FPC antenna, preparation method and electroplating forming mold

Abstract

The present invention discloses an FPC antenna, a preparation method and an electroplating molding mold. The FPC antenna includes a sheet metal antenna, a plastic base layer and an adhesive layer arranged in an electroplating manner, the top surface of the adhesive layer is attached to the bottom surface of the sheet metal antenna, and the plastic base layer covers the top surface of the sheet metal antenna. The preparation method includes the following steps: electroplating a sheet metal antenna on a reusable antenna mold; attaching a plastic base layer to the top surface of the sheet metal antenna and the top surface of the anti-sticking layer of the antenna mold; peeling off the antenna mold and the sheet metal antenna attached with the plastic base layer; attaching the adhesive layer to the bottom surface of the sheet metal antenna and the bottom surface of the plastic base layer to make an antenna package; cutting the package into single FPC antennas. The sheet metal antenna of the present invention is sandwiched between the plastic base layer and the adhesive layer, and there is no need to cover the surface of the sheet metal antenna with an ink solder mask layer. The structure and process of the FPC antenna are simple, and the cost is low.

Description

[Technical field]

[0001] The present invention relates to an antenna, and in particular to an FPC antenna, a preparation method thereof, and an electroplating forming die. [Background Technology]

[0002] Traditional mobile phone FPC antennas use copper foil as raw material, and the production process requires processes such as coating with photosensitive adhesive, exposure, development, etching, and film stripping, which consume a lot of metal and cause serious pollution problems. The utility model with patent number CN201420264748.8 provides a mobile phone FPC antenna to address the problems of existing mobile phone FPC antenna production processes wasting copper foil raw materials and generating a large amount of chemical wastewater. The mobile phone FPC antenna includes: a plastic substrate, a sheet metal antenna is provided on the upper surface of the plastic substrate by electroplating, an ink solder mask layer is provided on the surface of the sheet metal antenna, and an adhesive layer is provided on the lower surface of the plastic substrate. The mobile phone FPC antenna of this utility model no longer requires etching of the original copper foil to produce circuits. However, the mobile phone FPC antenna of this utility model needs to cover the surface of the sheet metal antenna with an ink solder mask layer, which has a complex structure and process and is costly. [Summary of the invention]

[0003] The technical problem to be solved by the present invention is to provide an FPC antenna with a simple structure and low cost.

[0004] Another technical problem to be solved by the present invention is to provide a method for preparing the above-mentioned FPC antenna.

[0005] Another technical problem to be solved by the present invention is to provide an electroplating forming mold for the above-mentioned FPC antenna.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is an FPC antenna, including a sheet metal antenna, a plastic base layer and a back adhesive layer arranged in an electroplating manner, the top surface of the back adhesive layer is attached to the bottom surface of the sheet metal antenna, and the plastic base layer covers the top surface of the sheet metal antenna.

[0007] In the FPC antenna described above, the top surface of the adhesive layer is bonded to the bottom surface of the plastic base layer on the periphery of the sheet metal antenna. The adhesive layer is double-sided adhesive.

[0008] The FPC antenna described above includes a plurality of metal electrodes. The plastic base layer includes windows corresponding to the metal electrodes, and the windows have the sheet metal antenna as the bottom surface. The metal electrodes are arranged in the windows and electroplated on the top surface of the sheet metal antenna.

[0009] The FPC antenna described above, the metal electrode includes a base plating and a top metal plating. The material of the base plating is copper, nickel, silver, tin, or a composite material of at least two of copper, nickel, tin and silver; the material of the top metal plating is gold, silver, copper, nickel, tin, or a composite material of at least two of gold, silver, copper, nickel and tin.

[0010] The FPC antenna described above includes a jumper printed on the top surface of the plastic base layer. The sheet metal antenna includes a planar spiral antenna and a pin line. The plastic base layer includes two jumper holes. The outer end of the planar spiral antenna is a first pin end, and the inner end is a first jumper end. The pin line includes a second pin end and a second jumper end. The first jumper hole is located directly above the first jumper end, and the second jumper hole is located directly above the second jumper end. The first end of the jumper passes downward through the first jumper hole and is connected to the first jumper end, and the second end of the jumper passes downward through the second jumper hole and is connected to the second jumper end.

