JP2010148035A - Antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna detecting radiation radio waves from a cellular phone or a portable radio transmission terminal having excellent directivity and receiving sensibility (a gain) in an ATM for a bank or the like or a cellular phone inhibition area in a hospital. <P>SOLUTION: A wave guide member (3) consisting of a metal-plated rod-shaped member is arranged in front of an element (2), the longitudinal direction of the wave guide member (3) is arranged in the direction orthogonal to the element (2) on the surface of a resin member, and a reflecting member (4) is so arranged at the rear of the element (2) excepting the front of the element (2) as to surround the element (2). The element (2) is formed in an L shape to handle polarized waves in both directions of horizontal (H) polarized waves and vertical (V) polarized waves. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to an antenna that detects a radiated radio wave of a mobile phone or a portable radio wave transmitting terminal. More particularly, the present invention relates to an antenna suitable for restricting the use of a mobile phone in an ATM such as a bank or a mobile phone prohibited area in a hospital.

In recent years, bank fraud using bank phones has been rapidly increasing in ATMs such as banks. One measure for dealing with this problem is monitoring with a surveillance camera. Although this measure has an advantage that the state around the ATM is captured by an image, when a plurality of people use the ATM terminal, there is a drawback that it is difficult to determine who is using the mobile phone. In addition, this measure does not have a function to alert use prohibition or display a message prohibiting use of mobile phone to suspicious mobile users, so it works well to prevent wire fraud. Not.

As another countermeasure, there is an antenna that detects radio waves of a mobile phone. However, since this antenna is a wide-angle receiving type, pinpoint reception sensitivity is insufficient, and pinpoint detection cannot actually be performed. Furthermore, this antenna has poor directivity and erroneously detects even the adjacent terminal. As a result, there is a problem that a mobile phone user in the vicinity of a specific terminal cannot be specified.

In this way, with the above-mentioned antenna, there was no need to narrow the range of use at that time, and in response to a suspicious mobile user, a warning indicating the prohibition of use or a message prohibiting the use of mobile phones was issued. Could not be displayed. Therefore, an antenna that has excellent reception sensitivity (hereinafter referred to as gain) and directivity and enables pinpoint detection in a limited area is desired.

Therefore, an object of the present invention is to provide an antenna that can reliably detect the radiated radio waves of a mobile phone or a portable radio wave transmitting terminal having excellent gain and directivity in an ATM such as a bank or a mobile phone prohibited area in a hospital. Is to provide.

As a result of paying attention to the selective radio wave reception function of the waveguide member, that is, the function of eliminating unnecessary radio waves coming from directions other than the front, the present inventors have added an antenna element and a reflection member to the waveguide member. The combined use has led to the realization of an antenna with excellent directivity and gain.

The antenna of the present invention has the following effects.
(1) Since the waveguide member receives only radio waves from a limited direction (area) in front of the antenna element, high directivity can be obtained, and the wave collection effect between the waveguide member and the reflecting member can be obtained. Together, the gain is greatly improved.
(2) The antenna is protected from external damage by the resin cover.
(3) Since the number of members is small, the configuration is simple and low cost. This effect is improved particularly when the rear portion of the resin cover also serves as a reflecting member.

  Hereinafter, the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a partially broken perspective view showing an embodiment of an antenna according to the present invention.
FIG. 2 is a partially broken perspective view showing another aspect of the antenna according to the present invention.
FIG. 3 is a radar chart showing gain and directivity with respect to the H polarization characteristics (hereinafter referred to as H characteristics) of the antenna of FIG.
FIG. 4 is a radar chart showing gain and directivity with respect to the H characteristic and V polarization characteristic (hereinafter referred to as V characteristic) of the antenna of FIG.
FIG. 5 is a perspective view showing a mounting example in which the antenna according to the present invention is installed in the vicinity of the ATM.

