JP2013089995A - Planar antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a planar antenna which has a dielectric substrate with excellent dimension stability, has low dielectric loss tangent and voltage standing wave ratio characteristics of 1.6 or lower, and stably obtains high antenna characteristics.SOLUTION: A planar antenna includes: a ground plate 12 formed by a conductor; a dielectric layer 14 formed by a dielectric substance; and a patch element 16 formed by a conductor. The dielectric layer 14 is a laminated body formed by laminating and thermally fusing a polyolefin resin and a glass fiber.

Description

  The present invention relates to a planar antenna that can be used, for example, for RFID communication and reception of broadcast radio waves, and more specifically to a low-frequency planar antenna that uses the UHF band of 860 to 960 MHz.

  2. Description of the Related Art Conventionally, for example, a kind of planar antenna that can be used for communication for RFID, reception of broadcast radio waves, and the like, an antenna having a narrow and wide directivity called a patch antenna or a microstrip antenna is known. .

  The patch antenna has a structure as disclosed in, for example, Patent Document 1 (Japanese Patent Laid-Open No. 5-121935). 23 and 24 are configuration diagrams for explaining the structure of a conventional patch antenna.

  FIG. 23A is a plan view schematically showing the configuration of a conventional patch antenna, and FIG. 23B is an MM cross-sectional view schematically showing the MM cross section of FIG. It is. FIG. 24A is a plan view schematically showing the configuration of a conventional patch antenna, and FIG. 24B is an MM schematically showing the MM cross section of FIG. It is sectional drawing.

  As shown in FIG. 23, the patch antenna 100 includes a ground plate 110, a dielectric substrate 120, a patch element 130, and a feed line 140. The dielectric substrate 120 sandwiched between the patch element 130 and the ground plate 110 is made of a material obtained by laminating fluororesin or polyethylene and glass fiber, and has a relative dielectric constant εr of 2 to 3. It was about.

  Such band characteristics of the patch antenna 100 depend on the relative dielectric constant εr of the dielectric substrate 120 and the thickness of the dielectric substrate, and in order to obtain a wide band, the relative dielectric constant εr is decreased (closer to 1). At the same time, it is necessary to increase the thickness.

  Further, in the patch antenna 200 shown in FIG. 24, the feed line 140 and the patch element 130 that are located with the ground plate 110 interposed therebetween are connected by the conductor pin 150 that passes through the opening 110 a of the ground plate 110.

  By configuring in this way, compared to the patch antenna 100 shown in FIG. 23, it is possible to realize the patch antenna 200 that suppresses the radiation loss of the feed line 140 and has broadband characteristics.

JP-A-5-121935

  However, even in the patch antenna 200 shown in FIG. 24, it is necessary to increase the thickness of the dielectric substrate 120b disposed between the patch element 130 and the ground plate 110, and the band characteristics of the patch antenna are It depends on the relative dielectric constant εr of the substrate 120 and the thickness of the dielectric substrate 120.

  In particular, in the case of a low-frequency antenna using the UHF band of 860 to 960 MHz, it is necessary to increase the thickness of the dielectric substrate 120 in order to improve the radio wave characteristics of the antenna. Thus, when the thickness of the dielectric substrate 120 is increased, the performance of the antenna is also affected by the material used for the dielectric substrate 120.

  Depending on the material used, the radiation loss of the feed line 140 increases or the gain of the antenna decreases. Further, when the dimensional stability of the material used is impaired, there is a problem that the loss further increases.

  As disclosed in Patent Document 1, conventionally, foamed polyethylene has been used as a dielectric and a spacer. However, foamed polyethylene has poor dimensional stability and tends to be large in shape as a whole. In other words, stable and high antenna characteristics could not be obtained.

  In view of such a current situation, the present invention uses a material obtained by laminating a polyolefin resin and glass fiber on a dielectric substrate (dielectric layer) of an antenna, so that the dielectric substrate has excellent dimensional stability and a low dielectric loss tangent. An object of the present invention is to provide a planar antenna that has a VSWR (Voltage Standing Wave Ratio) characteristic of 1.6 or less and can stably obtain high antenna characteristics.

