WO2002035652A1 - Internal antennas for portable terminals and mounting method thereof - Google Patents

Internal antennas for portable terminals and mounting method thereof Download PDF

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Publication number
WO2002035652A1
WO2002035652A1 PCT/KR2001/001673 KR0101673W WO0235652A1 WO 2002035652 A1 WO2002035652 A1 WO 2002035652A1 KR 0101673 W KR0101673 W KR 0101673W WO 0235652 A1 WO0235652 A1 WO 0235652A1
Authority
WO
WIPO (PCT)
Prior art keywords
conducting plate
antenna
internal antenna
circuit board
printed circuit
Prior art date
Application number
PCT/KR2001/001673
Other languages
French (fr)
Inventor
Jeong-Kun Oh
Kyung-Min Lee
Duk-Jae Park
Joo-Hyung Lee
Jong-Cheol Yun
Byoung-Nam Kim
Original Assignee
Ace Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ace Technology filed Critical Ace Technology
Publication of WO2002035652A1 publication Critical patent/WO2002035652A1/en

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Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01QANTENNAS, i.e. RADIO AERIALS
    • H01Q23/00Antennas with active circuits or circuit elements integrated within them or attached to them
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01QANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00Details of, or arrangements associated with, antennas
    • H01Q1/12Supports; Mounting means
    • H01Q1/22Supports; Mounting means by structural association with other equipment or articles
    • H01Q1/24Supports; Mounting means by structural association with other equipment or articles with receiving set
    • H01Q1/241Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM
    • H01Q1/242Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for hand-held use
    • H01Q1/243Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for hand-held use with built-in antennas
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01QANTENNAS, i.e. RADIO AERIALS
    • H01Q5/00Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
    • H01Q5/30Arrangements for providing operation on different wavebands
    • H01Q5/307Individual or coupled radiating elements, each element being fed in an unspecified way
    • H01Q5/342Individual or coupled radiating elements, each element being fed in an unspecified way for different propagation modes
    • H01Q5/357Individual or coupled radiating elements, each element being fed in an unspecified way for different propagation modes using a single feed point
    • H01Q5/364Creating multiple current paths
    • H01Q5/371Branching current paths
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01QANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04Resonant antennas
    • H01Q9/0407Substantially flat resonant element parallel to ground plane, e.g. patch antenna
    • H01Q9/0414Substantially flat resonant element parallel to ground plane, e.g. patch antenna in a stacked or folded configuration

Definitions

  • the present invention relates to an antenna for a portable terminal and, more
  • the present invention relates to a method of mounting such an antenna.
  • antennas for portable terminals include a monopole antenna having an electrical length of ⁇ /4 (where, ⁇ is a wavelength), a helical antenna having an electrical length of ⁇ /4, and a retractable antenna which is a combination of a monopole
  • antenna and a helical antenna Since all these antennas are installed or exposed outside the terminal, the antennas are being regarded as one of the major obstacles in miniaturizing the terminal. Accordingly, much efforts are being exerted to develop internal antennas which can be mounted directly on a surface of a printed circuit board of the terminal.
  • Antenna technologies for implementing the internal antennas include an inverted-F type antenna technology utilizing probe feeding in a radiator, a microstrip patch antenna technology using printed circuit board technology, and a ceramic chip antenna technology
  • the inverted-F type antenna has a narrow bandwidth and thus is inadequate for a terminal which is used for a wideband
  • the ceramic antenna is disadvantageous in that the loss in the antenna gain may be large because of the high dielectric constant of the ceramic dielectric material.
  • the microstrip patch antenna which is advantageous in that the frequency
  • the antenna itself may be bulky.
  • one object of the present invention is to provide an internal antenna which shows a high radiation efficiency a wide bandwidth with negligible loss caused by dielectric material.
  • Another object of the present invention is to provide a method of mounting an antenna in a manner that enhances the radiation efficiency.
  • An internal antenna for achieving one of the above objects includes two radiators
  • the wide bandwidth characteristics are obtained by adjusting the distance between the patches so as to result in an electromagnetic coupling and providing a vertical radiator coupled to the patches.
  • a ground conductor is electrically connected to the ground plane of the printed
  • Feeding means which is connected to the first conducting plate feeds signal from the feeding point to the first conducting plate and feeds
  • a second conducting plate is disposed parallel with the first conducting plate, and a connection conducting plate connects the first conducting plate to the second conducting plate.
