Internal heater for RF apertures

Patent metadata

Field	Value
Publication number	US-11109451-B2
Application number	US-201715653415-A
Country	US
Kind code	B2
Filing date	Jul 18, 2017
Priority date	Jul 20, 2016
Publication date	Aug 31, 2021
Grant date	Aug 31, 2021

Abstract

A heater for a radio frequency (RF) antenna and method for using the same are disclosed. In one embodiment, an antenna comprises a physical antenna aperture having an array of RF antenna elements; and a plurality of heating elements, each heating element being between pairs of RF elements of the array of RF elements.

First claim

We claim:

1. An antenna comprising:
a physical antenna aperture having an array of radio frequency (RF) antenna elements formed with first and second substrates and a liquid crystal (LC) layer between the first and second substrates, the first substrate being an iris substrate; and
a plurality of heating elements between the first and second substrates and interleaved between RF antenna elements in the array to heat the LC layer, each heating element integrated with iris elements as part of the iris layer on the iris substrate and contained within an area between a distinct pair of adjacently located RF elements in the array of RF elements.

2. The antenna defined in claim 1 wherein heating elements in the plurality of heating elements are equidistant between RF antenna elements in the array.

3. The antenna defined in claim 1 wherein heating elements in the plurality of heating elements are midway between rings of iris/patch antenna elements.

4. The antenna defined in claim 1 wherein heating elements in the plurality of heating elements are in rings between the RF antenna elements.

5. The antenna defined in claim 1 wherein the plurality of heating elements are wires.

6. The antenna defined in claim 5 wherein a majority of the wires are of equal length with cross sections that are similar in dimension over the length of the heating wires.

7. The antenna defined in claim 6 wherein the plurality of wires provides a same power dissipation per unit area over the antenna aperture.

8. The antenna defined in claim 5 wherein heating wires are evenly distributed over the antenna aperture area.

9. The antenna defined in claim 5 wherein width and height of a wire cross section of the heating wires varies over the antenna aperture while having a same power dissipation per unit area.

10. The antenna defined in claim 5 further comprising heater power buses electrically connected to supply power to the heating wires, wherein one or more heater power buses are traverse through a border seal structure of the aperture.

11. The antenna defined in claim 10 wherein the one or more heater power buses are electrically connected to a metal layer on an iris layer or a patch layer.

12. The antenna defined in claim 1 further comprising a temperature monitoring subsystem to monitor temperature of RF antenna elements and control the plurality of heating elements to adjust the temperature of the RF antenna elements.

13. The antenna defined in claim 12 wherein the temperature monitoring subsystem is operable to estimate a liquid crystal temperature of liquid crystal in the RF antenna elements.

14. The antenna defined in claim 13 wherein the temperature monitoring subsystem comprises:
one or more circuits comprising a voltage input, a current sense resistor and a transistor coupled in series wherein the transistor is integrated onto a patch layer in the antenna and in contact with liquid crystal;
a temperature controller to provide an input voltage to the circuit; and
a monitoring circuit to monitor voltage across the current sense resistor to obtain a measured current, wherein the temperature controller is operable to correlate the measured current to temperature of the transistor, the temperature of the transistor being indicative of the liquid crystal temperature.

15. The antenna defined in claim 13 wherein the temperature monitoring subsystem is operable to measure the liquid crystal temperature by monitoring a voltage across a current sense resistor that is coupled in series with a transistor integrated onto a layer in the antenna and in contract with the liquid crystal, measuring the current through the current sense resistor, and correlating the current to the transistor temperature, the temperature of the transistor being indicative of the liquid crystal temperature.

16. The antenna defined in claim 15 wherein the layer is a patch layer having a plurality of patches, wherein each of the patches is co-located over and separated from a slot in a plurality of slots, forming a patch/slot pair.

17. The antenna defined in claim 13 wherein the temperature monitoring subsystem is operable to measure capacitance of a capacitor by matching conductive surfaces on the patch and iris layers in the aperture with liquid crystal therebetween, measuring capacitance of the capacitor with a circuit coupled to the conductive surfaces, and correlating the capacitance to temperature of the liquid crystal.

18. The antenna defined in claim 13 wherein the temperature monitoring subsystem is operable to measure decay speed of a liquid crystal and correlate the decay speed to a temperature of the liquid crystal.

19. The antenna defined in claim 1 wherein the heating elements are part of a heater wire pattern on a superstrate between the patch substrate and a bottom of the superstrate.

20. The apparatus defined in claim 1 wherein the array of RF antenna elements comprises a tunable slotted array of antenna elements.

21. The apparatus defined in claim 20 wherein the tunable slotted array comprises:
a plurality of slots;
a plurality of patches, wherein each of the patches is co-located over and separated from a slot in the plurality of slots, forming a patch/slot pair, each patch/slot pair being turned off or on based on application of a voltage to the patch in the pair; and
a controller to apply a control pattern to control which patch/slot pairs are on and off to cause generation of a beam.

22. An antenna comprising:
a physical antenna aperture having an array of radio frequency (RF) antenna elements formed with first and second substrates and a liquid crystal (LC) layer between the first and second substrates, the first substrate being an iris substrate;
a plurality of heating elements between the first and second substrates and interleaved between RF antenna elements in the array within the antenna aperture to heat the LC layer, each heating element of the plurality of heating elements integrated with iris elements as part of the iris layer on the iris substrate and contained within an area between a distinct pair of adjacently located RF elements in the array of RF elements; and
a temperature monitoring subsystem to monitor temperature within the antenna aperture and control the plurality of heating elements to adjust the temperature of the RF antenna elements.

23. The antenna defined in claim 22 wherein the temperature monitoring subsystem is operable to estimate a liquid crystal temperature of liquid crystal in the RF antenna elements.

24. The antenna defined in claim 23 wherein the temperature monitoring subsystem comprises:
one or more circuits comprising a voltage input, a current sense resistor and a transistor coupled in series wherein the transistor is integrated onto a patch layer in the antenna and in contact with liquid crystal;
a temperature controller to provide an input voltage to the circuit; and
a monitoring circuit to monitor voltage across the current sense resistor to obtain a measured current, wherein the temperature controller is operable to correlate the measured current to temperature of the transistor, the temperature of the transistor being indicative of the liquid crystal temperature.

25. The antenna defined in claim 23 wherein the temperature monitoring subsystem is operable to measure the liquid crystal temperature by monitoring a voltage across a current sense resistor that is coupled in series with a transi

Assignees

• Kymeta Corp

Inventors

• Stevenson Ryan
• Harp Ken
• Linn Steven
• Severson Mike

Classifications

• H01Q21/0012 Primary

  Radial guide fed arrays · CPC title

• H01Q21/064

  using horn or slot aerials (slotted waveguides arrays H01Q21/005) · CPC title

• H05B2203/002

  Heaters using a particular layout for the resistive material or resistive elements · CPC title

• H01Q1/1278 Primary

  in association with heating wires or layers · CPC title

• H01Q21/065

  Patch antenna array · CPC title