JP6269857B2 - Planar antenna and manufacturing method thereof - Google Patents

Description

  The present invention relates to a planar antenna and a manufacturing method thereof, and more particularly, to a planar antenna including a radiating element on an antenna substrate and a manufacturing method thereof.

  Planar antennas are used to transmit and receive radio waves in radar devices and wireless communication devices. For example, Patent Documents 1 to 4 are known as related techniques.

  Patent Document 1 describes that a planar antenna includes a radome that covers an antenna circuit board, and the antenna element of the antenna circuit board is protected from the external environment by the radome. Patent Document 2 describes that in a planar antenna, a joint portion between a radome and a frame is bonded with silicon resin.

  Patent Document 3 describes that the rigidity of a radome is increased by disposing a honeycomb structure inside a casing of a planar antenna including a chassis and a radome (radome). Patent Document 4 describes that an airtight structure is formed by adhering a hard urethane foam to the surface of a slot array antenna in which a plurality of radiating elements are arranged.

JP 2010-4165 A Japanese Patent No. 3206016 JP-A-5-121931 Japanese Utility Model Publication No. 58-189611

  For example, in Patent Documents 1 and 2, the airtight structure of the planar antenna is realized by sealing the gap at the joint portion of the radome with a sealing material (sealing material).

  However, when the joint portion includes a material having a poor compatibility with a sealing material such as a dielectric, a sufficient adhesive force cannot be obtained. Therefore, in the related technology, there is a problem that depending on the material of the joining portion, the adhesive force is weak and the airtightness may be lowered.

  In view of such a problem, an object of the present invention is to provide a planar antenna capable of suppressing a decrease in airtightness and a manufacturing method thereof.

  The planar antenna according to the present invention includes an antenna substrate formed of a dielectric, a radiating element formed on a first surface of the antenna substrate, and the radiating element on the first surface of the antenna substrate. A metal pattern formed in a different region; a feed line formed on a second surface opposite to the first surface of the antenna substrate; and electrically connected to the radiating element; and the second surface. An antenna case for covering, and an antenna frame bonded to the metal pattern on the antenna substrate by a sealing material are provided.

  A planar antenna according to the present invention includes an antenna substrate formed of a dielectric, a radiating element formed on a first surface of the antenna substrate, and a region on the antenna substrate that is different from the radiating element. A formed metal pattern, a feed line formed on a surface different from the first surface of the antenna substrate, electrically connected to the radiating element, and an antenna case covering the feed line, The metal pattern and the antenna case are bonded with a sealing material.

  In the method for manufacturing a planar antenna according to the present invention, the antenna substrate is formed of a dielectric, and a radiating element is formed on the first surface of the antenna substrate by etching, and the antenna substrate is formed on the first surface of the antenna substrate. Forming a metal pattern in a region different from the radiating element, forming a feeding line electrically connected to the radiating element on a second surface of the antenna substrate opposite to the first surface; The second surface is covered with an antenna case, an antenna frame is fixed on the antenna substrate, and the antenna frame and the metal pattern are bonded together with a sealing material.

  ADVANTAGE OF THE INVENTION According to this invention, the planar antenna which can suppress the fall of airtightness, and its manufacturing method can be provided.

It is a top view which shows the outline | summary of the planar antenna which concerns on embodiment. It is sectional drawing which shows the outline | summary of the planar antenna which concerns on embodiment. 1 is an exploded perspective view showing a configuration of a planar antenna according to Embodiment 1. FIG. 1 is a plan view showing a configuration of a planar antenna according to a first embodiment. 1 is a cross-sectional view illustrating a configuration of a planar antenna according to a first embodiment. 2 is an enlarged cross-sectional view illustrating a configuration of a planar antenna according to Embodiment 1. FIG. 2 is an enlarged cross-sectional view showing an internal configuration of an antenna substrate according to Embodiment 1. FIG. 8 is a cross-sectional view for explaining the method for manufacturing the planar antenna according to the first embodiment. FIG. 8 is a cross-sectional view for explaining the method for manufacturing the planar antenna according to the first embodiment. FIG. 8 is a cross-sectional view for explaining the method for manufacturing the planar antenna according to the first embodiment. FIG. 8 is a cross-sectional view for explaining the method for manufacturing the planar antenna according to the first embodiment. FIG. 8 is a cross-sectional view for explaining the method for manufacturing the planar antenna according to the first embodiment. FIG. 6 is a plan view showing a configuration of a planar antenna according to Embodiment 2. FIG. 6 is a cross-sectional view illustrating a configuration of a planar antenna according to Embodiment 3. FIG. It is a top view which shows the outline | summary of the planar antenna of a reference example. It is sectional drawing which shows the outline | summary of the planar antenna of a reference example. It is a top view which shows the outline | summary of the planar antenna of another reference example. It is sectional drawing which shows the outline | summary of the planar antenna of another reference example.

