JP2009153076A - Wireless lan antenna and radio communications apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless LAN antenna which can obtain an input characteristic matched in wideband and non-directional radiation characteristics, can be bent in a planar structure and can also be mounted in a narrow space of a radio communications apparatus. <P>SOLUTION: The wireless LAN antenna includes: a ground; a meandering arm, extending in parallel with an edge of the ground while being bent into a meandering shape; and a linear arm extending in parallel with the edge of the ground with a tip end folded to connect to the meandering arm. A radio wave of a first frequency band is radiated by the radiation antenna as a whole, constituted of the meander arm and the linear arm, and a radio wave of a second frequency band is radiated by the meander arm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wireless LAN antenna that can be used with 2.4 / 5 GHz. By using this antenna, a 2.4 GHz band (2.4 to 2.4835 GHz) used in a wireless LAN (IEEE802.11a / b / g; see Non-Patent Document 1) or Bluetooth (see Non-Patent Document 2). And 5 GHz (5.15 to 5.875 GHz) can be transmitted and received efficiently in two frequency bands.

Many antennas that can be used at 2.4 / 5 GHz have been proposed. A structure in which a semicircular slot antenna is cut (see Non-Patent Document 3), and a planar inverted-F antenna (hereinafter referred to as PIFA) (Non-Patent Documents 4 and 5) And a dipole antenna having a radiating arm having a meandering strip (see Non-Patent Document 6).
http://www.ieee802.org/11 http://www.bluetooth.com/bluethooth/ HM. Hsiao, JW. Wu, JH. Lu, and YD. Wang, “A novel dual-broadband semi-circle slot antenna for wireless communication,” IEEE AP-S int. Symp., Pp. 385-388, 2007 HS Yoon and SO Park, “A dual-band internal antenna of PIFA type for Bluetooth / WLAN in mobile handsets,” IEEE AP-S Int. Symp., Pp. 665-668, 2007 YS Shin and SO Park, “A novel PIFA for 2.4 and 5 GHz WLAN application,” IEEE AP-S Int. Symp., Pp. 645-648, 2007 SH. Yeh, WC. Yang and WK. Su, “2.4 / 5.2 GHz WLAN unequal-arms dipole antenna with a meandered strip for omni-direcctional radiation patterns,” IEEE AP-S Int. Symp., Pp. 649-652, 2007

However, the conventional techniques disclosed in Non-Patent Documents 3 to 6 have the following problems.
The semicircular slot antenna disclosed in Non-Patent Document 3 has good input characteristics, but requires a large ground and is difficult to reduce in size.
The PIFAs disclosed in Non-Patent Documents 4 and 5 also use a large ground plate in the same manner as the semicircular slot antenna, and the radiation pattern changes greatly in both frequency bands, and the omnidirectionality is lost.
Although the dipole antenna disclosed in Non-Patent Document 6 does not require a ground, it requires a very long radiating arm, and there is a problem that the size becomes large.

  The present invention has been made in view of the above circumstances, and can obtain input characteristics that match in a wide band and almost non-directional radiation characteristics, can be bent with a planar structure, and can be mounted in a narrow space of a wireless communication device. An object is to provide a LAN antenna.

  In order to achieve the above object, the present invention provides a ground, a meandering arm extending in a direction parallel to the edge of the ground while being bent in a meander shape, and extending in parallel with the edge of the ground. A linear arm connected to the meander arm, and radiates radio waves in the first frequency band with the entire radiation arm composed of the meander arm and the linear arm, and the meander arm has a second arm. Provided is a wireless LAN antenna that radiates radio waves in a frequency band.

In the wireless LAN antenna of the present invention, it is preferable that the wireless LAN antenna has a planar structure, and an area including the ground and the radiation arm is 30 × 18 mm ² or less.

  In the wireless LAN antenna of the present invention, it is preferable that the wireless LAN antenna is made of a metal film or FPC and has flexibility.

  In the wireless LAN antenna of the present invention, it is preferable that a coaxial cable for power feeding arranged in a direction parallel to or intersecting with the linear arm is connected to the linear arm.

  The wireless LAN antenna according to the present invention has an input characteristic in which VSWR is 2 or less in both frequency bands of 2.4 to 2.4835 GHz and 4.9 to 5.9 GHz when the system characteristic impedance is 50Ω. It is preferable.

