JP2009017115A - Planar antenna with reflecting plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planar antenna with a reflecting plate, which has a shape having a short depth. <P>SOLUTION: A first tabular radiation element 11a and a second tabular radiation element 11b of the same shape are provided on a reflecting plate 10 having a channel-shaped cross-section. A first parasitic element 12a and a second parasitic element 12b are disposed between the first radiation element 11a and the second radiation element 11b. Thus a planar antenna 1 with the reflecting plate has directivity in a y direction approximately perpendicular to a plane including the first and second radiation elements 11a and 11b, so that the antenna 1 has a short depth. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a planar antenna having a reflector operable in the UHF band, and more particularly to a planar antenna with a reflector suitable for application to a UHF antenna that receives terrestrial digital broadcasting in the UHF frequency band.

  Unlike conventional analog broadcasting, terrestrial digital broadcasting is a digital signal as long as it can receive incoming radio waves at a certain level or higher, so that clear images can be obtained. Therefore, an antenna that receives terrestrial digital broadcasting does not necessarily have a high gain. For this reason, compared with the conventional antenna, an antenna having a small and easy-to-handle shape is expected. As a conventional UHF television antenna that can operate in the UHF band, an antenna in which a radiating element and a reflecting element (reflecting plate) having an operation principle of a Yagi / Uda antenna are arranged is known. In this antenna, the distance between the radiating element and the reflecting element (reflecting plate) is normally about λ / 4 when the wavelength of the center frequency in the operating frequency band is λ.

  However, in a planar antenna with a reflector based on the Yagi-Uda antenna, the distance between the radiating element and the reflecting element (reflecting plate) needs to have an appropriate distance in the frequency band, and the UHF band is 470 to 770 MHz. Then, since the wavelength at the center frequency is about 484 mm, an interval of at least 100 mm or more is required. For this reason, it has become a flat antenna with a reflector having a large shape and a long depth. Here, it is considered that the depth does not increase when a parasitic element is arranged close to the radiating element. As an example, FIG. 19 is a perspective view showing a configuration of an antenna in which a parasitic element 102 is arranged close to a dipole element 100. In FIG. 19, the dipole element 100 is supplied with power from a power supply unit 103 provided at the center. Let x be the direction of the rectangular parasitic element 102 arranged close to the dipole element 100, and y be the direction upward on the paper surface orthogonal to the x direction. Then, the operation gain in the x direction is improved due to the influence of the parasitic element 102, but the operation gain in the y direction is decreased. As described above, when the parasitic element is arranged close to the radiating element, the operation gain in the direction from the radiating element to the parasitic element is improved. Therefore, the reflector must be provided on the opposite side of the radiating element from the parasitic element. However, there was a problem that the depth was not necessarily shortened.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a planar antenna with a small reflector that can shorten the depth.

  In order to achieve the above object, a planar antenna with a reflector according to the present invention is a flat plate-like first antenna disposed between a first radiating element and a second radiating element and in proximity to the first radiating element. A feeding element, a second parasitic element disposed in proximity to the second radiating element, and a first radiating element or a second parasitic element are arranged to be spaced apart from each other by a predetermined distance. The most important feature is that it includes a radiating element and a U-shaped reflecting plate bent toward the second radiating element.

  According to the present invention, since the first radiating element and the second radiating element are substantially perpendicular to each other and have directivity in the direction opposite to the reflecting plate, the small planar antenna with a reflecting plate is short. It can be. Further, a small planar antenna with a reflector having a short depth can be an antenna that operates sufficiently in a wide frequency band of terrestrial digital broadcasting that is a UHF band.

The structure of the first embodiment of the planar antenna with a reflector according to the present invention is shown in FIGS. However, FIG. 1 is a perspective view showing the configuration of the planar antenna with a reflector of the first embodiment according to the present invention, and FIG. 2 is a plan view showing the configuration of the planar antenna with a reflector of the first embodiment according to the present invention. 3 is a side view showing in cross section the configuration of the planar antenna with a reflector according to the first embodiment of the present invention. FIG. 4 is a side view showing the configuration of the planar antenna with a reflector according to the first embodiment of the present invention. FIG.
As shown in these figures, the reflector-equipped planar antenna 1 according to the first embodiment of the present invention includes a first radiating element 11a and a second radiating element 11b made of a folded dipole, and a first radiating element 11a and a second radiating element. The first parasitic element 12a and the second parasitic element 12b, the first radiating element 11a and the second radiating element 11b, the first parasitic element 12a and the second parasitic element 12b, respectively, disposed between the elements 11b. And a reflector 10 disposed on the rear side. In addition, the 1st radiation element 11a and the 2nd radiation element 11b, and the 1st parasitic element 12a and the 2nd parasitic element 12b are arrange | positioned on the same surface.

