Information
-
Patent Grant
-
6218992
-
Patent Number
6,218,992
-
Date Filed
Thursday, February 24, 200024 years ago
-
Date Issued
Tuesday, April 17, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Le; Hoanganh
- Nguyen; Hoang
Agents
- Myers Bigel Sibley & Sajovec
-
CPC
-
US Classifications
Field of Search
US
- 343 702
- 343 846
- 343 700 MS
- 343 848
- 343 825
-
International Classifications
-
Abstract
Inverted-F antennas having elongated, conductive elements for use within communications devices, such as radiotelephones, are provided. An elongated, meandering conductive element having a plurality of spaced-apart U-shaped undulations is maintained in adjacent, spaced-apart relationship with a first ground plane. One or more of the U-shaped undulations capacitively couple to the ground plane and allow the antenna to resonate at lower frequencies and with a greater bandwidth. A second ground plane may be oriented in a direction transverse to the first ground plane so as to be positioned in adjacent, spaced-apart relationship with one or more of the U-shaped undulations. One or more of the U-shaped undulations can capacitively couple to the second ground plane, as well as to the first ground plane. In addition, one or more inductive elements may be electrically connected to an elongated conductive element.
Description
FIELD OF THE INVENTION
The present invention relates generally to antennas, and more particularly to antennas used with wireless communications devices.
BACKGROUND OF THE INVENTION
Radiotelephones generally refer to communications terminals which provide a wireless communications link to one or more other communications terminals. Radiotelephones may be used in a variety of different applications, including cellular telephone, land-mobile (e.g., police and fire departments), and satellite communications systems. Radiotelephones typically include an antenna for transmitting and/or receiving wireless communications signals. Historically, monopole and dipole antennas have been employed in various radiotelephone applications, due to their simplicity, wideband response, broad radiation pattern, and low cost.
However, radiotelephones and other wireless communications devices are undergoing miniaturization. Indeed, many contemporary radiotelephones are less than 11 centimeters in length. As a result, there is increasing interest in small antennas that can be utilized as internally-mounted antennas for radiotelephones.
In addition, it is becoming desirable for radiotelephones to be able to operate within multiple frequency bands in order to utilize more than one communications system. For example, GSM (Global System for Mobile) is a digital mobile telephone system that operates from 880 MHz to 960 MHz. DCS (Digital Communications System) is a digital mobile telephone system that operates from 1710 MHz to 1880 MHz. The frequency bands allocated for cellular AMPS (Advanced Mobile Phone Service) and D-AMPS (Digital Advanced Mobile Phone Service) in North America are 824-894 MHz and 1850-1990 MHz, respectively. Since there are two different frequency bands for these systems, radiotelephone service subscribers who travel over service areas employing different frequency bands may need two separate antennas unless a dual-frequency antenna is used.
Inverted-F antennas are designed to fit within the confines of radiotelephones, particularly radiotelephones undergoing miniaturization. As is well known to those having skill in the art, inverted-F antennas typically include a linear (i.e., straight) conductive element that is maintained in spaced apart relationship with a ground plane. Examples of inverted-F antennas are described in U.S. Pat. Nos. 5,684,492 and 5,434,579 which are incorporated herein by reference in their entirety.
Conventional inverted-F antennas, by design, resonate within a narrow frequency band, as compared with other types of antennas, such as helices, monopoles and dipoles. In addition, conventional inverted-F antennas are typically large. Lumped elements can be used to match a smaller non-resonant antenna to an RF circuit. Unfortunately, such an antenna would be narrow band and the lumped elements would introduce additional losses in the overall transmitted/received signal, would take up circuit board space, and add to manufacturing costs.
High dielectric substrates are commonly used to decrease the physical size of an antenna. Unfortunately, the incorporation of higher dielectrics can reduce antenna bandwidth and may introduce additional signal losses. As such, a need exists for small, internal radiotelephone antennas that can operate within multiple frequency bands, including low frequency bands.
