Information
-
Patent Grant
-
6266019
-
Patent Number
6,266,019
-
Date Filed
Friday, July 21, 200024 years ago
-
Date Issued
Tuesday, July 24, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Wood, Phillips, VanSanten, Clark & Mortimer
-
CPC
-
US Classifications
Field of Search
US
- 343 702
- 343 749
- 455 90
-
International Classifications
-
Abstract
A communications device having an antenna and a housing having a front section and a rear section, one of the front section and the rear section being conductive. A circuit board is mounted within the housing and includes a point of lowest potential and a perimeter of length P. An electrical connection between the conductive one section and the circuit board point of lowest potential has a length less than one-half P.
Description
BACKGROUND OF THE INVENTION
The present invention is directed toward a communications device, and more particularly toward increasing efficiency of an antenna for a communications device.
A communications device, for example a cellular telephone, typically includes a front section and a rear section, the front and rear sections acting as a housing for a circuit board. The circuit board includes the control circuitry for the cellular telephone. The cellular telephone further includes an antenna coupled to the circuit board used for transmitting and receiving information to and from a cellular base station. Cellular telephones are usually powered by a battery, the negative terminal of which is the lowest point of potential for the cellular telephone. When transmitting information from the cellular telephone to the cellular base station, battery power is consumed and therefore the operational availability of the device is shortened.
In a cellular telephone, one or both of the front and rear sections have in some cases been conductive, that is made of or coated with a conductive material. Where one or both of the sections are conductive, the conductive sections have sometimes been unconnected from the point of lowest potential, and in other cases have been connected to the point of lowest potential via a circuit board trace located around an entire perimeter of the circuit board. When the section(s) are conductive and connected to the point of lowest potential by the perimeter trace, the conductive sections serve as a ground plane for the antenna, aiding in the transmission and reception of information from and to the cellular telephone. However, antenna efficiency is not optimized. A less efficient cellular telephone antenna causes more battery power to be consumed when transmitting information to the cellular base station. Because battery power is limited, it is desirable to increase the efficiency of the antenna.
The present invention is directed to overcoming the problem discussed above.
SUMMARY OF THE INVENTION
In one aspect of the present invention, a communications device having an antenna includes a communication device housing having a front section and a rear section, wherein one of the front section and the rear section is conductive. A circuit board is mounted within the communications device body including a connection with a point of lowest potential for the communications device and having a perimeter of length P. An antenna is connected to the circuit board and is used for transmitting information from and receiving information to the communications device. An electrical connection electrically connects the conductive one of said front and rear sections to the circuit board point of lowest potential, where the electrical connection has a major dimension less than one-half P.
In various forms of this aspect of the invention, the electrical connection is located other than along the perimeter of the circuit board, and may comprise a plurality of contact locations. The electrical connection may be a capacitor or an inductor. The electrical connection may also have a major dimension of length less than one-tenth P. In another form, the antenna is mounted proximate an edge of the circuit board and the circuit board includes a ground plane coupled to the point of lowest potential and the electrical connection is positioned to cause a one-quarter wave waveguide trap to be formed between the one section and the ground plane, the one-quarter wave waveguide trap having a low current point proximate said edge. In another form, the communications device includes a negative power terminal, and the point of lowest potential is an electrical connection with the negative power terminal. In a further form, the electrical connection from the one section and the point of lowest potential is proximate to the negative power terminal.
In another form of this aspect, the one section may be metalized or may be formed from metal. In another form, where the other of the front section and the rear section is conductive, the communications device further comprises a second electrical connection between the other section and the point of lowest potential, where the second electrical connection has a length less than one-half P. In another form of this aspect, the other of the front section and the rear section is conductive, and the communications device further comprises a second electrical connection between the other section and the point of lowest potential substantially along the entire perimeter of the circuit board. In yet another form of this aspect, the other of the front section and the rear section is conductive and electrically unconnected from the point of lowest potential.
In another aspect of the invention, a communications device is provided including a communications device housing having a front section and a rear section, wherein one of the front section and the rear section is conductive. An antenna is mounted to the housing and is used for transmitting information from and receiving information to the communications device. A battery is mounted to the housing for powering the communications device where the battery includes a positive power terminal and a negative power terminal. A circuit board is mounted within the communications device housing and connected to the antenna and to the battery power jet terminals, where the circuit board has a perimeter of length P and includes a circuit board ground plane connected to the negative power terminal. An electrical connection electrically connects the conductive one of the front and rear sections to the circuit board ground plane, where the electrical connection has a major dimension less than ½P.