  • the internal antenna further includes a vertical conducting plate extending vertically from an edge of the second conducting plate to be electrically
  • At least one slit is formed penetrating the first conducting plate to provide a signal path. Also, it is preferable that
  • the internal antenna is first disposed in such a manner that a upper edge of the internal antenna is displaced outwards from an edge of
  • the ground conductor is connected to a ground of the printed circuit board, and the feeding means is connected to
  • a predetermined portion of a ground plane of the printed circuit board close to an edge is removed, and then the internal antenna is disposed on the printed circuit board on which the ground plane is
  • the ground conductor is connected to a ground of the printed circuit board, and the feeding means is connected to a feeding point of the printed circuit board.
  • FIGS. 1A and IB show an embodiment of an internal antenna according to the present invention
  • FIG. 2 shows the internal antenna of FIGS. 1 A and FIG. IB mounted on a printed circuit board of a portable terminal;
  • FIG. 3 shows a standing-wave ratio pattern of the internal antenna of FIGS. 1 A and
  • FIG. 4 A shows a radiation pattern in electrical field plane of the internal antenna of FIGS. 1 A and IB;
  • FIG. 4B shows a radiation patterns in magnetic field plane of the internal antenna FIGS. 1A and IB;
  • FIGS. 5 A and 5B show another embodiment of the internal antenna according to
  • FIG. 6 shows the internal antenna of FIGS. 5 A and FIG. 5B mounted on a printed circuit board of a portable terminal;
  • FIG. 7 shows a standing-wave ratio pattern of the internal antenna of FIGS. 5 A and 5B;
  • FIG. 8 A and FIG. 8B show yet another embodiment the internal antenna according
  • FIG. 9 shows the internal antenna of FIGS. 8 A and FIG. 8B mounted on a printed circuit board of a portable terminal.
  • FIG. 10 shows a standing- wave ratio pattern of the internal antenna of FIGS. 8 A and 8B.
  • FIG. lA is a perspective view of an internal antenna according to an embodiment of the present invention seen from the upper side and FIG. 5B is a perspective view of the antenna seen from the lower side.
  • the internal antenna Referring to FIGS. 1 A and IB, the internal antenna
  • a ground conductor 100 electrically connected to ground of printed circuit board (PCB) of a portable terminal (for example, by soldering), a first conducting plate 110 disposed parallel with the ground conductor 100 while being spaced apart from the ground conductor 100 by a certain distance, a second conducting
  • connection conducting plate 130 for connecting the first and the second conducting plates 110 and 120 to each other, a
  • Such an antenna is mounted on the PCB of the portable terminal having a ground plane and feeding point.
  • radiator runs across the center of the first conducting plate 110 to an edge, and thus the first conducting plate 110 is "U"-shaped. Also, a feeding probe pin 114 extends downward
  • connection conducting plate 130 is connected to the second conducting plate 120 by a connection conducting plate 130.
  • the second conducting plate 120 operating as a main radiator has a rectangular shape.
  • a circular hole 122 penetrates the second conducting plate 120 and a second slit 124 runs from the hole 122 toward the center of the plate.
  • "L"-shaped third slit 126 is formed to be spaced apart from the second slit 124 by a certain distance.
  • a fourth slit 128 having a rectangular a shape is further provided between the
  • the hole 122 divides the signal path of the signal input through the connection conducting plate 130 into two paths along the circumference of the hole 122, i.e. clockwise
  • the hole 122 may have a rectangular or triangular sectional shape rather than the circle shape. Since, however,
  • such an angular hole may give rise to a perturbation which prevents from the divergence
  • the hole 122 has a circular sectional shape for facilitating
  • the second slit 124 and the "L"-shaped third slit 126 forms a "U"-shaped signal
  • the length of the signal path along the circumference of the hole 122 may be adjusted by changing the length and the position of
  • the second and the third slits 124 and 126 which may be used for tuning of the operation
  • the fourth slit 128 divides the signal
  • the vertical radiating plate 150 is spaced apart from the second conducting plate
  • the bandwidth of the antenna depends on the electromagnetic coupling between the first and the second conducting
  • the plates 110 and 120 also, which may be adjusted by changing the height of the vertical radiating plate 150. Meanwhile, it is preferable to dispose the first and the second conducting plates 110 and 120 to be close in proximity so that the plates 110 and 120 are
  • the signal fed from an internal circuit of the terminal to the first conducting plate 110 through the feeding probe pin 114 is provided to the second
  • the signal is received through the first and the second conducting plates 110 and 120 and the vertical radiating plate 150 is provided the internal circuit of the terminal
  • the first conducting plate 110 has a dominant influence on input impedance
  • the first slit 112 is critical to the operation frequency of the
  • the vertical conducting plate 140 connected to a ground plane of the terminal through the ground conductor 100 may work as another
  • FIG. 2 shows the internal antenna of FIGS. 1 A and FIG. IB mounted on a printed
  • PCB circuit board of a portable terminal.
  • the antenna is installed such that upper edge of the antenna is displaced upwards from the upper edge of the PCB
  • the antenna may be installed inside the PCB or to be aligned to the edge of the PCB after the ground plane of the PCB is removed as much as the offset.