SUMMARY OF THE INVENTION
In view of the above discussion, the present invention can provide various configurations of compact, broadband inverted-F antennas for use within communications devices, such as radiotelephones. According to one embodiment, an inverted-F antenna has an elongated, meandering conductive element maintained in adjacent, spaced-apart relationship with a first ground plane, such as a printed circuit board. An elongated, meandering conductive element according to this embodiment, includes a set of spaced-apart, U-shaped undulations that extend towards the first ground plane. The U-shaped undulations capacitively couple to the first ground plane and allow the antenna to resonate at lower frequencies than a conventional inverted-F antenna.
According to another embodiment of the present invention, a second ground plane may be oriented in a direction transverse to the first ground plane so as to be positioned in adjacent, spaced-apart relationship with one or more of the U-shaped undulations. The one or more U-shaped undulations are capacitively coupled to the second ground plane, as well as to the first ground plane.
According to another embodiment of the present invention, one or more raised portions extend outwardly from a ground plane and capacitively couple to portions of an elongated conductive antenna element.
According to another embodiment of the present invention, one or more inductive elements may be electrically connected to an elongated conductive element. An inductive element may comprise helical turns formed in an elongated conductive element or one or more electronic components that serve an inductive function.
Antennas according to the present invention may be particularly well suited for use within a variety of communications systems utilizing different frequency bands. Furthermore, because of their small size, antennas according to the present invention may be easily incorporated within small communications devices. In addition, antenna structures according to the present invention may not require additional impedance matching networks, which may save internal radiotelephone space and which may lead to manufacturing cost savings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a perspective view of an exemplary radiotelephone within which an antenna according to the present invention may be incorporated.
FIG. 2
is a schematic illustration of a conventional arrangement of electronic components for enabling a radiotelephone to transmit and receive telecommunications signals.
FIG. 3A
is a perspective view of a conventional planar inverted-F antenna.
FIG. 3B
is a graph of the VSWR performance of the antenna of FIG.
3
A.
FIG. 4A
is a side elevation view of an inverted-F antenna having an elongated, meandering conductive element with a plurality of U-shaped undulations in spaced-apart, adjacent relationship with a ground plane according to an embodiment of the present invention.
FIG. 4B
is a side elevation view of the inverted-F antenna of
FIG. 4A
disposed on a dielectric material.
FIG. 4C
is a side elevation view of the inverted-F antenna of
FIG. 4A
disposed within a dielectric material.
FIG. 5
is a side elevation view of an inverted-F antenna having an elongated, meandering conductive element in spaced-apart, adjacent relationship with a first ground plane and a second ground plane oriented transverse to the first ground plane, according to an embodiment of the present invention.
FIG. 6A
is a side elevation view of an inverted-F antenna having an elongated conductive element in spaced-apart, adjacent relationship with a ground plane, and wherein the ground plane has a plurality of raised portions extending towards the elongated, conductive element, according to an embodiment of the present invention.
FIG. 6B
is a side elevation view of the inverted-F antenna of
FIG. 6A
disposed within a dielectric material.
FIG. 6C
is a side elevation view of the inverted-F antenna of
FIG. 6A
disposed on a dielectric material.
FIGS. 7A and 7B
are side elevation views of an inverted-F antenna having an inductive element electrically connected to an elongated conductive element on respective sides of an RF signal feed, according to respective embodiments of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the thickness of layers and regions may be exaggerated for clarity. Like numbers refer to like elements throughout the description of the drawings. It will be understood that when an element such as a layer, region or substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. Moreover, each embodiment described and illustrated herein includes its complementary conductivity type embodiment as well.
Referring now to
FIG. 1
, a radiotelephone
10
, within which antennas according to various embodiments of the present invention may be incorporated, is illustrated. The housing
12
of the illustrated radiotelephone
10
includes a top portion
13
and a bottom portion
14
connected thereto to form a cavity therein. Top and bottom housing portions
13
,
14
house a keypad
15
including a plurality of keys
16
, a display
17
, and electronic components (not shown) that enable the radiotelephone
10
to transmit and receive radiotelephone communications signals.