In various forms of this aspect of the present invention, the electrical connection may comprise a plurality of contact locations, and may be formed by a capacitor or an inductor. The electrical connection further may have a major dimension less than one-tenth P. In another form, the antenna is mounted proximate an edge of the circuit board and the circuit board includes a ground plane coupled to the point of lowest potential, and positioned to cause a one-quarter wave-guide trap to be formed between the one section and the ground plane, the one-quarter wave waveguide trap having a low current point proximate the edge. In another form where the other of the front section and the rear section is conductive, a second electrical connection is located between the other section and the circuit board ground plane, where the second electrical connection has a major dimension less than ½P.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
illustrates a communications device in accordance with the prior art;
FIG. 2
illustrates a communications device embodying the present invention;
FIGS. 3
a
and
3
b
are an exploded side view and side by side sections, respectively, of a communications device in accordance with one embodiment of the present invention;
FIGS. 4
a
and
4
b
are an exploded side view and side by side sections, respectively, of a communications device in accordance with another embodiment of the present invention;
FIGS. 5
a
and
5
b
are an exploded side view and side by side sections, respectively, of a communications device in accordance with still another embodiment of the present invention;
FIGS. 6
a
and
6
b
are an exploded side view and side by side sections, respectively, of a communications device in accordance with yet another embodiment of the present invention;
FIGS. 7
a
and
7
b
are an exploded side view and side by side sections, respectively, of a communications device in accordance with still another embodiment of the present invention;
FIG. 7
c
illustrates the electrical connection utilized in the embodiment of
FIGS. 7
a
and
7
b;
FIG. 8
is an exploded side view of a communications device in accordance with an embodiment of the present invention;
FIG. 9
is an exploded side view of a communications device in accordance with another embodiment of the present invention; and
FIG. 10
is an exploded side view of a communications device in accordance with still another embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1
illustrates the electrical connection between a printed circuit board (PCB) and a housing of a mobile terminal such as a cellular telephone
100
in accordance with the prior art. The cellular telephone
100
includes the housing designated by a front section
105
and a rear section
110
, and a PCB
115
. The front section
105
includes an LCD lens
120
and a keypad
125
. An antenna
130
is mounted to the rear section
110
for receiving and transmitting information to and from a cellular base station (not shown). A battery
135
with positive and negative power terminals
136
,
137
respectively is also mounted to the rear section
110
. The PCB
115
is connected to the power terminals
136
,
137
and to the antenna
130
. An LCD
140
is mounted on the PCB
115
, such that when the cellular telephone
100
is assembled, the LCD
140
is viewable through the LCD lens
120
. The PCB further includes a PCB trace
145
located along an entire perimeter P of the PCB
115
, where the PCB trace
145
is connected to a cellular telephone point of lowest potential. Typically, the point of lowest potential is the negative power terminal
137
. Although not shown, the PCB trace
145
may also be exposed on a back side of the PCB
115
.
Where one or both of the front and rear sections
105
and
110
are conductive, the conductive section(s) have sometimes been unconnected from the point of lowest potential, and in other cases have been connected to the point of lowest potential along the entire perimeter P of the PCB
115
via the PCB trace
145
. Where the conductive section(s) are connected to the point of lowest potential, the electrical connections are typically made using a conductive caulk, a conductive elastomer, or a conductive gasket along a perimeter of the respective front and rear section. When the cellular telephone
100
is assembled, the electrical connection connects the respective conductive section to the point of lowest potential along the entire perimeter P of the PCB
115
via the PCB trace
145
.
FIG. 2
illustrates a communications device embodying the present invention. Components of
FIG. 2
identified by reference numerals identical to those of
FIG. 1
are the same and will not be discussed in detail.
In one form of the
FIG. 2
embodiment, the front section
105
is conductive, that is formed from metal, formed from a conductive material such as a conductive plastic, or coated with a conductive material along an inner surface of the front section
105
. The front section
105
is unconnected from the point of lowest potential, for example the negative battery terminal
137
or some terminal connected thereto, except for an electrical connection between positions designated as
205
a
and
205
b,
where
205
b
is further connected to the point of lowest potential
137
.