  In the wireless LAN antenna of the present invention, when the system characteristic impedance is 50 Ω, the bandwidth at which the VSWR is 2 or less at 2.4 GHz is 4.5% or more, and the input characteristic at which the bandwidth is 26% or more at 5 GHz. It is preferable to have.

In the wireless LAN antenna of the present invention, it is preferable that the directivity index _nd is 0.3 or less in the 2.4 GHz band and 0.9 or less in the 5 GHz band in an arbitrary horizontal plane.

  The present invention also provides a wireless communication device comprising the wireless LAN antenna according to the present invention described above.

  In the wireless communication apparatus of the present invention, it is preferable that a planar wireless LAN antenna is attached to a planar portion of the wireless communication apparatus.

  In the wireless communication device of the present invention, the wireless LAN antenna may be deformed into an L shape or a U shape, or may be deformed according to the shape of the antenna installation position of the wireless communication device and attached to the wireless communication device.

  The wireless communication device of the present invention is preferably one type selected from the group consisting of a personal computer, a car navigator, a mobile phone, and a portable game machine.

The wireless LAN antenna according to the present invention includes a ground, a meander arm, and a straight arm that extends in parallel with the edge of the ground and has a tip bent and connected to the meander arm. And the linear arm radiate the first frequency band of the radio wave and the meander arm radiate the second frequency band of the radio LAN (IEEE802.11a). / B / g) and 2.4 GHz band (2.4 to 2.4835 GHz) and 5 GHz (5.15 to 5.875 GHz) used in Bluetooth can efficiently transmit and receive radio signals.
The wireless LAN antenna of the present invention can realize a wide-band matching input characteristic and a substantially omnidirectional radiation characteristic by combining a linear arm and a meandering arm provided in a direction crossing the linear arm. .
Further, the wireless LAN antenna of the present invention has a planar structure and can be easily deformed if it is made of a metal film, FPC, or the like, and the antenna can be mounted in a narrow space of the wireless communication device.

  As described above, the wireless communication apparatus of the present invention can obtain input characteristics that match in a wide band and almost non-directional radiation characteristics, can be bent in a planar structure, and can be mounted in a narrow space of the wireless communication apparatus. Since the wireless LAN antenna is provided, the antenna can be miniaturized and the size of the apparatus can be further reduced and made thinner as compared with the case where the antenna of the prior art is mounted.

  First, in order to realize use of a plurality of bands, an antenna having a radiating element as a meander will be described in detail based on the following reference example.

  FIG. 1 is a plan view showing an antenna structure of Reference Example 1. FIG. The antenna of Reference Example 1 has a ground 1 and a radiating arm 2 connected to one end of the antenna. The radiating arm 2 extends from one end of the ground 1 along the edge, and after being bent once, remains as it is. It has a shape that extends horizontally. A short pin 3 and a feeding point 4 are provided at the boundary between the ground 1 and the radiating arm 2. The dimensions a to e of this antenna are a = 18 mm, b = 17 mm, c = 8 mm, d = 2 mm, and e = 31 mm.

  The length of the radiation arm 2 is adjusted so that the radiation input characteristic of the antenna of the reference example 1 can be matched in the first frequency band (2.4 to 2.4835 GHz). Further, the position of the antenna feeding point 4 and the short pin 3 and the ground 1 are formed as in the dimensions a to e so that the antenna is small. A structure in which the radiating arm 2 is bent and then extended as in the antenna of the reference example 1 has a drawback that the radiating arm 2 becomes large.

  FIG. 2 shows a voltage standing wave ratio (VSWR) representing the input characteristics obtained with the antenna of the first reference example. However, the characteristic impedance of the system is 50Ω (hereinafter, this is the same as this example unless otherwise indicated). As shown in FIG. 2, in this antenna, the bands where VSWR ≦ 2 are 2.32 to 2.44 GHz (bandwidth BW is 5.0%) and 4.97 to 5.69 GHz (bandwidth BW is 13.5). %). Here, the bandwidth BW is defined by the following equation (1):

Here, f _l and f _h are the minimum and maximum frequencies in the band, respectively.
As described above, the structure of the reference example 1 cannot cover all the second frequency band (4.9 to 5.9 GHz capable of covering IEEE 802.11 with a margin).