A conventional arrangement of electronic components that enable a radiotelephone to transmit and receive radiotelephone communication signals is shown schematically in
FIG. 2
, and is understood by those skilled in the art of radiotelephone communications. An antenna
22
for receiving and transmitting radiotelephone communication signals is electrically connected to a radio-frequency transceiver
24
that is further electrically connected to a controller
25
, such as a microprocessor. The controller
25
is electrically connected to a speaker
26
that transmits a remote signal from the controller
25
to a user of a radiotelephone. The controller
25
is also electrically connected to a microphone
27
that receives a voice signal from a user and transmits the voice signal through the controller
25
and transceiver
24
to a remote device. The controller
25
is electrically connected to a keypad
15
and display
17
that facilitate radiotelephone operation.
As is known to those skilled in the art of communications devices, an antenna is a device for transmitting and/or receiving electrical signals. A transmitting antenna typically includes a feed assembly that induces or illuminates an aperture or reflecting surface to radiate an electromagnetic field. A receiving antenna typically includes an aperture or surface focusing an incident radiation field to a collecting feed, producing an electronic signal proportional to the incident radiation. The amount of power radiated from or received by an antenna depends on its aperture area and is described in terms of gain.
Radiation patterns for antennas are often plotted using polar coordinates. Voltage Standing Wave Ratio (VSWR) relates to the impedance match of an antenna feed point with a feed line or transmission line of a communications device, such as a radiotelephone. To radiate radio frequency (RF) energy with minimum loss, or to pass along received RF energy to a radiotelephone receiver with minimum loss, the impedance of a radiotelephone antenna is conventionally matched to impedance of a transmission line or feed point.
Conventional radiotelephones typically employ an antenna which is electrically connected to a transceiver operably associated with a signal processing circuit positioned on an internally disposed printed circuit board. In order to maximize power transfer between an antenna and a transceiver, the transceiver and the antenna are preferably interconnected such that their respective impedances are substantially “matched,” i.e., electrically tuned to filter out or compensate for undesired antenna impedance components to provide a 50 Ohm (Ω) (or desired) impedance value at the feed point.
Referring now to
FIG. 3A
, a conventional inverted-F antenna is illustrated. The illustrated antenna
30
includes a linear conductive element
32
maintained in spaced apart relationship with a ground plane
34
. Conventional inverted-F antennas, such as that illustrated in
FIG. 3A
, derive their name from a resemblance to the letter “F.” The conductive element
32
is grounded to the ground plane
34
as indicated by
36
. A hot RF connection
37
extends from underlying RF circuitry through the ground plane
34
to the conductive element
32
.
FIG. 3B
is a graph of the VSWR performance of the inverted-F antenna
30
of FIG.
3
A. As can be seen, the antenna
30
was designed to radiate at about 2375 Megahertz (MHz).
Referring now to
FIG. 4A
, an inverted-F antenna
40
having an elongated, meandering conductive element
42
, according to an embodiment of the present invention, is illustrated in an installed position within a wireless communications device, such as a radiotelephone. The elongated, meandering conductive element
42
is maintained in adjacent, spaced-apart relationship with a ground plane
44
(e.g., a printed circuit board). A signal feed
45
electrically connects the conductive element
42
to an RF transceiver
24
within a wireless communications device. A ground feed
47
grounds the conductive element
42
to the ground plane
44
.
In the illustrated embodiment, the elongated, meandering conductive element
42
includes a first plurality of segments
48
that are spaced apart from the first ground plane by a first distance H
1
. A second plurality of segments
49
are spaced apart from the first ground plane by a second distance H
2
which is greater than the first distance H
1
. The distance H
1
, between the conductive element segments
48
and the ground plane
44
is preferably maintained at between about 1 mm and about 5 mm. The distance H
2
between the conductive element segments
49
and the ground plane
44
is preferably maintained at between about 5 mm and about 15 mm.
In the illustrated embodiment, the elongated, meandering conductive element
42
includes a plurality of spaced-apart undulations
50
. Each undulation
50
has a U-shaped configuration that extends towards the ground plane
44
. Each U-shaped undulation
50
in the illustrated embodiment includes a pair of spaced-apart side segments
51
that extend towards the ground plane
44
. Each U-shaped undulation
50
also includes a base segment
48
that connects a respective pair of spaced-apart side segments
51
together. Each base segment
48
is capacitively coupled with the ground plane
44
.