  The first radiating element 11a and the second radiating element 11b are formed into a horizontally long rectangular shape by processing a metal plate, and are folded dipoles in which T-shaped grooves 11e and 11f are formed. The feed cable 13a is connected to the first feed point 11c of the first radiating element 11a, and the feed cable 13a is connected to the second feed point 11d of the second radiating element 11b. Power is supplied to the first radiating element 11a and the second radiating element 11b through the first radiating element 11a and the second radiating element 11b. The first radiating element 11a has a first parasitic element 12a arranged in parallel with a distance D, and the second radiating element 11b has a second parasitic element 12b arranged in parallel with a distance D. Has been. The distance D is, for example, about 20 mm when the planar antenna 1 with a reflecting plate is a receiving antenna for terrestrial digital broadcasting (470 MHz to 770 MHz). Also, the distance between the substantially parallel edges separated by the first radiating element 11a and the second radiating element 11b is L11, and the distance L11 is received by the planar antenna 1 with a reflector plate for terrestrial digital broadcasting (470 MHz to 770 MHz). In the case of an antenna, for example, it is about 260 mm.

The first radiating element 11a and the second radiating element 11b have the same shape, and the first parasitic element 12a and the second parasitic element 12b have the same shape and are arranged point-symmetrically. Therefore, FIG. 5 shows a configuration of the first radiating element 11a and the first parasitic element 12a as a representative.
A first parasitic element 12a is arranged on the same plane in close proximity to the first radiating element 11a with a distance D, and has a lateral length L1 and a width W1 of the first radiating element 11a. The distance L2 between the side edge of the T-shaped groove 11e and the side edge of the first radiating element 11a, the distance L3 between the upper edge of the T-shaped groove 11e and the upper edge of the first radiating element 11a, and the T-shape The width L4 of the groove in the lateral direction of the groove 11e means that when the reflector-equipped planar antenna 1 is a receiving antenna for digital terrestrial broadcasting (470 MHz to 770 MHz), for example, the length L1 is about 240 mm and the width W1 is about The distance L2 is about 15 mm, the distance L3 is about 10 mm, and the width L4 is about 10 mm.
Further, the lateral length L5 and width W2 of the first parasitic element 12a are, for example, a length L5 of about 160 mm when the planar antenna 1 with a reflector is a receiving antenna for terrestrial digital broadcasting (470 MHz to 770 MHz). The width W2 is about 40 mm.

Returning to FIG. 1 to FIG. 4, the reflecting plate 10 is formed to be bent at a substantially right angle so that both sides of the rectangular metal plate are opposed to each other, and includes the first radiating element 11 a and the second radiating element 11 b, and the first parasitic element. A plane portion 10a facing the element 12a and the second parasitic element 12b, and a bent portion 10b formed by being bent on both sides of the plane portion 10a toward the first radiating element 11a and the second radiating element 11b. It is configured. The horizontal length L10 and width W10 of the reflecting plate 10 and the height H10 of the bent portion 10b are set such that the length L10 is obtained when the planar antenna 1 with a reflecting plate is a receiving antenna for digital terrestrial broadcasting (470 MHz to 770 MHz). Is about 400 mm, the width W10 is about 250 mm, and the height H10 is about 40 mm.
When the reflector-equipped planar antenna 1 is a terrestrial digital broadcast (470 MHz to 770 MHz) receiving antenna, the first radiating element 11a and the second radiating element 11b, the first parasitic element 12a and the second parasitic element The distance H11 between the surface on which 12b is disposed and the upper edge of the bent portion 10b of the reflector 10 is about 10 mm.