4 and 5 show the radiation patterns on the xy plane at the center frequencies of the first and second frequency bands, 2.45 GHz and 5.4 GHz, in the antenna of Reference Example 1, respectively. 4 and 5 are created using the polar coordinates shown in FIG. 3 (the same applies to the following diagrams showing the radiation patterns). In this type of antenna, the omnidirectional xy plane is desired, the directivity of the antenna is assessed using a directional indicator n _d defined by the following equation (2):

However, G _max and G _min are the maximum and minimum values of the gain for all fields (E _total in the figure), and the unit is a true value. A large value indicates that the radiation characteristic is distorted, and n _d = 0 represents omnidirectionality.
At 2.45 GHz, G _min = −0.76 dBi, G _max = 1.92 dBi, n _d = 0.60,
At 5.40 GHz, G _min = −2.04 dBi, G _max = 3.30 dBi, n _d = 1.10.

  6 is a plan view showing an antenna of Reference Example 2. FIG. The antenna of the reference example 2 has a ground 1 and a radiating arm 2 connected to one end of the antenna. The radiating arm 2 extends from one end of the ground 1 along the edge, and then bends and extends. It has a shape that extends vertically again. A short pin 3 and a feeding point 4 are provided at the boundary between the ground 1 and the radiating arm 2. The dimensions a to e of this antenna are a = 18 mm, b = 17 mm, c = 8 mm, d = 2 mm, and e = 12 mm.

  The length of the radiation arm is adjusted so that the radiation input characteristic of the antenna of the reference example 2 can be matched in the first frequency band. Further, the position of the antenna feeding point 4 and the short pin 3 and the ground 1 are formed as in the dimensions a to e so that the antenna is small. The antenna of the reference example 2 has a drawback that the installation space for the antenna becomes large as the radiation arm 2 extends upward.

  FIG. 7 shows the VSWR obtained with the antenna of Reference Example 2. As shown in FIG. 7, the bands where VSWR ≦ 2 are 2.30 to 2.42 GHz (BW = 5.1%) and 4.88 to 5.50 GHz (BW = 11.9%). Thus, the structure of the reference example 2 cannot cover the entire second frequency band.

FIGS. 8 and 9 show radiation patterns on the xy plane at the center frequencies of the first and second frequency bands, 2.45 GHz and 5.4 GHz, in the antenna of Reference Example 2, respectively.
At 2.45 GHz, G _min = 0.97 dBi, G _max = 2.11 dBi, n _d = 0.26,
At 5.40 GHz, G _min = −2.02 dBi, G _max = 1.92 dBi, n _d = 0.85.

  As a structure for miniaturizing the antenna, the radiation arm 2 may be formed in a meander shape like the antenna of Reference Example 3 shown in FIG. The length of the radiation arm 2 is adjusted so that the radiation input characteristics of the antenna of the reference example 3 can be matched in the first frequency band. Also, the antenna feeding point 4, the short pin 3, and the ground 1 have dimensions a to f of a = 18 mm, b = 17 mm, c = 8 mm, d = 2 mm, f = It is set to 3 mm.

  FIG. 11 shows the VSWR obtained with the antenna of Reference Example 3. As shown in FIG. 11, the bands where VSWR ≦ 2 are 2.28 to 2.42 GHz (BW = 6.0%) and 4.48 to 4.66 GHz (BW = 3.9%). It can be seen that the bandwidth of the frequency band is narrow.

12 and 13 show the radiation patterns on the xy plane at 2.45 GHz and 5.4 GHz, which are the center frequencies of the first and second frequency bands, in the antenna of Reference Example 3, respectively.
At 2.45 GHz, G _min = 0.93 dBi, G _max = 1.83 dBi, n _d = 0.21,
At 5.40 GHz, G _min = −5.99 dBi, G _max = 2.25 dBi, n _d = 1.48.
In particular, it can be seen that the radiation pattern is distorted in the second frequency band.