  • FIG. 3 shows a standing-wave ratio pattern of the internal antenna of FIGS. 1 A and IB.
  • the horizontal axis indicates a frequency range [GHz] and the vertical
  • the internal antenna according to the present invention shows a wide bandwidth characteristics of having an operation bandwidth of
  • the size of the antenna used in the measurement is 30 x 12 x 4 [mm] and the distance between the first and the second conducting plates 110 and 120
  • FIGS. 4A and 4B show radiation patterns in electrical field plane (or a vertical
  • FIG. 4A shows a maximum gain of 2.1 [dBi] at 155 degree which is 25 degrees downwards from a vertical
  • FIG. 4B shows that the antenna shows the maximum gain of 1.3 [dBi] at 190 degree.
  • FIGS. 5 A and 5B show another embodiment of the internal antenna according to the present invention.
  • FIG. 5 A is a perspective view of the internal antenna seen from the upper side
  • FIG. 5B is a perspective view of the antenna seen from the lower side.
  • the internal antenna according to the present embodiment has an increased aspect ratio and the slit in a first conducting plate 210 is divided into two shorter slits 212 and 214. Further, slits 224, 226, and 228 in
  • a second conducting plate 220 are formed longitudinally, so that the second conducting
  • a second vertical conducting plate 260 is further provided at an edge the second
  • a fifth slit and a sixth slits 212 and 214 in the first conducting plate 210 forms
  • the second conducting plate 220 has the
  • first vertical conducting plate 140 extending from the top edge for the expansion of the bandwidth and the resonance in a higher frequency band, which is described below with
  • a seventh slit 224 formed longitudinally contrary to the second slit 124 shown in FIGS. 1 A and FIG. IB enables the signal to flow counterclockwise around a hole 222, which results in a phase difference between a signal flowing left directly from a connection
  • the antenna bandwidth may be enlarged because of a parasitic radiation owing to the interference of
  • Eighth slit 226 disposed periodically to form a shape of a "comb" and multiple ninth slit 228 alternating with the eighth slit 226 provides a zigzagging signal path which is sufficiently long in spite of the small size of the antenna and facilitates a resonance in lower
  • FIG. 6 shows the internal antenna of FIGS. 5 A and FIG. 5B mounted on a printed
  • the antenna is installed such that upper edge of the antenna is displaced upwards from the
  • the antenna may be installed inside the PCB or to be aligned to the edge of the PCB after the ground plane of the PCB is
  • FIG. 7 shows a standing- wave ratio pattern of the internal antenna of FIGS. 5 A and 5B.
  • the horizontal axis indicates a frequency range [MHZ] and the vertical axis indicates a reflection loss[dB].
  • the internal antenna according to the present embodiment shows a wide bandwidth characteristics of having an operation bandwidth of about 460 MHZ (1.74 - 2.2 GHz) for a reference standing- wave ratio of 2: 1.
  • another operation bandwidth is formed around 813MHz due
  • FIG. 8 A and FIG. 8B show yet another embodiment the internal antenna according to the present invention.
  • FIG. 8 A is a perspective view of the internal antenna seen from the upper side
  • FIG. 8B is a perspective view of the antenna seen from the lower side.
  • the internal antenna according to the present invention is a perspective view of the internal antenna seen from the upper side
  • FIG. 8B is a perspective view of the antenna seen from the lower side.
  • the antenna to the present embodiment includes a ground connection conducting plate 350 for connecting a second conducting plate 320 to a ground conductor 300. Also, the antenna
  • a feeding conductor plate 370 for feeding power in the lower position of the
  • a number of slits 327, 328, 302, and 304 are formed in the left side of a second
  • slits 342 and 344 are formed periodically in a first vertical conducting plate 340 to provide another transmission path, form another transmission line.
  • One slit 312 is formed in a first conducting plate 310. The zigzag path formed in the right side of the second conducting plate is connected to the first
  • the feeding conductor plate 370 is directly coupled to the internal circuit of the
  • FIG. 9 shows the internal antenna of FIGS. 8 A and FIG. 8B mounted on a printed
  • the antenna is installed such that upper edge of the antenna is displaced upwards from
  • FIG. 10 shows a standing- wave ratio pattern of the internal antenna of FIGS. 8 A
  • the horizontal axis indicates a frequency range [MHZ] and the vertical axis indicates a standing-wave ratio. It can be seen in the drawing that the
  • bandwidth of the lower frequency band is increased, compared with the embodiment of FIGS. 5 A and 5B, because of the transmission path formed in the left side of the second conducting plate 210 and the ground conductor 300.