  Furthermore, an object of the present invention is to provide a planar antenna that is very light compared to a conventional planar antenna, can be used in a wider range, and can stably obtain high antenna characteristics.

The present invention has been invented in order to achieve the above-described problems and objects in the prior art, and the planar antenna of the present invention is a planar antenna for transmitting and receiving UHF radio waves,
A ground plate constituted by a conductor;
A dielectric layer composed of a dielectric;
A patch element constituted by a conductor;
With
The dielectric layer is a laminate formed by laminating a polyolefin resin and a glass fiber resin and heat-sealing them.

  With this configuration, the dielectric layer has excellent dimensional stability, a low dielectric loss tangent, a VSWR (Voltage Standing Wave Ratio) characteristic of 1.6 or less, and a stable and high antenna. It can be set as the planar antenna from which a characteristic is acquired.

In the planar antenna of the present invention, the planar antenna further includes a second dielectric layer made of a dielectric, and a stripline layer constituting a stripline circuit,
The ground plate, the dielectric layer, the patch element, the second dielectric layer, and the stripline layer are stacked in this order.

  With this configuration, the antenna characteristics of the planar antenna can be adjusted by adjusting the stripline layer, so that antenna design corresponding to a desired band can be easily performed.

  In the planar antenna of the present invention, the polyolefin resin is a resin selected from polyethylene, polypropylene, polymethylpentene, cycloolefin polymer, polyetherimide, and polyethylene terephthalate.

  By using such a resin, the planar antenna can be reduced in weight. In particular, by using a resin having a specific gravity of 1 or less, such as polymethylpentene, the specific gravity of the planar antenna is 1 or less. It can be floated in water, and the use of planar antennas can be expanded.

  In the planar antenna of the present invention, the glass fiber is a woven or non-woven fiber base material containing a fiber selected from glass fiber, aramid fiber, polyester fiber, and carbon fiber. .

  By using such a fiber, the dimensional stability of the dielectric layer can be increased, and a planar antenna having good antenna characteristics can be easily manufactured.

  The planar antenna of the present invention is characterized in that a protective layer is provided on a part of the surface of the planar antenna.

  Thus, by providing the protective layer, the dielectric substrate can maintain good characteristics, prevent deterioration, maintain the shape, and the like.

  In the planar antenna of the present invention, the thickness of the planar antenna is 0.5 mm to 10 mm.

  In the planar antenna of the present invention, the UHF band radio wave is a radio wave having a frequency of 860 MHz to 960 MHz.

  Thus, in the case of a planar antenna using radio waves having a frequency of 860 MHz to 960 MHz, it is preferable that the thickness of the planar antenna is 1.5 mm or more because stable radio wave characteristics are exhibited. On the other hand, considering that the flat antenna is subjected to through-hole processing, it is preferable that the thickness be at least 10 mm.

  According to the present invention, since the dielectric layer is composed of a material in which polyolefin resin and glass fiber are laminated, the dimensional stability is excellent, the dielectric loss tangent is low, and the VSWR characteristic is 1.6 or less. It can be set as the planar antenna from which a high antenna characteristic is acquired.

  In addition, since polyolefin resin is used, it is very light compared to conventional planar antennas. In particular, the specific gravity can be reduced to 1 or less by using polymethylpentene (PMP) as the polyolefin resin. It can be floated on water, and the use of the planar antenna can be expanded.