  An antenna in a wireless LAN is required to be usable in two frequency bands, and in particular, a wide band is required in the 5 GHz band. When an antenna is installed in a mobile radio apparatus, it is desirable that the antenna is as small as possible and has a high gain. Furthermore, the radiation characteristics are required to be as omni as possible.

  In order to meet these requirements, the present invention provides a ground, a meandering arm that extends in a direction parallel to the edge of the ground while bending in a meander shape, and extends in parallel with the edge of the ground, with its tip bent. A linear arm connected to the meander arm, and radiates a radio wave of a first frequency band by the entire radiation arm composed of the meander arm and the linear arm, and the second meander arm Provided is a wireless LAN antenna characterized by radiating radio waves in the frequency band.

  FIG. 14 is a plan view showing one embodiment of a wireless LAN antenna (hereinafter abbreviated as an antenna) according to the present invention. The basic structure of the antenna 11 of this embodiment is a PIFA. As shown in FIG. 14, a feeding point 4 is provided between the ground 1 and the radiating arm 11A, and between the ground 1 and the radiating arm 11A in the vicinity thereof. A short bin 3 for short-circuiting is installed. The radiating arm 11 </ b> A includes a linear arm 6 that is linearly arranged substantially parallel to the edge of the ground 1 and a meandering arm 5 that is connected to the linear arm 6. The meandering arm 5 is bent at the tip of the straight arm 6 and then extends in a meander shape in which peaks and valleys are alternately connected along the straight arm 6.

The entire radiation arm 11A composed of the straight arm 6 and the meander arm 5 contributes to the operation of the first frequency band having a low frequency. The total length of time radiating arms 11A are substantially the λ _1/4. Where λ ₁ is the wavelength of the free space of the electromagnetic wave at the center frequency of the first frequency band. Also, if there is a dielectric in the vicinity of the radial arm 11A, the wavelength is shortened, in which case, lambda ₁ is a shortened wavelength.

In the antenna 11, the meandering arm 5 is bent at the tip of the linear arm 6, so that the second operating frequency is greatly shifted to the lower frequency side compared to the second operating frequency when not bent. The Thereby, multi-frequency use of 2.4 / 5 GHz becomes possible. That, if meandering arm 5 has not been folded once in the previous straight arm 6, the operating frequency f ₂ of the second is about 3 times the first operating frequency f _1. Therefore, if f ₁ = 2.4 GHz, f ₂ = 7.2 GHz, and the purpose of using in two frequency bands of 2.4 / 5 GHz cannot be achieved. However, simply bending the radiation arm extending beyond the straight arm cannot satisfy the use of the 2.4 / 5 GHz two-frequency band required for wireless LAN. In that case, it is difficult not only to shift the center frequency but also to adjust the frequency band. It is also difficult to match the radiation characteristics at each frequency used so that they are almost non-directional. In the present invention, by bending the tip of the linear arm 6 and connecting the meandering arm 5 therewith, not only can the antenna 11 be adjusted so as to achieve matching in a desired frequency band, but the radiation characteristics are almost non-directional. It becomes possible to adjust so that it may become. Moreover, the antenna 11 can be reduced in size by doing so.

The second operating frequency is determined by the degree of coupling between the linear arm 6 and the meandering arm 5. The meandering arm 5 can freely change the length (l _j ) and the approaching distance (d _i ) of the portion approaching the linear arm 6, so that the degree of coupling with the linear arm 6 can be adjusted. . Further, since the meandering arm 5 can change the position of the current distribution contributing to radiation, the directivity of the radiation characteristic can be adjusted. In the present invention, by using a structure in which the linear arm 6 and the meandering arm 5 are combined, desired characteristics that can use LAN and Bluetooth are realized.

In a preferred embodiment of the present invention, the antenna 11 desirably has the following characteristics.
(1) It has an input characteristic that VSWR is 2 or less in both frequency bands of 2.4 to 2.4835 GHz and 4.9 to 5.9 GHz.
(2) It has an input characteristic that the bandwidth at which VSWR is 2 or less at 2.4 GHz is 4.5% or more and the bandwidth is 26% or more at 5 GHz.
(3) In any horizontal plane, the directivity index _nd is 0.3 or less in the 2.4 GHz band and has a directivity of 0.9 or less in the 5 GHz band.
By having the characteristics (1) to (3), the 2.4 GHz band (2.4 to 2.4835 GHz) and 5 GHz (5. 5) used in the wireless LAN (IEEE802.11a / b / g) or Bluetooth. Radio signals can be efficiently transmitted and received in two frequency bands of 15 to 5.875 GHz.