The antenna of the present invention shown in FIG. 1 will be described taking a dipole antenna as an example. (1) is an antenna, (2) is a long-sided antenna element for H polarization that receives radio waves from a mobile phone, (3) is in front of the antenna element (2), and its longitudinal direction is the antenna A waveguide member orthogonal to the element (2), (4) is a reflecting member disposed behind the antenna element (2) and surrounding the antenna element (2), and (5) is an antenna element (2), a resin cover for housing the waveguide member (3) and the reflecting member (4), and (6) are high-frequency coaxial cables for transmitting the detected radio wave to the ATM equipment. In this example, the rear portion of the resin cover (5) also serves as the reflecting member (4).

FIG. 2 shows another aspect of the antenna according to the present invention. In the figure, the symbols (1), (2), (3), (4), (5), and (6) are the same as those in FIG. In this example, the waveguide member (3) is provided with L-shaped branch portions (3a) and (3b) in parallel with the L-shaped antenna element (2) at its end and in the middle. Any one of the L-shaped branch portions (3a) and (3b) may be used, but as shown in the figure, the sensitivity is further improved when there are a plurality of L-shaped branch portions (3a) and (3b). Further, the long-side antenna element (2) of FIG. 1 also corresponds to the L-shaped branch portions (3a) and (3b), and the H-polarization element (2a) and the V-polarization element (2b). It is transformed into an L-shape consisting of The branch portions (3a) and (3b) are respectively parallel to the H polarization element (2a) and the V polarization element (2b), and are parallel to the H polarization element (2a) and the V polarization element (2a). The wave elements (2b) are arranged at a constant interval with the overlapping phase.

FIG. 3 is a radar chart showing the directivity and gain with respect to the H characteristics of the antenna of FIG. Here, the used frequency band is 1.71 to 2.2 GHz (center frequency 1.98 GHz) of the WAN band. It can be seen from FIG. 3 that excellent gain characteristics and directivity are realized in the antenna using the antenna element of the present invention.

FIG. 4 is a radar chart showing gain and directivity with respect to the H characteristic and the V characteristic of the antenna of FIG. In the antenna using the antenna element of FIG. 2, it can be seen that further excellent gain characteristics and directivity characteristics are realized. Here, the used frequency band is 0.824 GHz to 0.96 GHz and 1.71 GHz to 2.2 GHz (center frequency 1.98 GHz) of the WAN band.

FIG. 5 shows an attachment example in which the antenna (1) according to the present invention is installed in the vicinity of an ATM. Here, (7) is an azimuth variable mechanism provided outside the antenna (1), and rotates around the azimuth adjustment axis (7a) as shown in the figure. (8) is an inclination angle variable mechanism, and rotates around the inclination angle adjusting rotary shaft (8a) as shown in the figure. (9) is a ceiling plate on which the antenna is placed and fixed, and (10) is an ATM terminal. In this example, the antenna (1) receives a radio wave from a specific mobile phone at a pinpoint and sends the received signal as an alarm signal to a cash withdrawal terminal such as an ATM. As a result, the ATM display screen that has received the alarm signal Displays a mobile phone use prohibition warning or a mobile phone use prohibition message.

What is characteristic of the antenna of FIG. 1 is that only a radio wave from a limited direction (area) in front of the antenna element can be received by the waveguide member (3) provided in front of the antenna element (2). The directivity is improved, and in addition to the wave collecting effect of the waveguide member (3) and the reflection member (4), unnecessary waves coming from directions other than the front are eliminated by the waveguide member (3). Therefore, a high gain can be obtained.

Further, in the antenna of FIG. 2, an L-shaped branch portion corresponding to polarization in both directions of H polarization and V polarization is provided in the waveguide member, and an L-shaped antenna element corresponding to the L-shaped branch portion is provided. By adopting, directivity and reception sensitivity are further improved. That is, by providing the branch portions (3a) and (3b) orthogonal to the axial direction of the waveguide member (3) at the end portion or in the middle of the waveguide member (3), the sensitivity variation due to the direction is eliminated and the concentration is increased. The wave effect is also improved. At the same time, by providing two independent elements, the H-polarization element (2a) and the V-polarization element (2b), sensitivity variations due to directions are eliminated.