In the illustrated embodiment, the base segment of each U-shaped undulation
50
is substantially orthogonal to the respective pair of spaced-apart side segments
51
(and substantially parallel with the ground plane
44
). It is understood, however, that an elongated, meandering conductive element according to the present invention can have undulations with various shapes and configurations and is not limited to the illustrated U-shaped undulations
50
.
Referring now to
FIGS. 4B and 4C
, alternative embodiments of the present invention are illustrated. In
FIG. 4B
, an inverted-F antenna
40
′ has an elongated, meandering conductive element
42
disposed (i.e., formed) on dielectric material
60
. The elongated, meandering conductive element
42
may be formed by etching a conductive layer formed on the dielectric material
60
. In
FIG. 4C
, an inverted-F antenna
40
″ has an elongated, meandering conductive element
42
disposed within dielectric material
60
′ (e.g., a dielectric substrate).
Referring to
FIG. 5
, the embodiment of
FIG. 4A
has been modified to include a second ground plane
70
that is oriented in a direction transverse to the first ground plane
44
. The illustrated second ground plane
70
is in adjacent, spaced-apart relationship with the U-shaped undulations
50
. Preferably, the second ground plane
70
is spaced apart from the U-shaped undulations
50
by a distance of less than or equal to 10 mm.
In the illustrated embodiment of
FIG. 5
, the U-shaped undulations
50
are capacitively coupled to the second ground plane
70
, as well as to the first ground plane
44
. The second ground plane
70
is not limited to the illustrated embodiment. The second ground plane
70
may be configured to be in adjacent, spaced apart relationship with one or more portions of the elongated, meandering conductive element
42
. For example, the second ground plane
70
may be in adjacent, spaced apart relationship with a single U-shaped undulation
50
. Alternatively, the second ground plane
70
may be in adjacent, spaced apart relationship with selected U-shaped undulations
50
. Multiple second ground planes also may be provided.
Referring now to
FIGS. 6A-6C
, additional embodiments of the present invention are illustrated. In
FIG. 6A
, an inverted-F antenna
140
having an elongated conductive element
142
, according to an embodiment of the present invention, is illustrated in an installed position within a wireless communications device, such as a radiotelephone. The elongated conductive element
142
is maintained in adjacent, spaced-apart relationship with a ground plane
44
. A signal feed
45
electrically connects the conductive element
142
to an RF transceiver
24
within a wireless communications device. A ground feed
47
grounds the conductive element
142
to the ground plane
44
.
In the illustrated embodiment, a plurality of raised portions
80
extend outwardly from the ground plane
44
. The illustrated grounded portions
80
may be extensions formed within a printed circuit board. The illustrated elongated conductive element
142
is spaced apart from the ground plane by a distance H
2
, and from each of the raised portions
80
by a distance H
1
that is less than the distance H
2
. The elongated conductive element
142
is capacitively coupled to the raised portions
80
of the ground plane
44
.
The distance H
1
between the conductive element
142
and the ground plane
44
is preferably maintained at between about 1 mm and about 5 mm. The distance H
2
between the conductive element
142
and the raised portions
80
extending from the ground plane
44
is preferably maintained at between about 5 mm and about 15 mm.
A ground plane incorporating raised portions
80
can be thought of as a meandering ground plane. The raised portions
80
can be thought of as spaced-apart undulations. An inverted-F antenna incorporating a meandering ground plane can resonate similarly to an inverted-F antenna having a meandering conductive element. The antenna of
FIG. 4A
is equivalent to the antenna of FIG.
6
A.
Referring now to
FIGS. 6B and 6C
, alternative embodiments of the antenna of
FIG. 6A
are illustrated. In
FIG. 6B
, an inverted-F antenna
140
′ has an elongated conductive element
142
disposed within dielectric material
60
(e.g., a dielectric substrate). In
FIG. 6C
, an inverted-F antenna
140
″ has an elongated conductive element
142
formed on a dielectric material
60
′ (e.g., a dielectric substrate).
