JP2008141780A - Mobile communication device with multi-band antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile communication device which includes a multi-band monopole antenna and reduces electromagnetic interference. <P>SOLUTION: A cellular telephone set 120 that is a mobile communication device, includes a lower circuit board 122, an upper circuit board 124, a multi-band antenna 121 fixed in a mounting structure 110, and a communication circuit 108. An upper housing 128 and a lower housing 130 are combined to house the circuit boards 122 and 124 and the antenna 121. The antenna 121 is connected to the communication circuit 108 at a feeding point 104 and is set so that a projection of foot print of the antenna onto the circuit board 122 may not be overlapped more than 50% with metallization of a ground surface of the circuit board. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to the technical field of multiband monopole antennas. More particularly, it relates to mobile communication devices such as personal digital assistants, cellular telephones, and pagers equipped with the antenna.

  Multiband antenna structures for use in mobile communication devices are known in the art. For example, one type of antenna structure commonly used as a built-in antenna for mobile communication devices is known as an “inverted F-shaped” antenna. When implemented inside a mobile communication device, the antenna often receives a significant amount of electromagnetic interference from another metal object inside the mobile communication device, particularly a ground plane.

  The inverted F-shaped antenna is supposed to operate appropriately as a built-in antenna as compared with other known antenna structures. However, inverted F-shaped antennas generally have limited bandwidth and therefore may not be well suited for bandwidth aggregation applications.

The multi-band monopole antenna for a mobile communication device of the present invention includes a common conductor coupled to both the first radiating arm and the second radiating arm. The common conductor includes a feed port that couples the antenna to a communication circuit in the mobile communication device. In one embodiment, the first radiating arm includes a space filling curve. In another embodiment, the first radiating arm includes a serpentine section extending in a first direction from the common conductor and an adjacent extension section extending in a second direction from the serpentine section.
A mobile communication device having a multiband monopole antenna includes a circuit board, a communication circuit, and a multiband monopole antenna. The circuit board includes an antenna feeding point and a ground plane. The communication circuit is coupled to the antenna feed point of the circuit board. The multiband monopole antenna includes a common conductor, a first radiating arm, and a second radiating arm. The common conductor includes a feed port coupled to the antenna feed point of the circuit board. The first radiating arm is coupled to the common conductor and includes a space filling curve. The second radiating arm is coupled to the common conductor. In one embodiment, the circuit board is mounted on a first plane in the mobile communication device and the multiband monopole antenna is mounted on a second plane in the mobile communication device.

  Reference is now made to the drawings. FIG. 1 is a top view of an example of a multiband monopole antenna 10 for a mobile communication device. The multiband monopole antenna 10 includes a first radiating arm 12 and a second radiating arm 14, both of which are coupled to a feed port 17 through a common conductor 16. The antenna 10 also includes a substrate material 18, such as a dielectric substrate, a flexible film substrate, or some other type of similar substrate material, on which the antenna structures 12, 14, 16 are fabricated. The antenna structures 12, 14, 16 are preferably patterned with a conductive material, such as a metal thick film paste that is printed and cured on the substrate material 18, but instead using other known fabrication techniques. May be produced.

  The first radiating arm 12 includes a meandering section 20 and an extension section 22. The meandering section 20 is connected to the common conductor 16 and extends away from it. The extension section 22 is adjacent to the meandering section 20 and extends in the opposite direction from the end of the meandering section 20 toward the common conductor 16. In the illustrated embodiment, the serpentine section 20 of the first radiating arm 12 is formed into a geometric shape known as a space-filling curve to reduce the overall size of the antenna 10. Has been. The space filling curve is formed by connecting at least 10 segments, and each segment forms an angle with an adjacent segment, that is, a large straight line segment is not formed by two adjacent segments. However, it goes without saying that the meandering section 20 may include a space filling curve other than that shown in FIG. 1, or may be arbitrarily arranged in an alternative meandering shape. For example, FIGS. 2-6 illustrate an antenna structure having meandering sections configured with several alternative shapes. Forming antenna structures using shape-filling curves is described in more detail in PCT application WO 01/54225, entitled Space-Filling Miniature Antennas, and the same owner as this application. The contents thereof are included in the present application by quoting here.

