Electronic frequency-comb detector

1. An electronic frequency-comb detection system, comprising:

an electronic frequency-comb detector comprising:

a frequency-comb generator configured to generate a frequency comb reference signal, wherein the frequency-comb generator comprises a series of inverter stages; and

a heterodyne mixer;

wherein the heterodyne mixer is configured to use the frequency comb reference signal to downconvert received millimeter wave (mm-wave) and terahertz (THZ) frequency tones into an intermediate frequency (IF) signal.

2. The electronic frequency-comb detection system of claim 1 , wherein the heterodyne mixer comprises an N-Channel MOSFET transistor (NFET).

3. The electronic frequency-comb detection system of claim 2 , wherein the gate of the NFET is connected to an output of the frequency-comb generator.

4. The electronic frequency-comb detection system of claim 3 , wherein a source of the NFET is configured to receive mm-wave and THZ frequency tones from an on-chip antenna.

5. The electronic frequency-comb detection system of claim 4 , wherein a gate of the NFET is configured to receive the frequency comb reference signal.

6. The electronic frequency-comb detection system of claim 5 , wherein the NFET is configured to generate an IF signal at the drain of the NFET.

7. The electronic frequency-comb detection system of claim 1 , further comprising an external clock configured to feed a clock to an input of the frequency-comb generator.

8. The electronic frequency-comb detection system of claim 1 , wherein the frequency comb reference signal is a local oscillator (LO) signal having a tunable repetition rate.

9. The electronic frequency-comb detection system of claim 1 , further comprising an IF amplifier.

10. The electronic frequency-comb detection system of claim 9 , wherein the IF amplifier is configured to feed a spectrum analyzer configured to detect a signature of a material under test (MUT).

11. The electronic frequency-comb detection system of claim 10 , further comprising:

a processor, and

a memory containing a machine learning classifier application,

where the machine learning classifier application configures the processor to classify materials under test based upon inputs received from the spectrum analyzer.

12. The electronic frequency-comb detection system of claim 11 , wherein the machine learning classifier application further configures the processor to identify repetitive patterns in recorded data.

13. The electronic frequency-comb detection system of claim 11 , wherein the machine learning classifier application further configures the processor to monitor at least one of heart rate and breathing rate of a subject.

14. The electronic frequency-comb detection system of claim 1 , wherein the electronic frequency-comb detector further comprises an on-chip antenna.

15. The electronic frequency-comb detection system of claim 14 , wherein the on-chip antenna is an elliptical antenna.

16. The electronic frequency-comb detection system of claim 15 , wherein the on-chip antenna comprises a metasurface layer.

17. The electronic frequency-comb detection system of claim 14 , wherein the electronic frequency-comb detector is fabricated using a CMOS process.

18. An electronic frequency-comb detector, comprising:

a frequency-comb generator with an output, the frequency-comb generator having a plurality of inverter stages;

an NFET having its gate connected to the output of the frequency-comb generator; and

an IF amplifier having a plurality of amplifier stages,

wherein the frequency-comb generator, the NFET and the IF amplifier, in combination, are configured to downconvert a received radio frequency signal into an IF signal and amplify the IF signal.

19. A method of electronic frequency-comb spectroscopy, the method comprising:

radiating electromagnetic waves in a direction of a material under test (MUT), wherein the MUT transmits a portion of the electromagnetic waves;

generating a reference signal using a frequency-comb generator, wherein the frequency-comb generator comprises a series of inverter stages;

receiving the portion of the electromagnetic waves transmitted by the MUT by an on-chip antenna;

mixing the portion of the electromagnetic waves received by the on-chip antenna and the reference signal using a mixer to generate an IF signal;

amplifying the IF signal using an amplifier to produce an amplified IF signal;

feeding the amplified IF signal to a spectrum analyzer; and

detecting a signature of the MUT using the spectrum analyzer.