will affect the long-term stability of the sapphire resonator

But still can not meet the needs, so it is necessary to provide a sapphire microwave oscillator with low phase noise

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