(Outline of the embodiment)
When supplying a large amount of power to a planar antenna, it is necessary to consider the discharge generated between a plurality of feed lines that feed power to the radiating element of the antenna. In general, this discharge phenomenon tends to occur when the atmospheric pressure around the feeder line is low.

  For example, when a plane antenna is mounted on an aircraft or the like, there is a problem that the possibility of occurrence of a discharge phenomenon increases because the external air pressure decreases as the flight altitude increases. Therefore, in order to set the input power high and supply large power to the planar antenna, it is necessary to suppress the influence of the discharge phenomenon when the atmospheric pressure is lowered.

  First, a reference example before application of the embodiment is examined. FIG. 8A is a schematic plan view of a planar antenna 900 of a reference example, and FIG. 8B is a schematic cross-sectional view thereof. As shown in FIGS. 8A and 8B, the planar antenna 900 of the reference example includes an antenna substrate 1, an antenna case 2, and a radome 10. In the present specification, the positive side in the Z-axis direction may be referred to as “up” and the negative side in the Z-axis direction may be referred to as “down”.

  A plurality of radiating elements 4 are arranged in a matrix, for example, on the radiating element forming surface 1a (the first surface or the upper surface of the antenna substrate 1) of the flat antenna substrate 1. A plurality of radiating elements 4 are electrically connected to the feed line forming surface 1b (the second surface facing the first surface or the lower surface of the antenna substrate 1) of the antenna substrate 1 facing the radiating element forming surface 1a. A plurality of feed lines 9 are arranged in a strip-line shape, for example.

  The antenna case 2 is formed in a concave shape so as to cover the entire feed line forming surface 1b of the antenna substrate 1, and the antenna substrate 1 can be accommodated inside the concave shape. A support portion 2 a that is a step for supporting the antenna substrate 1 is formed on the entire inner wall of the antenna case 2. The support portion 2 a is lower than the edge portion 2 b of the antenna case 2 and is formed to be one step higher than the bottom portion of the antenna case 2.

  The support portion 2 a is fixed so as to support the entire outer periphery of the antenna substrate 1, and an airtight space 8 a is formed between the feed line forming surface 1 b of the antenna substrate 1 and the bottom portion of the antenna case 2. Further, the entire outer periphery of the flat radome 10 is fixed to the edge 2 b of the antenna case 2, and an airtight space 8 b is formed between the radiating element forming surface 1 a of the antenna substrate 1 and the radome 10.

  In the planar antenna 900 of the reference example of FIGS. 8A and 8B, the entire antenna case 2 that houses the antenna substrate 1 is sealed by the radome 10 to form airtight spaces 8a and 8b. For this reason, when a planar antenna is large, a large radome is required according to the antenna, and the strength of the radome may be insufficient. It is difficult in terms of strength to realize an airtight structure with a large radome so as to cope with an environment where air pressure is low such as an aircraft. In addition, when the airtight radome 10 is installed at a position near the radiation surface of the radiating element 4, a reflected wave 11 is generated by the radome, so that there is a high possibility that the radiation pattern is degraded.

  Further, another reference example before application of the embodiment will be examined. FIG. 9A is a schematic plan view of a planar antenna 910 of a reference example, and FIG. 9B is a schematic cross-sectional view thereof. As shown in FIGS. 9A and 9B, the planar antenna 910 of the reference example includes an antenna substrate 1, an antenna case 2, and an antenna frame 3.

