Antenna structures and methods thereof for selecting antenna configurations

Abstract

A system incorporating the subject disclosure may include, for example, a method including determining, by a communication device comprising a processor, a usage state of the communication device. The communication device includes selectable antennas, and the usage state includes an orientation of the communication device. The method also includes selecting a set of antennas according to the usage state, and obtaining an antenna gain pattern for an antenna in the selected set of antennas. The method further includes evaluating an expected performance of an antenna configuration corresponding to the selected set of antennas, relative to a performance of an existing antenna configuration. The method also includes initiating usage of the antenna configuration in accordance with improved performance relative to the existing antenna configuration. The antenna configuration comprises a polarization configuration, and the selected set of antennas comprises elements in different planes. Other embodiments are disclosed.

What is claimed is: 
     
         1 . A method comprising:
 determining, by a communication device comprising a processor, a usage state of the communication device, wherein the communication device comprises a plurality of selectable antennas for engaging in wireless communications, the usage state including an orientation of the communication device;   selecting, by the communication device, a set of antennas from the plurality of antennas in accordance with the usage state;   obtaining, by the communication device, an antenna gain pattern for an antenna in the selected set of antennas;   evaluating, by the communication device, an expected performance of an antenna configuration corresponding to the selected set of antennas relative to a performance of an existing antenna configuration; and   initiating, by the communication device, usage of the antenna configuration corresponding to the selected set of antennas in accordance with improved performance relative to the existing antenna configuration,   wherein the antenna configuration comprises a polarization configuration, and   wherein the selected set of antennas comprises a first antenna element in a first plane and a second antenna element in a different second plane.   
     
     
         2 . The method of  claim 1 , wherein the selected set of antennas comprises a first antenna and a second antenna, the first antenna including the first antenna element, the second antenna element, and a connector connecting the first antenna element and the second antenna element, wherein the obtaining comprises obtaining a first antenna gain pattern for the first antenna and obtaining a second antenna gain pattern for the second antenna, and wherein the second antenna gain pattern fits a null in the first antenna gain pattern. 
     
     
         3 . The method of  claim 1 , wherein the evaluating further comprises evaluating a first envelope correlation coefficient for the existing antenna configuration and a second envelope correlation coefficient for the antenna configuration corresponding to the selected set of antennas. 
     
     
         4 . The method of  claim 1 , wherein the evaluating further comprises evaluating a first antenna isolation for the existing antenna configuration and a second antenna isolation for the antenna configuration corresponding to the selected set of antennas. 
     
     
         5 . The method of  claim 1 , wherein the first antenna element and the second antenna element are oriented at 180° relative to each other, and wherein the first plane and the second plane are orthogonal. 
     
     
         6 . The method of  claim 5 , wherein the selected set of antennas further comprises a third antenna element and a fourth antenna element, the first, second, third and fourth antenna elements being arranged in an array with the first antenna element and the third antenna element diagonally opposite and substantially coplanar, and wherein the fourth antenna is in a plane orthogonal to the first plane and orthogonal to the second plane. 
     
     
         7 . The method of  claim 1 , wherein the first antenna element comprises a first antenna segment connected to a ground plane and having a first current therein, wherein the second antenna element comprises a second antenna segment connected to the ground plane and having a second current therein, wherein the first current and the second current are in planes orthogonal to each other, and wherein the antenna configuration has a reduced envelope correlation coefficient relative to the existing antenna configuration. 
     
     
         8 . The method of  claim 1 , wherein a first antenna of the selected set of antennas is provided with a motor for moving the first antenna relative to a second antenna of the selected set of antennas, and further comprising directing the motor to move the first antenna relative to the second antenna so that the first antenna and the second antenna are in different planes. 
     
     
         9 . The method of  claim 1 , further comprising:
 measuring electric fields associated with the selected set of antennas while in use and their corresponding phase difference;   determining whether the fields are additive based on the phase difference; and   responsive to a determination that the fields are additive, adjusting electric fields of at least one antenna of the selected set of antennas to cause the fields to be subtractive.   
     
