U.S. patent application number 12/536419 was filed with the patent office on 2011-02-10 for antenna with multiple coupled regions.
Invention is credited to Laurent Desclos, Chew Chwee Heng, Sebastian Rowson, Jeffrey Shamblin.
Application Number | 20110032165 12/536419 |
Document ID | / |
Family ID | 43534439 |
Filed Date | 2011-02-10 |
United States Patent
Application |
20110032165 |
Kind Code |
A1 |
Heng; Chew Chwee ; et
al. |
February 10, 2011 |
ANTENNA WITH MULTIPLE COUPLED REGIONS
Abstract
An antenna having a driven element coupled to multiple
additional elements to resonate at multiple frequencies. A magnetic
dipole mode is generated by coupling a driven element to a second
element, and additional resonances are generated by coupling
additional elements to either or both of the driven or second
element. One or multiple active components can be coupled to one or
more of the coupled elements to provide dynamic tuning of the
coupled or driven elements.
Inventors: |
Heng; Chew Chwee;
(Singapore, SG) ; Desclos; Laurent; (San Diego,
CA) ; Rowson; Sebastian; (San Diego, CA) ;
Shamblin; Jeffrey; (San Marcos, CA) |
Correspondence
Address: |
Coastal Patent, LLC
P.O.BOX 232340
San Diego
CA
92193
US
|
Family ID: |
43534439 |
Appl. No.: |
12/536419 |
Filed: |
August 5, 2009 |
Current U.S.
Class: |
343/745 ;
343/700MS; 343/848 |
Current CPC
Class: |
H01Q 19/005 20130101;
H01Q 5/385 20150115; H01Q 5/378 20150115; H01Q 9/42 20130101; H01Q
5/321 20150115; H01Q 7/005 20130101; H01Q 9/16 20130101; H01Q 9/06
20130101; H01Q 5/328 20150115 |
Class at
Publication: |
343/745 ;
343/700.MS; 343/848 |
International
Class: |
H01Q 1/36 20060101
H01Q001/36; H01Q 1/48 20060101 H01Q001/48 |
Claims
1. An antenna, comprising: a first element and a second element
positioned above a ground plane, said first element connected to a
transceiver, said second element connected to ground and coupled to
said first element to form a first coupling region, and a third
element positioned above the ground plane, said third element
connected to ground and coupled to at least one of the first
element and second element to form a second coupling region.
2. The antenna of claim 1, comprising four or more elements, said
four or more elements including at least one driven element,
wherein each element is coupled to at least one of a driven element
and a grounded element.
3. The antenna of claim 1, wherein at least one of the second
element or the third element is connected to ground by a component
for varying the frequency of the antenna.
4. The antenna of claim 3, wherein said component is one of a
capacitor, inductor, resistor, diode, active tuning component, or a
switch.
5. The antenna of claim 4, comprising multiple components.
6. The antenna of claim 1, wherein said first element and said
second element are configured to form an Isolated Magnetic Dipole
(IMD) element.
7. The antenna of claim 6, wherein the IMD element comprises a
first portion connected the transceiver and a second portion
coupled to the first portion.
8. The antenna of claim 7, wherein the third element is connected
to the ground plane at one end and coupled to the first portion of
the IMD element.
9. The antenna of claim 8, wherein multiple elements are coupled to
the IMD element at the first portion.
10. The antenna of claim 9, wherein at least one element is
connected to a component selected from the group consisting of: a
capacitor, inductor, resistor, diode, active tuning component, and
a switch.
11. The antenna of claim 10, wherein said component is connected to
ground.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to the field of
wireless communication. In particular, the present invention
relates to antennas and methods of improving frequency response and
selection for use in wireless communications.
BACKGROUND OF THE INVENTION
[0002] Commonly owned U.S. Pat. Nos. 6,677,915 filed Feb. 12, 2001,
titled "SHIELDED SPIRAL SHEET ANTENNA STRUCTURE AND METHOD";
6,906,667 filed Feb. 14, 2002, titled "MULTIFREQUENCY MAGNETIC
DIPOLE ANTENNA STRUCTURES FOR VERY LOW PROFILE ANTENNA
APPLICATIONS"; 6,900,773 filed Nov. 18, 2002, titled "ACTIVE
CONFIGUREABLE CAPACITIVELY LOADED MAGNETIC DIPOLE"; and 6,919,857
filed Jan. 27, 2003, titled "DIFFERENTIAL MODE CAPACITIVELY LOADED
MAGNETIC DIPOLE ANTENNA"; describe an Isolated Magnetic Dipole
(IMD) antenna formed by coupling one element to another in a manner
that forms a capacitively loaded inductive loop, setting up a
magnetic dipole mode, the entire contents of which are hereby
incorporated by reference. This magnetic dipole mode provides a
single resonance and forms an antenna that is efficient and well
isolated from the surrounding structure. This is, in effect, a self
resonant structure that is de-coupled from the local
environment.
