JP2013201711A - Antenna substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a broad band antenna substrate capable of excellently transmitting/receiving an electric wave in a wide frequency band.SOLUTION: An antenna substrate includes: a first dielectric layer 1; a strip conductor 5 disposed on a bottom face of the first dielectric layer 1 and extending in a first direction to terminate; a ground conductor layer 6 disposed on a top face of the first dielectric layer 1 and having a slot 6a extending in a second direction orthogonal to the strip conductor 5; a second dielectric layer 2 stacked on the first dielectric layer 1 and the ground conductor layer 6; and a first patch conductor 7 disposed on a top face of the second dielectric layer 2 so as to cover a position where the slot 6a is formed. An opening 7a is formed at a central portion of the first patch conductor 7. A multiple resonance favorably occurs in the first patch conductor 7 having the opening 7a, and therefore it is possible to favorably transmit/receive a signal in a wide frequency band.

Description

  The present invention relates to an antenna substrate formed by laminating a dielectric layer and a conductor layer in multiple layers.

  Conventionally, as an antenna substrate, as shown in a schematic cross-sectional view in FIG. 3 and an exploded perspective view in FIG. 4, a first dielectric layer 11 and a lower surface of the first dielectric layer 11 in a first direction. A strip-shaped strip conductor 14 extending and terminating, and a ground conductor layer 15 deposited on the upper surface of the first dielectric layer 11 with a slot 15a extending in a second direction perpendicular to the strip conductor 14; The second dielectric layer 12 laminated on the first dielectric layer 11 and the ground conductor layer 15, and the slot 15 a is formed on the upper surface of the second dielectric layer 12. The deposited first patch conductor 16, the third dielectric layer 13 stacked on the second dielectric layer 12 and the first patch conductor 16, and the upper surface of the third dielectric layer 13 So as to cover the position where the first patch conductor 16 is formed. Antenna substrate is known in which a second patch conductor 17.

  In this antenna substrate, when a high-frequency signal is supplied to the strip conductor 14, the signal is transmitted to the first and second patch conductors 16 and 17 through the slot 15a by electromagnetic coupling, and the first and second patch conductors 16 and 17 are transmitted. High-frequency signals are radiated as electromagnetic waves through the patch conductors 16 and 17. By the way, such an antenna substrate includes the first and second two-layer patch conductors 16 and 17 so as to overlap each other, by providing the two-layer patch conductors 16 and 17 so as to overlap each other. This is because the frequency band of the antenna can be widened.

  However, for example, in a wireless personal area network, the frequency band to be used is different in each country, and it is necessary to cover a wide frequency band of 57 to 66 GHz so that one antenna substrate can be used all over the world. For this purpose, it is necessary to provide an antenna substrate having a wider frequency band than the conventional antenna substrate.

JP 7-212125 A

  An object of the present invention is to provide a broadband antenna substrate capable of transmitting and receiving a good signal even in a wide frequency band of, for example, 57 to 66 GHz.

  The antenna substrate of the present invention includes a first dielectric layer, a strip-shaped strip conductor disposed on the lower surface of the first dielectric layer, extending in a first direction, and terminating in the first direction. A ground conductor layer having a slot extending in a second direction perpendicularly crossing the strip conductor, and laminated on the first dielectric layer and the ground conductor layer. An antenna substrate comprising: a second dielectric layer; and a first patch conductor disposed so as to cover a position where the slot is formed on the upper surface of the second dielectric layer, An opening is formed at the center of the first patch conductor.

  According to the antenna substrate of the present invention, since the opening portion is provided in the center portion of the first patch conductor, complex resonance occurs favorably in the first patch conductor provided with the opening portion. It is possible to provide a broadband antenna substrate capable of transmitting and receiving favorable signals in a wide frequency band of 66 GHz.

FIG. 1 is a schematic cross-sectional view for explaining an example of an embodiment of an antenna substrate of the present invention. FIG. 2 is an exploded perspective view of the antenna substrate shown in FIG. FIG. 3 is a cross-sectional view showing a conventional antenna substrate. FIG. 4 is an exploded perspective view of the antenna substrate shown in FIG.