[0011] A method for preparing the above-mentioned FPC antenna comprises the following steps:

[0012] 601) Electroplating a sheet metal antenna on a reusable antenna mold: the antenna mold includes a metal carrier and an anti-sticking layer attached to the top surface of the metal carrier, the anti-sticking layer includes a plurality of unit patterns arranged in a matrix, the unit patterns include hollow patterns corresponding to the shape of the sheet metal antenna, and copper is electroplated in the hollow pattern area to form the sheet metal antenna;

[0013] 602) affixing a plastic base layer on the top surface of the sheet metal antenna and the top surface of the anti-sticking layer;

[0014] 603) peeling off the antenna mold and the sheet metal antenna with the plastic substrate layer attached thereto;

[0015] 604) Adhesive layers are attached to the bottom surface of the sheet metal antenna and the bottom surface of the plastic base layer to form a package of a continuous FPC antenna;

[0016] 605) Cut the package into individual FPC antennas.

[0017] In the above-described preparation method, the plastic base layer includes a plurality of windows corresponding to the unit patterns. After step 602 is completed, metal electrodes are electroplated on the top surface of the sheet metal antenna in the window region of the plastic base layer.

[0018] The above-mentioned preparation method, the method for making the antenna mold includes the following steps:

[0019] 801) Using a stainless steel sheet as a metal carrier, coating the top surface of the stainless steel sheet with a photosensitive anti-sticking layer;

[0020] 802) The anti-sticking layer is exposed and developed to form a plurality of unit patterns arranged in a matrix, and the bottom surface of the hollow pattern is the top surface of the metal carrier.

[0021] The above-mentioned preparation method, the method for making the antenna mold includes the following steps:

[0022] 901) Using a stainless steel sheet as a metal carrier plate, coating an anti-sticking layer on the top surface of the stainless steel sheet;

[0023] 902) Scanning the anti-sticking layer with a laser to form a plurality of unit patterns arranged in a matrix, wherein the bottom surface of the hollowed-out pattern is the top surface of the metal carrier plate.

[0024] The above-mentioned preparation method, the method for making the antenna mold includes the following steps:

[0025] 1001) Using a stainless steel sheet as a metal carrier, coating a photosensitive adhesive on the top surface of the stainless steel sheet;

[0026] 1002) etching a plurality of protruding unit patterns arranged in a matrix on the photosensitive resin by photolithography, wherein the unit pattern includes a protruding pattern having the same shape as the sheet antenna,

[0027] 1003) applying an anti-stick coating on the top surface of the stainless steel sheet, removing the anti-stick coating on the surface of the photosensitive adhesive by mechanical means, removing the photosensitive adhesive layer with alkaline solution, retaining the remaining anti-stick coating, and obtaining a hollow pattern consistent with the shape of the sheet antenna.

[0028] In the preparation method described above, the sheet metal antenna includes a planar spiral antenna and a pin line, and the plastic base layer includes a plurality of groups of jumper holes corresponding to the unit pattern; each group of jumper holes includes two jumper holes, the outer end of the planar spiral antenna is a first pin end, and the inner end is a first jumper end; the pin line includes a second pin end and a second jumper end, the first jumper hole is located directly above the first jumper end, and the second jumper hole is located directly above the second jumper end; after step 602 is completed, a conductive paste is printed on the top surface of the plastic base layer to form a jumper, the first end of the jumper passes downward through the first jumper hole and is connected to the first jumper end, and the second end of the jumper passes downward through the second jumper hole and is connected to the second jumper end.

[0029] A plating forming mold for the above-mentioned FPC antenna includes a metal carrier and an anti-sticking layer coated on the top surface of the metal carrier. The anti-sticking layer includes a plurality of unit patterns arranged in a matrix. The unit patterns include hollow patterns corresponding to the shape of the sheet metal antenna. The bottom surface of the hollow pattern is the top surface of the metal carrier.

[0030] The sheet metal antenna of the present invention is sandwiched between the plastic base layer and the adhesive layer, and does not need to be covered with an ink solder resist layer on the surface of the sheet metal antenna. The structure and process of the FPC antenna are simple and the cost is low. [Brief Description of the Drawings]

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Figure 1 This is a front view of the FPC antenna according to embodiment 1 of the present invention.

[0033] Figure 2 FIG. 1 is a top view of the FPC antenna according to embodiment 1 of the present invention.

