Chip-scale radio-frequency localization devices and associated systems and methods

1. A device comprising:

a substrate;

a semiconductor die mounted on the substrate;

a transmit antenna fabricated on the substrate and configured to transmit, to a target device different from the device, radio-frequency (RF) signals at least at a first center frequency equal to or greater than 50 GHz;

a receive antenna fabricated on the substrate and configured to receive, from the target device, RF signals at least at a second center frequency different than the first center frequency;

circuitry integrated with the semiconductor die and comprising a frequency multiplier and a mixer having first and second inputs and an output, the first input of the mixer being coupled to the frequency multiplier and the second input of the mixer being coupled to the receive antenna; and

at least one processor configured to receive a first signal obtained based on the output of the mixer and to determine a distance between the device and the target device using the first signal.

2. The device of claim 1 , further comprising a waveform generator coupled to both the transmit antenna and the frequency multiplier.

3. The device of claim 1 , wherein the device is a packaged device comprising:

first level connections formed by flip-chip bonding the semiconductor die to the substrate;

second level connections configured to connect the packaged device to a printed circuit board; and

a protective encapsulation for at least the semiconductor die.

4. The device of claim 3 , wherein the second level connections comprise a ball grid array formed on the bottom surface of the substrate.

5. The device of claim 1 , wherein the substrate comprises a printed circuit board having at least one conductive layer, and wherein the transmit antenna and the receive antenna are fabricated on the substrate by patterning the at least one conductive layer.

6. The device of claim 5 , wherein at least one of the transmit antenna and the receive antenna are isotropic.

7. The device of claim 5 , wherein at least one of the transmit antenna and the receive antenna are directional.

8. The device of claim 1 , wherein the second center frequency is greater than and is a harmonic of the first center frequency.

9. The device of claim 1 , wherein the frequency multiplier comprises a frequency doubler.

10. The device of claim 1 , wherein the frequency multiplier comprises a diode.

11. The device of claim 1 , wherein the second center frequency is equal to or greater than 50 GHz.

12. A device comprising:

a substrate;

a semiconductor die mounted on the substrate;

a transmit antenna fabricated on the substrate and configured to transmit, to a target device different from the device, radio-frequency (RF) signals circularly polarized in a first rotational direction and having a first center frequency equal to or greater than 50 GHz;

a receive antenna fabricated on the substrate and configured to receive, from the target device, RF signals circularly polarized in a second rotational direction different from the first rotational direction;

circuitry integrated with the semiconductor die and comprising a frequency multiplier and a mixer having first and second inputs and an output, the first input of the mixer being coupled to the frequency multiplier and the second input of the mixer being coupled to the receive antenna; and

at least one processor configured to receive a first signal obtained based on the output of the mixer and to determine a distance between the device and the target device using the first signal.

13. The device of claim 12 , further comprising a waveform generator coupled to both the transmit antenna and the frequency multiplier.

14. The device of claim 12 , wherein the device is a packaged device comprising:

first level connections formed by flip-chip bonding the semiconductor die to the substrate;

second level connections configured to connect the packaged device to a printed circuit board; and

a protective encapsulation for at least the semiconductor die.

15. The device of claim 14 , wherein the second level connections comprise a ball grid array formed on the bottom surface of the substrate.

16. The device of claim 12 , wherein the substrate comprises a printed circuit board having at least one conductive layer, and wherein the transmit antenna and the receive antenna are fabricated on the substrate by patterning the at least one conductive layer.

17. The device of claim 14 , wherein at least one of the transmit antenna and the receive antenna are isotropic.

18. The device of claim 14 , wherein at least one of the transmit antenna and the receive antenna are directional.

19. The device of claim 12 , wherein the frequency multiplier comprises a frequency doubler.

20. The device of claim 12 , wherein the frequency multiplier comprises a diode.

21. The device of claim 12 , wherein the receive antenna is configured to receive, from the target device, RF signals at least at a second center frequency equal to or greater than 50 GHz.

22. The device of claim 1 , wherein the first center frequency is between 50 GHz and 240 GHz.

23. The device of claim 11 , wherein each of the first and second center frequencies is between 50 GHz and 240 GHz.

24. The device of claim 23 , wherein the first center frequency is between 50 GHz and 70 GHz and the second center frequency is between 100 GHz and 140 GHz.

25. The device of claim 12 , wherein the first center frequency is between 50 GHz and 240 GHz.

26. The device of claim 21 , wherein each of the first and second center frequencies is between 50 GHz and 240 GHz.

27. The device of claim 26 , wherein the first center frequency is between 50 GHz and 70 GHz and the second center frequency is between 100 GHz and 140 GHz.