In another form of the
FIG. 2
embodiment, where the front section
105
is conductive, the front section
105
is unconnected from the point of lowest potential
137
except for an electrical connection between an entire side
210
a
of the front section
105
designated by area
210
a
and a side of the PCB
115
along, for example, the portion of the PCB trace
145
designated within the area
210
b.
In yet another form, where the front section
105
is conductive, the front section
105
is unconnected from the point of lowest potential
137
except for two (2) electrical connections coupling the front section
105
to the point of lowest potential
137
. For example, electrical connections extending between positions
215
a
and
215
b
and positions
220
a
and
220
b
electrically couple the front section
105
to the point of lowest potential
137
, where the electrical connections
215
b
and
220
b
are connected to the point of lowest potential
137
.
In other forms the rear section
110
is conductive, and is unconnected from the point of lowest potential except for an electrical connection between a position
225
a
located on a back of the PCB
115
, and a position
225
b,
where the position
225
a
is connected to the point of lowest potential
137
.
In additional forms (not shown), both the front and rear sections
105
and
110
are conductive and one of the front and rear sections is connected to the point of lowest potential
137
with the electrical connection having a major dimension less than ½P. The other of the front and rear sections is coupled to the point of lowest potential by a second electrical connection having a major dimension less then ½P, or via an electrical connection around the entire perimeter P of the circuit board via the PCB trace
145
.
For the embodiments just described, the electrical connection from the respective conductive section to the point of lowest potential, having a major dimension less than one-half the perimeter of the PCB
115
, increases the antenna efficiency of the antenna
130
. Increasing antenna efficiency allows the cellular telephone to transmit a signal having the same strength as a cellular telephone utilizing prior art electrical connection techniques between the conductive section(s) and the point of lowest potential, while consuming less battery power. Alternatively, the electrical connections utilized in the embodiment just described allow a greater signal strength to be transmitted from the cellular telephone over that of the prior art, while consuming the same battery power as the cellular telephone utilizing prior art electrical connections between the conductive section(s) and the point of lowest potential.
The electrical connections may be formed using wire, conductive foam, conductive elastomer, conductive gasket material, or any other material sufficient for forming an adequate electrical ground.
The size of the electrical connection is not vital so long as it is sufficient (large enough) to form an adequate ground, and has a major dimension less than one-halfP. A minimum size for an electrical connection to form an adequate electrical ground is known to one skilled in the art. A typical thickness for the electrical connection ranges from a width of a wire, or conductive sheet of approximately 1 mm width, to a width of a circular bead of conductive material (for example conductive foam or gasket) of approximately 6 mm diameter. The width of the electrical connection may be less so long as an adequate electrical ground is formed, and the width may be greater where placement of components in the communications device or other manufacturing considerations allow. The height of the electrical connection is typically that of a distance between the respective positions between which the electrical connection is made when the front section
105
, the rear section
110
and the PCB
115
are assembled together. One skilled in the art will realize that the height of the electrical connection may be greater, especially for example, where the electrical connection is formed from a compressible material such as a conductive foam or gasket, or from a conductive material having spring-like properties. In addition, the electrical connection may be formed using an inductor or a capacitor, further discussed below.
When determining the position for the electrical connection between the respective conductive section and the point of lowest potential, it is preferable to select a position proximate the negative battery terminal
137
. However, due to manufacturing considerations or placement of certain components on the respective conductive section or the PCB, the preferred position may not always be achieved. For example, if it is desired to connect a conductive front section
105
to the point of lowest potential, and the negative battery terminal
137
is positioned directly beneath the LCD
140
and the LCD lens
120
, a connection between the front section
105
and the PCB
115
could not be achieved directly above the negative battery terminal
137
. In such situations, the position of the electrical connection is selected such that the point of contact between the front section
105
and the PCB
115
are close to but not directly above the negative battery terminal
137
.
Although it is preferable that the electrical connection be proximate the negative battery terminal, improved antenna performance is also achieved where the electrical connection is not proximate the negative battery terminal.