The second radiating arm 14 includes three straight portions. As shown in FIG. 1, the first straight portion extends in the vertical direction so as to be away from the common conductor 16. The second straight portion extends in the horizontal direction from the end of the first straight portion toward the first radiating arm. The third straight portion extends perpendicularly from the end of the second straight portion, in the same direction as the first straight portion, and adjacent to the serpentine section 20 of the first radiating arm 14.
As noted above, the common conductor 16 of the antenna 10 connects the feed port 17 to the first and second radiating arms 12, 14. The common conductor 16 extends horizontally (as viewed in FIG. 1) beyond the second radiating arm 14 and is vertical as shown in FIG. 10 to connect the feed port 17 to communication circuitry in the mobile communication device. It can also be bent in the direction (perpendicular to the drawing).

  In operation, the first and second radiating arms 12, 14 are each tuned to a different frequency band, resulting in a dual band antenna. The antenna 10 can be tuned to the desired dual band operating frequency of the mobile communication device by pre-selecting the total conductor length of each of the radiating arms 12,14. For example, the illustrated embodiment operates in one or more lower frequency bands, such as PDC (800 MHz), CDMA (800 MHz), GSM (850 MHz), GSM (900 MHz), PGS, or any other frequency band. As such, the first radiating arm 12 can be tuned. Similarly, such as GPS, PDC (1500 MHz), GSM (1800 MHz), Korean PCS, CDMA / PCS (1900 MHz), CDMA2000 / UMTS, IEEE 802.11 (2.4 GHz), or any other frequency band, 1 Alternatively, the second radiating arm 14 can be tuned to operate in multiple high frequency bands. It will be appreciated that in some embodiments, the lower frequency band of the first radiating arm 12 may overlap the frequency band of the second radiating arm 14 resulting in a wider single band. It will also be appreciated that the multiband antenna 10 may be extended to include additional frequency bands by adding additional radiating arms. For example, if a third radiating arm is added to the antenna 10, a three-band antenna can be formed.

  FIG. 2 is a top view of an example of a multiband monopole antenna 30 that includes one other space-filling shape. The antenna 30 shown in FIG. 2 is multiband similar to the multiband antenna 10 shown in FIG. 1, but the meandering section 32 in the first radiating arm 12 includes a space filling curve different from that shown in FIG. It is out.

  3-9 show several alternative multiband monopole antenna configurations 50, 70, 80, 90, 93, 95, 97. FIG. Similar to the antennas 10, 30 shown in FIGS. 1 and 2, the multiband monopole antenna 50 shown in FIG. 3 includes a common conductor 52 coupled to a first radiating arm 54 and a second radiating arm 56. The common conductor 52 includes a feed port 62 on a straight portion of the common conductor 52 that extends horizontally (when viewed in FIG. 3) away from the radiating arms 54, 56, and is connected to the mobile communication device. In order to connect the power supply port 62 to the communication circuit, it can also be bent in the vertical direction (perpendicular to the drawing).

The first radiating arm 54 includes a meandering section 58 and an extension section 60. The meandering section 58 is coupled to the common conductor 52 and extends away from it. The extension section 60 is adjacent to the meandering section 58 and has an arcuate path extending from the end of the meandering section 58 and returning toward the common conductor 52.
The second radiating arm 56 includes three straight portions. As shown in FIG. 3, the first linear portion extends diagonally from the common conductor 52. The second straight portion extends horizontally from the end of the first straight portion toward the first radiating arm. The third straight portion extends perpendicularly from the end of the second linear portion, away from the common conductor 52 and adjacent to the serpentine section 58 of the first radiating arm 54.