FIG. 1 is a plan view illustrating a structure according to an embodiment of the planar antenna of the present invention. FIG. 2 is a partially enlarged view of FIG. FIG. 3 is a rear view of the planar antenna of FIG. FIG. 4 is a partially enlarged view of FIG. FIG. 5 is a partially enlarged AA sectional view of the planar antenna of FIG. FIG. 6 is a schematic diagram for explaining an example of a method for forming a planar antenna according to the present embodiment. FIG. 7 is a plan view illustrating the structure according to another embodiment of the planar antenna of the present invention. FIG. 8 is a partially enlarged view of FIG. FIG. 9 is a rear view of the planar antenna of FIG. FIG. 10 is a partially enlarged view of FIG. 11 is a partially enlarged AA sectional view of the planar antenna of FIG. FIG. 12 is a plan view illustrating a structure according to still another embodiment of the planar antenna of the present invention. FIG. 13 is a partially enlarged view of FIG. FIG. 14 is a configuration diagram of a conductor layer constituting the ground plate of the planar antenna of FIG. FIG. 15 is a rear view of the planar antenna of FIG. FIG. 16 is a partially enlarged view of FIG. 17 is a partially enlarged AA cross-sectional view of the planar antenna of FIG. FIG. 18 is a partially enlarged BB cross-sectional view of the planar antenna of FIG. FIG. 19 is a graph showing VSWR characteristics of a planar antenna according to an embodiment of the present invention. FIG. 20 is a graph showing the axial ratio characteristics of the planar antenna in one embodiment of the present invention. FIG. 21 is a graph showing the radiation directivity on the XY plane (horizontal plane) of the planar antenna in one embodiment of the present invention, and FIG. 21A is a graph showing the radiation directivity at a measurement frequency of 952 MHz. 21 (b) is a graph showing the radiation directivity at a measurement frequency of 953 MHz, and FIG. 21 (c) is a graph showing the radiation directivity at a measurement frequency of 954 MHz. FIG. 22 is a graph showing the radiation directivity on the XZ plane (vertical plane) of the planar antenna in one embodiment of the present invention, and FIG. 22 (a) is a graph showing the radiation directivity at a measurement frequency of 952 MHz, FIG. 22B is a graph showing the radiation directivity at a measurement frequency of 953 MHz, and FIG. 22C is a graph showing the radiation directivity at a measurement frequency of 954 MHz. FIG. 23 is a configuration diagram for explaining the configuration of a conventional patch antenna. FIG. 24 is a configuration diagram for explaining the configuration of a conventional patch antenna.

  Hereinafter, embodiments (examples) of the present invention will be described in more detail with reference to the drawings.

  1 is a plan configuration diagram for explaining a structure according to an embodiment of the planar antenna of the present invention, FIG. 2 is a partially enlarged view of FIG. 1, and FIG. 3 is a rear configuration diagram of the planar antenna of FIG. 4 is a partially enlarged view of FIG. 3, and FIG. 5 is a partially enlarged AA sectional view of the planar antenna of FIG.

  As shown in FIGS. 1 to 5, the planar antenna 10 in this embodiment is a planar antenna for linear polarization, and includes a conductor layer 12 that constitutes a ground plate, a dielectric layer 14, and a conductor that constitutes a patch element. Layer 16.

  Further, the planar antenna 10 is provided with a through hole 26 penetrating from the ground plate (conductor layer 12) to the patch element (conductor layer 16), and the ground plate (conductor layer 12) is passed through the through hole 26. A feed line (not shown) is inserted from the side to the patch element (conductor layer 16) side and connected to the feed point 16a of the patch element (conductor layer 16). In addition, when connecting the feed point 16a and a feed line, it can adhere | attach with a solder etc., for example.

  The ground plate (conductor layer 12) is provided with a grounding point 12a, and the grounding point 12a and an earth wire (not shown) are connected. With this configuration, when the planar antenna 10 is used, the ground plate (conductor layer 12) can be electrically grounded. In addition, when connecting the grounding point 12a and a ground wire, it can adhere | attach with a solder etc., for example.

  Reference numeral 12b denotes an adhesion point for bonding the power supply line and the conductor layer 12 with, for example, solder so that the power supply line inserted into the through hole 26 does not wobble or fall off.

In addition, as shown in FIG. 4, a part of the conductor layer 12 is removed so that the bonding point 12b and the ground plate 12c are not electrically connected. (Hereinafter, when simply referred to as the ground plate 12c, it means “a portion of the conductor layer 12 excluding the bonding point 12b”.)
Although the material of the conductor layer 12 and the conductor layer 16 will not be specifically limited if it is an electroconductive material, For example, it is preferable to use metals with high conductivity, such as copper and gold | metal | money. As will be described later, in order to form the planar antenna 10 by being laminated with the dielectric layer 14, the conductor layer 12 and the conductor layer 16 are made of a film-like conductive material, that is, a copper foil (eg, an electrolytic copper foil or Rolled copper foil) or gold foil is preferably used.