  In the planar antenna 910 of the reference example, similarly to FIGS. 8A and 8B, a plurality of radiating elements 4 are arranged in a matrix on the radiating element forming surface 1 a of the antenna substrate 1, and on the feed line forming surface 1 b of the antenna substrate 1. A plurality of feed lines 9 are arranged in a strip shape. In addition, the support portion 2 a of the antenna case 2 is fixed so as to support the entire outer periphery of the antenna substrate 1, and an airtight space 8 is formed between the feed line forming surface 1 b of the antenna substrate 1 and the bottom portion of the antenna case 2. The plurality of radiating elements 4 are not sealed and are exposed to the outside.

  In this example, the antenna frame 3 is fixed to the antenna substrate 1 and the antenna case 2 from the radiation element forming surface 1 a side of the antenna substrate 1. In a state where the antenna substrate 1 is accommodated in the antenna case 2, the height of the edge 2 b of the antenna case 2 and the radiation element forming surface 1 a of the antenna substrate 1 is substantially the same. A frame-like antenna frame 3 surrounding the outer periphery of the antenna substrate 1 is fixed across the edge 2b of the antenna case 2 and the radiation element forming surface 1a of the antenna substrate 1. Further, the gap between the antenna frame 3 and the radiating element forming surface 1 a of the antenna substrate 1 is sealed with a sealing material 6, and the gap between the antenna frame 3 and the antenna case 2 is sealed with a sealing material 7.

  In the planar antenna 910 of the reference example of FIGS. 9A and 9B, the airtight space 8 is formed by sealing with the antenna frame 3 having the same shape as the outer periphery of the antenna substrate 1. As shown in FIGS. 8A and 8B, since the radome is not provided, there is no fear that the radome is insufficient in strength when the size is increased, and that no reflected wave is generated by the radome.

  However, a dielectric substrate material is generally used for the antenna substrate 1, and the dielectric substrate material such as a fluororesin (for example, Teflon (registered trademark)) has a property that the sealing material is difficult to adhere. Then, in the reference example of FIGS. 9A and 9B, the adhesive force between the antenna substrate 1 which is a dielectric substrate and the sealing material 6 is weak, and a sufficiently strong airtight structure cannot be realized.

  As described above, in the related technology, when a large amount of power is input to the planar antenna, a discharge phenomenon is likely to occur in an environment with a low atmospheric pressure, and it is difficult to determine the limit of power that can be input. Further, as in the reference example, there is a problem in strength even when a radome is used, and there is a problem in airtightness even when the antenna frame is simply bonded with a sealing material.

  Therefore, in the embodiment, the adhesive force of the sealing material is improved with respect to the reference example of FIGS. 9A and 9B. FIG. 1A is a schematic plan view of a planar antenna 100 according to an embodiment, and FIG. 1B is a schematic cross-sectional view thereof. As shown in FIGS. 1A and 1B, the planar antenna 100 includes an antenna substrate 1, an antenna case 2, and an antenna frame 3.

  In planar antenna 100 according to the embodiment, similarly to FIGS. 9A and 9B, a plurality of radiating elements 4 are arranged in a matrix on radiating element forming surface 1a of antenna substrate 1, and feed line forming surface of antenna substrate 1 is formed. A plurality of feed lines 9 are arranged in a strip shape in 1b. Further, a sealing copper foil (metal pattern) 5 is formed on the radiating element forming surface 1 a of the antenna substrate 1 at a distance from the plurality of radiating elements 4, for example, in the vicinity of the outer peripheral end of the antenna substrate 1.

  The antenna case 2 is fixed so that the entire outer periphery of the antenna substrate 1 is supported by the support portion 2a of the antenna case 2, and the antenna frame 3 is fixed across the edge 2b of the antenna case 2 and the radiation element forming surface 1a of the antenna substrate 1. . Further, the sealing frame 6 is sealed between the antenna frame 3 and the sealing copper foil 5 on the antenna substrate 1, and the sealing material 7 is sealed between the antenna frame 3 and the antenna case 2.

  As shown in FIG. 1A and FIG. 1B, in the embodiment, a metal pattern is formed on a dielectric substrate to which a sealing material is applied in order to increase the adhesive strength of the sealing material that secures airtightness inside and outside the antenna having a large pressure difference. To do. This metal pattern is formed by etching, for example. Compared to the dielectric, metal has a higher adhesive force of the sealing material, so that a strong airtight structure can be realized between the antenna frame and the metal pattern formed on the antenna substrate. Therefore, it is possible to suppress the risk of the discharge phenomenon by realizing an airtight structure in a reduced pressure environment such as that used in an aircraft. In particular, by forming the metal pattern by etching, the radiating element and the metal pattern can be simultaneously formed on the antenna substrate, and the metal pattern can be prevented from peeling off from the antenna substrate.