FIGS. 3
a
and
3
b
are exploded side and side by side section views, respectively, of an Ericsson cellular telephone
300
, model #A1228d, in accordance with an embodiment of the present invention. A front section
305
, a rear section
310
, and a PCB
315
are shown. The PCB
315
includes a PCB trace
317
exposed on a front and a back of the PCB
315
along the perimeter of the PCB. The PCB trace
317
is connected to a PCB ground plane
318
which is connected to the point of lowest potential for the cellular telephone, typically a negative power terminal
319
of a battery
320
. The PCB
315
further includes a shield can
321
which is connected to the PCB ground plane
318
. The shield can is conductive, and is typically used for electrostatic discharge protection, and/or to reduce emissions from the cellular telephone. The PCB is connected to an antenna
322
, used for receiving and transmitting information to and from the cellular telephone. Both the front and rear section
305
and
310
are metalized, that is coated with a conductive material. The rear section
310
is connected to the PCB ground plane around an entire perimeter P of the PCB
315
via the PCB trace
317
. The front section
305
is isolated from the PCB ground plane except for an electrical connection
335
which extends between a position
340
a
on the front section
305
, and a position
340
b
located on the shield can
321
. Positions
340
a
and
340
b
are located approximately 21 mm from a top of the cellular telephone
300
, designated generally by arrow
350
, and approximately 11 mm from a left side of the cellular telephone
300
, designated generally by an arrow
355
. The electrical connection
335
is formed from a conductive elastomer having a substantially circular configuration of approximately 3 mm diameter. The elastomer is of sufficient height such that when the PCB
315
is assembled within the front section
305
, the electrical connection
335
contacts both the front section
305
and the shield can
320
. Electrically connecting the front section
305
to the point of lowest potential in this manner improves antenna efficiency of the antenna
322
by approximately 65%.
FIGS. 4
a
and
4
b
are exploded side and side by side views, respectively, of an Ericsson cellular telephone
400
, model #T28s, in accordance with another embodiment of the present invention. A front section
405
, a rear section
410
, and a PCB
415
are shown. The PCB
415
includes a PCB trace
417
exposed on a front and a back of the PCB
415
along the perimeter of the PCB. The PCB trace
417
is connected to a PCB ground plane
418
which is connected to the point of lowest potential for the cellular telephone, typically a negative power terminal
419
of a battery
420
. The PCB
415
is electrically connected to an antenna
422
. Both the front and rear sections
405
and
410
are conductive, where the front section
405
is metalized, and the rear section
410
is made of metal. The rear section
410
is connected to the PCB ground plane
418
around the entire perimeter P of the PCB
415
via the PCB trace
417
. The front section
405
is isolated from the PCB ground plane except for an electrical connection
435
which extends between a position
440
a
on the front section
405
, and a position
440
b
located on the PCB
415
. The positions
440
a
and
440
b
are located approximately 20 mm from a top of the cellular telephone
400
designated generally by an arrow
450
, and approximately 24 mm from a right side of the cellular telephone designated generally by an arrow
457
. The electrical connection
435
is formed from an inductor. The inductor may have from 2 to 6 turns, such as 3.5 to 4 turns. The inductor has an air core with a diameter of approximately 4 mm. Electrically connecting the front section
405
to the point of lowest potential
419
in this manner improves antenna efficiency of the antenna
422
by approximately 65%.
FIGS. 5
a
and
5
b
are exploded side and side by side views, respectively, of an Ericsson cellular telephone
500
, model #KH668, in accordance with an embodiment of the present invention. A front section
505
, a rear section
510
, and a PCB
515
are shown. The PCB
515
includes a PCB trace
517
exposed on a front and a back of the PCB
515
along a perimeter of the PCB. The PCB trace
517
is connected to a PCB ground plane
518
which is coupled to the point of lowest potential for the cellular telephone
500
, typically a negative power terminal
519
of a battery
520
. The PCB
515
is electrically connected to an antenna
522
. The front section
505
is metalized, and the rear section
510
is made of metal. The rear section
510
is connected to the PCB point of lowest potential around the entire perimeter P of the PCB
515
via PCB trace
517
. The front section
505
is isolated from the PCB point of lowest potential except for two electrical connections
535
and
537
. One electrical connection
535
extends between a position
535
a
located on the front section
505
and a position
535
b
which is located on the front of the PCB
515
. The other electrical connection
537
extends between a position
537
a
located on the front section
505
and a position
537
b
located on the front of the PCB
515
. The positions
535
b
and
537
b
are coupled to the point of lowest potential for the cellular telephone
500
, for example, via the PCB trace
517
. Positions
535
a
and
535
b
are located approximately 6 mm from a left side of the cellular telephone
500
designated generally by an arrow
555
, and approximately 6 mm from a bottom of the cellular telephone designated generally by an arrow
559
. Positions
537
a
and
537
b
are located approximately 6 mm from a right side of the cellular telephone
500
designated generally by an arrow
557
, and approximately 6 mm from the bottom designated at
559
. Here, the electrical connections
535
and
537
are formed from respective screw bosses approximately 5 mm in diameter, which electrically connect the front section
505
to the PCB
515
when the front section and the PCB are assembled. Electrically connecting the front section
505
to the point of lowest potential
519
in this manner improves antenna efficiency of the antenna
522
by approximately 20%.