  • the internal antenna according to the present invention is comprised of radiators made of metallic conducting plates only and does not employ any
  • the antenna may show
  • the antenna shows a wide bandwidth due to the introduction of the adjacent dual patches and the vertical patch.
  • the internal antennas may be used for cellular phones or the other kinds of portable terminals.

Abstract

An internal antenna showing high radiation efficiency and having a wide operation bandwidth while minimizing reflection loss due to dielectric material. A ground conductor (100) is electrically to ground of a PCB of a portable terminal. A first conducting plate (110) is disposed parallel with the ground conductor (100). Feeding means (112) is installed beneath the first conducting plate (110) to feed signal from a feeding point of the terminal to the first conducting plate (110) and feed signal from the first conducting plate (110) to the feeding point. A second conducting plate (120) is disposed parallel with the first conducting plate (110) and a connection conducting plate (130) connects the first and second conducting plates (110, 120).

Description

INTERNALANTENNAS FORPORTABLE TERMINALS AND MOUNTINGMETHOD THEREOF
Technical Field The present invention relates to an antenna for a portable terminal and, more
particularly, to an internal antenna which is mounted inside the portable terminal. Also, the present invention relates to a method of mounting such an antenna.
Background Art Currently available antennas for portable terminals include a monopole antenna having an electrical length of λ/4 (where, λ is a wavelength), a helical antenna having an electrical length of λ/4, and a retractable antenna which is a combination of a monopole
antenna and a helical antenna. Since all these antennas are installed or exposed outside the terminal, the antennas are being regarded as one of the major obstacles in miniaturizing the terminal. Accordingly, much efforts are being exerted to develop internal antennas which can be mounted directly on a surface of a printed circuit board of the terminal.
Antenna technologies for implementing the internal antennas include an inverted-F type antenna technology utilizing probe feeding in a radiator, a microstrip patch antenna technology using printed circuit board technology, and a ceramic chip antenna technology
using ceramic material of high dielectric constant. However, the internal antennas
according to the above technologies are confronting a design problem that the bandwidth
of an antenna decreases with the size of the antenna. The inverted-F type antenna has a narrow bandwidth and thus is inadequate for a terminal which is used for a wideband
service. The ceramic antenna is disadvantageous in that the loss in the antenna gain may be large because of the high dielectric constant of the ceramic dielectric material. On the other hand, the microstrip patch antenna, which is advantageous in that the frequency
tuning and the increase of the bandwidth is facilitated owing to the various slots and
stacking skills, has a drawback that the antenna itself may be bulky.
Thus, in order to satisfy needs on wideband communication services in the case that another kind of wideband communication service such as rjVIT-2000 is provided in addition
to the currently available services, an antenna technology which enables a single antenna to cover multiple band services and show a high radiation efficiency is required. In other
words, internal antenna of a new concept outstanding over a current internal antenna is strongly needed.
Disclosure of the Invention
To solve the above problems, one object of the present invention is to provide an internal antenna which shows a high radiation efficiency a wide bandwidth with negligible loss caused by dielectric material.
Another object of the present invention is to provide a method of mounting an antenna in a manner that enhances the radiation efficiency.
An internal antenna for achieving one of the above objects includes two radiators
disposed parallel in a structure of dual patches. The wide bandwidth characteristics are obtained by adjusting the distance between the patches so as to result in an electromagnetic coupling and providing a vertical radiator coupled to the patches.
A ground conductor is electrically connected to the ground plane of the printed
circuit board, and a first conducting plate is disposed parallel with a the ground conductor
displaced by a predetermined distance. Feeding means which is connected to the first conducting plate feeds signal from the feeding point to the first conducting plate and feeds
signal from the first conducting plate to the feeding point. A second conducting plate is disposed parallel with the first conducting plate, and a connection conducting plate connects the first conducting plate to the second conducting plate.
Preferably, the internal antenna further includes a vertical conducting plate extending vertically from an edge of the second conducting plate to be electrically
connected to the ground conductor. It is preferable that at least one slit is formed penetrating the first conducting plate to provide a signal path. Also, it is preferable that
at least one slit is formed penetrating the second conducting plate to provide a signal path. Meanwhile, according to an aspect of the internal antenna mounting method for achieving another one of the above objects, the internal antenna is first disposed in such a manner that a upper edge of the internal antenna is displaced outwards from an edge of
the printed circuit board by a predetermined distance. Then, the ground conductor is connected to a ground of the printed circuit board, and the feeding means is connected to
a feeding point of the printed circuit board.
According to an aspect of the internal antenna mounting method, a predetermined portion of a ground plane of the printed circuit board close to an edge is removed, and then the internal antenna is disposed on the printed circuit board on which the ground plane is
removed. Afterwards, the ground conductor is connected to a ground of the printed circuit board, and the feeding means is connected to a feeding point of the printed circuit board.