[0003] The overall structure of the IMD antenna can be considered
as a capacitively loaded inductive loop. The capacitance is formed
by the coupling between the two parallel conductors with the
inductive loop formed by connecting the second element to ground.
The length of the overlap region between the two conductors along
with the separation between conductors is used to adjust the
resonant frequency of the antenna. A wider bandwidth can be
obtained by increasing the separation between the conductors, with
an increase in overlap region used to compensate for the frequency
shift that results from the increased separation.
[0004] An advantage of this type of antenna structure is the method
in which the antenna is fed or excited. The impedance matching
section is almost independent from the resonant portion of the
antenna. This leaves great flexibility for reduced space
integration. The antenna size reduction is obtained in this case by
the capacitive loading that is equivalent to using a low loss, high
dielectric constant material. At resonance a cylindrical current
going back and forth around the loop is formed. This generates a
magnetic field along the axis of the loop which is the main
mechanism of radiation. The electrical field remains highly
confined between the two elements. This reduces the interaction
with surrounding metallic objects and is essential in obtaining
high isolation.
[0005] The IMD technology is relatively new, and there is a need
for improvements over currently available antenna assemblies. For
example, because cell phones and other portable communications
devices are moving in the direction of providing collateral
services, such as GPS, video streaming, radio, and various other
applications, the demand for multi-frequency and multi-band
antennas is at a steady increase. Other market driven constraints
on antenna design include power efficiency, low loss, reduced size
and low cost. Therefore, there is a need in the art for antennas
which exceed the current market driven requirements and provide
multiple resonant frequencies and multiple bandwidths.
Additionally, there is a need for improved antennas which are
capable of being tuned over a multitude of frequencies.
Furthermore, there is a need for improved antennas which are
capable of dynamic tuning over a multitude of frequencies in real
time.
SUMMARY OF THE INVENTION
[0006] This invention solves these and other problems in the art,
and provides solutions which include forming additional
capacitively loaded inductive loops by adding additional elements
that couple to one of the two elements that form the basic IMD
antenna. Other solutions provided by the invention include active
tuning of multiple coupling regions, switching over a multitude of
frequencies, and dynamic tuning of resonant frequencies.
[0007] In one embodiment, an antenna is formed by coupling a first
element to a second element, and then adding a third element which
is coupled to the second element. The first element is driven by a
transceiver, with both the second and third elements connected to
ground. The additional resonance that is generated is a product of
two coupling regions on the composite antenna structure.
[0008] In another embodiment, an antenna is formed having a first
element driven by a transceiver, and two or more grounded elements
coupled to the first element. The space between each of the two or
more grounded elements and the first element defines a coupling
region, wherein the coupling region forms a single resonant
frequency from the combined structure. The resonant frequency is
adjusted by the amount of overlap of the two elements. The
separation between the two elements determines the bandwidth of the
resonance.
[0009] In another embodiment, an antenna is formed having a first
element driven by a transceiver, a second element connected to
ground wherein the second element overlaps with the first element
to form a capacitive coupling region, and a third element. The
third element can be either driven or grounded and overlaps with at
least one of the first element and the second element. Each
overlapping region between the first, second and third elements
creates a capacitive coupling region forming a resonant frequency,
wherein the resonant frequency is adjusted by the amount of overlap
and the bandwidth is determined by the separation distance between
the overlapping elements. In this embodiment, an overlapping region
can be formed between the driven element and a grounded element, or
alternatively the overlapping region can be formed between two
grounded elements.
[0010] In another embodiment, the grounded elements are parallel to
the driven element. Alternatively, the grounded elements can be
orthogonal with respect to the driven element. One or more elements
can comprise an active tuning component. The active tuning
component can be configured within or near a ground plane.
Alternatively, one or more active components can be configured on
an antenna element. One or more antenna elements can be bent. One
or more antenna elements can be linear, or planar. One or more
antenna elements can be fixedly disposed above a ground plane.
Alternatively, one or more antenna elements can be configured
within a ground plane.