In the embodiments discussed above, it is common that a conductive section is connected to the point of lowest potential via an electrical connection having a length less than one-half the perimeter of the PCB, or is completely unconnected from the point of lowest potential. In such circumstances, it may be necessary to remove a portion of the metalized coating on the conductive section, or to insulate a portion of the conductive section from the point of lowest potential to ensure that a complete contact between the respective conductive section and the point of lowest potential is not made. For example, referring to
FIG. 5
a,
a portion around a perimeter of the front section
505
, designated in the area
570
, is not metalized with the rest of the front section
505
, to ensure that when the PCB
515
is assembled with the front section
505
, the front section
505
is not connected to the point of lowest potential along the entire perimeter of the front section
505
via the PCB trace
517
. Alternatively, the entire front section
505
may be metalized, with an insulating material placed around the perimeter of the front section
505
to ensure that the front section
505
does not contact the point, of lowest potential around the entire perimeter of the front section via the PCB trace
517
.
FIGS. 6
a
and
6
b
are exploded side and side by side views, respectively, of an Ericsson cellular telephone
600
, model #A2218d, in accordance with another embodiment of the present invention. A front section
605
, a rear section
610
, and a PCB
615
are shown. The PCB
615
includes a PCB trace
617
exposed on a front and a back of the PCB
615
extending along a perimeter of the PCB. The PCB trace
617
is connected to a PCB ground plane
618
which is coupled to a point of lowest potential for the cellular telephone
600
, typically a negative power terminal
619
of a battery
620
. A shield can
621
is formed from metalized plastic and is coupled to the back of the PCB
615
via the PCB trace
617
. The PCB
615
is further coupled to an antenna
622
. The front section
605
is metalized, and the rear section
610
is made of plastic. The shield can
621
is connected to the point of lowest potential around the entire perimeter P of the PCB
615
via the PCB trace
617
. The front section
605
is unconnected from the point of lowest potential except for an electrical connection
635
which extends between a position
635
a
on the front section
605
, and a position
635
b
located on the front and side of the PCB
615
. The electrical connection
635
and the corresponding position
635
a
and
635
b
are located along a left side of the cellular telephone
600
, generally designated by an arrow
655
, approximately 77 mm from a top of the cellular telephone, generally designated by an arrow
650
. The electrical connection
635
is formed from a conductive elastomer of approximately 4 mm width and 5 mm length, such that when the front section
605
and the PCB
615
are assembled, the front section
605
is coupled to the point of lowest potential. Electrically connecting the front section
605
to the point of lowest potential
625
in this manner improves antenna efficiency by approximately 50%.
In an alternate embodiment (not shown), the electrical connection
635
and respective positions
635
a
and
635
b
are located on a right side of the cellular telephone
600
approximately 77 mm from the top
650
.
FIGS. 7
a
and
7
b
are exploded side and side by side views, respectively, of an Ericsson cellular telephone
700
, model #KF788, according to another embodiment of the present invention. A front section
705
, a rear section
710
and a PCB
715
are shown. The PCB
715
includes a PCB ground plane
718
which is connected to the point of lowest potential for the cellular telephone
700
, typically a negative power terminal
719
of a battery
720
. The PCB
715
further includes a shield can
721
which is coupled to the PCB ground plane. The PCB
715
is electrically connected to an antenna
722
. Both the front and rear sections
705
and
710
are metalized. The front section
705
is isolated from the point of lowest potential. The rear section
710
is isolated from the point of lowest potential except for an electrical connection
735
extending between a position
735
a
located on the shield can
721
, and a position
735
b
located on the rear section
710
. The positions
735
a
and
735
b
are located approximately 41 mm from a top of the cellular telephone
700
designated generally by an arrow
750
, and approximately 1 mm from a right side of the cellular telephone
700
designated generally by an arrow
757
.