Brief Description of the Drawings
The above objectives and advantages of the present invention will become more apparent by describing in detail preferred embodiments thereof with reference to the attached drawings in which:
FIGS. 1A and IB show an embodiment of an internal antenna according to the present invention;
FIG. 2 shows the internal antenna of FIGS. 1 A and FIG. IB mounted on a printed circuit board of a portable terminal;
FIG. 3 shows a standing-wave ratio pattern of the internal antenna of FIGS. 1 A and
IB; FIG. 4 A shows a radiation pattern in electrical field plane of the internal antenna of FIGS. 1 A and IB;
FIG. 4B shows a radiation patterns in magnetic field plane of the internal antenna FIGS. 1A and IB;
FIGS. 5 A and 5B show another embodiment of the internal antenna according to
the present invention;
FIG. 6 shows the internal antenna of FIGS. 5 A and FIG. 5B mounted on a printed circuit board of a portable terminal; FIG. 7 shows a standing-wave ratio pattern of the internal antenna of FIGS. 5 A and 5B;
FIG. 8 A and FIG. 8B show yet another embodiment the internal antenna according
to the present invention;
FIG. 9 shows the internal antenna of FIGS. 8 A and FIG. 8B mounted on a printed circuit board of a portable terminal; and
FIG. 10 shows a standing- wave ratio pattern of the internal antenna of FIGS. 8 A and 8B.
Embodiments
FIG. lAis a perspective view of an internal antenna according to an embodiment of the present invention seen from the upper side and FIG. 5B is a perspective view of the antenna seen from the lower side. Referring to FIGS. 1 A and IB, the internal antenna
according to present embodiment includes a ground conductor 100 electrically connected to ground of printed circuit board (PCB) of a portable terminal (for example, by soldering), a first conducting plate 110 disposed parallel with the ground conductor 100 while being spaced apart from the ground conductor 100 by a certain distance, a second conducting
plate 120 disposed over the first conducting plate 110, a connection conducting plate 130 for connecting the first and the second conducting plates 110 and 120 to each other, a
vertical conducting plate 140 extending from an edge of the second conducting plate 120
downward to be electrically connected to the ground conductor 100, and a vertical radiating plate 150 extending from an edge of the first conducting plate 110 toward the second conducting plate 120. Such an antenna is mounted on the PCB of the portable terminal having a ground plane and feeding point.
A first slit 112 penetrating the first conducting plate 110 which operates as a first
radiator runs across the center of the first conducting plate 110 to an edge, and thus the first conducting plate 110 is "U"-shaped. Also, a feeding probe pin 114 extends downward
from the bottom surface of the first conducting plate 110. One edge of the first conducting
plate 110 near the feeding probe pin 114 is connected to the second conducting plate 120 by a connection conducting plate 130.
In the present embodiment, the second conducting plate 120 operating as a main radiator has a rectangular shape. A circular hole 122 penetrates the second conducting plate 120 and a second slit 124 runs from the hole 122 toward the center of the plate. A
"L"-shaped third slit 126 is formed to be spaced apart from the second slit 124 by a certain distance. A fourth slit 128 having a rectangular a shape is further provided between the
hole 122 and the third slit 126. The hole 122 divides the signal path of the signal input through the connection conducting plate 130 into two paths along the circumference of the hole 122, i.e. clockwise
and counterclockwise, and thus increases the antenna bandwidth. The hole 122 may have a rectangular or triangular sectional shape rather than the circle shape. Since, however,
such an angular hole may give rise to a perturbation which prevents from the divergence
of the signal, it is preferable that the hole 122 has a circular sectional shape for facilitating
the divergence of the signal. The second slit 124 and the "L"-shaped third slit 126 forms a "U"-shaped signal
path along the circumference of the hole 122. The length of the signal path along the circumference of the hole 122 may be adjusted by changing the length and the position of
the second and the third slits 124 and 126, which may be used for tuning of the operation
frequency of the antenna along with the first slit 112. The fourth slit 128 divides the signal
and incudes the perturbation of the divided signals, and thus increases the antenna bandwidth owing to a parasitic radiation.
The vertical radiating plate 150 is spaced apart from the second conducting plate
120 by a certain distance and works as a vertical radiator. The bandwidth of the antenna depends on the electromagnetic coupling between the first and the second conducting
plates 110 and 120, also, which may be adjusted by changing the height of the vertical radiating plate 150. Meanwhile, it is preferable to dispose the first and the second conducting plates 110 and 120 to be close in proximity so that the plates 110 and 120 are
coupled electromagnetically. In such a case, the electromagnetic coupling between the
plates enhances the antenna gain and increases the antenna bandwidth.