[0034] Figure 3 This is a top view of the FPC antenna in Example 1 of the present invention without the plastic base layer.

[0035] Figure 4 yes Figure 2 AA section view in.

[0036] Figure 5 Schematic diagram of step 1 of the method for preparing an FPC antenna according to embodiment 1 of the present invention.

[0037] Figure 6 Schematic diagram of step 2 of the method for preparing an FPC antenna according to embodiment 1 of the present invention.

[0038] Figure 7 Schematic diagram of step 3 of the method for preparing an FPC antenna according to embodiment 1 of the present invention.

[0039] Figure 8 Schematic diagram of step 4 of the method for preparing an FPC antenna according to embodiment 1 of the present invention.

[0040] Figure 9 Schematic diagram of step 5 of the method for preparing an FPC antenna in Example 1 of the present invention.

[0041] Figure 10 Schematic diagram of step 6 of the method for preparing an FPC antenna according to embodiment 1 of the present invention.

[0042] Figure 11 Schematic diagram of step 7 of the method for preparing an FPC antenna according to embodiment 1 of the present invention.

[0043] Figure 12 1 is a top view of the FPC antenna according to embodiment 2 of the present invention.

[0044] Figure 13 yes Figure 12 BB cross-section view in.

[0045] Figure 14 This is a top view of the FPC antenna in Example 2 of the present invention without the plastic base layer.

[0046] Figure 15 yes Figure 12 CC section view in. [Specific implementation method]

[0047] The structure of the FPC antenna in embodiment 1 of the present invention is as follows Figures 1 to 4 As shown, a dipole antenna for a mobile phone includes a sheet metal antenna 10 formed by electroplating copper, a plastic base layer 20 , a backing adhesive layer 30 and three metal electrodes 60 .

[0048] The top surface of the adhesive layer 30 is attached to the bottom surface of the sheet metal antenna 10, and the plastic base layer 20 covers the top surface of the sheet metal antenna 10. The sheet metal antenna 10 is composed of two parts 11 and 12.

[0049] At the periphery of the sheet metal antenna 10, the top surface of the adhesive layer 30 is bonded to the bottom surface of the plastic base layer 20. In this embodiment, the adhesive layer 30 is a double-sided adhesive.

[0050] The plastic base layer 20 has three windows 21 corresponding to the three metal electrodes 60, and the windows 21 have the sheet metal antenna 10 as the bottom surface; the metal electrodes 60 are arranged in the windows 21, fixed on the top surface of the sheet metal antenna 10 by electroplating, and electrically connected to the sheet metal antenna 10.

[0051] The metal electrode 60 includes a base metal coating 61 and a top metal coating 62. The base metal coating 61 is made of copper, nickel, silver, tin, or a composite material of at least two of the following: copper, nickel, tin, and silver. The top metal coating 62 is made of gold, silver, copper, nickel, tin, or a composite material of at least two of the following: gold, silver, copper, nickel, tin, and tin.

[0052] The method for preparing an FPC antenna according to embodiment 1 of the present invention comprises the following steps:

[0053] 1) If Figure 5 As shown, a flat stainless steel sheet 40 is used as a metal carrier, and a photosensitive anti-sticking layer 50 (release layer) is coated on the top surface of the stainless steel sheet 40:

[0054] 101) Cut the stainless steel sheet into rectangles of 280×120 mm in size. The thickness of the steel sheet is selected to be 0.152±0.008 mm. After cutting, paper is required between the stainless steel sheets to prevent scratches. A pallet is used between the processes to prevent deformation of the steel sheet.

[0055] 102) The surface of the stainless steel sheet is sandblasted and cleaned in sequence to ensure that there is no sand residue on the surface of the stainless steel sheet;

[0056] 103) For single-sided molds, green glue can be applied to the bottom of the steel sheet. The green glue should be free of wrinkles, steam pockets, and protrusions. Degrease the stainless steel sheet with the green glue applied to ensure that there is no oil stain on the surface of the stainless steel sheet.