FIG. 7
c
further illustrates the electrical connection
735
, which may be formed from a sheet of metal bent in a “J” configuration. The electrical connection
735
has a height of approximately 5 mm, a length of approximately 12 mm, and a curved portion designated generally at
760
having a diameter of approximately 2 mm. In an alternate embodiment, the length of the electrical connection
735
may be approximately 1 cm.
A bottom portion
760
of the electrical connection
735
is installed in a battery clip for the negative power terminal
719
and makes contact with metalized rear housing
710
, and a top portion of the electrical connector
735
designated at the curved section
765
makes contact with the shield can
721
. Electrically connecting the rear section
710
to the point of lowest potential in this manner improves antenna efficiency by approximately 40%.
In at least the embodiments discussed above where the front section is coupled to the point of lowest potential via an electrical connection having a length less than one-half the perimeter of the PCB, it is believed that the electrical connection between the front section and the PCB causes a quarter wave, wave guide trap to be formed between the front section and the PCB, as described with respect to
FIGS. 8-10
.
FIGS. 8-10
are exploded side views of a cellular telephone in accordance with embodiments of the present invention.
FIGS. 8-10
show a front section
805
, a rear section
810
, and a PCB
815
. The PCB
815
includes a ground plane
818
which is connected to the cellular telephone
800
point of lowest potential, typically a negative power terminal (not shown) of a battery
820
. The PCB further includes a PCB trace (not shown) exposed on a front and a back of the PCB, similar to the PCB traces of
FIGS. 3
b,
4
b,
5
b
and
6
b
extending around a complete perimeter of the PCB, and connected to the PCB ground plane
818
. The rear section
810
is connected to the PCB
815
around the entire perimeter P of the PCB
815
via the PCB trace. An antenna
822
is coupled to the PCB
815
used for receiving and transmitting information to/from the cellular telephone.
In
FIG. 8
, an electrical connection
825
is formed between position
825
a
on the front section
805
and position
825
b
located on the PCB
815
. Position
825
b
is further coupled to the PCB ground plane
818
. The electrical connection is positioned approximately λ/4 from a top of the front section
805
and PCB
815
such that a quarter wave, wave guide trap is formed between the front section and the PCB
815
, with a low current point (or high impedance Z) near the antenna
822
. This presents a very high impedance to the normal current path down the front of the telephone, causing the ground currents i
t
to flow down the rear section
810
of the cellular telephone as designated by an arrow
830
. The ground currents i
t
are not restricted from flowing down the sides and the rear section of the cellular telephone
800
, so a necessary antenna ground plane for the antenna
822
may be realized within the cellular telephone
800
. The length of the quarter wave trap will be somewhat shorter than a free space quarter wave length due to dielectric loading between the conductive front section
805
and conductive rear section
810
and PCB
815
. The connection
825
in
FIG. 8
may be formed from a wire, or a conductive elastomer or gasket as discussed above.
FIG. 9
illustrates use of inductive loading to significantly shorten the length of the quarter-wave wave guide trap between the front section
805
and the PCB
815
. Here, the electrical connection
840
is an inductor providing inductive loading. The inductive loading provided by the inductor
840
is advantageous as it is not always possible to locate the electrical connection between the front section
805
and the PCB
815
at the λ/4 distance from the top of the front section
805
and PCB
815
because of, for example, location of a cellular telephone LCD or a cellular telephone keypad, or due to other manufacturing considerations.
FIG. 10
illustrates utilization of capacitive loading to shorten the length of the quarter wave, wave guide trap. Shortening the length of the quarter wave wave-guide trap using a capacitor is advantageous as it is not always possible to locate the electrical connection between the front section
805
and the PCB
815
at the λ/4 distance because of components on the front section
805
and PCB
815
, or because of other manufacturing considerations. Here, the electrical connection includes an electrical connection
845
a
similar to the electrical connection
825
discussed above with respect to FIG.
8
and an electrical connection
845
b
formed by a capacitor. The value of the capacitor and position of both the electrical connections
845
a
and
845
b
may be determined experimentally to achieve the advantages of the present invention, as would be realized by one skilled in the art.
Although the present invention has been discussed in the context of a cellular telephone, one skilled in the art would realize that the advantages gained therefrom would be realized in any communications device.