(Embodiment 1)
The first embodiment will be described below with reference to the drawings. The planar antenna according to the present embodiment is mounted on a radar device or a wireless communication device such as an aircraft, for example, and an antenna used in a low-pressure environment or a discharge phenomenon between feed lines may be a concern. An antenna that uses large power.

  2 is an exploded perspective view of the planar antenna 100 according to the present embodiment, FIG. 3 is a plan view thereof, FIG. 4A is a sectional view thereof, and FIG. 4B is an enlarged sectional view thereof. As shown in FIGS. 2, 3, 4A and 4B, the planar antenna 100 includes an antenna substrate 1, an antenna case 2, and an antenna frame 3.

  The antenna substrate 1 is a rectangular planar substrate, and a plurality of substrates each having a honeycomb material as a core are fused and laminated. The antenna substrate 1 is not limited to a rectangular shape, but may be other polygonal shapes or circular shapes. The antenna substrate 1 has a dielectric layer and a honeycomb layer laminated. The dielectric layer is a layer formed of a fluororesin (for example, Teflon), and the honeycomb layer (honeycomb structure) is a plate-like layer having a non-metallic insulator material such as a resin having a honeycomb structure.

  For example, as shown in FIG. 4B, the antenna substrate 1 has dielectric layers 101, 103, 106, and 109 and honeycomb layers 105 and 108 laminated thereon. Specifically, a plurality of feed lines 9 are formed in a strip-like pattern under the dielectric layer 101 (feed line forming surface 1b). The plurality of feed lines 9 are supplied with electric power from the outside and feed the plurality of radiation elements 4. A GND line 102 is formed on the dielectric layer 101, and a dielectric layer 103 is stacked on the dielectric layer 101 and the GND line 102. On the dielectric layer 103, an internal line 104 that is electrically connected to the feeder line 9 via a through hole or the like is formed. The internal line 104 may have the same pattern as the feeder line 9 or other patterns.

  A honeycomb layer 105 and a dielectric layer 106 are sequentially laminated on the dielectric layer 103 and the internal line 104. An internal element 107 that is electrically connected to the internal line 104 by electromagnetic coupling or the like is formed on the dielectric layer 106. The internal element 107 may have the same pattern as the radiating element 4 or other patterns. A honeycomb layer 108 and a dielectric layer 109 are sequentially stacked on the dielectric layer 106 and the internal element 107. For example, as shown in FIG. 4C, the honeycomb layers 105 and 108 are formed by arranging hexagonal resins in a honeycomb shape. By providing the antenna substrate 1 with the honeycomb layer, the strength of the substrate can be improved.

  A plurality of radiating elements 4 and a sealing copper foil 5 are formed on the dielectric layer 109 (radiating element forming surface 1a). The plurality of radiating elements 4 are electrically connected to the internal element 107 by electromagnetic coupling or the like, and radiate radio waves in a radiation pattern corresponding to power feeding from the power feeding line 9. As shown in FIG. 3, the plurality of radiating elements 4 are rectangular metal films (metal patterns) such as copper, and are formed by etching so as to be arranged in a pattern such as a matrix. For example, when the planar antenna 100 is a dual-polarized antenna, each radiating element 4 may be square, and when one polarization is not used, each radiating element 4 may be rectangular.

  The sealing copper foil 5 is a metal pattern for sealing and adhering between the antenna frame 3 and the antenna substrate 1 with a sealing material 6. The sealing copper foil 5 is made of the same material as the radiating element 4 and is made of copper as an example of a metal. By using the same material for the sealing copper foil 5 and the radiating element 4, they can be simultaneously formed in one etching process. In the present embodiment, copper is used as the sealing material, but the material is not limited to copper, and other metals such as aluminum, alloys containing copper, and the like may be used. Furthermore, the material is not limited to metal, and any material may be used as long as it can achieve both adhesion with the antenna substrate 1 and adhesion with the sealing material 6. For example, the sealing copper foil 5 and the radiating element 4 may be formed of different materials, and the adhesiveness may be improved by using the sealing copper foil 5 as a material having higher adhesive force. The sealing copper foil 5 and the radiating element 4 may be plated with gold or the like in order to prevent corrosion. A form in which a material for preventing corrosion is applied is not limited to gold plating.