[0057] 104) Screen printing photosensitive anti-sticking ink, use 200T screen printing, thickness 5-8μm, the ink should be evenly printed, and baked after screen printing at a temperature of 75℃ for 25 minutes;

[0058] 2) If Figure 6 As shown, the photosensitive anti-sticking layer 50 is exposed and developed to form a plurality of unit patterns arranged in a matrix, thereby forming a reusable antenna mold (antenna electroplating molding mold); the unit patterns include a hollow pattern 51 corresponding to the shape of the sheet metal antenna 10, and the bottom surface of the hollow pattern 51 is the top surface of the stainless steel sheet 40 to form the electroplating molding mold of the FPC antenna:

[0059] 201) using a film with a unit pattern drawn on it to perform registration exposure on the photosensitive anti-sticking layer, and controlling the exposure energy to be about 500 millijoules;

[0060] 202) The developing speed is controlled at 1.3-1.5m / min and the temperature is controlled at 30±2℃. The image accuracy after development should be controlled within the tolerance range of ±0.025mm; after development, the plate is baked at a temperature of 150℃ for 30min; and washed with water to make the exposed stainless steel sheet clean and free of pits;

[0061] 3) If Figure 7 As shown, copper is electroplated in the area of the hollow pattern 51 of the electroplating forming mold of the reusable FPC antenna, and the copper layer thickness is 5-6 μm to form a sheet metal antenna 10;

[0062] 4) If Figure 8 As shown, a plastic base layer 20 is laminated on the top surface of the sheet metal antenna 10 and the top surface of the anti-sticking layer 50, and the plastic base layer 20 has multiple groups of windows 21 corresponding to the unit patterns;

[0063] 5) If Figure 9 and Figure 10 As shown, a metal electrode 60 is electroplated on the top surface of the sheet metal antenna 10 within the window 21 of the plastic base layer 20. The metal electrode 60 includes a base nickel plating layer 61 and a top metal gold plating layer 62. The base nickel plating layer 61 has a thickness of 2-5 μm, and the top metal gold plating layer 62 has a thickness of about 2U".

[0064] 6) If Figure 10 As shown, the antenna mold composed of the stainless steel sheet 40 and the anti-sticking layer 50 is peeled off from the sheet metal antenna 10 and the plastic base layer 20; the peeled antenna mold can be reused;

[0065] 7) If Figure 11 As shown, a backing adhesive layer 30 is attached to the bottom surface of the sheet metal antenna 10 and the bottom surface of the plastic base layer 20. The backing adhesive layer 30 is a double-sided adhesive with a thickness of about 30 μm. The package of the sheet FPC antenna is made;

[0066] 8) Cutting the package into multiple individual FPC antennas: Using laser or mold forming, the connected package is divided into individual FPC antennas.

[0067] The FPC antenna electroplating forming mold prepared in steps 1 and 2 of the above embodiment of the method for preparing the FPC antenna can also be prepared by the following alternative method:

[0068] Method 1) A non-stick coating (release layer) is applied to a stainless steel sheet to be electroplated. A laser is then used to scan the surface of the non-stick coating multiple times to carve out a plurality of unit patterns arranged in a matrix. The unit patterns include windows that are consistent with the shape of the antenna, and a sheet metal antenna is electroplated in the windows.

[0069] Method 2) A layer of photosensitive resin is coated on a stainless steel sheet for electroplating. A plurality of raised unit patterns arranged in a matrix are formed on the photosensitive resin using a photolithography process. The unit patterns include raised patterns that are consistent with the shape of the sheet antenna. An anti-stick coating (release layer) is sprayed on the top surface of the stainless steel sheet and the raised patterns. The anti-stick coating on the surface of the raised pattern of the photosensitive resin is removed by grinding. The photosensitive resin layer is then removed with an alkaline solution, while retaining the anti-stick coating. A window consistent with the shape of the antenna is obtained, and the sheet metal antenna is electroplated in the window.

