Frequency shifted, vacuum pressure sensor

1. A pressure sensing device, comprising:

a varactor including an aperture having a gas disposed therein;

an inductor, coupled to the varactor to form a resonant circuit, configured to resonate at a resonant frequency, the resonant frequency being a function of a pressure of the gas; and

a switch configured to pass a voltage to the resonant circuit when closed and not pass the voltage to the resonant circuit when opened.

2. The device of claim 1 , wherein the varactor comprises:

a first layer of p-type material;

a first layer of n-type material; and

a first np junction formed between the layer of p-type material and the layer of n-type material,

wherein the aperture extends at least partially through the layer of p-type material, at least partially through the layer of n-type material, and entirely through the np junction.

3. The pressure sensing device of claim 1 , wherein the aperture is from among a plurality of apertures, each of the plurality of apertures having the gas disposed therein.

4. The pressure sensing device of claim 1 , wherein the gas comprises: air, or argon.

5. The pressure sensing device of claim 2 , wherein the varactor is configured to have a capacitance that varies as a function of a number of a photons, and charge particles, impacting the np junction.

6. The pressure sensing device of claim 2 , wherein the varactor further comprises:

a second layer of p-type material;

a second layer of n-type material; and

a second np junction formed between the second layer of p-type material and the second layer of n-type material;

wherein the aperture extends at least partially through the second layer of p-type material, at least partially through the second layer of n-type material, and entirely through the second np junction.

7. The pressure sensing device of claim 6 , further comprising:

a voltage source configured to provide a voltage across the first np junction,

wherein the inductor is coupled to the second layer of p-type material and the second layer of n-type material.

8. The pressure sensing device of claim 1 , wherein a largest dimension of the pressure sensing device is not more than 20 mm.

9. The pressure sensing device of claim 1 , wherein the pressure sensing device is configured to produce a micro-discharge of light, and charge particles, at an intensity that depends on the pressure of the gas.

10. The pressure sensing device of claim 9 , further comprising a sensor configured to detect the resonant frequency.

11. A method for operating a pressure sensing device, the method comprising:

coupling a varactor of the pressure sensing circuit to an inductor to form a resonant circuit;

ionizing a gas within an aperture of the varactor by applying a pulse or a repetitive series of pulses to the varactor to form a plasma within the aperture;

using the plasma to cause a micro-discharge within the aperture, wherein a number of photons in the micro-discharge impacting the aperture is related to a capacitance of a varactor of the pressure sensing device; and

measuring a resonant frequency of the pressure sensing device.

12. The method of claim 11 , further comprising:

determine the pressure of a gas in the one or more apertures based on the measured resonant frequency.

13. The pressure sensing device of claim 1 , wherein the inductor is coupled to the varactor in parallel to form a parallel resonant circuit.