Furthermore, by providing these antennas with the azimuth varying mechanism (7) and the tilt angle varying mechanism (8), the optimum position and sensitivity of the antenna can be adjusted.

The requirements of the present invention are described below.

The shape of the antenna element (2) is not particularly limited, and examples thereof include a plate shape, a wire shape, and a rod shape. The element resonance method may be appropriately selected from a monopole method, a dipole method, a patch method, a slit (slot) method, and the like. Here, it is assumed that the antenna element (2) is a dipole system and the frequency band is the WAN band (0.824 GHz to 0.96 GHz and 1.71 GHz to 2.2 GHz) used in mobile phones and the like. The length may be set in the vicinity of half of the wavelength used.

As a material of the antenna element (2), a conductive metal such as white (brass), copper, iron, or brass, or a resin substrate obtained by laminating a copper foil on a resin base material (epoxy substrate) is etched. Among them, a conductive metal is preferably employed. In creating this element, a single metal plate may be punched out by electric discharge machining or the like. At that time, the element width is preferably 1 mm to 6 mm, and particularly preferably set in the range of 2 mm to 4 mm. On the other hand, the thickness of the element (2) is not particularly limited, and may be an appropriate thickness considering strength.

The waveguide member (3) has a function of collecting radio waves coming from the front of the antenna when using a mobile phone. In other words, it can be said to be a waveguide. The waveguide member (3) may be a metal waveguide, resin tube, or rod-shaped resin outer surface plated with metal, and the latter is preferable in terms of weight reduction of the antenna. The cross-sectional shape is not particularly limited as long as it has a waveguide function. Further, the length is preferably set in the vicinity of a quarter wavelength of the wavelength used in order to obtain a sufficient collecting effect.

The reflection member (4) has a function of collecting again the radio waves that have not passed through the antenna element (2) and cannot be captured by the waveguide member (3) among the radio waves arriving from the front of the antenna. It also has a function of shielding radio waves from a mobile phone used in the vicinity of an adjacent ATM terminal device or unnecessary radio waves coming from behind the element. Since the reflecting member (4) is arranged so as to surround almost all members of the element (2) except for the front of the element (2), the forward opening angle becomes a factor for determining the directivity of the antenna. The opening angle (θ) at this time is preferably 120 ° to 180 °.

Here, the reflection member (4) is disposed concentrically with the center of the antenna element (2) so that the reception sensitivity characteristic thereof does not become left-right unbalanced. The material may be any member that reflects radio waves, such as a metal plate or metal plating, and may be either a single member formed by applying metal plating to the rear inner surface of a resin cover (5), which will be described later, or another member. In practical use, the former is preferably adopted from the viewpoint of the number of parts and assemblability.

The resin cover (5) houses the antenna element (2), the waveguide member (3), or the reflection member (4) described above, and has a function of protecting the antenna from external damage. The shape is not particularly limited, but from the viewpoint of space efficiency and appearance, at least a part of the resin cover is preferably formed of a curved surface such as a spherical shape, an elliptical shape, or a cylindrical shape. The material of the resin cover (5) is not particularly limited, and a general-purpose resin such as ABS resin or PC (polycarbonate) may be used.

The arrangement positions of the antenna element (2), the waveguide member (3), and the reflection member (4) will be described. Both the distance (L1) between the element (2) and the waveguide member (3) and the distance (L2) between the waveguide member (3) and the reflection member (4) are set to be in the vicinity of one quarter of the wavelength used. Is appropriate.

  A mounting example in which the antenna according to the present invention is installed in the vicinity of an ATM will be described with reference to FIG. As described above, (7) is an azimuth variable mechanism provided outside the antenna, (8) is a tilt angle variable mechanism, (9) is a fixed plate for fixing the antenna to the ceiling, and (10) is an ATM terminal device. is there. Here, the variable direction mechanism (7) and the variable tilt angle mechanism (8) are connected to each other on the fixed plate (9).