[0070] The structure of the FPC antenna in embodiment 2 of the present invention is as follows Figures 12 to 15 The figure shows a single-sided NFC antenna, comprising a sheet metal antenna 10 formed using electroplated copper, a plastic base layer 20, an adhesive layer 30, and a jumper wire 70 printed on the top surface of the plastic base layer 20. The sheet metal antenna 10 includes a planar spiral antenna 13 and a lead wire 14. The plastic base layer 20 has two jumper wire holes 22. The outer end of the planar spiral antenna 13 has a first pin 131, and the inner end is a jumper wire end 132. The outer end of the lead wire 14 has a second pin 141, and the inner end is a jumper wire end 142. The first jumper wire hole is located directly above the jumper wire end 132, and the second jumper wire hole is located directly above the jumper wire end 142. The first end of the jumper wire 70 extends downward through the first jumper wire hole to connect to the jumper wire end 132 of the planar spiral antenna 13. The second end of the jumper wire 70 extends downward through the second jumper wire hole to connect to the jumper wire end 142 of the lead wire 14. The middle portion of the jumper wire 70 is separated and insulated from the rest of the planar spiral antenna 13 by the plastic base layer 20. A double-sided adhesive layer 30 is adhered to the bottom surfaces of the planar helical antenna 13 and lead wire 14, as well as the bottom surface of the main portion of the plastic base layer 20. The first lead 131 and the second lead 141 are exposed outside the adhesive layer 30. In this embodiment, to reduce the overall resistance of the jumper 70, the jumper 70 is composed of a jumper base 71 formed by printing conductive paste and an electroplated metal layer 72 on the outer surface of the jumper base 71.

[0071] The method for preparing the FPC antenna of Example 2 of the present invention is substantially the same as the method for preparing the FPC antenna of Example 1 of the present invention, with the main difference being step 5. In step 5 of preparing the FPC antenna of Example 2 of the present invention, after step 4 of Example 1 is completed, a conductive paste is printed on the top surface of the plastic base layer 20 to form a jumper base 71. The first end of the jumper base 71 is passed downward through the first jumper hole of the plastic base layer 20 to connect to the jumper end 132 of the planar helical antenna 13. The second end of the jumper base 71 is passed downward through the second jumper hole of the plastic base layer 20 to connect to the jumper end 142 of the lead wire 14. The middle portion of the jumper base 71 is separated and insulated from the rest of the planar helical antenna 13 by the plastic base layer 20. The outer surface of the jumper base 71 may be electroplated with a metal layer 72 to reduce the overall resistance of the jumper 70. After step 5 is completed, steps 6 to 8 of Example 1 are continued to obtain a single NFC antenna.

[0072] In the FPC antenna of the above embodiment of the present invention, the sheet metal antenna is sandwiched between the plastic base layer and the adhesive layer. There is no need to cover the surface of the sheet metal antenna with an ink solder mask layer. The structure and manufacturing process of the FPC antenna are simple and the cost is low. After the antenna mold is manufactured in the above embodiment of the present invention, the sheet metal used to produce the antenna no longer needs to use an FPC substrate. Instead, the antenna mold is simply electroplated, thus avoiding the substrate and the processes of coating the substrate with photosensitive adhesive, exposing the photosensitive adhesive, developing, etching, and stripping the film required by the traditional process. During the electroplating of the surface metal of the antenna mold, since the rigidity of the antenna mold is much higher than that of the FPC, quality problems such as wrinkles caused by the operation process can be avoided. The entire process of the above embodiment of the present invention is simple, stable, resource-saving, and low-cost.

Claims

1. An FPC antenna, comprising a sheet metal antenna, a plastic base layer and an adhesive layer arranged in an electroplating manner, characterized in that: The top surface of the adhesive layer is attached to the bottom surface of the sheet metal antenna, and the plastic base layer covers the top surface of the sheet metal antenna; the sheet metal antenna is formed by electroplating on a reusable antenna mold and then transferred to the plastic base layer.

2. The FPC antenna according to claim 1, wherein: On the periphery of the sheet metal antenna, the top surface of the adhesive layer is bonded to the bottom surface of the plastic base layer, and the adhesive layer is a double-sided adhesive.

3. The FPC antenna according to claim 1, wherein: It comprises a plurality of metal electrodes. The plastic base layer comprises windows corresponding to the metal electrodes. The windows have a sheet metal antenna as the bottom surface. The metal electrodes are arranged in the windows and electroplated on the top surface of the sheet metal antenna.

4. The FPC antenna according to claim 3, characterized in that: The metal electrode includes a base coating and a top metal coating, wherein the material of the base coating is copper, nickel, silver, tin or a composite material of at least two of copper, nickel, tin and silver; the material of the top metal coating is gold, silver, copper, nickel, tin or a composite material of at least two of gold, silver, copper, nickel and tin.