  An antenna having a 15 μm thick copper foil on a polyimide substrate and having a planar shape as shown in FIG. 15 was produced. This antenna has a ground 1, a meandering arm 5, and a straight arm 6 that extends in parallel with the edge of the ground 1 and whose front end is bent and connected to the meandering arm 5. And a part of the ground 1 are connected via a short pin 3, and a feeding point 4 is provided at the center of the linear arm 6 and the ground 1 in the vicinity thereof. In this embodiment, the tip of the straight arm 6 is bent at a right angle and extends upward, and one end of the meander arm 5 is connected to the middle. Dimensions a to g shown in FIG. 15 are a = 18 mm, b = 18 mm, c = 6 mm, d = 2 mm, e = 3 mm, f = 4 mm, and g = 5 mm.

  In the antenna of the present embodiment, the length of the radiation arm 11A is adjusted so that the radiation input characteristics are matched in the first frequency band (2.4 to 2.4835 GHz). Further, the positions of the feeding point 4 and the short pin 3 of the antenna and the size of the ground 1 are set to the illustrated dimensions a to g so that the antenna is small. The meandering arm 5 is adjusted so that the input characteristics can be matched in the second frequency band (4.9 to 5.9 GHz) and the radiation characteristics are omnidirectional.

  In the antenna of this example, VSWR was measured. The result is shown in FIG. As shown in FIG. 16, the bands where VSWR ≦ 2 are 2.37 to 2.53 GHz (BW = 6.5%) and 4.73 to 6.16 GHz (BW = 26.3%). In particular, the second frequency band has a wide bandwidth.

FIGS. 17 and 18 show the radiation characteristics of the xy plane at the center frequencies of the first and second bands, 2.45 GHz and 5.4 GHz, respectively.
At 2.45 GHz, G _min = 1.79 dBi, G _max = 2.59 dBi, n _d = 0.18,
At 5.40 GHz, G _min = −0.55 dBi, G _max = 2.81 dBi, n _d = 0.74.
Thus, it was found that the antenna of this example has good omnidirectionality in any frequency band.

  An antenna made of a copper foil having a thickness of 15 μm on a polyimide substrate and having a planar shape shown in FIG. 19 was produced. This antenna has a ground 1, a meandering arm 5, and a straight arm 6 that extends in parallel with the edge of the ground 1 and whose front end is bent and connected to the meandering arm 5. And a part of the ground 1 are connected via a short pin 3, and a feeding point 4 is provided at the center of the linear arm 6 and the ground 1 in the vicinity thereof. In this embodiment, the tip of the straight arm 6 is bent at a right angle and extends upward, and one end of the meandering arm 5 is connected to the tip. The dimensions a to g shown in FIG. 19 are a = 18 mm, b = 18 mm, c = 6 mm, d = 2 mm, e = 3 mm, f = 4 mm, and g = 5 mm. Compared to the first embodiment, the size of the entire antenna is further reduced.

  In the antenna of the present embodiment, the length of the radiation arm 11A is adjusted so that the radiation input characteristics are matched in the first frequency band (2.4 to 2.4835 GHz). Further, the positions of the feeding point 4 and the short pin 3 of the antenna and the size of the ground 1 are set to the illustrated dimensions a to g so that the antenna is small. The meandering arm 5 is adjusted so that the input characteristics can be matched in the second frequency band (4.9 to 5.9 GHz) and the radiation characteristics are omnidirectional.

  In the antenna of this example, VSWR was measured. The result is shown in FIG. As shown in FIG. 20, the bands where VSWR ≦ 2 are 2.37 to 2.48 GHz (BW = 4.5%) and 4.72 to 6.13 GHz (BW = 26.0%). In particular, the second frequency band has a wide bandwidth.