[0011] In another embodiment, an antenna is provided having a high
band radiating element and a low band radiating element. A switched
network can be integrated with at least one of the high band or low
band radiating elements.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 illustrates an exemplary isolated magnetic dipole
(IMD) antenna comprised of a first element attached to a
transmitter and coupled to a second element which is connected to
ground.
[0013] FIG. 2 shows a plot of return loss as a function of
frequency for the IMD antenna in FIG. 1. A single resonance is
present.
[0014] FIG. 3 illustrates an isolated magnetic dipole (IMD) antenna
comprised of a first element attached to a transmitter and coupled
to a second element which is connected to ground along with a third
element which is coupled to the second element.
[0015] FIG. 4 shows the return loss as a function of frequency for
the antenna shown in FIG. 3. A second resonance is present which is
formed by the addition of the third element.
[0016] FIG. 5 illustrates an IMD antenna with two additional
elements, a third and fourth, each coupled to the second element of
the IMD antenna.
[0017] FIG. 6 illustrates an isolated magnetic dipole (IMD) antenna
comprised of an element attached to a transmitter and coupled to a
second element which is connected to ground along with a third
element which is coupled to the first element.
[0018] FIG. 7 illustrates an IMD antenna with two additional
elements, a third and fourth, each coupled to the first element of
the IMD antenna.
[0019] FIG. 8 illustrates an isolated magnetic dipole (IMD) antenna
comprised of a first element attached to a transmitter and coupled
to a second element which is connected to ground along with a third
element which is coupled to the second element. A component is
connected between the third element and ground.
[0020] FIG. 9 illustrates an isolated magnetic dipole (IMD) antenna
comprised of a first element attached to a transmitter and coupled
to a second element which is connected to ground along with a third
element which is coupled to the first element. A component is
connected between the third element and ground.
[0021] FIG. 10 illustrates an IMD antenna with two additional
elements, a third and fourth, each coupled to the second element of
the IMD antenna. A component is connected between the third element
and ground, with another component connected between the second
element and ground.
[0022] FIG. 11 illustrates an IMD antenna with an additional
element coupled to the second element of the IMD antenna. The
additional element is configured in a 3-dimensional shape and is
not restricted to a plane containing the first two elements.
[0023] FIG. 12 illustrates an IMD antenna with two additional
elements, a third and fourth, with the third element coupled to the
second element and the fourth element coupled to the first element.
Both the third and fourth elements are bent in 3 dimensional shapes
and are not restricted to a plane containing the first two
elements. A component is connected between the fourth element and
ground.
[0024] FIG. 13 illustrates an IMD antenna with two additional
elements, a third and fourth, with a component connecting two
portions of the third element.
[0025] FIG. 14 illustrates an IMD antenna with two additional
elements, a third and fourth, with a component connecting the third
and fourth elements.
[0026] FIG. 15 illustrates an IMD antenna with two additional
elements, a third and fourth, with all four elements positioned in
the plane of the ground plane.
[0027] FIG. 16 illustrates an antenna configuration where a switch
network is integrated into the low band radiating element to
provide a tunable antenna. The switch network can be implemented in
a MEMS process, integrated circuit, or discrete components.
[0028] FIG. 17 illustrates an antenna configuration where a switch
network is integrated into the high band radiating element to
provide a tunable antenna. The switch network can be implemented in
a MEMS process, integrated circuit, or discrete components.
[0029] FIG. 18 illustrates an antenna configuration where switch
networks are integrated into the low band and high band radiating
elements to provide a tunable antenna. The switch networks can be
implemented in a MEMS process, integrated circuit, or discrete
components.
[0030] FIG. 19 illustrates an antenna implementation of the concept
described in FIG. 3. A driven element is coupled to two additional
elements, resulting in a low band and high band resonance.
[0031] FIG. 20 shows the return loss of the antenna configuration
shown in FIG. 19. The two traces refer to two capacitor values for
component loadings of the second element. The capacitor is not
shown in FIG. 19.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] In the following description, for purposes of explanation
and not limitation, details and descriptions are set forth in order
to provide a thorough understanding of the present invention.
However, it will be apparent to those skilled in the art that the
present invention may be practiced in other embodiments that depart
from these details and descriptions.