Still other aspects and advantages of the present invention can be obtained from a study of the specification, the drawings, and the appended claims. It should be understood, however, that the present invention could be used in alternate forms where less than all of the advantages of the present invention and preferred embodiments as described above would be obtained.
Claims
- 1. A communications device, comprising:a communications device housing having a front section and a rear section, wherein one of the front section and the rear section is conductive; an antenna for transmitting information from and receiving information to the communications device; a circuit board mounted within the communications device housing, where the circuit board has a perimeter of length P, is electrically connected to the antenna, and includes a point of lowest potential for the communications device; and an electrical connection electrically connecting said conductive one of said front and rear sections to said circuit board point of lowest potential, said electrical connection having a major dimension less than ½P.
- 2. The communications device of claim 1 wherein the electrical connection is located other than along the perimeter of the circuit board.
- 3. The communications device of claim 1 wherein the electrical connection comprises a plurality of contact locations.
- 4. The communications device of claim 1 wherein the antenna is mounted proximate an edge of the circuit board and the circuit board includes a ground plane coupled to the point of lowest potential, and the electrical connection is positioned to cause a ¼ wave waveguide trap to be formed between said conductive one of said front and rear sections and the ground plane, the ¼ wave waveguide trap having a low current point proximate said edge.
- 5. The communications device of claim 1 wherein the electrical connection is an inductor.
- 6. The communications device of claim 1 wherein the communications device includes a negative power terminal, and the point of lowest potential is the negative power terminal.
- 7. The communications device of claim 6 wherein the electrical connection from said conductive one of said front and rear sections and the point of lowest potential is proximate to the negative power terminal.
- 8. The communications device of claim 1 wherein the communications device is a cellular telephone.
- 9. The communications device of claim 1 wherein the electrical connection has a major dimension less than one-tenth P.
- 10. The communications device of claim 1 wherein said conductive one of said front and rear sections includes a metalized coating deposited thereon.
- 11. The communications device of claim 1 wherein said conductive one of said front and rear sections is metal.
- 12. The communications device of claim 1 wherein the electrical connection is a capacitor.
- 13. The communications device of claim 1 wherein the other of the front section and the rear section is conductive, and further comprising a second electrical connection between said other section and said point of lowest potential, said second electrical connection having a length less than ½P.
- 14. The communications device of claim 1 wherein the other of the front section and the rear section is conductive, and further comprising a second electrical connection between said other section and said point of lowest potential substantially along the entire perimeter of the circuit board.
- 15. The communications device of claim 1 wherein the other of the front section and the rear section is conductive but not connected to the point of lowest potential.
- 16. A communications device, comprising:a communications device housing having a front section and rear section, wherein one of the front section and the rear section is conductive; an antenna mounted to the housing for transmitting information from and receiving information to the communications device; a battery mounted to the housing for powering the communications device and including a positive power terminal and a negative power terminal; a circuit board mounted within the communications device housing and connected to the antenna and to the battery power terminals, the circuit board having a perimeter of length P and including a circuit board ground plane connected to the negative power terminal; and an electrical connection electrically connecting said conductive one of the front and rear sections to the circuit board ground plane, said electrical connection having a major dimension less than ½P.
- 17. The communications device of claim 16 wherein the electrical connection comprises a plurality of contact locations.
- 18. The communications device of claim 16 wherein the antenna is mounted proximate an edge of the circuit board and the circuit board includes a ground plane coupled to the point of lowest potential, and positioned to cause a ¼ wave wave-guide trap to be formed between said one section and the ground plane, the ¼ wave waveguide trap having a low current point proximate said edge.
- 19. The communications device of claim 16 wherein the electrical connection is an inductor.
- 20. The communications device of claim 16 wherein the electrical connection is a capacitor.
- 21. The communications device of claim 16 wherein the other of the front section and the rear section is conductive, and further comprising a second electrical connection between said other section and said circuit board ground plane, said second electrical connection having a major dimension less than ½P.
- 22. The communications device of claim 16 wherein the electrical connection has a major dimension less than one-tenth P.
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Number |
Name |
Date |
Kind |
5020136 |
Patsiokas et al. |
May 1991 |
|
5606733 |
Kanayama et al. |
Feb 1997 |
|
5977917 |
Hirose |
Nov 1999 |
|