The azimuth of the antenna (1) can be freely rotated 360 degrees as shown in the figure by an azimuth adjusting rotary shaft (7a) located at the center of the azimuth varying mechanism (7). On the other hand, the tilt angle can be freely rotated 360 degrees as shown in the figure by the tilt angle adjusting rotary shaft (8a) provided in the tilt angle variable mechanism (8). Usually, the waveguide member (3) side is adjusted toward the ATM terminal device (10) side. As a result, both azimuths and inclination angles can be adjusted independently and freely, so that optimum gain and directivity can be obtained.

Here, the azimuth varying mechanism (7) and the tilt angle varying mechanism (8) are compact and do not reflect radio waves, or do not reflect radio waves, so as not to interfere with radio waves from the mobile phone. It is preferable to use a material such as low plastic. In the above description, the azimuth variable mechanism (7) and the tilt angle variable mechanism (8) are configured as separate members. However, as in the case of a joystick, the azimuth variable mechanism (at which the azimuth and tilt angle can be adjusted simultaneously) 7) and the tilt angle variable mechanism (8) may be a single member.

[Example 1]
The following is a specific example in which reception in the WAN band (1.71 GHz to 2.2 GHz (center frequency 1.98 GHz)) is realized for the antenna (1) shown in FIG.

A rectangular flat plate made of white and white having a length of 50 mm, a width of 50 mm, and a thickness of 0.4 mm was processed with an electric discharge machine to obtain an antenna element (2) having a length of 40 mm and a width of 40 mm. As the waveguide member (3), a cylindrical resin (ABS) having a length of 45 mm and an outer diameter of 4 mm and having a surface plated with copper of 10 μm was used. The distance (L1) between the two at this time was 23 mm.

  As the reflecting member (4), a resin cover (thickness: 2 mm) made of hemispherical (outer diameter: 100 mm) ABS with a copper plating of 10 μm thick was used. Next, the reflector (4) is connected to the rear end of a cylindrical body (thickness 2 mm) having an outer diameter of 100 mm and a length of 20 mm, and a non-plated hemispherical resin cover is connected to the front end of the cylinder. A cover (5) was obtained. At this time, the distance (L2) from the antenna element (1) was 23 mm.

The antenna element (2) and the waveguide member (3) were accommodated in the resin cover (5) to obtain an antenna. At this time, the distance (L1) between the antenna element (2) and the waveguide member (3) and the distance (L2) between the antenna element (2) and the reflector (4) were both 23 mm. Further, a high-frequency coaxial cable (6) covered with a fluororesin (PFA) having an outer diameter of 1.37 mm and a conductor diameter of 0.24 mm was connected to the center of the antenna element.

The azimuth variable mechanism (7) and the tilt angle variable mechanism (8) were attached to the antenna (1), and then fixed to the fixed plate (9) near the ATM terminal (FIG. 5). Then, after adjusting the azimuth adjustment rotation axis (7a) and the inclination angle adjustment rotation axis (8a) so that the antenna (1) has an optimum sensitivity, radio waves of the mobile phone were received.

The result is the gain and directivity characteristics in the WAN band 1.71 GHz to 2.2 GHz (center frequency 1.98 GHz) shown in the radar chart of FIG. It turns out that it is improving.

[Example 2]
The following is a specific example in which the antenna shown in FIG. 2 is realized in the WAN band of 0.824 GHz to 0.96 GHz and 1.71 GHz to 2.2 GHz (center frequency 1.98 GHz).

In Example 1, the same operation was repeated except that the shape of the antenna element was changed to an L shape and the L-shaped branch portions (3a) and 3b) were provided on the waveguide member (3). A rectangular flat plate made of white and white used in Example 1 was processed with an electric discharge machine to obtain an L-shaped antenna element (2) shown in FIG. The length of the antenna element (2a) was 40 mm at the outer portion of the L shape, the length of the antenna element (2b) was 40 mm at the outer portion of the L shape, and the lateral (lateral width) was 10 mm for both.

In FIG. 2, the antenna element (2a) in the xy-axis direction is an H-polarization receiving element, and the z-axis antenna element (2b) is a V-polarization receiving element, both of which have a dipole antenna resonance configuration. Therefore, a high frequency coaxial cable (6) is connected to the center of each element.