Referring now to
FIGS. 7A and 7B
, inverted-F antennas according to the present invention may include one or more inductive elements
90
. One or more inductive elements
90
may be electrically connected to the elongated conductive element
142
between the RF signal feed
45
and the ground feed
47
, as illustrated in FIG.
7
A. Alternatively, one or more inductive elements
90
may be electrically connected to the elongated conductive element
142
adjacent the RF signal feed
45
as illustrated in FIG.
7
B. An inductive element
90
may comprise helical turns formed in the elongated conductive element
142
. Alternatively, various electronic components that can serve an inductive function may be electrically connected to the elongated conductive element
142
.
In each of the above-illustrated embodiments, a preferred conductive material out of which an elongated conductive element (
42
of
FIGS. 4A-4C
and
FIG. 5
;
142
of
FIGS. 6A-6C
and
FIGS. 7A-7B
) may be formed is copper. For example, the conductive elements
42
,
142
may be formed from copper wire. Alternatively, the conductive elements
42
,
142
may be a copper trace disposed on or within a substrate, as illustrated in
FIGS. 4B
,
4
C,
6
B,
6
C. However, an elongated conductive element according to the present invention may be formed from various conductive materials and is not limited to copper.
The elongated conductive element
42
,
142
is typically 0.5 ounce (14 grams) copper. However, conductive elements
42
,
142
according to the present invention may have various thicknesses. The width of an elongated conductive element according to the present invention may vary (either widened or narrowed), and need not remain constant.
Antennas according to the present invention may also be used with wireless communications devices which only transmit or receive radio frequency signals. Such devices which only receive signals may include conventional AM/FM radios or any receiver utilizing an antenna. Devices which only transmit signals may include remote data input devices.
The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although a few exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims. Therefore, it is to be understood that the foregoing is illustrative of the present invention and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the appended claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.
Claims
- 1. An inverted-F antenna, comprising:a first ground plane; an elongated conductive element capacitively coupled to the first ground plane, wherein the elongated conductive element is in adjacent, spaced-apart relationship with the first ground plane, wherein a first plurality of segments of the elongated conductive element are spaced apart from the first ground plane by a first distance, and wherein a second plurality of segments of the elongated conductive element are spaced apart from the first ground plane by a second distance greater than the first distance; an RF signal feed extending from the elongated conductive element; and a ground feed extending from the elongated conductive element adjacent the RF signal feed and electrically grounding the elongated conductive element.
- 2. The antenna according to claim 1 wherein the first distance is less than or equal to about five millimeters (5 mm), and wherein the second distance is less than or equal to about fifteen millimeters (15 mm).
- 3. The antenna according to claim 1 wherein the elongated conductive element comprises a meandering section having a plurality of spaced-apart undulations that extend towards the first ground plane.
- 4. The antenna according to claim 3 wherein the plurality of spaced-apart undulations comprises a plurality of U-shaped portions.
- 5. The antenna according to claim 4 wherein each U-shaped portion comprises a pair of spaced-apart side segments that extend towards the first ground plane and a base segment substantially orthogonal to the pair of spaced-apart side segments that connects the spaced-apart side segments together, and wherein each base segment is spaced apart from the first ground plane by a distance of less than or equal to about five millimeters (5 mm).
- 6. The antenna according to claim 1 wherein the ground plane is a meandering ground plane having a plurality of spaced-apart undulations that extend towards the elongated conductive element.
- 7. The antenna according to claim 1 wherein the elongated conductive element is disposed on dielectric material.
- 8. The antenna according to claim 1 wherein the elongated conductive element is disposed within dielectric material.
- 9. The antenna according to claim 1 further comprising a second ground plane oriented in a direction transverse to the first ground plane, wherein the second ground plane is in adjacent, spaced-apart relationship with at least a portion of the elongated conductive element, and wherein the at least one portion of the elongated conductive element is capacitively coupled to the second ground plane.
- 10. The antenna according to claim 9 wherein the second ground plane is spaced-apart from the at least one portion of the elongated conductive element by a distance of less than or equal to ten millimeters (10 mm).
