Devices and methods for implementing mimo in metal ring structures using tunable electrically small antennas

Patent metadata

Field	Value
Publication number	US-2019252786-A1
Application number	US-201916271776-A
Country	US
Kind code	A1
Filing date	Feb 8, 2019
Priority date	Feb 9, 2018
Publication date	Aug 15, 2019
Grant date	—

Abstract

Devices and methods for implementing MIMO in metal ring structures using tunable electrically small antennas. In some embodiments, the metal ring structure includes a mobile device including electrically small antennas arranged on it, tunable band-stop circuits, wherein each of the electrically small antennas has a largest dimension that is substantially equal to or less than one-tenth of a length of a wavelength corresponding to a frequency within a communications operating frequency band. In some embodiments, the tunable electrically small antennas utilize parts of the metal ring structure of the mobile device as antenna radiators. The TESA are tunable for low-band frequencies between about 600 MHz-960 MHz. Additionally, the TESA have a wide bandwidth in high-band between about 1700 MHz-2700 MHz. In order to separate the TESA radiators from the rest of the metal ring structure, the radiators are connected by insulating material.

First claim

What is claimed is:

1 . A mobile device comprising:
a plurality of electrically small antennas on the mobile device; and a plurality of tunable band-stop circuits; wherein each of the plurality of electrically small antennas is in communication with at least one of the plurality of tunable band-stop circuits and every tunable band-stop circuit is connected to a signal node; wherein each of the plurality of tunable band-stop circuits is tunable to adjust a band-stop frequency within a frequency range above a low-band communications operating frequency range and below a high-band communications operating frequency range of the plurality of electrically small antennas; and wherein each of the plurality of electrically small antennas has a largest dimension that is substantially equal to or less than one-tenth of a length of a wavelength corresponding to a frequency within the low-band communications operating frequency range that is below the band-stop frequency.

2 . The mobile device of claim 1 , wherein a first of the plurality of electrically small antennas has a first radiation pattern and a second of the plurality of electrically small antennas has a second radiation pattern, the second radiation pattern being substantially decoupled from the first radiation pattern.

3 . The mobile device of claim 1 , wherein a first of the plurality of electrically small antennas and a second of the plurality of electrically small antennas are substantially identical in physical structure and electrical performance such that a gain imbalance of the first of the plurality of electrically small antennas and the second of the plurality of electrically small antennas is about 0.5 dB.

4 . The mobile device of claim 3 , wherein the first of the plurality of electrically small antennas and the second of the plurality of electrically small antenna are configured such that an angle between the first radiation pattern and the second radiation pattern is between about 80 degrees and 100 degrees; and
wherein the first of the plurality of electrically small antennas and the second of the plurality of electrically small antennas have an Envelope Correlation Coefficient (ECC) below 0.5.

5 . The mobile device of claim 1 , wherein a first of the plurality of electrically small antennas and a second of the plurality of electrically small antennas are both tunable for low-band frequencies between about 600 MHz and 960 MHz.

6 . The mobile device of claim 1 , comprising a plurality of bandwidth control capacitors wherein each of the plurality of bandwidth control capacitors is connected between one of the plurality of tunable band-stop circuits and the signal node, each of the bandwidth control capacitors having a series capacitance selected to achieve a desired bandwidth within the high-band communications operating frequency range above the band-stop frequency.

7 . The mobile device of claim 1 , comprising a plurality of resonance control capacitors wherein each of the plurality of resonance control capacitors comprises a first terminal connected between each of the tunable band-stop circuits and the signal node and a second terminal connected to a ground, each of the resonance control capacitors having a shunt capacitance selected to achieve a resonance within the high-band communications operating frequency range above the band-stop frequency.

8 . The mobile device of claim 1 , wherein a first of the plurality of electrically small antennas is positioned in a first location on the mobile device and a second of the plurality of electrically small antennas is positioned in a second location of the mobile device different from the first location; and
wherein the first location and the second location are selected to optimally minimize antenna coupling and diversity of antenna radiation patterns of the first of the plurality of electrically small antennas and the second of the plurality of electrically small antennas.

9 . The mobile device of claim 8 , wherein the first location is a first corner of a first edge of the mobile device and the second location is a second corner of the first edge of the mobile device.

10 . The mobile device of claim 8 , wherein the first of the plurality of electrically small antennas is positioned at a first end of the mobile device and the second of the plurality of electrically small antennas is positioned at a second end of the mobile device, wherein the second end is opposite of the first end.

11 . The mobile device of claim 1 , wherein the mobile device further comprises a ground plane that is in communication with a first of the plurality of tunable band-stop circuits and a second of the plurality of tunable band-stop circuits; and
wherein the ground plane is positioned between about 4 mm and 10 mm away from the plurality of electrically small antennas.

12 . The mobile device of claim 1 , wherein each of the plurality of tunable band-stop circuits comprises:
a tunable capacitor connected between a respective one of the plurality of electrically small antennas and the signal node; and a band-stop inductor connected in parallel with the tunable capacitor between the respective one of the plurality of electrically small antennas and the signal node, the band-stop inductor having an inductance selected to achieve a desired range of band-stop frequencies.

13 . The mobile device of claim 12 , wherein the tunable capacitor comprises a variable capacitor selected from a group consisting of a micro-electro-mechanical systems (MEMS) variable capacitor, a semiconductor switch-based variable capacitor, a Barium Strontium Titanate (BST) variable capacitor, or a varactor diode.

14 . The mobile device of claim 12 , wherein the tunable capacitor is tunable to adjust a capacitance of its corresponding band-stop circuit to a range of 2 pF to 5 pF.

15 . The mobile device of claim 12 , wherein each of the plurality of tunable band-stop circuits comprises a fixed capacitor connected in parallel with the tunable capacitor and the band-stop inductor between each of the plurality of electrically small antennas and the signal node;
wherein a capacitance of the fixed capacitor is selected to achieve a desired minimum capacitance of each of the plurality of tunable band-stop circuits.

16 . The mobile device of claim 1 , comprising a plurality of reactive circuit elements wherein each of the plurality of reactive circuit elements is coupled between a respective one of the plurality of tunable band-stop circuits and the signal node;
wherein the respective one of the plurality of reactive circuit elements has a reactance selected to achieve a system resonance for a respective one of the plurality of tunable band-stop circuits and the respective one of the electrically small antennas at a desired low-band frequency within the low-band communications operating frequency range below the band-stop frequency.

17 . The mobile device of claim 16 , wherein each of the plurality of reactive circuit elements comprises an inductor connected in a shunt arrangement with a first terminal of the inductor being connected between one of the tunable band-stop circuits and the signal node and a second terminal of the inductor being connected to a ground.

18 . The mobile device of claim 1 , comprising one or more capacitors wherein each of the one or more of capacitors is connected between one of the electrically small antennas and a respective one of the plurality of tunable band-stop circuits to pass a radio frequency (RF) signal and provide electrostatic discharg

Assignees

• Wispry Inc

Inventors

• Shin Joungsub

Classifications

• H01Q1/243

  with built-in antennas · CPC title

• H01Q5/335

  at the feed, e.g. for impedance matching · CPC title

• H01Q21/28

  Combinations of substantially independent non-interacting antenna units or systems {(multiple beam H01Q25/00)} · CPC title

• H01Q9/42

  with folded element, the folded parts being spaced apart a small fraction of the operating wavelength · CPC title

• H01Q9/0442 Primary

  with particular tuning means · CPC title