FIGS. 21 and 22 show the radiation characteristics of the xy plane at the center frequencies of the first and second bands, 2.45 GHz and 5.4 GHz, respectively.
At 2.45 GHz, G _min = 1.48 dBi, G _max = 2.33 dBi, n _d = 0.20,
At 5.40 GHz, G _min = −0.56 dBi, G _max = 3.16 dBi, n _d = 0.81.
Thus, it was found that the antenna of this example has good omnidirectionality in any frequency band.

  The antenna 11 of the present invention can be fed by connecting a coaxial cable to the feeding point 4. FIG. 23 is a diagram illustrating a first example of coaxial cable connection. In this example, the coaxial cable 7 is arranged in a direction orthogonal to the longitudinal direction of the linear arm 6, and the conductor of the coaxial cable 7 is connected to the feeding point 4. In this case, the outer conductor 9 of the coaxial cable 7 is connected to the ground 1 and the inner conductor 8 is connected to the linear arm 6 of the radiating arm 11A through the connection area 10, respectively.

  FIG. 24 is a diagram illustrating a second example of coaxial cable connection. In this example, the coaxial cable 7 is arranged in parallel with the longitudinal direction of the linear arm 5, and the conductor of the coaxial cable 7 is connected to the feeding point 4. In this case, a space can be provided in the ground 1 and the straight arm 6 so that the coaxial cable 7 can be easily connected to the antenna 11. If the structure of the feeding point 4 is devised, the outer conductor 9 of the coaxial cable 7 can be connected to the radiation arm 11A side, and the inner conductor 8 can be connected to the ground 1 side. The coaxial cable 7 can supply power from either the left or right direction.

Since the antenna 11 according to the present invention has a planar structure and is thin and small, it can be mounted on various wireless communication devices.
FIG. 25 is a conceptual diagram when the antenna 11 according to the present invention is mounted on the display 14 of the notebook PC 12 which is an example of a personal computer. In the figure, reference numeral 12 wave and PC, 13 is a keyboard, and 14 is a display. In this example, the antenna 11 is mounted on the back side of the display 14, but the antenna 11 is normally mounted near the edge of the display 14 in order to reduce the influence of the metal plate on the back side of the display 14 on the antenna 11. . Further, if necessary, a plurality of antennas 11 can be simultaneously mounted on the same device. In addition to the notebook PC 12, it can be mounted on a display for a desktop PC or a television.

  FIG. 26 is a conceptual diagram in which the antenna 11 according to the present invention is mounted on the car navigator 15. As illustrated, the antenna 11 is desirably mounted on the side surface of the car navigator 15 near the display 16.

  The antenna 11 according to the present invention has a planar structure including the ground 1 and can be manufactured using a thin metal film or a flexible printed circuit (FPC). In that case, the antenna 11 can be mounted by being deformed according to the mounting position of the device. FIG. 27 shows a state in which the antenna 11 is bent in an L shape and mounted on the corner of the device 17. In that case, it is desirable not to deform the radiation arm 11A and the feeding portion of the antenna 11, as shown.

  In addition, as shown in FIG. 28, the antenna 11 can be bent in a U shape and mounted on a part of the device 18 in a bowl shape. In this case, it is desirable not to deform the feeding portion of the antenna 11 as shown.