- 11. An inverted-F antenna, comprising:a first ground plane; an elongated, meandering conductive element capacitively coupled to the first ground plane, wherein the elongated, meandering conductive element is in adjacent, spaced-apart relationship with the first ground plane, wherein the elongated, meandering conductive element comprises a plurality of U-shaped portions that extend towards the first ground plane; an RF signal feed extending from the elongated, meandering conductive element; and a ground feed extending from the elongated, meandering conductive element adjacent the RF signal feed and electrically grounding the meandering conductive element.
- 12. The antenna according to claim 11 wherein each U-shaped portion comprises a pair of spaced-apart side segments that extend towards the first ground plane and a base segment that connects the side segments together, and wherein each base segment is spaced apart from the first ground plane by a distance of less than or equal to about five millimeters (5 mm).
- 13. The antenna according to claim 11 wherein the elongated, meandering conductive element is disposed on dielectric material.
- 14. The antenna according to claim 11 wherein the elongated, meandering conductive element is disposed within dielectric material.
- 15. The antenna according to claim 11 further comprising a second ground plane oriented in a direction transverse to the first ground plane, wherein the second ground plane is in adjacent, spaced-apart relationship with at least one U-shaped portion, and wherein the at least one U-shaped portion is capacitively coupled to the second ground plane.
- 16. An inverted-F antenna, comprising:a ground plane; at least one grounded portion extending outwardly from the ground plane; an elongated conductive element in adjacent, spaced-apart relationship with the ground plane and with the at least one outwardly extending grounded portion, wherein the elongated conductive element is spaced apart from the ground plane by a first distance, and wherein the elongated conductive element is spaced apart from the at least one outwardly extending grounded portion by a second distance less than the first distance; an RF signal feed extending from the elongated conductive element; and a ground feed extending from the elongated conductive element adjacent the RF signal feed and electrically grounding the elongated conductive element.
- 17. The antenna according to claim 16 wherein the first distance is less than or equal to about fifteen millimeters (15 mm), and wherein the second distance is less than or equal to about five millimeters (5 mm).
- 18. The antenna according to claim 16 wherein the at least one outwardly extending grounded portion comprises a plurality of spaced-apart, outwardly extending grounded portions.
- 19. The antenna according to claim 16 wherein the elongated conductive element is disposed on dielectric material.
- 20. The antenna according to claim 16 wherein the elongated conductive element is disposed within dielectric material.
- 21. An inverted-F antenna, comprising:a ground plane; an elongated conductive element in adjacent, spaced-apart relationship with the ground plane; an RF signal feed extending from the elongated conductive element; a ground feed extending from the elongated conductive element adjacent the RF signal feed and electrically grounding the elongated conductive element; and an inductive element electrically connected to the elongated conductive element adjacent the RF signal feed, wherein the inductive element comprises a plurality of helical turns.
- 22. The antenna according to claim 21 wherein the inductive element is electrically connected to the elongated conductive element between the RF signal feed and the ground feed.
- 23. A wireless communicator, comprising:a housing configured to enclose a transceiver that transmits and receives wireless communications signals; and an inverted-F antenna disposed within the housing, comprising: a first ground plane; an elongated conductive element capacitively coupled to the first ground plane, wherein the elongated conductive element is in adjacent, spaced-apart relationship with the first ground plane, wherein a first plurality of segments of the elongated conductive element are spaced apart from the first ground plane by a first distance, and wherein a second plurality of segments of the elongated conductive element are spaced apart from the first ground plane by a second distance greater than the first distance; an RF signal feed extending from the elongated conductive element; and a ground feed extending from the elongated conductive element adjacent the RF signal feed and electrically grounding the elongated conductive element.
- 24. The wireless communicator according to claim 23 wherein the first distance is less than or equal to about five millimeters (5 mm), and wherein the second distance is less than or equal to about fifteen millimeters (15 mm).
- 25. The wireless communicator according to claim 23 wherein the elongated conductive element comprises a meandering section having a plurality of spaced-apart undulations that extend towards the first ground plane.
- 26. The wireless communicator according to claim 25 wherein the plurality of spaced-apart undulations comprises a plurality of U-shaped portions.