  The multi-band monopole antennas 70, 80, 90 shown in FIGS. 4-6 are similar to the antenna 50 shown in FIG. 3, but are respectively serpentine portions 72, 82, included in the first radiating arm 54, respectively. The 92 patterns are different. For example, the meandering portion 92 of the multiband antenna 90 shown in FIG. 6 has a space filling curve as described above. However, each of the serpentine portions 58, 72, 82 shown in FIGS. 3-5 includes different shaped periodic curves, which do not meet the requirements of the space filling curve.

  The multiband monopole antennas 93, 95, 97 shown in FIGS. 7-9 are the same as the antenna 30 shown in FIG. 2, but the additional regions 94, 96, 98 are formed in the straight portion 22 of the first radiating arm 12. It is different to be included. In FIG. 7, the extended portion 22 of the first radiating arm includes a polygonal portion 94. 8 and 9, the straight portion 22 of the first radiating arm 12 includes portions 96, 98 having arcuate longitudinal edges.

  FIG. 10 is a top view illustrating an embodiment 100 of the mobile communication device circuit board 102 coupled to the multiband monopole antenna 10 of FIG. The circuit board 102 includes a feeding point 104 and a ground plane 106. The ground plane 106 may be disposed on one of the surfaces of the circuit board 102 or may be a single layer of a multilayer printed circuit board, for example. Feed point 104 is, for example, a metal bonding pad and is coupled to circuit trace 105 on one or more layers of circuit board 102. As shown, the communication circuit 108 is connected to the feeding point 104. The communication circuit 108 is, for example, a multiband transmission / reception circuit, and is connected to the feeding point 104 through a circuit trace 105 on a circuit board.

  In order to reduce electromagnetic interference from the ground plane 106, the antenna 10 is placed in the mobile communications device so that the projection of the antenna footprint on the circuit board 102 intersects the metallization of the ground plane 106 at less than 50%. Implemented. In the illustrated embodiment 100, the antenna 10 is mounted above the circuit board 102. That is, the circuit board 102 is mounted on the first surface, and the antenna 10 is mounted on the second surface of the mobile communication device. In addition, the antenna 10 is offset laterally from the edge of the circuit board 102, and in this embodiment 100, the projection of the antenna footprint onto the circuit board 102 does not completely intersect the ground plane 106 metallization. I try not to.

  In order to further reduce electromagnetic interference from the ground plane 106, the feeding point 104 is disposed at a position on the circuit board 102 adjacent to the corner of the ground plane 106. Preferably, when the antenna 10 is coupled to the feeding point 104, a part of the common conductor 16 is bent vertically toward the surface of the circuit board 102, and the feeding port 17 of the antenna 10 is connected to the feeding point 104 of the circuit board 102. Connect to. The feed port 17 of the antenna 10 is coupled to the feed point 104 by, for example, using a commercially available connector, by joining the feed port 17 directly to the feed point 104, or by any other suitable coupling means. Can do. However, in another embodiment, the feed port 17 of the antenna 10 may be coupled to the feed point 104 by some means other than bending the common conductor 16.

FIG. 11 shows an example of a mounting structure 111 for fixing a multiband monopole antenna 112 in a mobile communication device. The illustrated embodiment 110 uses a multiband monopole antenna 112 having a serpentine section similar to that shown in FIG. However, it will be appreciated that other multiband monopole antenna configurations such as those described with respect to FIGS. 1-9 may be used.
The mounting structure 111 includes a flat surface 113 and at least one protruding section 114. The antenna 112 is preferably fixed to the flat surface 113 of the mounting structure 111 using an adhesive. For example, the antenna 112 can be formed on a soft film substrate, and has a peelable adhesive on the surface of the substrate opposite to the antenna structure. With the antenna 112 secured to the mounting structure 111, the mounting structure 111 is positioned in the mobile communication device such that the protruding section 114 extends beyond the circuit board. The mounting structure 111 and the antenna 112 can then be secured to the circuit board and the housing of the mobile communication device using one or more openings 116, 117 in the mounting structure 111.

