Radio frequency isolator

• US 10,505,258 B2
• Filed: 08/02/2016
• Issued: 12/10/2019
• Est. Priority Date: 08/02/2016
• Status: Active Grant

• Current Assignee: Analog Devices International Unlimited Company (Analog Devices, Inc.)
• Original Assignee: Analog Devices Global Unlimited Company (Analog Devices, Inc.)
• Inventors: Lee, Check F., Stenson, Bernard P., Chen, Baoxing
• Primary Examiner(s): Mancuso, Huedung X
• Application Number:
  US15/226,438
• Publication Number:
  US 20180040941A1
• Time in Patent Office: 1,225 Days
• Field of Search: 343772
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 1/48 Earthing means; Earth screens; Counterpoises
• CPC Class Codes: H01Q 13/02 Waveguide horns
• CPC Class Codes: H01Q 13/06 Waveguide mouths horns H01Q13/02
• CPC Class Codes: H01Q 15/14 Reflecting surfaces; Equivalent structures electromagnetic shields H01Q1/526
• CPC Class Codes: H01Q 19/30 the primary active element being centre-fed and substantially straight, e.g. Yagi antenna
• CPC Class Codes: H01Q 9/065 Microstrip dipole antennas patch antenna H01Q9/0407
• CPC Class Codes: H04B 5/43 Antennas
• CPC Class Codes: H04B 5/75 for isolation purposes

Abstract

Radio frequency (RF) isolators are described, coupling circuit domains operating at different voltages. The RF isolator may include a transmitter which emits a directional signal toward a receiver. Layers of materials having different dielectric constants may be arranged to confine the emission along a path to the receiver. The emitter may be an antenna having an aperture facing the receiver.

Claims

1. A radio frequency (RF) isolator, comprising:

a dielectric layer having a dielectric constant between 12 and 500 for frequencies between 5 GHz and 200 Ghz;

first and second antennae disposed at least partially within, or within ten microns of, the dielectric layer; and

a feed circuit disposed in a first die and coupled to the first antenna via a first surface of the first die,

wherein the first antenna is configured to emit a radio frequency signal, and the dielectric layer is configured to confine and transmit the radio frequency signal, and wherein

at least a portion of the first surface does not overlap the dielectric layer in a direction perpendicular from the first surface.

2. The RF isolator of claim 1, wherein a thickness of the dielectric layer is between 5 microns and 5 mm.

3. The RF isolator of claim 1, wherein the first and second antennae are dipole antennae.

4. The RF isolator of claim 3, wherein the dipole antennae are linear or curved.

5. The RF isolator of claim 3, wherein the first antenna is a dipole antenna with a reflector, and wherein the reflector is linear, planar, or curved.

6. The RF isolator of claim 1, wherein the first antenna comprises a feed and a horn formed by a plurality of conductive vertical vias defining an aperture of the first antenna.

7. The RF isolator of claim 1, wherein the horn has a shaped selected from the group consisting of:

piece-wise linear polygon;

a parabola;

or a section of an ellipse.

8. The RF isolator of claim 1, wherein the dielectric layer is a first dielectric layer, wherein the isolator further comprises a second dielectric layer having a dielectric constant less than that of the first dielectric layer, and wherein the first antenna is disposed in the second dielectric layer.

9. The RF isolator of claim 1, wherein the dielectric layer is a first layer, and wherein the isolator further comprises a second dielectric layer adjacent the first dielectric layer and having a dielectric constant less than 12, wherein the first antenna is in the second dielectric layer.

10. A method of operation of a micro-scale isolator, comprising:

emitting a radio frequency signal from a first microfabricated antenna operating in a first voltage domain, the radio frequency signal having a frequency between 5 GHz and 200 GHz, wherein the first microfabricated antenna is coupled to a first surface of a die having a feed circuit;

confining and transmitting the radio frequency signal through a dielectric layer having a dielectric constant between 12 and 500, wherein at least a portion of the first surface does not overlap the dielectric layer in a direction perpendicular from the first surface; and

receiving the radio frequency signal with a second microfabricated antenna operating in a second voltage domain different than the first voltage domain.

11. The method of claim 10, wherein confining and transmitting the radio frequency signal through the dielectric layer comprises confining the radio frequency signal within a height between 5 microns and 5 mm.

12. The method of claim 10, further comprising directing the radio frequency signal through the dielectric layer using an antenna horn.

13. The method of claim 10, further comprising directing the radio frequency signal through the dielectric layer using a reflector of the first antenna.

14. The method of claim 10, wherein confining and transmitting the radio frequency signal through the dielectric layer comprises diffracting the radio frequency signal with a diffraction grating.

15. The method of claim 10, wherein confining and transmitting the radio frequency signal through the dielectric layer comprises confining the radio frequency signal between conductive plates.

16. A system, including:

a first circuit operating in a first voltage domain and disposed on a first die;

a second circuit operating in a second voltage domain less than the first voltage domain and disposed on a second die; and

a radio frequency isolator coupling the first and second circuits to each other, the radio frequency isolator comprising;

a dielectric layer having a dielectric constant between 12 and 500 for frequencies between 5 GHz and 200 Ghz;

first and second antennae disposed at least partially in, or within 10 microns of, the dielectric layer; and

a feed circuit coupled to the first antenna via a first surface of the first die, wherein;

at least a portion of the first surface does not overlap the dielectric layer in a direction perpendicular from the first surface.

17. The system of claim 16, wherein the first and second antennae are formed on a first die flip-chip mounted to a die on which the first circuit is formed.

18. The system of claim 16, wherein the first antenna comprises a feed and a horn formed by a plurality of conductive vertical vias defining the aperture of the first antenna.

19. The system of claim 16, wherein the first antenna is disposed in the dielectric layer.

20. The system of claim 16, further comprising a third die, wherein the dielectric layer is disposed on the third die, and wherein the first and second antennae are disposed in a plane parallel to the first surface.