In the antenna above, the signal fed from an internal circuit of the terminal to the first conducting plate 110 through the feeding probe pin 114 is provided to the second
conducting plate 120 and the vertical radiating plate 150. Thus, the radiation is
accomplished by the first and the second conducting plates 110 and 120 and the vertical radiating plate 150. A portion of the signal provided to the second conducting plate 120
is transmitted to the ground conductor 100 through the vertical conducting plate 140.
Meanwhile, the signal is received through the first and the second conducting plates 110 and 120 and the vertical radiating plate 150 is provided the internal circuit of the terminal
through the feeding probe pin 114.
The first conducting plate 110 has a dominant influence on input impedance
characteristics of the antenna because it has a feeding point connected to the internal circuit of the terminal. In particular, the first slit 112 is critical to the operation frequency of the
antenna since the length of the first slit 112 determines the total length of the signal path in the first conducting plate 110. Also, the vertical conducting plate 140 connected to a ground plane of the terminal through the ground conductor 100 may work as another
vertical radiator, and its height is one of the principal variables which may be used for increasing the antenna bandwidth.
FIG. 2 shows the internal antenna of FIGS. 1 A and FIG. IB mounted on a printed
circuit board (PCB) of a portable terminal. As shown in FIG. 2, the antenna is installed such that upper edge of the antenna is displaced upwards from the upper edge of the PCB
by a certain offset DI to maintain the radiation characteristics of the antenna which
deteriorates when the ground plane of the PCB is close to the antenna. In an alternative embodiment, the antenna may be installed inside the PCB or to be aligned to the edge of the PCB after the ground plane of the PCB is removed as much as the offset.
FIG. 3 shows a standing-wave ratio pattern of the internal antenna of FIGS. 1 A and IB. In the drawing, the horizontal axis indicates a frequency range [GHz] and the vertical
axis indicates a reflection loss [dB], The internal antenna according to the present invention shows a wide bandwidth characteristics of having an operation bandwidth of
about 420 MHZ (1.58 - 2 GHz) with respect to a reference of -10 dB corresponding to a standing- wave ratio of 2: 1. The size of the antenna used in the measurement is 30 x 12 x 4 [mm] and the distance between the first and the second conducting plates 110 and 120
is 1.5 [mm].
FIGS. 4A and 4B show radiation patterns in electrical field plane (or a vertical
plane pattern) and in magnetic field plane (or a vertical plane pattern), respectively, of the internal antenna of FIGS. 1 A and IB. It can be seen, in FIG. 4A, that the antenna shows a maximum gain of 2.1 [dBi] at 155 degree which is 25 degrees downwards from a vertical
plane of the antenna since the antenna is installed on the top end of the PCB and thus the beam pattern declines to the ground plane. FIG. 4B shows that the antenna shows the maximum gain of 1.3 [dBi] at 190 degree. The size of the antenna used in the
measurement is same with that described with reference to FIG. 3.
FIGS. 5 A and 5B show another embodiment of the internal antenna according to the present invention. FIG. 5 A is a perspective view of the internal antenna seen from the upper side and FIG. 5B is a perspective view of the antenna seen from the lower side.
Compared with the embodiment of FIGS. 1 A and FIG. IB, the internal antenna according to the present embodiment has an increased aspect ratio and the slit in a first conducting plate 210 is divided into two shorter slits 212 and 214. Further, slits 224, 226, and 228 in
a second conducting plate 220 are formed longitudinally, so that the second conducting
plate 220 shows a signal path different from that of the antenna of FIGS. 1A and FIG. IB. Also, a second vertical conducting plate 260 is further provided at an edge the second
conducting plate 220 in addition to a first vertical conducting plate 240. A fifth slit and a sixth slits 212 and 214 in the first conducting plate 210 forms
another signal path crossing between them and induces an increase of the antenna bandwidth owing to the multi-path transmission. The second conducting plate 220 has the
a second vertical conducting plate 260 extending downwards from the left edge in addition
to a first vertical conducting plate 140 extending from the top edge for the expansion of the bandwidth and the resonance in a higher frequency band, which is described below with
reference to FIG. 7.
A seventh slit 224 formed longitudinally contrary to the second slit 124 shown in FIGS. 1 A and FIG. IB enables the signal to flow counterclockwise around a hole 222, which results in a phase difference between a signal flowing left directly from a connection
conducting plate (not shown in FIGS. 5 A and 5B) and a signal rotating counterclockwise from a lower part of the edge, i.e. the connection conducting plate. Thus the antenna bandwidth may be enlarged because of a parasitic radiation owing to the interference of
signals having the phase difference.