  As shown in FIG. 3, the sealing copper foil 5 is formed in a region different from the radiating element 4 of the single antenna substrate. In particular, the sealing copper foil 5 is formed in a strip shape by etching along the inner side of the antenna frame 3 so as not to affect the radiation pattern by keeping an appropriate distance from the radiation element 4. Specifically, it is preferable that the distance is not less than 1 / 4λ (λ: wavelength of radio wave used) as an appropriate interval. Furthermore, it is preferable that the appropriate interval is more than 1 / 2λ (λ: wavelength of radio wave used). However, the interval is not limited to the above-described appropriate interval, and may be any interval that does not affect the radiation pattern. It can be said that the sealing copper foil 5 is formed so as to surround the vicinity of the outer peripheral end portion of the antenna substrate 1. By forming the sealing copper foil 5 in the vicinity of the outer peripheral end portion of the antenna substrate 1 to be a bonded portion with the antenna frame 3, the adhesive force between the antenna frame 3 and the antenna substrate 1 can be reliably improved. In the present embodiment, the outer periphery of the antenna substrate 1 is formed so as to extend. However, the sealing copper foil 5 may be formed only partially in a range in which airtightness is ensured. Specifically, the case where it forms in the shape of a broken line, a U-shape, C-shape etc. can be considered.

  As shown in FIG. 4A, the antenna case 2 is a case that houses the antenna substrate 1 and is a concave case that matches the shape of the antenna substrate 1. For example, the antenna case 2 is formed of a metal such as aluminum. The entire inner wall of the antenna case 2 has a support portion 2a which is a step for placing and supporting the antenna substrate 1. The support portion 2 a is lower than the edge portion 2 b of the antenna case 2 and is formed to be one step higher than the bottom portion of the antenna case 2. A support portion 2 a of the antenna case 2 is fixed so as to support the entire outer periphery of the antenna substrate 1, and an airtight space 8 is formed between the feed line forming surface 1 b of the antenna substrate 1 and the bottom portion of the antenna case 2. The feed line 9 is exposed in the airtight space 8. The radiating element 4 is exposed to the outside.

  As shown in FIG. 4A, the antenna frame 3 is provided on the upper side of the antenna substrate 1 in order to sandwich the antenna substrate 1 with the antenna case 2. The height of the edge 2b of the antenna case 2 and the radiation element forming surface 1a of the antenna substrate 1 is substantially the same, straddling the edge 2b of the antenna case 2 and the radiation element forming surface 1a of the antenna substrate 1, The antenna frame 3 is fixed. For example, the antenna frame 3 is formed of a metal such as aluminum.

  As shown in FIGS. 2 and 3, the antenna frame 3 has a shape that surrounds the outer periphery of the antenna substrate 1 and has the same shape as the end of the antenna case 2. The antenna frame 3, the antenna substrate 1, and the antenna case 2 are fixed by a plurality of bolts 12, and the antenna substrate 1 is sandwiched between the antenna frame 3 and the support portion 2 a of the antenna case 2. In a state where the antenna substrate 1 is sandwiched, the antenna frame 3 and the sealing copper foil 5 may be in contact with each other or may not be in contact with each other. For example, the corrosion of the copper foil 5 for sealing can be suppressed by making the antenna frame 3 and the copper foil 5 for sealing non-contact.

  A gap between the sealing copper foil 5 and the antenna frame 3 is filled with a sealing material 6. That is, the surface of the sealing copper foil 5 and the inner peripheral portion of the antenna frame 3 are sealed and bonded by the sealing material 6 so that there is no gap. Further, the gap between the antenna case 2 and the antenna frame 3 is filled with a sealing material 7. That is, the edge portion 2b of the antenna case 2 and the outer peripheral portion of the antenna frame 3 are sealed and bonded by the sealing material 7 so that there is no gap. The sealing copper foil 5 and the antenna frame 3 are bonded to each other with the sealing material 6, and further, the antenna case 2 and the antenna frame 3 are bonded to each other with the sealing material 7, thereby providing a completely sealed confidential structure. . For example, the sealing materials 6 and 7 are silicon-based or epoxy-based sealing materials.