- 27. The wireless communicator according to claim 26 wherein each U-shaped portion comprises a pair of spaced-apart side segments that extend towards the first ground plane and a base segment substantially orthogonal to the pair of spaced-apart side segments that connects the spaced-apart side segments together, and wherein each base segment is spaced apart from the first ground plane by a distance of less than or equal to about five millimeters (5 mm).
- 28. The wireless communicator according to claim 23 further comprising a second ground plane oriented in a direction transverse to the first ground plane, wherein the second ground plane is in adjacent, spaced-apart relationship with at least a portion of the elongated conductive element, and wherein the at least one portion of the elongated conductive element is capacitively coupled to the second ground plane.
- 29. The wireless communicator according to claim 28 wherein the second ground plane is spaced-apart from the at least one portion of the elongated conductive element by a distance of less than or equal to ten millimeters (10 mm).
- 30. The wireless communicator according to claim 23 wherein the wireless communicator comprises a radiotelephone.
- 31. A wireless communicator, comprising:a housing configured to enclose a transceiver that transmits and receives wireless communications signals; and an inverted-F antenna disposed within the housing, comprising: a first ground plane; an elongated, meandering conductive element capacitively coupled to the first ground plane, wherein the elongated, meandering conductive element is in adjacent, spaced-apart relationship with the first ground plane, wherein the elongated, meandering conductive element comprises a plurality of U-shaped portions that extend towards the first ground plane; an RF signal feed extending from the elongated, meandering conductive element; and a ground feed extending from the elongated, meandering conductive element adjacent the RF signal feed and electrically grounding the meandering conductive element.
- 32. The wireless communicator according to claim 31 wherein each U-shaped portion comprises a pair of spaced-apart side segments that extend towards the first ground plane and a base segment that connects the side segments together, and wherein each base segment is spaced apart from the first ground plane by a distance of less than or equal to about five millimeters (5 mm).
- 33. The wireless communicator according to claim 31 further comprising a second ground plane oriented in a direction transverse to the first ground plane, wherein the second ground plane is in adjacent, spaced-apart relationship with at least one of the U-shaped portions, and wherein at least one U-shaped portion is capacitively coupled to the second ground plane.
- 34. The wireless communicator according to claim 31 wherein the wireless communicator comprises a radiotelephone.
- 35. A wireless communicator, comprising:a housing configured to enclose a transceiver that transmits and receives wireless communications signals; and an inverted-F antenna disposed within the housing, comprising: a ground plane; at least one grounded portion extending outwardly from the ground plane; an elongated conductive element in adjacent, spaced-apart relationship with the ground plane and with the at least one outwardly extending grounded portion, wherein the elongated conductive element is spaced apart from the ground plane by a first distance, and wherein the elongated conductive element is spaced apart from the at least one outwardly extending grounded portion by a second distance less than the first distance; an RF signal feed extending from the elongated conductive element; and a ground feed extending from the elongated conductive element adjacent the RF signal feed and electrically grounding the elongated conductive element.
- 36. The wireless communicator according to claim 35 wherein the first distance is less than or equal to about fifteen millimeters (15 mm), and wherein the second distance is less than or equal to about five millimeters (5 mm).
- 37. The wireless communicator according to claim 35 wherein the at least one outwardly extending grounded portion comprises a plurality of spaced-apart, outwardly extending grounded portions.
- 38. The wireless communicator according to claim 35 wherein the wireless communicator comprises a radiotelephone.
- 39. A wireless communicator, comprising:a housing configured to enclose a transceiver that transmits and receives wireless communications signals; and an inverted-F antenna disposed within the housing, comprising: a ground plane; an elongated conductive element in adjacent, spaced-apart relationship with the ground plane; an RF signal feed extending from the elongated conductive element; a ground feed extending from the elongated conductive element adjacent the RF signal feed and electrically grounding the elongated conductive element; and an inductive element electrically connected to the elongated conductive element adjacent the RF signal feed, wherein the inductive element comprises a plurality of helical turns.
- 40. The wireless communicator according to claim 39 wherein the inductive element is electrically connected to the elongated conductive element between the RF signal feed and the ground feed.
- 41. The wireless communicator according to claim 39 wherein the wireless communicator comprises a radiotelephone.
US Referenced Citations (7)