Next, the structure of the planar antenna 2 with a reflector according to the second embodiment of the present invention is shown in FIGS. However, FIG. 6 is a plan view showing the configuration of the planar antenna 2 with a reflector according to the second embodiment of the present invention, and FIG. 7 is a side view showing the configuration of the planar antenna 2 with a reflector according to the second embodiment of the present invention. FIG.
As shown in these drawings, the reflector-equipped planar antenna 2 according to the second embodiment of the present invention includes the first parasitic element 22a and the second parasitic element 22a disposed between the first radiating element 11a and the second radiating element 11b, respectively. The configuration is the same except for the configuration of the two parasitic elements 22b. Accordingly, the first parasitic element 22a and the second parasitic element 22b will be described. The first parasitic element 22a is disposed substantially in parallel with the first radiating element 11a at a distance D, and the second radiating element 11b. The second parasitic elements 22b are arranged substantially in parallel with a distance D between them. In the first parasitic element 22a and the second parasitic element 22b, the corners on both sides of the edge facing the first radiating element 11a and the second radiating element 11b are cut off. In this way, when the planar antenna 2 with a reflector is used as a receiving antenna for terrestrial digital broadcasting (470 MHz to 770 MHz) by cutting the corners of the first radiating element 11a and the second radiating element 11b, the low-frequency band to the middle band The high frequency electrical characteristics can be improved while maintaining the electrical characteristics.

The first radiating element 11a and the second radiating element 11b have the same shape, and the first parasitic element 22a and the second parasitic element 22b have the same shape and are arranged point-symmetrically. Therefore, FIG. 8 shows the configuration of the first radiating element 11a and the first parasitic element 22a as a representative.
The first parasitic element 22a is disposed close to and parallel to the first radiating element 11a with a distance D, and the dimensions of the respective parts of the first radiating element 11a are as described above. In addition, the lateral length L5 and the width W2 of the first parasitic element 22a are as described above. If the planar antenna 2 with a reflector is a receiving antenna for terrestrial digital broadcasting (470 MHz to 770 MHz), for example, cut The length L6 of the upper edge is about 140 mm, and the width W3 until the side edge is cut is about 20 mm.
The first radiating element 11a and the second radiating element 11b, and the first parasitic element 22a and the second parasitic element 22b are arranged on the same plane as shown in FIG. 2 is a receiving antenna for terrestrial digital broadcasting (470 MHz to 770 MHz), the distance H11 between the above surface and the upper edge of the bent portion 10b of the reflector 10 is about 10 mm.

In the planar antennas 1 and 2 according to the first embodiment and the second embodiment of the present invention configured as described above, the planar surface with a reflective plate exhibiting particularly good electrical characteristics when the dimensions are raised as an example. Antennas 1 and 2 can be used. When the planar antennas 1 and 2 with reflectors are reception antennas for terrestrial digital broadcasting (470 MHz to 770 MHz), assuming that the wavelength at the center frequency (620 MHz) is λ ₀ , the first parasitic elements 12a and 22a and the first The lateral length L5 of the two parasitic elements 12b and 22b can be in the range of about 0.29λ ₀ (about 140 mm) to about 0.34λ ₀ (about 165 mm), and the width W2 is about 0.04λ. ₀ (about 20 mm) to about 0.08λ ₀ (about 40 mm).

  Therefore, the distance D between the first radiating element 11a and the second radiating element 11b and the first parasitic elements 12a and 22a and the second parasitic elements 12b and 22b is about 20 mm, and the first parasitic elements 12a, 22a and the second The frequency characteristics of the operating gains of the planar antennas 1 and 2 with reflectors when the length L5 of the parasitic elements 12b and 22b is about 160 mm, the width W2 is about 40 mm, and the other dimensions are those of the above-described example. In contrast to the case where the parasitic elements 12a and 22a and the second parasitic elements 12b and 22b are omitted, FIG. 9 shows the frequency characteristics of the voltage standing wave ratio (VSWR). However, the electrical characteristics of the operating gain are such that each element is arranged on the surface where the first radiating element 11a and the second radiating element 11b, the first parasitic elements 12a and 22a, and the second parasitic elements 12b and 22b are arranged. The electrical characteristics in the horizontal direction (x direction in FIG. 1). Referring to the frequency characteristics of the operating gain shown in FIG. 9, the gain increases in the high frequency range of 470 MHz to 770 MHz, which is the frequency band of terrestrial digital broadcasting, but no gain that can operate over the entire frequency band is obtained. . Further, referring to the frequency characteristics of the VSWR shown in FIG. 10, the flat antennas 1 and 2 according to the first and second embodiments show good VSWR characteristics, but the parasitic elements are omitted. In the case of the planar antenna with a reflecting plate, it can be seen that the VSWR characteristic is deteriorated.