  Next, an embodiment of the antenna substrate of the present invention will be described with reference to the accompanying drawings. The antenna substrate of this example is shown in a schematic cross-sectional view in FIG. 1 and in an exploded perspective view in FIG. 2, in a first direction on the lower surface of the first dielectric layer 1 and the first dielectric layer 1. A strip-shaped strip conductor 5 extending to the end of the first dielectric layer 1 and a ground conductor layer 6 deposited on the upper surface of the first dielectric layer 1 with a slot 6a extending in a second direction perpendicular to the strip conductor 5. And the second dielectric layer 2 laminated on the first dielectric layer 1 and the ground conductor layer 6, and the slot 6 a formed on the upper surface of the second dielectric layer 2. A first patch conductor 7 deposited on the second dielectric layer 2, a third dielectric layer 3 laminated on the second dielectric layer 2 and the first patch conductor 7, and a third dielectric layer 3 A second patch conductor 8 deposited so as to cover the position where the first patch conductor 7 is formed on the upper surface; and a third dielectric layer And the fourth dielectric layer 4 laminated on the second patch conductor 8, and the second dielectric layer 4 is deposited so as to cover the position where the second patch conductor 8 is formed on the upper surface of the fourth dielectric layer 4. The third patch conductor 9 is provided.

  The dielectric layers 1 to 4 are, for example, an insulating sheet obtained by impregnating a glass cloth with a thermosetting resin such as an epoxy resin, a bismaleimide triazine resin, or an allyl-modified polyphenylene ether resin, an epoxy resin, a bismaleimide triazine resin, or an allyl-modified polyphenylene ether. An insulating sheet in which an inorganic insulating filler such as silica powder is dispersed in a resin is cured. These insulating layers 1 to 4 preferably have a relative dielectric constant of 4 or less, and preferably have a thickness of about 50 to 200 μm. Each of the strip conductor 5, the ground conductor layer 6, and the patch conductors 7 to 9 is made of a highly conductive conductive material such as a copper foil or a copper plating layer having a thickness of 5 to 20 μm.

  The strip conductor 5 disposed on the lower surface of the first dielectric layer 1 is a strip-shaped conductor having a width of about 50 to 350 μm. The strip conductor 5 extends in the first direction on the lower surface of the first dielectric layer 1 and ends at the lower surface of the first dielectric layer. The strip conductor 5 functions as a transmission path for inputting and outputting a high-frequency signal in the antenna substrate of this example, and the high-frequency signal is transmitted to the strip conductor 5.

  The ground conductor layer 6 disposed on the upper surface of the first dielectric layer 1 is disposed so as to cover most of the upper surface of the first dielectric layer, and the second direction crosses the strip conductor 5 at a right angle. A rectangular slot 6a extending in the direction is provided. The slot 6a has a width parallel to the first direction of about 0.1 to 1 mm, a length parallel to the second direction of about 0.5 to 150 mm, and the end side of the strip conductor 5 is the strip conductor. 5 is provided so as to cross a position of 0.2 to 8 mm from one end where 5 ends. The ground conductor layer 6 supplies a high frequency signal transmitted through the strip conductor 5 as an electromagnetic wave to the patch conductors 7 to 9 via the slot 6a, or receives an electromagnetic wave of the high frequency signal received by the patch conductors 7 to 9 in the slot 6a. The function to transmit to the strip conductor 5 is achieved.

  The first patch conductor 7 disposed on the upper surface of the second dielectric layer 2 has a short side parallel to the first direction in which the strip conductor 5 extends and a second direction in which the slot 6a extends. It is a quadrangle having a long side, and has a square opening 7a at the center. The patch conductor 7 has a function of radiating an electromagnetic wave of a high-frequency signal from the slot 6a to the outside and transmitting the electromagnetic wave to the second and third patch conductors 8 and 9.