     
         10 . The method of  claim 1 , wherein the determining further comprises detecting a change in the orientation of the communication device between a vertical orientation and a horizontal orientation. 
     
     
         11 . An antenna structure for a communication device, comprising:
 a set of antennas selected from a plurality of antennas of the communication device, the set of antennas being selected in accordance with a usage state of the communication device; and   a controller that facilitates selection of the set of antennas based on an evaluation of a performance of an antenna configuration corresponding to the selected set of antennas indicating an improved performance relative to a previous antenna configuration, wherein the evaluation comprises an envelope correlation coefficient for the antenna configuration corresponding to the selected set of antennas and an antenna isolation for the antenna configuration corresponding to the selected set of antennas.   
     
     
         12 . The antenna structure of  claim 11 , wherein the selected set of antennas comprises a first antenna and a second antenna, the first antenna including a first antenna element, a second antenna element, and a connector connecting the first antenna element and the second antenna element, wherein the evaluation is performed based on a first antenna gain pattern for the first antenna and a second antenna gain pattern for the second antenna, and wherein the second antenna gain pattern fits a null in the first antenna gain pattern. 
     
     
         13 . The antenna structure of  claim 11 , wherein the selected set of antennas comprises a first antenna and a second antenna, wherein the first antenna is in a first plane and the second antenna is in a different second plane, wherein a first antenna element of the first antenna and a second antenna element of the second antenna are oriented at 180° relative to each other, and wherein the first plane and the second plane are orthogonal. 
     
     
         14 . The antenna structure of  claim 11 , wherein the selected set of antennas comprises a first antenna and a second antenna, and further comprising a motor coupled to the first antenna for moving the first antenna relative to the second antenna. 
     
     
         15 . The antenna structure of  claim 14 , further comprising:
 a sensor for detecting an orientation of the communication device; and   a processor coupled to the sensor and to the motor for directing the motor to move the first antenna in accordance with a change in the orientation,   wherein the processor directs the motor to move the first antenna relative to the second antenna so that the first antenna and the second antenna are in different planes.   
     
     
         16 . The antenna structure of  claim 11 , further comprising:
 a plurality of near-field sensors, each located in a vicinity of the plurality of antennas for measuring a phase differential between the set of antennas selected; and   a phase shifter for adjusting radiated signals from at least one of the set of antennas when the phase differential between the set of antennas is additive.   
     
     
         17 . A machine-readable storage medium comprising instructions, wherein responsive to executing the instructions, a processor performs operations comprising:
 detecting a usage state of a communication device, wherein the communication device comprises a plurality of selectable antennas for engaging in wireless communications, the usage state including an orientation of the communication device;   selecting a set of antennas from the plurality of antennas in accordance with the usage state;   obtaining a first antenna gain pattern for a first antenna in the selected set of antennas;   obtaining a second antenna gain pattern for a second antenna in the selected set of antennas; and   evaluating an expected performance of an antenna configuration corresponding to the selected set of antennas relative to a performance of an existing antenna configuration, wherein the evaluating comprises determining an envelope correlation coefficient for the antenna configuration corresponding to the selected set of antennas and an antenna isolation for the antenna configuration corresponding to the selected set of antennas, wherein the evaluating is based on the first antenna gain pattern and the second antenna gain pattern, and wherein the second antenna gain pattern fits a null in the first antenna gain pattern.   
     
     
         18 . The machine-readable storage medium of  claim 17 , wherein the first antenna is in a first plane and the second antenna is in a different second plane, wherein the first antenna and the second antenna respectively include a first antenna element and a second antenna element, and wherein the first antenna element and the second antenna element are oriented at 180° relative to each other. 
     
     
         19 . The machine-readable storage medium of  claim 17 , wherein the first antenna is provided with a motor for moving the first antenna relative to the second antenna. 
     
     
         20 . The machine-readable storage medium of  claim 19 , wherein the operations further comprise directing the motor to move the first antenna relative to the second antenna so that the first antenna and the second antenna are in different planes.