Next, the reflector 10 perpendicular to the surface on which the first radiating element 11a and the second radiating element 11b, the first parasitic elements 12a and 22a, and the second parasitic elements 12b and 22b are arranged without changing the conditions. FIG. 11 and FIG. 12 show the gain characteristics and VSWR characteristics in the vertical direction (y direction in FIG. 1) from each to the respective elements.
FIG. 11 shows frequency characteristics of the operating gain. In the planar antennas 1 and 2 according to the first and second embodiments, the operating gain is good over almost the entire frequency band of 470 MHz to 770 MHz, which is the frequency band of digital terrestrial broadcasting. Is obtained. However, in the planar antenna 1 with a reflector according to the first embodiment, the gain is slightly reduced in the high range. Further, in the case of a planar antenna with a reflector in which a parasitic element is omitted, the operating gain is reduced over the entire frequency band. FIG. 12 shows the frequency characteristics of the VSWR, which is similar to the frequency characteristics of the VSWR shown in FIG. 10, and the planar antennas 1 and 2 with reflectors according to the first and second embodiments are almost all over the frequency band. Good VSWR characteristics of 2.5 or less are shown. However, in the planar antenna 1 with a reflector according to the first embodiment, the VSWR is slightly deteriorated in the high range. In addition, it can be seen that in the case of a planar antenna with a reflector without a parasitic element, the VSWR characteristics deteriorate.

  From the electrical characteristics shown in FIGS. 9 to 12, in the planar antennas 1 and 2 according to the first and second embodiments, the operating gain in the horizontal direction (x direction) in which the parasitic element is provided is reduced. However, the operating gain in the vertical direction (y direction) increases. This is because the first parasitic elements 12a and 22a and the second parasitic elements 12b and 22b are provided so as to face each other between the first radiating element 11a and the second radiating element 11b. It is considered that the gain in the vertical direction (y direction) is increased by canceling each other and being reflected by the reflecting plate 10. In addition, the first parasitic element 22a and the second parasitic element 22b in which the corners on both sides of the first radiating element 11a and the second radiating element 11b side in the first parasitic element 12a and the second parasitic element 12b are cut. It can be seen that the high band electrical characteristics can be improved while maintaining the low band and middle band good electrical characteristics.

  Next, in the planar antenna 1 with a reflector according to the first embodiment, the lateral length L5 of the first parasitic element 12a and the second parasitic element 12b is set to about 140 mm, about 160 mm, and about 165 mm as parameters. The frequency characteristic of VSWR is shown in FIG. However, the distance D between the first radiating element 11a and the second radiating element 11b and the first parasitic element 12a and the second parasitic element 12b is about 20 mm, and the width of the first parasitic element 12a and the second parasitic element 12b. W2 is about 40 mm, and the other dimensions are those of the above-described example. Referring to FIG. 13, it can be seen that even if the length L5 is about 140 mm to about 165 mm, it operates almost satisfactorily over the entire frequency band.

  Next, in the planar antenna 1 with a reflector according to the first embodiment, the frequency characteristics of VSWR when the width W2 of the first parasitic element 12a and the second parasitic element 12b is set to about 20 mm, about 30 mm, and about 40 mm as parameters. Is shown in FIG. However, the distance D between the first radiating element 11a and the second radiating element 11b and the first parasitic element 12a and the second parasitic element 12b is about 20 mm, and the side of the first parasitic element 12a and the second parasitic element 12b. The length L5 in the direction is about 160 mm, and the other dimensions are the above-described example dimensions. Referring to FIG. 14, it can be seen that even if the width W2 is set to about 20 mm to about 40 mm, the operation is almost satisfactory over the entire frequency band.

  Next, in the planar antenna 1 with a reflector according to the first embodiment, the distance D between the first radiating element 11a and the second radiating element 11b and the first parasitic element 12a and the second parasitic element 12b is about 20 mm as a parameter. FIG. 15 shows the frequency characteristics of VSWR when the thickness is about 30 mm and about 40 mm. However, the width W2 of the first parasitic element 12a and the second parasitic element 12b is about 40 mm, and the lateral length L5 of the first parasitic element 12a and the second parasitic element 12b is about 160 mm. The dimensions are those of the above example. Referring to FIG. 15, it can be seen that the high frequency VSWR characteristics deteriorate as the distance D exceeds about 20 mm.