  Moreover, although the thickness of the conductor layer 12 and the conductor layer 16 is not specifically limited, Usually, it is 5-70 micrometers, Preferably, it is about 9-35 micrometers.

  The dielectric layer 14 is formed by laminating a polyolefin resin and glass fiber.

  The polyolefin resin is not particularly limited. For example, polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), cycloolefin polymer (COP), polyetherimide (PEI), polyethylene terephthalate ( PEN) can be used. Polyolefin resin foam materials are not preferred because they lack dimensional stability.

  In addition, by selecting a low specific gravity material such as polymethylpentene (PMP) as the polyolefin resin, for example, the specific gravity of the planar antenna can be reduced to 1 or less, and can be floated on water, for example. The use of a planar antenna can be expanded.

  Further, the glass fiber is not particularly limited, but for example, a woven or non-woven fiber base material containing fibers selected from glass fibers, aramid fibers, polyester fibers, carbon fibers and the like may be used. it can.

  In addition, in order to laminate | stack polyolefin resin and glass fiber, it is preferable to use what formed the polyolefin resin and glass fiber in the film form.

  The thickness of the film-like polyolefin resin (hereinafter also referred to as “polyolefin resin film”) is not particularly limited, but is preferably about 50 μm. As such a polyolefin resin film, for example, a commercially available “OPYRAN (registered trademark)” (manufactured by Mitsui Chemicals, Inc.) can be used as a PMP film.

  The thickness of the film-like glass fiber (hereinafter also referred to as “glass fiber film”) is not particularly limited, but is preferably about 30 μm to 190 μm. As such a glass fiber film, for example, “E14A 04 (trade name)” (manufactured by Unitika Ltd.), “WEA18T (trade name)” (manufactured by Nittobo Co., Ltd.) and the like can be used.

  The polyolefin resin film 14a, the glass fiber film 14b, and the conductor layer 16 constituting the conductor layer 12 and the dielectric layer 14 are laminated, and the laminate is heated and pressurized and heat-sealed as will be described later. Thus, the planar antenna 10 of this embodiment is manufactured.

  The thickness of the planar antenna 10 is usually about 1.5 mm to 10 mm, preferably about 2 mm to 6 mm. If the thickness of the planar antenna 10 is less than 1.5 mm, stable desired radio wave characteristics cannot be obtained. If the thickness is greater than 10 mm, the workability is poor, and for example, a problem that through-hole processing cannot be performed occurs.

  Therefore, the thickness of the conductor layer 12, the polyolefin resin film 14a, the glass fiber film 14b, and the conductor layer 16 and the number of the polyolefin resin film 14a and the glass fiber film 14b are set so that the thickness of the planar antenna 10 is as described above. Need to be determined.

  The planar antenna 10 of the present embodiment is formed by laminating the conductor layer 12, the dielectric layer 14, and the conductor layer 16 as described above, and heating and pressurizing and heat-sealing.

  Specifically, as shown in FIG. 6, the buffer metal layer 18 in a state where the conductor layer 12, the polyolefin resin film 14 a and the glass fiber film 14 b constituting the dielectric layer 14, and the conductor layer 16 are laminated in multiple layers. , 20 and sandwiched by heating / pressurizing dies 19, 21.

  Reference numeral 14c denotes a polyolefin resin film that has been subjected to a surface treatment such as an etching treatment or a plasma treatment in order to enhance the adhesion to the conductor layers 12 and 16.

In this state, the heating and pressurizing dies 19, 21 are heated to the melting point of the polyolefin resin film 14a or higher (in this embodiment, 240 ° C or higher, preferably 240 ° C to 260 ° C, which is the melting point of PMP). Then, pressure is applied in the thickness direction (in the direction of arrow X shown in FIG. 6) at a predetermined pressure for a predetermined time (in this embodiment, about 8 to 15 kg / cm ² for about ² to 10 minutes).