6 is a plan view of the antenna of Reference Example 1. FIG. 10 is a graph showing the input characteristics (VSWR) of the antenna of Reference Example 1. It is a figure which shows the polar coordinate at the time of measuring the radiation characteristic of an antenna. 4 is a graph showing radiation characteristics on the xy plane at 2.45 GHz of the antenna of Reference Example 1. 4 is a graph showing radiation characteristics on the xy plane at 5.4 GHz of the antenna of Reference Example 1. 10 is a plan view of an antenna of Reference Example 2. FIG. 10 is a graph showing input characteristics (VSWR) of an antenna of Reference Example 2. 5 is a graph showing radiation characteristics on the xy plane at 2.45 GHz of the antenna of Reference Example 2. 10 is a graph showing the radiation characteristics of the antenna of Reference Example 2 on the xy plane at 5.4 GHz. 10 is a plan view of an antenna of Reference Example 3. FIG. 10 is a graph showing input characteristics (VSWR) of an antenna of Reference Example 3. 10 is a graph showing the radiation characteristics of the antenna of Reference Example 3 on the xy plane at 2.45 GHz. 10 is a graph showing the radiation characteristics of the antenna of Reference Example 3 on the xy plane at 5.4 GHz. It is a top view which shows one Embodiment of the antenna of this invention. 1 is a plan view of an antenna of Example 1. FIG. 4 is a graph showing input characteristics (VSWR) of the antenna of Example 1. 6 is a graph showing radiation characteristics on the xy plane at 2.45 GHz of the antenna of Example 1. FIG. 6 is a graph showing radiation characteristics on the xy plane at 5.4 GHz of the antenna of Example 1. 6 is a plan view of an antenna according to Embodiment 2. FIG. It is a graph which shows the input characteristic (VSWR) of the antenna of Example 2. It is a graph which shows the radiation characteristic of xy surface in 2.45 GHz of the antenna of Example 2. FIG. It is a graph which shows the radiation | emission characteristic of the xy plane in the antenna of Example 2 in 5.4 GHz. 6 is a plan view showing a first example of coaxial cable connection to an antenna in Example 3. FIG. 10 is a plan view showing a second example of coaxial cable connection to an antenna in Example 3. FIG. FIG. 10 is a perspective view illustrating a state where an antenna is mounted on a notebook PC according to a fourth embodiment. It is a perspective view which shows the mounting state of the antenna to the car navigator in Example 4. FIG. It is a perspective view which shows the mounting state to the device of the antenna bent in the L shape in Example 5. FIG. It is a perspective view which shows the mounting state to the device of the antenna bent in the U shape in Example 5. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Ground, 2 ... Radiation arm, 3 ... Short pin, 4 ... Feeding point, 5 ... Meander arm, 6 ... Linear arm, 7 ... Coaxial cable, 8 ... Internal conductor, 9 ... External conductor, 10 ... Connection area 11 ... Antenna, 11A ... Radiation arm, 12 ... Laptop, 13 ... Keyboard, 14 ... Display, 15 ... Car navigator, 16 ... Display, 17 ... Device, 18 ... Device.

Claims (11)

  A ground, a meander-shaped arm extending in a direction parallel to the edge of the ground while being bent in a meander shape, and a linear arm extending in parallel to the edge of the ground and bent at a tip thereof and connected to the meander-shaped arm. A radiation arm of the first frequency band is radiated by the entire radiation arm including the meander arm and the linear arm, and a radio wave of the second frequency band is radiated by the meander arm. Wireless LAN antenna. 2. The wireless LAN antenna according to claim 1, wherein the wireless LAN antenna has a planar structure, and an area including the ground and the radiation arm is 30 × 18 mm ² or less.   The wireless LAN antenna according to claim 1 or 2, wherein the wireless LAN antenna is made of a metal film or FPC and has flexibility.   The wireless LAN antenna according to any one of claims 1 to 3, wherein a power supply coaxial cable is connected to the linear arm in a direction parallel to or intersecting with the linear arm. .   The system has an input characteristic in which VSWR is 2 or less in both frequency bands of 2.4 to 2.4835 GHz and 4.9 to 5.9 GHz when the system characteristic impedance is 50Ω. 5. The wireless LAN antenna according to any one of 4 above.   The system has an input characteristic in which when the system characteristic impedance is 50Ω, the bandwidth at which VSWR is 2 or less at 2.4 GHz is 4.5% or more, and the bandwidth at 26 GHz is 26% or more at 5 GHz. The antenna for wireless LAN in any one of 1-5. The directivity index _nd is not more than 0.3 in the 2.4 GHz band on an arbitrary horizontal plane, and has directivity that is not more than 0.9 in the 5 GHz band. The antenna for wireless LAN as described in 2.   A wireless communication apparatus comprising the wireless LAN antenna according to claim 1.   9. The wireless communication apparatus according to claim 8, wherein a planar wireless LAN antenna is attached to a planar portion of the wireless communication apparatus.   The wireless LAN antenna according to claim 8, wherein the wireless LAN antenna is deformed into an L shape or a U shape, or is deformed according to a shape of an antenna installation position of the wireless communication device and attached to the wireless communication device. Communication device.   The wireless communication apparatus according to any one of claims 8 to 10, wherein the wireless communication apparatus is one selected from the group consisting of a personal computer, a car navigator, a mobile phone, and a portable game machine.

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