[0033] Embodiments of the present invention provide an active tuned
loop-coupled antenna capable of optimizing an antenna over
incremental bandwidths and capable of tuning over a large total
bandwidth. The active loop element is capable of serving as the
radiating element or an additional radiating element may also be
coupled to this active loop. In various embodiments, multiple
active tuned loops can be coupled together in order to extend the
total bandwidth of the antenna. Such active components may be
incorporated into the antenna structure to provide further
extensions of the bandwidth along with increased optimization of
antenna performance over the frequency range of the antenna.
[0034] In a primary embodiment, the invention includes a first
element and a second element positioned above a ground plane. The
first and second element can be wire, or preferably a planar
element. The first element is connected to a transceiver. The
second element is connected to ground and at least partially
overlaps with the first element to form a first coupling region.
The coupling region is defined by the amount of overlap between the
first and second elements, and the distance between the first and
second elements. The coupling region can include a capacitive
coupling between two antenna elements. By adjusting the amount of
overlap and the distance between the elements, one can adjust the
frequency and bandwidth of the antenna. A third element connected
to ground is further positioned near at least one of the first
element and the second element. The third element can form a second
coupling region when placed near one of the first element or the
second element, thus creating a second resonant frequency for which
the antenna is operational. Optionally, the third element can be
placed within the vicinity of the first and second elements,
thereby further generating a third coupling region. Any number of
subsequent elements can be positioned near an antenna element to
create a coupling region.
[0035] In a preferred embodiment, each of the antenna elements are
planar elements and are substantially parallel to the ground plane.
In certain embodiments, the antenna elements are not parallel with
the ground plane. Other embodiments are described below in more
detail.
[0036] FIG. 1 illustrates a driven element 1, and a capacitively
coupled element 2 that is grounded forming an inductive loop. The
coupling region 3 between elements 1 and 2 forms a single resonant
frequency from the combined structure. The resonant frequency is
adjusted by the amount of overlap of the two elements. The
separation between the two elements determines the bandwidth of the
resonance.
[0037] FIG. 2 illustrates a plot of frequency vs. return loss
showing the effect of coupling a driven element and one
capacitively coupled element that is grounded. A single resonant
frequency is shown.
[0038] FIG. 3 illustrates a driven element 20, and two capacitively
coupled elements 21 and 22 that are grounded forming inductive
loops. The coupling 23 between elements 20 and 21, and the coupling
24 between 21 and 22 produces two resonant frequencies each
determined by the amount of overlap and separation between the two
elements. The separation between the elements determines the
bandwidth for each resonance.
[0039] FIG. 4 illustrates a plot of frequency vs. return loss
showing the effect of coupling a driven element and two
capacitively coupled elements. Two resonate frequencies are
shown.
[0040] FIG. 5 illustrates a driven element 30, and three
capacitively coupled elements 31, 32 and 33 that are grounded
forming inductive loops. The coupling 34 between elements 30 and
32, the coupling 35 between 31 and 32 and coupling 36 between 32
and 33 produces three resonant frequencies each determined by the
amount of overlap and separation between the three elements. The
separation between the elements determines the bandwidth for each
resonance.
[0041] FIG. 6 illustrates a driven element 40, and two capacitively
coupled elements 41 and 42 that are grounded forming inductive
loops. The positioning of the elements creates an overlapping
between the elements that forms three couplings 43, 44 and 45. The
separation between the elements determines the bandwidth for each
resonance.
[0042] FIG. 7 illustrates a driven element 50, and four
capacitively coupled elements 51, 52, 53 and 54 that are grounded
forming inductive loops. The positioning of the elements creates an
overlapping between the elements that forms four couplings 55, 56,
57 and 58. The separation between the elements determines the
bandwidth for each resonance.
[0043] FIG. 8 illustrates a driven element 60 with one capacitively
coupled element 61 that is connected to ground forming an inductive
loop and a coupling region 65. The frequency response generated by
this coupling region 65 will be dependent upon the amount of
overlap and separation distance of the elements 60 and 61. A second
coupled element 62 is connected to ground via a component 63. If
this component is passive (inductor, capacitor, resistor) it will
create a fixed frequency response from the coupling region 64. If
the component is tunable (tunable capacitor, varactor diode, etc.)
then the frequency response can be dynamically tuned (in real
time).
[0044] FIG. 9 illustrates a driven element 70 with one capacitively
coupled element 72 that is connected to ground forming an inductive
loop and a coupling region 75. The frequency of this coupling
region 75 will be dependent upon the amount of overlap and
separation distance of the elements 70 and 72. The driven element
70 is also coupled to a second element 71 that is connected to
ground via a component 73. If this component is passive (inductor,
capacitor, resistor) it will create a fixed frequency response from
the coupling region 76. If the component is tunable (tunable
capacitor, varactor diode, etc.) then the frequency response can be
dynamically tuned (in real time). Element 71 is also coupled to
element 72 and will have a fixed or dynamically tuned frequency
response, dependent on the type and value of component 73.