  Thus, by heating and pressurizing and heat-sealing, the conductor layer 12, the dielectric layer 14, and the conductor layer 16 are joined and integrated, and the planar antenna 10 is manufactured.

  In this embodiment, the dielectric layer 14 is formed using 19 sheets of the polyolefin resin film 14a, 20 sheets of the glass fiber film 14b, and 2 sheets of the polyolefin resin film 14c subjected to the surface treatment. The number of antennas is not particularly limited, and can be changed as appropriate as long as the thickness of the planar antenna 10 is selected as described above.

  In this embodiment, a protective layer 28 and a protective layer 30 are provided to protect the surfaces of the conductor layer 12 and the conductor layer 16. In addition, in order to form the grounding point 12a, the adhesion point 12b, and the feeding point 16a described above, the protective layers 28 and 30 are not provided on the conductor layer 12 and part of the conductor layer 16.

  Such a protective layer is not particularly limited, and a resist such as a photoresist or a screen printing resist, a protective film, or the like can be used. In this embodiment, the protective layer 28 and the protective layer 30 are provided, but the protective layer may not be provided.

  In FIG. 5, the thicknesses of the conductor layer 12, the dielectric layer 14, the conductor layer 16, the protective layer 28, and the protective layer 30 are drawn differently from actual scales for explanation. In FIG. 6, the conductor layer 12, the polyolefin resin film 14 a, the glass fiber film 14 b, the surface-treated polyolefin resin film 14 c, the conductor layer 16, the buffer metal layers 18 and 20, and the heating and pressurizing mold 19. , 21 are drawn differently from the actual scale for the purpose of explanation.

  7 is a plan configuration diagram for explaining a structure according to another embodiment of the planar antenna of the present invention, FIG. 8 is a partially enlarged view of FIG. 7, and FIG. 9 is a rear configuration diagram of the planar antenna of FIG. 10 is a partially enlarged view of FIG. 9, and FIG. 11 is a partially enlarged AA sectional view of the planar antenna of FIG. 7.

  The planar antenna 10 of this embodiment has basically the same configuration as that of the planar antenna 10 shown in FIGS. 1 to 6 and also has the same principle. Therefore, the same components are denoted by the same reference numerals. Detailed description thereof will be omitted.

  In FIG. 11, the thicknesses of the conductor layer 12, the dielectric layer 14, the conductor layer 16, the protective layer 28, and the protective layer 30 are drawn differently from actual scales for explanation.

  The planar antenna 10 in this embodiment is a planar antenna for circular polarization, and has a component mounting portion 12d formed so that a part of the conductor layer 12 is removed and is not electrically connected to the ground plate 12c. ing.

  The impedance of the planar antenna 10 can be controlled by mounting an electronic component (not shown) such as a chip resistor on the component mounting portion 12d.

  12 is a plan view illustrating a structure according to still another embodiment of the planar antenna of the present invention, FIG. 13 is a partially enlarged view of FIG. 12, and FIG. 14 is a ground plate of the planar antenna of FIG. FIG. 15 is a rear view of the planar antenna of FIG. 12, FIG. 16 is a partially enlarged view of FIG. 15, and FIG. 17 is a partially enlarged AA of the planar antenna of FIG. 18 is a partially enlarged BB sectional view of the planar antenna of FIG.

  The planar antenna 10 of this embodiment has basically the same configuration as that of the planar antenna 10 shown in FIGS. 1 to 6 and also has the same principle. Therefore, the same components are denoted by the same reference numerals. Detailed description thereof will be omitted.

  The planar antenna 10 in this embodiment is a broadband planar antenna, and is provided with a second dielectric layer 32 and a stripline circuit 34.

  The second dielectric layer 32 can be formed from a laminate of a polyolefin resin film and a glass fiber film, as with the dielectric layer 14.

