Radio-frequency localization techniques and associated systems, devices, and methods
A system comprising synchronization circuitry, a first interrogator, and a second interrogator. The first interrogator includes a transmit antenna; a first receive antenna, and circuitry configured to generate, using radio-frequency (RF) signal synthesis information received from the synchronization circuitry, a first RF signal for transmission by the transmit antenna, and generate, using the first RF signal and a second RF signal received from a target device by the first receive antenna, a first mixed RF signal indicative of a distance between the first interrogator and the target device. The second interrogator includes a second receive antenna, and circuitry configured to generate, using the RF signal synthesis information, a third RF signal; and generate, using the third RF signal and a fourth RF signal received from the target device by the second receive antenna, a second mixed RF signal indicative of a distance between the second interrogator and the target device.
1. A device, comprising:
a substrate;
a semiconductor die mounted on the substrate;
a receive antenna fabricated on the substrate and configured to receive, from an interrogator device, radio-frequency (RF) signals circularly polarized in a first rotational direction and having a first center frequency;
a transmit antenna fabricated on the substrate and configured to transmit, to the interrogator device, RF signals circularly polarized in a second rotational direction different from the first rotational direction and having a second center frequency different from the first center frequency; and
circuitry integrated with the semiconductor die and configured to:
generate, from RF signals provided from the receive antenna and having the first center frequency, the RF signals having the second center frequency, and provide the generated RF signals having the second center frequency to the transmit antenna for transmission.
2. The device of claim 1 , wherein the second center frequency is a harmonic of the first center frequency.
3. The device of claim 1 , wherein the transmit antenna comprises a patch antenna or a planar spiral antenna.
4. The device of claim 1 , wherein the transit antenna comprises a first linearly polarized antenna and a second linearly polarized antenna disposed orthogonally to the first linearly polarized antenna.
5. The system of claim 1 , wherein the first rotational direction is a counter-clockwise direction and the second rotational direction is a clockwise direction.
6. The device of claim 1 , wherein the circuitry comprises a frequency multiplier configured to generate the RF signals having the second center frequency based on the RF signals having the first center frequency.
7. The device of claim 1 , wherein the semiconductor die is flip-chip bonded to the substrate.
8. 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.
9. The device of claim 8 , wherein the second level connections comprise a ball grid array formed on the bottom surface of the substrate.
10. 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.
11. A system, comprising:
an interrogator device, comprising:
a first substrate;
a first semiconductor die mounted on the first substrate;
a first transmit antenna fabricated on the first substrate and configured to transmit, to a target device, radio-frequency (RF) signals circularly polarized in a first rotational direction and having a first center frequency;
a first receive antenna fabricated on the first substrate and configured to receive, from the target device, RF signals circularly polarized in a second rotational direction different from the first rotational direction and having a second center frequency different from the first center frequency; and
first circuitry integrated with the first semiconductor die and configured to provide RF signals to the first transmit antenna and to receive RF signals from the first receive antenna; and
the target device, comprising:
a second substrate;
a second semiconductor die mounted on the second substrate;
a second receive antenna fabricated on the second substrate and configured to receive, from the interrogator device, RF signals circularly polarized in the first rotational direction and having the first center frequency;
a second transmit antenna fabricated on the second substrate and configured to transmit, to the interrogator device, RF signals circularly polarized in the second rotational direction and having the second center frequency; and
second circuitry integrated with the second semiconductor die and configured to:
generate, from RF signals provided from the second receive antenna and having the first center frequency, RF signals having the second center frequency, and
provide the generated RF signals having the second center frequency to the second transmit antenna for transmission.
12. The system of claim 11 , wherein the second center frequency is a harmonic of the first center frequency.
13. The system of claim 11 , wherein the first rotational direction is a counter-clockwise direction and the second rotational direction is a clockwise direction.
14. The system of claim 11 , wherein the first circuitry is configured to generate, based on the RF signals provided to the first transmit antenna and the RF signals received from the first receive antenna, a RF signals indicative of a distance between the interrogator device and the target device.
15. The system of claim 11 , wherein the first semiconductor die is flip-chip bonded to the first substrate.
16. The system of claim 11 , wherein the interrogator device is a packaged device comprising:
first level connections formed by flip-chip bonding the first semiconductor die to the first substrate;
second level connections configured to connect the packaged device to a printed circuit board; and
a protective encapsulation for at least the first semiconductor die.
17. The system of claim 16 , wherein the second level connections comprise a ball grid array formed on the bottom surface of the first substrate.
18. The system of claim 11 , wherein the first substrate comprises a printed circuit board having at least one conductive layer, and wherein the first transmit antenna and the first receive antenna are fabricated on the first substrate by patterning the at least one conductive layer.
19. A method for determining a location of a target device comprising a substrate relative to an interrogator device comprising a substrate, the method comprising:
transmitting, using a first transmit antenna disposed on the substrate of the interrogator device, a first radio-frequency (RF) signal having a first center frequency and circularly polarized in a first rotational direction;
receiving, using a second receive antenna disposed on the substrate of the target device, a second RF signal having the first center frequency and circularly polarized in the first rotational direction, the second RF signal resulting from propagation of the first RF signal;
generating, from the second RF signal and using signal transformation circuitry formed in a semiconductor die disposed on the substrate of the target device, a third RF signal having a second center frequency that is different from the first center frequency;
transmitting, using a second transmit antenna disposed on the substrate of the target device, a fourth RF signal having a second center frequency and circularly polarized in a second rotational direction different from the first rotational direction, the fourth RF signal generated using the third RF signal;
receiving, using a first receive antenna disposed on the substrate of the interrogator device, a fifth RF signal circularly polarized in the second rotational direction, the RF fifth signal resulting from propagation of the fourth RF signal; and
determining the location of the target device using the fifth signal.
20. The method of claim 19 , wherein the second center frequency is a harmonic of the first center frequency.