Eighth slit 226 disposed periodically to form a shape of a "comb" and multiple ninth slit 228 alternating with the eighth slit 226 provides a zigzagging signal path which is sufficiently long in spite of the small size of the antenna and facilitates a resonance in lower
frequency band which is described below with reference to FIG. 7. Besides, the zigzag
path formed by the eighth slit 226 and the ninth slit 228 in the present embodiment enlarges
the bandwidth through a parasitic coupling because the width of the path is wide but the
distance between two adjacent lines in the zigzagging path is narrow. FIG. 6 shows the internal antenna of FIGS. 5 A and FIG. 5B mounted on a printed
circuit board of a portable terminal. Similarly to the embodiment shown in FIG. 2, the antenna is installed such that upper edge of the antenna is displaced upwards from the
upper edge of the PCB by a certain offset D2. Also, the antenna may be installed inside the PCB or to be aligned to the edge of the PCB after the ground plane of the PCB is
removed as much as the offset, as well.
FIG. 7 shows a standing- wave ratio pattern of the internal antenna of FIGS. 5 A and 5B. In the drawing, the horizontal axis indicates a frequency range [MHZ] and the vertical axis indicates a reflection loss[dB]. The internal antenna according to the present embodiment shows a wide bandwidth characteristics of having an operation bandwidth of about 460 MHZ (1.74 - 2.2 GHz) for a reference standing- wave ratio of 2: 1. Here, it can be seen in the drawing that another operation bandwidth is formed around 813MHz due
to the zigzag signal path in the second conducting plate 220.
FIG. 8 A and FIG. 8B show yet another embodiment the internal antenna according to the present invention. FIG. 8 A is a perspective view of the internal antenna seen from the upper side and FIG. 8B is a perspective view of the antenna seen from the lower side. Compared with the embodiment of FIGS. 5 A and FIG. 5B, the internal antenna according
to the present embodiment includes a ground connection conducting plate 350 for connecting a second conducting plate 320 to a ground conductor 300. Also, the antenna
includes a feeding conductor plate 370 for feeding power in the lower position of the
antenna. A number of slits 327, 328, 302, and 304 are formed in the left side of a second
conducting plate 320 and a ground conductor 300. Also, slits 342 and 344 are formed periodically in a first vertical conducting plate 340 to provide another transmission path, form another transmission line. One slit 312 is formed in a first conducting plate 310. The zigzag path formed in the right side of the second conducting plate is connected to the first
vertical conducting plate 340. The feeding conductor plate 370 is directly coupled to the internal circuit of the
terminal by soldering, for example, for feeding signal to the first and the second conducting plates 310 and 320 and the ground conductor 300 through the first vertical conducting plate 340. Two types of transmission paths are formed on the second conducting plate 320
owing to the various slits 322, 324, 325, 326, 327 and 328 of a various shape. The signal feeding through the first vertical conducting plate 340 connected to such transmission
paths result in two resonant frequency bands as shown in FIG. 10.
The zigzag path in the left side of the second conducting plate 320 and the zigzag
path in the ground conductor 300 connected to the second conducting plate 320 through the ground connection conducting plate 350 increase a total length of the signal path and
enhances the resonance characteristics in a low frequency band as shown in FIG. 10. The zigzag path in the left side of the second conducting plate 320 having a narrow width compared with the wide slits increases the inductive reactance component. The tuning of
operation frequencies and the adjustment of bandwidth may be carried out by changing the widths and the lengths of the slits. FIG. 9 shows the internal antenna of FIGS. 8 A and FIG. 8B mounted on a printed
circuit board of a portable terminal. Similarly to the embodiment shown in FIGS. 2 and 6, the antenna is installed such that upper edge of the antenna is displaced upwards from
the upper edge of the PCB by a certain offset.
FIG. 10 shows a standing- wave ratio pattern of the internal antenna of FIGS. 8 A
and 8B. In the drawing, the horizontal axis indicates a frequency range [MHZ] and the vertical axis indicates a standing-wave ratio. It can be seen in the drawing that the
bandwidth of the lower frequency band is increased, compared with the embodiment of FIGS. 5 A and 5B, because of the transmission path formed in the left side of the second conducting plate 210 and the ground conductor 300.
Although the present invention has been described in detail above, it should be understood that the foregoing description is illustrative and not restrictive. Those of ordinary skill in the art will appreciate that many obvious modifications can be made to the invention without departing from its spirit or essential characteristics. Thus, it should be
apparent that the invention can be modified in arrangement and detail without departing
from such principles. We claim all modifications and variation coming within the spirit and scope of the following claims.
Industrial Applicability
As described above, the internal antenna according to the present invention is comprised of radiators made of metallic conducting plates only and does not employ any
dielectric material other than air. In case that the antenna is implemented using metallic thin films so that any radiator supporting member is not required, the antenna may show
a radiation efficiency of nearly 100% and can be further miniaturized. Also, mass production is facilitated through an automated process because the antenna can be
mounted directly on the PCB of the terminal.