  The stripline circuit 34 is a stripline circuit provided on the surface of the second dielectric layer 32, and the stripline circuit is designed so that high antenna characteristics can be stably obtained in a desired band. Can do.

  The planar antenna 10 in this embodiment configured as described above is provided with through holes 26a, 26b, and 26c that penetrate from the stripline circuit 34 to the patch element (conductor layer 16) side.

  The through holes 26a, 26b, and 26c are respectively mounted through holes, the through holes 26a and 26b are connected to the patch element 16, and the through hole 26c is connected to the ground plate 12c.

  As shown in FIG. 14, through-hole avoidance processing 12e is performed at locations corresponding to the through holes 26a and 26b of the conductor layer 12 so that the stripline circuit 34 and the ground plate 12c do not conduct.

  In the planar antenna 10 of this embodiment configured as described above, the feed line is connected to the feed point 34 a of the strip line circuit 34, and the ground line is connected to the ground point 34 b of the strip line circuit 34.

  It should be noted that the impedance of the planar antenna can be controlled by mounting electronic components (not shown) such as chip resistors on the component mounting portions indicated by reference numerals 34c and 34d.

  Thus, in the planar antenna 10 of the present embodiment, the ground plate 12c is constituted by the patch element (conductor layer 16) responsible for the radio wave radiation function, the second dielectric layer 32 responsible for adjustment of the antenna characteristics, and the stripline circuit 34. It is comprised so that it may be pinched | interposed.

  With this configuration, the antenna characteristics of the planar antenna 10 can be adjusted by adjusting the thickness of the second dielectric layer 32 and the line width of the stripline circuit 34, and according to a desired band. Antenna design can be easily performed.

  17 and 18, the thicknesses of the conductor layer 12, the dielectric layer 14, the conductor layer 16, the second dielectric layer 32, the stripline circuit 34, the protective layer 28, and the protective layer 30 are for explanation. It is drawn differently from the actual scale.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to this. For example, in the above embodiment, laminated polyolefin resin films, glass fiber films, etc. are arranged in the thickness direction. On the other hand, the planar antenna is formed by heating and pressing from above and below, but the planar antenna may be formed by pressing only the heating and pressing mold 21 downward in the thickness direction. Various changes can be made without departing from the object of the present invention, such as the formation method is not particularly limited.

  Hereinafter, measurement data of VSWR characteristics, axial ratio characteristics, and directivity of a planar antenna for circular polarization in one embodiment of the present invention, and for circular polarization manufactured using a material having poor dimensional stability as a comparative example The measurement data of the VSWR characteristic, the axial ratio characteristic, and the directivity of the planar antenna are shown.

  In the following examples and comparative examples, a planar antenna designed to have the best antenna characteristics with respect to a radio wave having a frequency of 953 MHz is used. If the VSWR characteristics are used, the value of VSWR at 953 MHz is It is preferable to minimize the axial ratio, and it is preferable that the axial ratio (Axis Ratio) at 953 MHz is minimized if it is an axial ratio characteristic.

  In the graph showing the VSWR characteristics, the horizontal axis indicates the frequency, and the central axis is 953 MHz. The vertical axis indicates the value of VSWR, and the smaller the value, the better the antenna characteristics are obtained.

  Moreover, in the graph which shows an axial ratio characteristic, the horizontal axis has shown the frequency (unit: MHz). The vertical axis indicates the value of the axial ratio (Axis Ratio). If the value of the axial ratio near 953 MHz is 3 or less, it can be said that good antenna characteristics are obtained.

  FIG. 19 is a graph showing the VSWR characteristic of the planar antenna in one embodiment of the present invention, FIG. 20 is a graph showing the axial ratio characteristic of the planar antenna in one embodiment of the present invention, and FIG. 21 is one embodiment of the present invention. It is a graph which shows the radiation directivity in XY plane (horizontal plane) of the planar antenna in a form, FIG.21 (a) is a graph which shows the radiation directivity in measurement frequency 952MHz, FIG.21 (b) is measurement frequency 953MHz. FIG. 21C is a graph showing the radiation directivity at a measurement frequency of 954 MHz.

