Nonreciprocal devices having reconfigurable nonreciprocal transfer functions through nonreciprocal coupling

Patent metadata

Field	Value
Publication number	US-10693206-B2
Application number	US-201816121915-A
Country	US
Kind code	B2
Filing date	Sep 5, 2018
Priority date	Sep 7, 2017
Publication date	Jun 23, 2020
Grant date	Jun 23, 2020

Abstract

A nonreciprocal device includes a waveguide through which waves at a first frequency propagate with a first wavevector and with a second wavevector in a direction opposite to the first wavevector; a frequency-dependent device that operates within a frequency range and modifies the waves through the waveguide in a way that is dependent on the first frequency; and a set of couplers to couple the waveguide and the frequency-dependent device. Coupling rates of the set of couplers are modulated to enable nonreciprocal coupling, with respect to the frequency-dependent device, of the first wavevector compared to the second wavevector.

First claim

What is claimed is:

1. A nonreciprocal device comprising:
a waveguide through which waves at a first frequency propagate with a first wavevector and with a second wavevector in a direction opposite to the first wavevector;
a frequency-dependent device that operates within a frequency range and modifies the waves through the waveguide in a way that is dependent on the first frequency; and
a set of couplers to couple the waveguide and the frequency-dependent device, wherein coupling rates of the set of couplers are modulated to enable nonreciprocal coupling, with respect to the frequency-dependent device, of the first wavevector compared to the second wavevector.

2. The nonreciprocal device of claim 1 , wherein the set of couplers comprises at least a first coupler and a second coupler located at spatially distinct coupling sites between the waveguide and the frequency-dependent device, and wherein a coupling rate of each of the first and second couplers is to vary with time.

3. The nonreciprocal device of claim 2 , wherein the spatially distinct coupling sites are evenly separated by a defined distance, wherein the defined distance is set to create a phase mismatch between the waveguide and the frequency-dependent device.

4. The nonreciprocal device of claim 2 , further comprising at least one of a signal generator, a signal splitter, or a phase shifting circuit coupled to the set of couplers and to modulate the first coupler at the first frequency and the second coupler at a second frequency.

5. The nonreciprocal device of claim 2 , wherein the set of couplers further comprises a third coupler located at one of the spatially distinct coupling sites, and wherein separation between the spatially distinct coupling sites is such that the waves in the waveguide cannot enter the frequency-dependent device due to destructive interference of the first frequency within the frequency range.

6. The nonreciprocal device of claim 1 , wherein each of the set of couplers is one of a variable capacitor or a varactor diode.

7. The nonreciprocal device of claim 1 , wherein the frequency-dependent device comprises one of a resonator, a network of coupled resonators, an antenna, an amplifier, an oscillator, or a sensor.

8. The nonreciprocal device of claim 1 , wherein the frequency-dependent device is a microstrip resonator and the waveguide is a microstrip waveguide.

9. The nonreciprocal device of claim 1 , wherein the frequency-dependent device and the waveguide operate with one of radio-frequency electromagnetic waves, optical-frequency electromagnetic waves, or acoustic waves.

10. The nonreciprocal device of claim 1 , wherein, in response to modulation of the set of couplers, the nonreciprocal device is to operate as one of an isolator, a circulator, a gyrator, a full-duplex antenna, or a nonreciprocal filter.

11. A system comprising:
a waveguide through which waves at a first frequency propagate with a first wavevector and with a second wavevector in a direction opposite to the first wavevector;
a frequency-dependent device that operates within a frequency range and modifies the waves through the waveguide in a way that is dependent on the first frequency;
a set of couplers to couple the waveguide to the frequency-dependent device at spatially separated coupling sites, the set of couplers comprising at least a first coupler and a second coupler; and
a signal processor coupled to the set of couplers, the signal processor to:
generate a sinusoidal signal;
generate a first modulated coupling constant via modulation of a first coupling constant, of the first coupler, using the sinusoidal signal;
generate a second modulated coupling constant via modulation of a second coupling constant, of the second coupler, using the sinusoidal signal; and
apply a phase offset of the second modulated coupling constant as compared to the first modulated coupling constant, to induce nonreciprocal coupling, with respect to the frequency-dependent device, of the first wavevector compared to the second wavevector.

12. The system of claim 11 , wherein to apply the phase offset, the signal processor is to modulate the first coupler with a first phase and the second coupler with a second phase different than the first phase.

13. The system of claim 11 , wherein the spatially separated coupling sites are evenly separated by a defined distance that is set, in view of the first wavevector and the second wavevector, such that the frequency-dependent device is to cause:
first waves that propagate in a first direction to not be absorbed by the frequency-dependent device; and
second waves that propagate in a second direction, opposite to the first direction, to be absorbed by the frequency-dependent device.

14. The system of claim 11 , wherein each of the set of couplers comprises a varactor diode, and wherein the signal processor is further to:
modulate a first voltage bias applied to the first coupler to generate the first modulated coupling constant; and
modulate a second voltage bias applied to the second coupler to generate the second modulated coupling constant, wherein a combination of the first and second modulated coupling constants is direction sensitive in relation to the direction of the waves within the waveguide.

15. The system of claim 14 , wherein the signal processor comprises:
a signal generator to generate the sinusoidal signal; and
a signal splitter to split the sinusoidal signal from the signal generator into two independently-controlled alternating current (AC) signals, the system further comprising:
a first band-pass filter coupled between the signal processor and the first coupler; and
a second band-pass filter coupled between the signal processor and the second coupler, wherein the first and second band-pass filters are to isolate lower-frequency bias modulation from a higher frequency of the frequency-dependent device.

16. The system of claim 14 , wherein the first and second modulated coupling constants each contain a set of frequency components comprising at least one of a positive sideband component or a negative sideband component, and wherein the set of frequency components of the first modulated coupling constant has a different phase than the set of frequency components of the second modulated coupling constant.

17. A method comprising:
coupling, using a set of couplers, a waveguide to a frequency-dependent device, wherein waves at a first frequency propagate in the waveguide with a first wavevector and with a second wavevector in a direction opposite to the first wavevector, and wherein the frequency-dependent device operates within a frequency range;
modifying, with the frequency-dependent device, the waves within the waveguide in a way that is dependent on the first frequency; and
inducing, via modulation of coupling rates of the set of couplers, nonreciprocal coupling, with respect to the frequency-dependent device, of the first wavevector compared to the second wavevector.

18. The method of claim 17 , further comprising:
separating at least a first coupler and a second coupler, of the set of couplers, at spatially distinct coupling sites between the waveguide and the frequency-dependent device; and
causing a coupling rate of each of the first and second couplers to vary with time in way that emulates a sinusoidal traveling wave with a second frequency and a third wavevector.

19. The method of claim 18 , wherein the third wavevector is one of the first wavevector or the second wavevector.

20. The method

Assignees

• Univ Illinois
• Board Of Trustees Of The Univ Of Illinois

Inventors

• Bahl Gaurav
• Peterson Christopher

Classifications

• H01P1/36

  Isolators · CPC title

• H01P5/18

  consisting of two coupled guides, e.g. directional couplers · CPC title

• H01P1/38

  Circulators · CPC title

• G02B6/4208

  using non-reciprocal elements or birefringent plates, i.e. quasi-isolators (optical isolators per se G02F1/093, G02F1/0955) · CPC title

• H01P1/32 Primary

  Non-reciprocal transmission devices (H01P1/02 - H01P1/30 take precedence) · CPC title