The antenna shows a wide bandwidth due to the introduction of the adjacent dual patches and the vertical patch. An antenna according to an embodiment of the present
invention, which has a size of 30 x 12 x 4 [mm], has shown an operation band width over 420 MHZ, about four times that of a conventional antenna. An adjustment of central
frequency can be adjusted easily by changing the slits.
The internal antennas may be used for cellular phones or the other kinds of portable terminals.

Claims

What is claimed is:
1. An internal antenna mounted on a printed circuit board of a portable terminal having a ground plane and a feeding point, comprising:
a ground conductor electrically connected to the ground plane of the printed circuit board; a first conducting plate disposed parallel with said ground conductor displaced by
a predetermined distance; means, connected to said first conducting plate, for feeding signal from the feeding point to said first conducting plate and feeding signal from said first conducting plate to
the feeding point; a second conducting plate disposed parallel with said first conducting plate; and
a connection conducting plate for connecting said first conducting plate to said second conducting plate.
2. The internal antenna as claimed in claim 1, further comprising:
a vertical conducting plate extending vertically from an edge of said second conducting plate to be electrically connected to said ground conductor.
3. The internal antenna as claimed in claim 1, wherein at least one slit is
formed penetrating said first conducting plate to provide a signal path.
4. The internal antenna as claimed in claim 2, wherein at least one slit is
formed penetrating said second conducting plate to provide a signal path.
5. The internal antenna as claimed in claim 4, wherein a penetrating hole for
dividing signal and a first slit extending from an edge of the penetrating hole are provided
in said second conducting plate.
6. The internal antenna as claimed in claim 5, wherein a "L"-shaped second slit spaced apart from the first slit by a predetermined distance and a third slit for inducing a current perturbation between an edge of said second slit and the penetrating hole is further provided in said second conducting plate.
7. The internal antenna as claimed in claim 1, further comprising: a vertical radiating plate extending vertically from an edge of said first conducting
plate toward said second conducting plate.
8. A method of mounting an internal antenna of claim 1 on a printed circuit board of a portable terminal, comprising the steps of:
disposing the internal antenna so that a upper edge of the internal antenna is
displaced outwards from an edge of the printed circuit board by a predetermined distance;
and connecting the ground conductor to a ground of the printed circuit board, and connecting the feeding means to a feeding point of the printed circuit board.
9. A method of mounting an internal antenna of claim 1 on a printed circuit board of a portable terminal, comprising the steps of:
removing a predetermined portion of a ground plane of the printed circuit board close to an edge;
disposing the internal antenna on the printed circuit board on which the ground plane is removed; and connecting the ground conductor to a ground of the printed circuit board, and connecting the feeding means to a feeding point of the printed circuit board.
PCT/KR2001/001673 2000-10-05 2001-10-05 Internal antennas for portable terminals and mounting method thereof WO2002035652A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR2000/58615 2000-10-05
KR10-2000-0058615A KR100368939B1 (en) 2000-10-05 2000-10-05 An internal antenna having high efficiency of radiation and characteristics of wideband and a method of mounting on PCB thereof

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WO2002035652A1 true WO2002035652A1 (en) 2002-05-02

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WO2007143230A2 (en) * 2006-05-17 2007-12-13 Sony Ericsson Mobile Communications Ab Multi-band antenna for gsm, umts, and wifi applications
US7342553B2 (en) 2002-07-15 2008-03-11 Fractus, S. A. Notched-fed antenna
US7403164B2 (en) 2002-12-22 2008-07-22 Fractus, S.A. Multi-band monopole antenna for a mobile communications device
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US7579992B2 (en) 2004-06-26 2009-08-25 E.M.W. Antenna Co., Ltd. Multi-band built-in antenna for independently adjusting resonant frequencies and method for adjusting resonant frequencies
US7719470B2 (en) 2007-08-23 2010-05-18 Research In Motion Limited Multi-band antenna, and associated methodology, for a radio communication device
US7872605B2 (en) 2005-03-15 2011-01-18 Fractus, S.A. Slotted ground-plane used as a slot antenna or used for a PIFA antenna
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US7342553B2 (en) 2002-07-15 2008-03-11 Fractus, S. A. Notched-fed antenna
WO2004012298A2 (en) * 2002-07-26 2004-02-05 Amphenol Socapex Thin patch antenna
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US7932863B2 (en) 2004-12-30 2011-04-26 Fractus, S.A. Shaped ground plane for radio apparatus
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US7432860B2 (en) 2006-05-17 2008-10-07 Sony Ericsson Mobile Communications Ab Multi-band antenna for GSM, UMTS, and WiFi applications
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