  FIG. 22 is a graph showing the radiation directivity on the XZ plane (vertical plane) of the planar antenna in one embodiment of the present invention, and FIG. 22 (a) shows the radiation directivity at a measurement frequency of 952 MHz. FIG. 22B is a graph showing the radiation directivity at a measurement frequency of 953 MHz, and FIG. 22C is a graph showing the radiation directivity at a measurement frequency of 954 MHz.

  As described above, the planar antenna according to one embodiment of the present invention has excellent dimensional stability as compared with the conventional antenna, and can stably obtain high antenna characteristics as shown in FIGS. Results were obtained.

  In addition, like the planar antenna of the present invention, the production stability is improved by using a laminate formed by laminating a polyolefin resin and a glass fiber resin on a dielectric substrate and heat-sealing, Since a planar antenna having poor antenna characteristics cannot be formed, the manufacturing cost can be suppressed as a whole.

DESCRIPTION OF SYMBOLS 10 Planar antenna 12 Conductor layer 12a Grounding point 12b Adhesion point 12c Ground board 12d Component mounting part 12e Through-hole avoidance processing 14 Dielectric layer 14a Polyolefin resin film 14b Glass fiber film 14c Polyolefin resin film 16 surface-treated polyolefin resin film 16 Conductor layer ( Patch element)
16a Feed point 18 Buffer metal layer 19 Heating / pressing mold 20 Buffer metal layer 21 Heating / pressing mold 26 Through hole 26a Through hole 26b Through hole 26c Through hole 28 Protective layer 30 Protective layer 32 Second dielectric Layer 34 Stripline circuit 34a Feed point 34b Ground point 34c Component mounting part 34d Component mounting part 100 Patch antenna 110 Ground plate 110a Opening 120 Dielectric substrate 120b Dielectric substrate 130 Patch element 140 Feed line 150 Conductor pin 200 Patch antenna

The present invention has been invented in order to achieve the above-described problems and objects in the prior art, and the planar antenna of the present invention is a planar antenna for transmitting and receiving UHF radio waves,
A ground plate constituted by a conductor;
A dielectric layer composed of a dielectric;
A patch element constituted by a conductor;
With
The dielectric layer is a laminate formed by laminating a polyolefin resin and glass fiber and heat-sealing them.

Further, as in the planar antenna of the present invention, manufacturing stability is improved by using a laminate formed by laminating a polyolefin resin and glass fiber on a dielectric substrate and heat-sealing the antenna. Since a flat antenna with poor characteristics cannot be formed, the manufacturing cost can be suppressed as a whole.

Claims (7)

A planar antenna for transmitting and receiving UHF radio waves,
A ground plate constituted by a conductor;
A dielectric layer composed of a dielectric;
A patch element constituted by a conductor;
With
The planar antenna, wherein the dielectric layer is a laminate formed by laminating a polyolefin resin and a glass fiber resin and thermally fusing them. The planar antenna further includes a second dielectric layer made of a dielectric and a stripline layer constituting a stripline circuit,
2. The planar antenna according to claim 1, wherein the planar antenna is configured by laminating the ground plate, the dielectric layer, the patch element, the second dielectric layer, and the stripline layer in this order.   The planar antenna according to claim 1 or 2, wherein the polyolefin resin is a resin selected from polyethylene, polypropylene, polymethylpentene, cycloolefin polymer, polyetherimide, and polyethylene terephthalate.   The said glass fiber is a fiber base material of the woven fabric or nonwoven fabric containing the fiber selected from glass fiber, an aramid fiber, a polyester fiber, and a carbon fiber, In any one of Claim 1 to 3 characterized by the above-mentioned. The described planar antenna.   The planar antenna according to claim 1, wherein a protective layer is provided on a part of the surface of the planar antenna.   The planar antenna according to any one of claims 1 to 5, wherein the planar antenna has a thickness of 1.5 mm to 10 mm.   The planar antenna according to any one of claims 1 to 6, wherein the UHF band radio wave is a radio wave having a frequency of 860 MHz to 960 MHz.

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