  Similarly, the second patch conductor 8 disposed on the upper surface of the third dielectric layer 3 also has a short side parallel to the first direction in which the strip conductor 5 extends and a second direction in which the slot 6a extends. It is a quadrangle having parallel long sides, and has a square opening 8a at the center. The patch conductor 8 functions to radiate an electromagnetic wave of a high-frequency signal from the first patch conductor 7 to the outside and transmit the electromagnetic wave to the third patch conductor 9.

  Similarly, the third patch conductor 9 disposed on the upper surface of the fourth dielectric layer 4 is also parallel to the short side parallel to the first direction in which the strip conductor 5 extends and to the second direction in which the slot 6a extends. It is a quadrangle having a long side, and has a square opening 9a at the center. The patch conductor 9 functions to radiate electromagnetic waves of high-frequency signals from the first and second patch conductors 7 and 8 to the outside.

  In addition, the length of the short side and the long side in the 1st-3rd patch conductors 7-9 is 0.5-5 mm, respectively. Here, for convenience, they are expressed as short sides and long sides, and the lengths of both may be the same, or the lengths of both may be reversed. Moreover, the length of one side in opening part 7a, 8a, 9a is 0.1-4.9 mm, respectively.

  In this example, it is important that openings 7 a, 8 a, and 9 a are formed at the center portions of the first patch conductor 7, the second patch conductor 8, and the third patch conductor 9, respectively. Since complex resonance occurs due to the presence of these openings 7a, 8a, and 9a, the frequency band of the high-frequency signal radiated through the first to third patch conductors 7 to 9 becomes wide.

  Each of the openings 7a, 8a, 9a is preferably formed so as to overlap vertically with a region facing the strip conductor 5.

Here, in the antenna substrate shown in FIG. 2 by the present inventor, the relative dielectric constant of the insulating layers 1 to 4 is 3.7, the thickness of the insulating layers 1 and 2 is 100 μm, and the thickness of the insulating layers 3 and 4 is respectively The thickness of the strip conductor 5 is 15 μm, the width is 200 μm, the thickness of the ground conductor layer 6 and the patch conductors 7 to 11 is 11 μm, the width of the slot 6a is 0.2 mm, the length is 1 mm, and the strip conductor from the slot 6a is 200 μm. The distance to the end of 5 is set to 0.75 mm, and these dimensions are made common, the short side dimension of the first patch conductor 7 is set to 0.6 mm, and the long side dimension is set to 0.7 mm. The patch conductor 8 has a short side dimension of 0.6 mm, a long side dimension of 0.9 mm, a third patch conductor 9 has a short side dimension of 0.8 mm, and a long side dimension of 1.0 mm. Furthermore, one side of each opening 7a, 8a, 9a The first model corresponding to the present invention having a length of 0.2 mm and the configuration outside the scope of the present invention having the same configuration as the first model except that the openings 7a, 8a, 9a are not provided. As a result of comparing the second model with a simulation using an electromagnetic field simulator, the second model corresponding to the outside of the scope of the present invention has a reflection loss of −10 dB or less in a band of 55 to 73 GHz. In the first model corresponding to the invention, it was confirmed that the band having a reflection loss of −10 dB or less was as wide as 53 to 74 GHz. This indicates that a good signal can be transmitted and received with a sufficient margin even in a wide frequency band of, for example, 57 to 66 GHz.

DESCRIPTION OF SYMBOLS 1 1st dielectric layer 2 2nd dielectric layer 5 Strip conductor 6 Grounding conductor layer 6a Slot 7 1st patch conductor

Claims (1)

  A first dielectric layer, a strip-shaped strip conductor disposed on the lower surface of the first dielectric layer, extending in a first direction and terminating, and an upper surface of the first dielectric layer; A ground conductor layer having a slot extending in a second direction perpendicular to the strip conductor and a second dielectric layer stacked on the first dielectric layer and the ground conductor layer; An antenna substrate comprising a first patch conductor disposed on the upper surface of the second dielectric layer so as to cover the position where the slot is formed, the center of the first patch conductor being An antenna substrate, wherein an opening is formed in the portion.

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