5. The FPC antenna according to claim 1, wherein: It includes a jumper printed on the top surface of the plastic base layer. The sheet metal antenna includes a planar spiral antenna and a pin line. The plastic base layer includes two jumper holes. The outer end of the planar spiral antenna is a first pin end, and the inner end is a first jumper end. The pin line includes a second pin end and a second jumper end. The first jumper hole is located directly above the first jumper end, and the second jumper hole is located directly above the second jumper end. The first end of the jumper passes downward through the first jumper hole and is connected to the first jumper end, and the second end of the jumper passes downward through the second jumper hole and is connected to the second jumper end.

6. A method for preparing the FPC antenna according to claim 1, characterized in that: The following steps are involved: 601) Electroplating a sheet metal antenna on a reusable antenna mold: The antenna mold includes a metal carrier and an anti-sticking layer attached to the top surface of the metal carrier, the anti-sticking layer includes a plurality of unit patterns arranged in a matrix, the unit patterns include hollow patterns corresponding to the shape of the sheet metal antenna, and copper is electroplated in the hollow pattern area to form the sheet metal antenna; 602) Laying a plastic base layer on the top surface of the sheet metal antenna and the top surface of the anti-sticking layer; 603) peeling off the antenna mold and the sheet metal antenna with the plastic substrate layer attached thereto; 604) Adhesive layers are attached to the bottom surface of the sheet metal antenna and the bottom surface of the plastic base layer to form a package of a continuous FPC antenna; 605) Cut the package into individual FPC antennas.

7. The preparation method according to claim 6, characterized in that The plastic base layer includes a plurality of windows corresponding to the unit patterns. After step 602 is completed, metal electrodes are electroplated on the top surface of the sheet metal antenna in the window areas of the plastic base layer.

8. The preparation method according to claim 6, characterized in that The method for manufacturing the antenna mold includes the following steps: 801) Using a stainless steel sheet as a metal carrier, a photosensitive anti-sticking layer is coated on the top surface of the stainless steel sheet; 802) The anti-sticking layer is exposed and developed to form a plurality of unit patterns arranged in a matrix, and the bottom surface of the hollow pattern is the top surface of the metal carrier.

9. The preparation method according to claim 6, characterized in that The method for manufacturing the antenna mold includes the following steps: 901) Using a stainless steel sheet as a metal carrier, an anti-sticking layer is coated on the top surface of the stainless steel sheet; 902) Scanning the anti-sticking layer with a laser to form a plurality of unit patterns arranged in a matrix, wherein the bottom surface of the hollowed-out pattern is the top surface of the metal carrier plate.

10. The preparation method according to claim 6, characterized in that The method for manufacturing the antenna mold includes the following steps: 1001) Using a stainless steel sheet as a metal carrier, a photosensitive adhesive is coated on the top surface of the stainless steel sheet; 1002) A plurality of protruding unit patterns arranged in a matrix are formed on the photosensitive resin by photolithography, wherein the unit pattern includes a protruding pattern having the same shape as the sheet antenna. 1003) Apply an anti-stick coating to the top surface of the stainless steel sheet, remove the anti-stick coating on the surface of the photosensitive resin by mechanical means, remove the photosensitive resin layer with alkaline solution, and retain the remaining anti-stick coating to obtain a hollow pattern consistent with the shape of the sheet antenna.

11. The preparation method according to claim 6, characterized in that The sheet metal antenna includes a planar spiral antenna and a pin line, and the plastic base layer includes a plurality of groups of jumper holes corresponding to the unit graphics; each group of jumper holes includes two jumper holes, the outer end of the planar spiral antenna is a first pin end, and the inner end is a first jumper end; the pin line includes a second pin end and a second jumper end, the first jumper hole is located directly above the first jumper end, and the second jumper hole is located directly above the second jumper end; after step 602 is completed, a conductive paste is printed on the top surface of the plastic base layer to form a jumper, the first end of the jumper passes downward through the first jumper hole and is connected to the first jumper end, and the second end of the jumper passes downward through the second jumper hole and is connected to the second jumper end.

12. An electroplating forming mold for the FPC antenna according to claim 1, characterized in that: It includes a metal carrier and an anti-sticking layer coated on the top surface of the metal carrier. The anti-sticking layer includes a plurality of unit patterns arranged in a matrix. The unit patterns include hollow patterns corresponding to the shape of the sheet metal antenna. The bottom surface of the hollow pattern is the top surface of the metal carrier.

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