  Next, in the planar antenna 1 with a reflector according to the first embodiment, the first parasitic element 12a and the second parasitic element 12b have a width W2 of about 20 mm, and the first parasitic element 12a and the second parasitic element. FIG. 16 shows the frequency characteristics of the VSWR when the lateral length L5 of 12b is set to about 140 mm, about 160 mm, and about 165 mm. However, the distance D between the first radiating element 11a and the second radiating element 11b and the first parasitic element 12a and the second parasitic element 12b is about 20 mm, and the other dimensions are the above-described dimensions. Referring to FIG. 16, it can be seen that when the width W2 is set to about 20 mm, the length L5 is set to about 140 mm to about 165 mm, and the entire frequency band operates substantially well.

  Next, in the planar antenna 1 with a reflector according to the first embodiment, the lateral length L5 of the first parasitic element 12a and the second parasitic element 12b is set to about 150 mm, and the first radiating element 11a and the second FIG. 17 shows the frequency characteristics of VSWR when the distance D between the radiating element 11b and the first parasitic element 12a and the second parasitic element 12b is set to about 20 mm, about 30 mm, and about 40 mm. However, the width W2 of the first parasitic element 12a and the second parasitic element 12b is about 40 mm, and the other dimensions are the above-described dimensions. Referring to FIG. 17, it can be seen that even if the distance D is about 20 mm to about 40 mm, the operation is almost satisfactory over the entire frequency band.

Next, in the planar antenna 1 with a reflector according to the first embodiment, the lateral length L5 of the first parasitic element 12a and the second parasitic element 12b is about 155 mm, and the first parasitic element 12a and the second parasitic element 12a The width W2 of the two parasitic elements 12b is about 20 mm, and the distance D between the first and second radiating elements 11a and 11b and the first and second parasitic elements 12a and 12b is set to about 20 mm and about 30 mm. FIG. 18 shows the frequency characteristics of the VSWR when about 40 mm. However, the other dimensions are those of the above example. Referring to FIG. 18, even if the length L5 is set to about 155 mm and the width W2 is set to about 20 mm, when the interval D is set to about 20 mm to about 40 mm, the middle range VSWR is slightly deteriorated, but the high range VSWR is improved. It can be seen that it operates almost well over the entire frequency band. In this case, it can be seen that the same good VSWR characteristic can be obtained over the entire frequency band regardless of the distance D from about 20 mm to about 40 mm.
The electrical characteristics shown in FIGS. 13 to 18 are the frequency characteristics of the VSWR in the planar antenna 1 with a reflector according to the first embodiment, but the respective parameters were changed in the planar antenna 2 with a reflector according to the second embodiment. In some cases, the frequency characteristic of VSWR shows the same tendency. However, the VSWR characteristic at the high frequency is further improved.

As described above, the planar antennas 1 and 2 according to the first and second embodiments of the present invention have a directivity characteristic in the vertical direction (y direction), and thus a small planar antenna with a reflector having a short depth. Thus, the antenna can operate sufficiently in the frequency band of terrestrial digital broadcasting, which is the UHF band.
In the planar antennas 1 and 2 with reflectors according to the first and second embodiments of the present invention, the dimensions of each part as an example are also shown. However, the dimensions and dimension ranges are only examples, and are not limited to the dimensions, and deviate to some extent. Even if the size is enough, it works as an antenna. However, the electrical characteristics are slightly deteriorated. In the present invention, a configuration in which a parasitic element is provided between two radiating elements facing the reflecting plate is the main feature, and the dimensions of each part are not the main features. Further, the radiating elements in the planar antennas 1 and 2 according to the first and second embodiments of the present invention are configured in a plate shape, but the present invention is not limited to this and may be configured in a rod shape.

  In the above description, a planar antenna with a reflector that receives digital terrestrial broadcasting is used. However, the present invention is not limited to this, and can be applied to a planar antenna with a reflector that transmits and receives a UHF band.