Branch portions (3a) and (3b) each having an L shape in the xy direction and the z direction were connected to the central portion of the waveguide member (3) and the end surface on the element side. At this time, the branches (3a) and (3b) were arranged in phase so as to be parallel to the elements (2a) and (2b), respectively. The branch part (3a) has a length of 15 mm and an outer diameter of 4 mm, the branch part (3b) has a length of 10 mm and an outer diameter of 4 mm, and both the branch part (3a) and the branch part (3b) of Example 1 As in the case of the conductive member (3), a cylindrical resin (ABS) surface with a copper plating having a thickness of 10 μm was used.

Similar to the first embodiment, the result of receiving the radio wave of the mobile phone is 0.824 GHz to 0.96 GHz and 1.71 GHz to 2.2 GHz (center frequency of 1.24 GHz) in the WAN band shown in the radar chart of FIG. The gain and directivity characteristics at 98 GHz). 4A shows the H characteristic at 0.824 GHz, FIG. 4B shows the V characteristic at 0.824 GHz, FIG. 4C shows the H characteristic at 1.98 GHz, and FIG. ) Is a V characteristic at 1.98 GHz, and it can be seen that sufficient sensitivity is obtained in both the H and V directions in any band. At the same time, sufficient directivity is obtained in both the H and V directions with respect to the directivity.

In the second embodiment, 0.824 GHz in the frequency band of the WAN band (0.824 GHz to 0.96 GHz) and a center frequency of 1.98 GHz in the frequency band of 1.71 GHz to 2.17 GHz are given as examples. Needless to say, the present invention provides sufficient gain and directivity over the entire WAN band (0.8 GHz to 2.2 GHz) used in mobile phones. Furthermore, although the antenna element has been described as an example of a dipole, this is only an example of the present invention, and it goes without saying that various modifications and applications are possible within the scope of the idea of the present invention.

The antenna of the present invention can be applied not only to radio wave reception of mobile phones but also to information home appliances using radio waves.

The partially broken perspective view which shows the one aspect | mode of the antenna which concerns on this invention The partially broken perspective view which shows another aspect of the antenna which concerns on this invention The radar chart which shows the receiving sensitivity (gain) and directivity of the antenna of FIG. 3 is a radar chart showing reception sensitivity (gain) and directivity with respect to the H polarization characteristics (H characteristics) and V polarization characteristics (V characteristics) of the antenna of FIG. The perspective view which shows the example of attachment which installed the antenna which concerns on this invention in ATM vicinity.

Explanation of symbols

1 Antenna 2 Element
2a Element for H polarization 2b Element for V polarization 3 Waveguide member 3a, 3b L-shaped branch
4 Reflecting member 5 Resin cover 6 High-frequency coaxial cable 7 Orientation variable mechanism 8 Inclination angle varying mechanism L1 Distance between antenna element (2) and waveguide member (3)
L2 Distance between antenna element (2) and reflecting member (4)

Claims (7)

An antenna comprising: an antenna element; a waveguide member disposed in front of the antenna element; and a reflecting member disposed in the rear of the antenna element are housed in a resin cover. The antenna according to claim 1, wherein the reflecting member forms a part of a resin cover formed of a concave curved surface, and the reflecting surface is formed of a metal plating layer. The antenna according to claim 1 or 2, wherein the resin cover is formed of a spherical, elliptical, or cylindrical curved surface. The antenna according to any one of claims 1 to 3, wherein the waveguide member is a rod-shaped member obtained by metal plating on a surface of a resin member, and a longitudinal direction thereof is orthogonal to the antenna element. The antenna according to claim 4, wherein the waveguide member has an L-shaped branch portion orthogonal to the longitudinal direction thereof, and thereby can cope with polarization in both directions of H polarization and V polarization. The antenna according to claim 5, wherein the antenna element has an L shape corresponding to the L-shaped branch portion and is disposed in parallel with the L-shaped branch portion. The antenna according to claim 1, wherein an orientation variable mechanism and an inclination angle variable mechanism are added to the resin cover.

Images