  Next, a method for manufacturing planar antenna 100 according to the present embodiment will be described with reference to FIGS. 5A to 5E.

  First, as shown in FIG. 5A, the antenna substrate 1 is formed. That is, the antenna substrate 1 is formed by laminating the dielectric layer and the honeycomb layer. Specifically, as shown in FIG. 4B, dielectric layer 101, GND line 102, dielectric layer 103, internal line 104, honeycomb layer 105, dielectric layer 106, internal element 107, honeycomb layer 108, dielectric layer 109 Are sequentially stacked to form the antenna substrate 1.

  Subsequently, as shown in FIG. 5B, metal films 110 are formed on the upper and lower sides of the antenna substrate 1. A metal film 110 is formed on the entire surface of the dielectric layer 109 (radiating element forming surface 1a) and the entire surface of the lower surface of the dielectric layer 101 (feeding line forming surface 1b) by vapor deposition or the like. By forming the metal film 110 by vapor deposition, the metal film 110 can be firmly attached to the antenna substrate 1. Therefore, even if the sealing copper foil 5 is formed from the metal film 110 and sealing is performed on the sealing copper foil 5 as in the present embodiment, the sealing copper foil 5 is not peeled off from the antenna substrate 1. .

  Subsequently, as shown in FIG. 5C, the radiation element 4, the sealing copper foil 5, and the feed line 9 are formed on the upper and lower sides of the antenna substrate 1 by etching. That is, the metal film 110 on the upper surface of the antenna substrate 1 is etched to form the radiating element 4 and the copper foil 5 for sealing, and the metal film 110 on the lower surface of the antenna substrate 1 is etched to perform the feeding line. 9 are formed simultaneously. For the etching process, a general photolithography technique or etching technique may be used. For example, a mask that matches the pattern of the radiating element 4 and the copper foil 5 for sealing is formed on the metal film 110 on the upper surface of the antenna substrate 1, and a pattern of the feed line 9 is formed below the metal film 110 on the lower surface of the antenna substrate 1. The mask is formed of a photoresist or the like, dry etching or wet etching is performed through the mask to remove unnecessary portions of the metal film 110, and the mask is further removed, whereby a radiating element like the pattern of FIG. 4 and the copper foil 5 for sealing, and the feeder line 9 are formed. Here, the radiating element 4 and the sealing copper foil 5 and the feeder line 9 are formed simultaneously, but the radiating element 4 and the sealing copper foil 5 and the feeder line 9 are formed in separate steps. May be.

  Subsequently, as illustrated in FIG. 5D, the antenna substrate 1 is disposed on the antenna case 2, and the antenna frame 3 is fixed to the antenna substrate 1 and the antenna case 2 as illustrated in FIG. 5E. The outer peripheral end portion of the antenna substrate 1 is placed on the support portion 2 a that is the step of the antenna case 2, and the antenna frame 3 is placed on the outer peripheral portion of the antenna substrate 1 and the edge portion 2 b of the antenna case 2. The antenna board 1 is fixed between the antenna frame 3 and the antenna case 2 by inserting and fastening a plurality of bolts 12 from above the antenna case 2.

  Thereafter, sealing materials 6 and 7 are applied and sealed, and the planar antenna 100 is completed as shown in FIG. 4A. That is, the sealing copper foil 5 and the antenna frame 3 are sealed with the sealing material 6 along the entire inner periphery of the antenna frame 3, and the antenna case 2 and the antenna frame 3 are aligned along the entire outer periphery of the antenna frame 3. Is sealed with a sealing material 7.

  As described above, in the present embodiment, a sealing copper foil that is a metal pattern is formed on the antenna substrate by etching, and the sealing copper foil and the antenna frame are sealed with the sealing material. Since the sealing copper foil has a higher adhesive force with the sealing material than the antenna substrate which is a dielectric, the airtightness of the planar antenna can be improved. For example, by realizing an airtight structure in a reduced pressure environment such as that used in an aircraft or the like, it is possible to keep the air pressure relatively higher than the external pressure and suppress the occurrence of a discharge phenomenon.