  FIG. 12 is an exploded view of an example of a clamshell cellular telephone 120 having a multiband monopole antenna 121. The cellular telephone 120 includes a lower circuit board 122, an upper circuit board 124, and a multiband antenna 121 secured to the mounting structure 110. Further, the upper housing 128 and the lower housing 130 house the circuit boards 122 and 124 and the antenna 121 when combined. The illustrated multiband monopole antenna 121 is the same as the multiband antenna 30 shown in FIG. However, it will be appreciated that alternative antenna configurations such as those described above with reference to FIGS.

  The lower circuit board 122 is the same as the circuit board 102 described with reference to FIG. 10, and includes a ground plane 106, a feeding point 104, and a communication circuit 108. As described above with reference to FIGS. 10 and 11, the multiband antenna 121 is fixed to the mounting structure 110 and coupled to the lower circuit board 122. Further, the lower circuit board 122 is connected to the upper circuit board 124 by a hinge 126 so that the upper and lower circuit boards 122, 124 can be folded together in a manner typical of clamshell cellular phones. It can be done. In order to further reduce electromagnetic interference from the upper and lower circuit boards 122, 124, the multiband antenna 121 is preferably mounted on the lower circuit board 122 adjacent to the hinge 126.

FIG. 13 is an exploded view of an example of a candy bar type cellular telephone 200 having a multiband monopole antenna 201. The cellular telephone 200 includes a multiband monopole antenna 201, a circuit board 214, and upper and lower housings 220 and 222 that are fixed to the mounting structure 110. The circuit board 214 is similar to the circuit board 102 described above with reference to FIG. 10, and includes the ground plane 106, the feeding point 104, and the communication circuit 108. The illustrated antenna 201 is similar to the multiband monopole antenna shown in FIG. 3, but the alternative antenna configuration described above with reference to FIGS. 1-9 can also be used.
As described above with reference to FIGS. 10 and 11, the multiband antenna 201 is fixed to the mounting structure 110 and connected to the circuit board 214. Next, the upper and lower housings 220 and 222 are combined to seal the antenna 212 and the circuit board 214.

  FIG. 14 is an exploded view of an example of a personal digital assistant (PDA) 230 having a multiband monopole antenna 231. The PDA 230 includes a multiband monopole antenna 231, a circuit board 236, and upper and lower housings 242 and 244 fixed to the mounting structure 110. The PDA circuit board 236 has a different shape but is similar to the circuit board 102 described above with reference to FIG. 10 and includes a ground plane 106, a feeding point 104, and a communication circuit 108. The illustrated antenna 231 is similar to the multiband monopole antenna shown in FIG. 5, but the alternative antenna configuration described above with reference to FIGS. 1 to 9 can also be used.

  The multiband antenna 231 is fixed to the mounting structure 110 and coupled to the circuit board 214 as described above with reference to FIGS. 10 and 11. However, slightly different from FIG. 10, the PDA circuit board 236 defines an L-shaped slot along the edge of the circuit board 236, and the antenna 231 and the mounting structure 110 are fixed in the slot so that the space inside the PDA 230 is fixed. Is unnecessary. After fixing, the upper and lower housings 242 and 244 are joined together, and the antenna 231 and the circuit board 236 are sealed.

  The description set forth herein is given by way of example to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art.

It is a top view of an example of the multiband monopole antenna for mobile communication devices. It is a top view of an example of a multiband monopole antenna including one alternating space filling shape. An alternative multiband monopole antenna configuration is shown. An alternative multiband monopole antenna configuration is shown. An alternative multiband monopole antenna configuration is shown. An alternative multiband monopole antenna configuration is shown. An alternative multiband monopole antenna configuration is shown. An alternative multiband monopole antenna configuration is shown. An alternative multiband monopole antenna configuration is shown. FIG. 2 is a top view of an example of the multiband monopole antenna of FIG. 1 coupled to a mobile communication device circuit board. 1 shows an example of a mounting structure in which a multiband monopole antenna is fixed inside a mobile communication device. FIG. 3 is an exploded view of an example of a clamshell cellular telephone having a multiband monopole antenna. It is an exploded view of an example of a candy bar-shaped cellular telephone having a multiband monopole antenna. 1 is an exploded view of an example of a personal digital assistant (PDA) having a multiband monopole antenna. FIG.

