Terahertz sensors and related systems and methods
An active radio-frequency (RF) sensing technology for determining the relative and/or absolute state (e.g., position, velocity, and/or acceleration) of a target object (e.g., a person, a car, a truck a lamp post, a utility pole, a building) is described. The sensors described herein operate in the Terahertz band (300 GHz to 3 THz). An active RF sensing device comprises a substrate and first and second semiconductor dies mounted on the substrate. The first semiconductor die has an RF transmit antenna array integrated thereon, and the transmit antenna array comprises a first plurality of RF antennas configured to generate an RF signals having frequency content in the 300 GHz-3 THz band. The second semiconductor die has an RF receive antenna array integrated thereon, and the receive antenna array comprises a second plurality of RF antennas configured to receive RF signals having frequency content in the 300 GHz-3 THz band.
1. A method of imaging a target object using a device, the method comprising:
controlling the device to transmit a first radio-frequency (RF) signal having frequency content in a frequency band of 300 GHz-3 THz, the first RF signal comprising pulses having a duration between 0.1 ms and 10 ms, the frequency band having at least first and second frequency sub-bands;
receiving, using the device, a second RF signal produced by reflection of the first RF signal from the target object; and
generating a multi-channel image having a first channel and a second channel, wherein data in the first channel is determined using frequency content of the second RF signal in the first sub-band, wherein data in the second channel is determined using frequency content of the second RF signal in the second sub-band.
2. The method of claim 1 , wherein the frequency band has a bandwidth of 10 GHz-60 GHz.
3. The method of claim 1 , wherein the first frequency sub-band has a bandwidth of 2 GHz-20 GHz.
4. The method of claim 1 , wherein the frequency content is in a frequency band of 650 GHz-690 GHz.
5. The method of claim 1 , further comprising determining a position of the target object relative to the device using the multi-channel image.
6. The method of claim 1 , further comprising determining a characteristic of the target object using a machine learning model based on the data in the first channel and the data in the second channel.
7. The method of claim 1 , further comprising:
assigning a first color to the data in the first channel; and
assigning a second color to the data in the second channel,
wherein generating the multi-channel image comprises combining the data in the first channel having the first color assigned thereto with the data in the second channel having the second color assigned thereto.
8. The method of claim 1 , wherein controlling the device to transmit the first RF signal comprises generating an RF reference signal and frequency up-converting the RF reference signal, and
wherein generating the multi-channel image comprises mixing the second RF signal with the frequency up-converted RF reference signal.
9. The method of claim 8 , wherein frequency up-converting the RF reference signal comprises frequency up-converting the RF reference signal by a factor between 30 and 80.
10. The method of claim 8 , wherein generating the RF reference signal comprises generating a chirped RF reference signal.
11. The method of claim 1 , wherein the frequency band further comprises a third frequency sub-band, wherein the multi-channel image further comprises a third channel, and wherein data in the third channel is determined using frequency content of the second RF signal in the third sub-band.
12. A device for imaging a target object, comprising:
a radio-frequency (RF) transmit antenna configured to transmit a first RF signal having frequency content in a frequency band of 300 GHz-3 THz, the first RF signal comprising pulses having a duration between 0.1 ms and 10 ms, the frequency band having at least first and second frequency sub-bands;
an RF receive antenna configured to receive a second RF signal produced by reflection of the first RF signal from the target object; and
processing circuitry configured to generate a multi-channel image having a first channel and a second channel, wherein the processing circuitry is configured to determine data in the first channel using frequency content of the second RF signal in the first sub-band, and to determine data in the second channel using frequency content of the second RF signal in the second sub-band.
13. The device of claim 12 , wherein the frequency band has a bandwidth of 10 GHz-60 GHz.
14. The device of claim 12 , wherein the frequency content is in a frequency band of 650 GHz-690 GHz.
15. The device of claim 12 , wherein the processing circuitry is further configured to determine a position of the target object relative to the device using the multi-channel image.
16. The device of claim 12 , wherein the processing circuitry is further configured to:
assign a first color to the data in the first channel, and
assign a second color to the data in the second channel,
wherein generating the multi-channel image comprises combining the data in the first channel having the first color assigned thereto with the data in the second channel having the second color assigned thereto.
17. The device of claim 12 , further comprising:
a signal generator configured to generate an RF reference signal; and
frequency up-conversion circuitry configured to frequency up-convert the RF reference signal,
wherein the processing circuitry is configured to generate the multi-channel image by mixing the second RF signal with the frequency up-converted RF reference signal.
18. The device of claim 17 , wherein the frequency up-conversion circuitry is configured to frequency up-convert the RF reference signal by a factor between 30 and 80.
19. The device of claim 17 , wherein the signal generator is configured to generate the RF reference signal to be chirped.
20. The device of claim 12 , wherein the frequency band further comprises a third frequency sub-band, wherein the multi-channel image further comprises a third channel, and wherein the processing circuitry is further configured to determine data in the third channel using frequency content of the second RF signal in the third sub-band.