  In the reference example of FIGS. 9A and 9B, since there is no sealing copper foil 5 as in the present embodiment, the adhesive force between the sealing material 6 and the antenna substrate 1 is insufficient, and airtight leakage from the adhesive portion 6a occurs. It is highly probable that it is difficult to apply a similar structure in an environment with a large pressure difference. 9A and 9B is not a sealing structure, but a method of sealing with packing is conceivable. However, if there is a large pressure difference, there is a limit to the sealing with packing.

  In general, the adhesive strength of the sealing material is much higher for metal materials than for Teflon-based materials. Therefore, in the present embodiment, the sealing material is not directly applied to the material used as the antenna substrate, but the sealing copper foil 5 is left as a pattern on the antenna substrate 1 by etching as described above, so that a metal antenna frame is formed. 3 is filled with the sealing material 6 to realize a strong airtight structure.

  When the atmospheric pressure outside the antenna is reduced, the structure is such that pressure is applied from the airtight space 8 to the outside of the antenna at the position of the sealing material 6, so that the strength of the sealing material 6 becomes very important. By sealing between the antenna frame 3 and the copper foil 5 for sealing with high strength, it is possible to suppress fluctuations in the air pressure in the airtight space even when the air pressure outside the antenna changes.

  Further, the required radiation pattern specification is strict, and the present invention can be applied to an antenna in which a radome for keeping airtightness cannot be provided at a short distance (for example, about several centimeters) from the antenna body. Since there is no radome, if the pressure difference between the airtight space and the outside of the antenna is large, the antenna substrate may bend due to the pressure, which not only affects the radiation pattern performance, but may also be unstable in the airtight structure There is. For this reason, in this embodiment, by using a honeycomb structure material for the antenna substrate to increase the substrate strength, it is possible to prevent the bending due to the pressure and to maintain the flatness. In particular, the strength can be further increased by stacking a plurality of honeycomb structures.

(Embodiment 2)
The present embodiment is another example of the shape of the metal pattern used for sealing. Except for the metal pattern, the second embodiment is the same as the first embodiment.

  FIG. 6 is a plan view of planar antenna 100 according to the present embodiment. As shown in FIG. 6, the metal pattern 5 a according to the present embodiment is formed in the vicinity of the outer peripheral end of the antenna substrate 1, and is also formed in a region between the plurality of radiating elements 4. A grid-like metal pattern 5 a is formed on the entire surface of the antenna substrate 1 except for a region separated from the plurality of radiating elements 4 at a predetermined interval. The metal pattern 5a is formed by etching as in the first embodiment. For example, in the metal pattern 5a, the pattern in the vicinity of the outer peripheral end portion of the antenna substrate 1 and the pattern between the plurality of radiating elements 4 may be continuously formed integrally, or separated and separated. It may be formed. The antenna characteristics can be set in more detail by forming them integrally or separately.

  By forming the metal pattern 5a between the plurality of radiating elements 4, the metal pattern 5a becomes a conductor cover of the planar antenna. That is, the metal pattern 5a can avoid unnecessary radiation from the feeder line and obtain desired antenna characteristics.

  As described above, by forming the metal pattern also between the plurality of radiating elements, the airtightness between the antenna frame and the antenna substrate is improved and desired antenna characteristics are obtained as in the first embodiment. It becomes possible.

(Embodiment 3)
This embodiment is an example in which an antenna case and an antenna frame are integrally formed. Except for the antenna case and the antenna frame, the second embodiment is the same as the first embodiment.

  FIG. 7 is a cross-sectional view of planar antenna 100 according to the present embodiment. As shown in FIG. 7, in the present embodiment, the antenna case 2 is configured by integrally forming a case portion 21 and a frame portion 22. Case portion 21 has the same shape as antenna case 2 of the first embodiment, and frame portion 22 has the same shape as antenna frame 3 of the first embodiment. In this case, the sealing material 6 bonds the frame 22 of the antenna case and the sealing copper foil 5 of the antenna substrate 1.