Claims (13)

In mobile communication devices,
A circuit board having an antenna feed point and a ground plane;
A communication circuit coupled to an antenna feed point of the circuit board;
A multiband antenna,
A common conductor having a feed port coupling the antenna to a communication circuit of the mobile communication device;
A first radiating arm coupled to the common conductor;
And an antenna having a second radiating arm coupled to the common conductor, wherein the projection of the antenna footprint onto the circuit board is set so as not to overlap more than 50% with the metallization of the ground plane. A mobile communication device. The mobile communication device according to claim 1, wherein the circuit board is mounted in a first plane. The mobile communication device according to claim 1, wherein the antenna is shifted laterally from an edge of the ground plane. The mobile communication device according to claim 1, wherein the feeding point is mounted at a position adjacent to a corner of the ground plane. 2. The mobile communication device according to claim 1, wherein the antenna is fixed to a mounting mechanism, and the mounting mechanism is fixed to the circuit board or the housing of the mobile communication device using one or a plurality of openings. A mobile communication device characterized by the above. A clamshell type multi-band mobile communication device,
An upper circuit board;
A lower circuit board including a ground plane, a feeding point and a multiband communication circuit device;
A hinge connecting the lower circuit board to the upper circuit board so that the two circuit boards can be folded together;
A multiband antenna,
A first radiating arm coupled to a common conductor;
A mobile communication device comprising: an antenna having a second radiating arm coupled to the common conductor and mounted on the lower circuit board adjacent to the hinge. The mobile communication device of claim 6, further comprising:
An upper housing containing the upper circuit board;
A lower housing that encloses the lower circuit board, and the antenna is enclosed in the upper and lower housings, and the housing and the upper and lower circuit boards are folded together to form a clamshell configuration. A mobile communication device configured to be in an overlapping state. 7. The mobile communication device according to claim 6, wherein the projection of the footprint of the antenna onto the plane of the lower circuit board is set so as not to overlap 50% or more with the metallization of the ground plane. Mobile communication device A clamshell type multi-band mobile communication device,
An upper circuit board;
A lower circuit board including a ground plane, a feeding point and a communication circuit device;
A multi-band antenna coupled to the communication circuit and mounted on the lower circuit board, the common conductor connected to the feed point to couple the antenna to the communication circuit device of the mobile communication device An antenna with
A first radiating arm and a second radiating arm coupled to the common conductor;
Upper and lower housings hinged to each other, the housings including the upper circuit board and the lower circuit board, respectively, and the antenna, the housings, the upper and lower circuit boards, Comprises upper and lower housings configured to be folded so as to have a clamshell configuration and to be extended to provide a communication configuration, wherein the lower circuit board is the upper circuit A mobile communication device hinged to a board, wherein the upper and lower circuit boards are configured to be folded so as to be in a closed position. 10. The mobile communication device according to claim 9, wherein the projection of the antenna footprint onto the plane of the lower circuit board is set so as not to overlap 50% or more with the metallization of the ground plane. Mobile communication device The mobile communication device according to claim 9, wherein the antenna is shifted laterally from an edge of the ground plane. 10. The mobile communication device according to claim 9, wherein the antenna is fixed to a mounting mechanism, and the mounting mechanism is fixed to the circuit board or the housing of the mobile communication device using one or a plurality of openings. A mobile communication device characterized by the above. The mobile communication device according to claim 9, wherein the antenna is mounted on the lower circuit board adjacent to the hinge.

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