[0045] FIG. 10 illustrates a driven element 80 coupled to a second
element 81 that is connected to ground via a component 86. If this
component is passive (inductor, capacitor, resistor) it will create
a fixed frequency response from the coupling region 76. If the
component is tunable (tunable capacitor, varactor diode, etc.) then
the frequency response can be dynamically tuned (in real time).
Element 81 forms a coupling 87 with element 84 that is connected to
ground. The frequency of this coupling region 87 will be dependent
upon the amount of overlap and separation distance of the elements
81, 84 and the driven element 80. Another coupling region 89 is
formed by elements 81 and 82. Both elements are connected to ground
by components 85 and 86.
[0046] FIG. 11 illustrates a driven element 90 with one
capacitively coupled element 91 that is connected to ground forming
an inductive loop and a coupling region 93. An additional coupling
is formed between capacitively coupled elements 91 and 92. The
frequency of this coupling region 94 will be dependent upon the
amount of overlap and separation distance of the elements 91 and 92
and driven element 90.
[0047] FIG. 12 illustrates a driven element 100 with a capacitively
coupled element 102 that is connected to ground forming an
inductive loop and coupling region 106. Element 102 is capacitively
coupled to element 103 that is connected to ground forming an
inductive loop and coupling region 105. Element 103 is bent in a 3
dimensional shape and is not restricted to a plane containing the
other elements. The driven element 100 is also coupled to a second
element 101 that is connected to ground via a component 104 forming
a coupling region 107 with driven element 100. If the component 104
is tunable (tunable capacitor, varactor diode, etc.) then the
frequency response can be dynamically tuned (in real time). Element
101 is bent in a 3 dimensional shape and is not restricted to a
plane containing the other elements.
[0048] FIG. 13 illustrates a driven element 200 in-line with
element 201 that is connected to ground. The driven element 200 is
coupled to a second element 202 that is connected to ground via a
component 204 forming a coupling region 207 with driven element
200. If the component 204 is tunable (tunable capacitor, varactor
diode, etc.) then the frequency response can be dynamically tuned
(in real time). Element 202 also forms a coupling 209 with element
203 that is grounded via a component 205. In addition element 203
has a component 206 that connects the two parts of element 203
further extending frequency tuning and response.
[0049] FIG. 14 illustrates a driven element 300 in-line with
element 301 that is connected to ground. The driven element 300 is
coupled to a second element 302 that is connected to ground via a
component 304 forming a coupling region 309 with driven element
300. If the component 304 is tunable (tunable capacitor, varactor
diode, etc.) then the frequency response can be dynamically tuned
(in real time). Element 302 also forms a coupling 308 with element
301 that is connected to ground forming an inductive loop. A
further coupling is formed between element 302 and element. A
component 306 is connected to elements 302 and 303, providing
additional tuning of the frequency response.
[0050] FIG. 15 FIG. 12 illustrates a driven element 400 with
capacitively coupled elements 401, 402 and 403 that are connected
to the edge of a ground plane producing three couplings 404, 405
and 406 respectively.
[0051] FIG. 16 illustrates an antenna configuration where a switch
network 500 is integrated into the low band radiating element 501
to provide a tunable antenna. The switch network can be implemented
in a MEMS process, integrated circuit, or discrete components.
[0052] FIG. 17 illustrates an antenna configuration where a switch
network is integrated into the high band 600 radiating element to
provide a tunable antenna. The switch network 601 can be
implemented in a MEMS process, integrated circuit, or discrete
components.
[0053] FIG. 18 illustrates an antenna configuration where switch
networks are integrated into the low band 700 and high band 702
radiating elements to provide a tunable antenna. The switch
networks 701 and 703 can be implemented in a MEMS process,
integrated circuit, or discrete components.
[0054] FIG. 19 illustrates antenna implementation of the concept
described in FIG. 3. A driven element 720 is coupled to two
additional elements, 721 and 722, resulting in a low band and high
band resonance.
[0055] FIG. 20 illustrates a plot of frequency vs. return loss for
the antenna described in FIG. 19. The two traces refer to two
capacitor values for a component loading element 721.
* * * * *