  Thus, even when the antenna case and the antenna frame are integrally formed, the airtightness between the antenna case and the antenna substrate can be improved as in the first embodiment.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

  For example, in order to suppress the discharge phenomenon that occurs when a large amount of power is input, it is better to have a higher atmospheric pressure. Therefore, the above airtight structure is used, and an air pressure higher than 1 atm is enclosed in the airtight space in the planar antenna. May be. In addition, the withstand power may be improved by filling the gas that fills the airtight space in the planar antenna with a gas that is less likely to cause a discharge phenomenon than air other than normal air.

  In addition, not only in a decompressed state such as an aircraft, but also in an outdoor environment where the temperature difference on the ground is severe, the pressure inside the antenna changes in proportion to the temperature, so sufficient airtightness is maintained. Otherwise, moisture may accumulate inside. Therefore, by improving the airtightness as described above, it is possible to prevent the antenna performance from being affected by dew condensation or the like in an environment where there is a great difference in temperature.

  Furthermore, in the case of an antenna used for an important line where communication is not allowed to be interrupted, even in a system in which an alarm is output when the pressure level is constantly lowered and pressure is constantly applied from the inside of the antenna. By using an antenna having an airtight structure, occurrence of communication interruption can be suppressed.

  Although the present invention has been described with reference to the exemplary embodiments, the present invention is not limited to the above. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the invention.

  This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2014-227676 for which it applied on November 10, 2014, and takes in those the indications of all here.

DESCRIPTION OF SYMBOLS 1 Antenna board | substrate 1a Radiation element formation surface 1b Feeding line formation surface 2 Antenna case 2a Support part 2b Edge part 3 Antenna frame 4 Radiation element 5 Copper foil for sealing 5a Metal pattern 6 Seal material 6a Adhesion part 7 Seal material 8, 8a, 8b Airtight space 9 Feed line 10 Radome 11 Reflected wave 12 Bolt 21 Case part 22 Frame part 100 Planar antenna 101 Dielectric layer 102 GND line 103 Dielectric layer 104 Internal line 105 Honeycomb layer 106 Dielectric layer 107 Internal element 108 Honeycomb layer 109 Dielectric Body layer 110 Metal film

Claims (10)

An antenna substrate formed of a dielectric;
A radiating element formed on the first surface of the antenna substrate;
A metal pattern formed in a region different from the radiating element on the first surface of the antenna substrate;
A feed line formed on a second surface opposite to the first surface of the antenna substrate and electrically connected to the radiation element;
An antenna case covering the second surface;
An antenna frame bonded to the metal pattern on the antenna substrate with a sealing material;
A planar antenna comprising: The metal pattern is formed by an etching process.
The planar antenna according to claim 1. The metal pattern is formed by the same etching process as the radiating element,
The planar antenna according to claim 2. The metal pattern is formed in the vicinity of the outer peripheral end of the first antenna substrate.
The planar antenna as described in any one of Claims 1 thru | or 3. A plurality of the radiating elements;
The metal pattern is further formed between the plurality of radiating elements,
The planar antenna according to claim 4. The metal pattern in the vicinity of the outer peripheral edge of the first antenna substrate and the metal pattern between the plurality of radiating elements are formed integrally or separately.
The planar antenna according to claim 5. The antenna substrate includes a honeycomb structure,
The planar antenna as described in any one of Claims 1 thru | or 6. The metal pattern is formed of the same material as the radiating element,
The planar antenna as described in any one of Claims 1 thru | or 7. An antenna substrate formed of a dielectric;
A radiating element formed on the first surface of the antenna substrate;
A metal pattern formed on a region different from the radiating element on the antenna substrate;
A feed line formed on a surface different from the first surface of the antenna substrate and electrically connected to the radiation element;
An antenna case covering the feeder line,
The planar antenna, wherein the metal pattern and the antenna case are bonded together by a sealing material. The antenna substrate is made of a dielectric,
Etching treatment forms a radiating element on the first surface of the antenna substrate, and forms a metal pattern in a region different from the radiating element on the first surface of the antenna substrate,
Forming a feed line electrically connected to the radiating element on a second surface opposite to the first surface of the antenna substrate;
Covering the second surface with an antenna case;
Fixing an antenna frame on the antenna substrate;
Bonding the antenna frame and the metal pattern with a sealing material,
A method for manufacturing a planar antenna.

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