It is a perspective view which shows the structure of the planar antenna with a reflecting plate of 1st Example concerning this invention. It is a top view which shows the structure of the planar antenna with a reflector of 1st Example concerning this invention. It is a side view which shows the structure of the planar antenna with a reflecting plate of 1st Example concerning this invention in a cross section. It is a side view which shows the structure of the planar antenna with a reflector of 1st Example concerning this invention. It is a figure which shows only the structure of the 1st radiation element and the 1st parasitic element in the planar antenna with a reflector of 1st Example concerning this invention. It is a top view which shows the structure of the planar antenna 2 with a reflecting plate of 2nd Example concerning this invention. It is a side view which shows the structure of the planar antenna 2 with a reflecting plate of 2nd Example concerning this invention. It is a figure which shows only the structure of the 1st radiation element and the 1st parasitic element in the planar antenna with a reflector of 2nd Example concerning this invention. It is a figure which shows the frequency characteristic of the horizontal operation gain in the planar antenna with a reflector of the 1st, 2nd Example concerning this invention. It is a figure which shows the frequency characteristic of VSWR in the planar antenna with a reflector of the 1st, 2nd Example concerning this invention. It is a figure which shows the frequency characteristic of the operational gain of the perpendicular direction in the planar antenna with a reflector of the 1st, 2nd Example concerning this invention. It is a figure which shows the frequency characteristic of VSWR in the planar antenna with a reflector of the 1st, 2nd Example concerning this invention. In the planar antenna with a reflector of 1st Example of this invention, it is a figure which shows the frequency characteristic of VSWR when the length of the horizontal direction of a 1st parasitic element and a 2nd parasitic element is used as a parameter. In the planar antenna with a reflector of 1st Example of this invention, it is a figure which shows the frequency characteristic of VSWR when making the width | variety of a 1st parasitic element and a 2nd parasitic element into a parameter. In the planar antenna with a reflector according to the first embodiment of the present invention, the frequency characteristics of VSWR when the distance between the first radiating element and the second radiating element and the first parasitic element and the second parasitic element is used as a parameter are shown. FIG. In the planar antenna with a reflector according to the first embodiment of the present invention, the widths of the first parasitic element and the second parasitic element are changed, and the lateral lengths of the first parasitic element and the second parasitic element are changed. It is a figure which shows the frequency characteristic of VSWR when setting it as a parameter. In the planar antenna with a reflector according to the first embodiment of the present invention, the lateral lengths of the first parasitic element and the second parasitic element are changed, and the first and second radiating elements and the first parasitic element are changed. It is a figure which shows the frequency characteristic of VSWR when the space | interval with an element and a 2nd parasitic element is used as a parameter. In the planar antenna with a reflector according to the first embodiment of the present invention, the lateral lengths of the first parasitic element and the second parasitic element and the widths of the first parasitic element and the second parasitic element are changed, It is a figure which shows the frequency characteristic of VSWR when the space | interval of 1 radiating element and 2nd radiating element, 1st parasitic element, and 2nd parasitic element is made into the parameter. It is a perspective view which shows the structure of the antenna which has arrange | positioned the parasitic element adjacent to the conventional dipole element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Planar antenna with a reflecting plate, 2 Planar antenna with a reflecting plate, 10 Reflecting plate, 10a Plane part, 10b Bending part, 11a 1st radiation element, 11b 2nd radiation element, 11c 1st feeding point, 11d 2nd feeding point, 11e T-shaped groove, 12a first parasitic element, 12b second parasitic element, 13 feeding section, 13a feeding cable, 22a first parasitic element, 22b second parasitic element, 100 dipole element, 102 parasitic element, 103 Power supply unit

Claims (3)

A flat first radiating element and a flat second radiating element having the same shape;
Between the first radiating element and the second radiating element, disposed on a surface including the first radiating element and the second radiating element, and in proximity to the first radiating element; A flat plate-shaped first parasitic element disposed; a second parasitic element having the same shape as the first parasitic element disposed in proximity to the second radiating element;
The first radiating element, the second radiating element, and the first parasitic element and the second parasitic element are arranged to be spaced apart from each other by a predetermined distance, and both side portions are the first radiating element and the second radiating element. A reflector having a U-shaped cross section bent toward the element side,
A planar antenna with a reflector, which is substantially perpendicular to a surface formed by the first radiating element and the second radiating element, and has directivity in a direction opposite to the reflector.   The first parasitic element and the second parasitic element are formed in a horizontally long, substantially rectangular shape, corners on both sides of the first parasitic element on the first radiating element side, and the second parasitic element The planar antenna with a reflector according to claim 1, wherein corners on both sides of the second radiating element are cut off.   The first parasitic element and the second parasitic element have a horizontally long rectangular shape, and the first parasitic element and the second parasitic element when the wavelength of the center frequency of the used frequency band is λ. 3. The flat surface with a reflector according to claim 1, wherein the lateral length of the element is about 0.29λ to about 0.34λ, and the width is about 0.04λ to about 0.08λ. antenna.

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