JP2012182591A - Antenna substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wide band antenna substrate which allows for excellent transmission and reception of radio waves over a wide frequency band.SOLUTION: In the antenna substrate, a first patch conductor 7, a second patch conductor 8, and a third patch conductor 9 are quadrilaterals having short sides 7a, 8a, 9a parallel with the first direction and long sides 7b, 8b, 9b parallel with the second direction, respectively, where the area of the second patch conductor 8 is larger than that of the first patch conductor 7, and the area of the third patch conductor 9 is larger than that of the second patch conductor 8. Preferably, the short side 7a of the first patch conductor 7 has the same length as that of the short side 8a of the second patch conductor 8, the long side 7b of the first patch conductor 7 is shorter than the long side 8b of the second patch conductor 8, the short side 8a of the second patch conductor 8 is shorter than the short side 9a of the third patch conductor 9, and the long side 8b of the second patch conductor 8 is shorter than the long side 9b of the third patch conductor 8.

Description

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

  Conventionally, as shown in a schematic cross-sectional view in FIG. 3 and an exploded perspective view in FIG. 4, the first dielectric layer 11 and the lower surface of the first dielectric layer 11 extend in the first direction. A strip-shaped strip conductor 14 that terminates, a ground conductor layer 15 that is 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, and a first conductor layer 15 The second dielectric layer 12 laminated on the dielectric layer 11 and the ground conductor layer 15, and the second dielectric layer 12 was deposited so as to cover the position where the slot 15 a was formed on the upper surface of the second dielectric layer 12. The first patch conductor 16, the third dielectric layer 13 laminated on the second dielectric layer 12 and the first patch conductor 16, and the first dielectric layer 13 on the upper surface of the third dielectric layer 13 The second patch conductor is attached so as to cover the position where the patch conductor 16 is formed. Antenna substrate and a 7 are known.

  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. A second dielectric layer; a first patch conductor disposed over the position where the slot is formed on the upper surface of the second dielectric layer; the second dielectric layer and the first dielectric layer; A third dielectric layer stacked on the patch conductor, and a second patch conductor disposed so as to cover the position where the first patch conductor is formed on the upper surface of the third dielectric layer; A fourth dielectric layer overlying the third dielectric layer and the second patch conductor; And a third patch conductor disposed so as to cover a position where the second patch conductor is formed on the upper surface of the fourth dielectric layer, and the first patch conductor and the second patch conductor Each of the patch conductor and the third patch conductor is a quadrangle having a short side parallel to the first direction and a long side parallel to the second direction, and the area of the first patch conductor Further, the area of the second patch conductor is larger, and the area of the third patch conductor is larger than the area of the second patch conductor.

  According to the antenna substrate of the present invention, the first patch conductor, the second patch conductor, and the third patch conductor are respectively parallel to the short side and the second direction, which are parallel to the first direction. It is a rectangle having a long side, the area of the second patch conductor is larger than the area of the first patch conductor, and the area of the third patch conductor is larger than the area of the second patch conductor. Therefore, the first, second, and third patch conductors arranged in this manner have good composite resonance, and therefore, for example, it is possible to send and receive good signals in a wide frequency band of 57 to 66 GHz. A wide-band antenna substrate can be provided.

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. As shown in a schematic cross-sectional view in FIG. 1 and an exploded perspective view in FIG. 2, the antenna substrate of this example includes a first dielectric layer 1 and a lower surface of the first dielectric layer 1 in a first direction. 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 and the above are 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 8 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.

  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 7a parallel to the first direction in which the strip conductor 5 extends and a second direction in which the slot 6a extends. It has a rectangular shape having a long side 7b, and functions to radiate an electromagnetic wave of a high-frequency signal from the slot 6a to the outside and to transmit it 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 8a parallel to the first direction in which the strip conductor 5 extends and a second direction in which the slot 6a extends. And has a long side 8 b parallel to the surface, and serves to radiate an electromagnetic wave of a high-frequency signal from the first patch conductor 7 to the outside and transmit it to the third patch conductor 9.

  Similarly, the third patch conductor 9 disposed on the upper surface of the fourth dielectric layer 4 also has a short side 9a 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 9b, and fulfills the function of radiating electromagnetic waves of high-frequency signals from the first and second patch conductors 8 to the outside.

  The lengths of the short sides 7a to 9a and the long sides 7b to 9b in the first to third patch conductors 7 to 9 are 0.5 to 5 mm, respectively. Here, for the sake of convenience, they are expressed as short sides 7a to 9a and long sides 7b to 9b, and the lengths of both may be the same, or the lengths of both may be reversed.

  In this example, the second patch conductor 8 is arranged so as to cover the position where the first patch conductor 7 is formed, and the third patch conductor 9 is covered so as to cover the position where the second patch conductor 8 is formed. The area of the second patch conductor 8 is larger than the area of the first patch conductor 7, and the area of the third patch conductor 9 is larger than the area of the second patch conductor 8. In this way, the second patch conductor 8 is disposed so as to cover the position where the first patch conductor 7 is formed, and the third patch conductor 9 is disposed so as to cover the position where the second patch conductor 8 is formed. If the area of the second patch conductor 8 is larger than the area of the first patch conductor 7 and the area of the third patch conductor 9 is larger than the area of the second patch conductor 8, for example, When a high-frequency signal is radiated through the patch conductors 7 to 9, the high-frequency signal is radiated from the lower patch conductor 7 so as to sequentially spread along the outer peripheral edges of the upper patch conductors 8 and 9, so that the first to third The frequency band of the high-frequency signal radiated through the patch conductors 7 to 9 is wide.

  Further, the first patch conductor 7 and the second patch conductor 8 have the same short side 7a and the short side 8a, and the third patch conductor 9 is shorter than the short sides 7a and 8a. The side 9a is lengthened, the length of the long side 9b of the third patch conductor 9 is made longer than the length of the long side 8b of the second patch conductor 9, and the length of the long side 8b of the second patch conductor 8 is set to be longer. It is preferable that the length of the long side 7b of the first patch conductor 7 is longer. In this way, the first patch conductor 7 and the second patch conductor 8 have the same short side 7a and the short side 8a, and the third patch conductor 9 has a shorter length than the short sides 7a and 8a. While making the short side 9a longer, the length of the long side 9b of the third patch conductor 9 is made longer than the length of the long side 8b of the second patch conductor 8, and the length of the long side 8b of the second patch conductor 8 Is made longer than the length of the long side 7b of the first patch conductor 7, thereby further widening the frequency band of the high-frequency signal radiated through the first to third patch conductors 7-9. it can.

  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 200 μm, 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 9 is 11 μm, the width of the slot 6a is 0.2 mm, the length is 1 mm, and the strip conductor 5 The distance to the end of the first patch conductor 7 is 0.75 mm, and these dimensions are made common, and the first patch conductor 7 has dimensions 7a of 0.6 mm and 7b of 0.7 mm. A first model corresponding to the present invention in which the dimension is 8 mm for 8a, 0.9 mm for 8b, and the dimension of the third patch conductor 9 is 0.8 mm for 9a and 1.0 mm for 9b; The size of the patch conductor 7 7a is 0.6 mm, 7b is 0.7 mm, and the dimensions of the second patch conductor 8 and the third patch conductor 9 are the same dimensions as the first patch conductor. As a result of comparing the model with a simulation using an electromagnetic field simulator, in the second model corresponding to the outside of the scope of the present invention, a band with a reflection loss of −10 dB or less is 55 to 70 GHz, and a band with a reflection loss of −15 dB or less is 65. In the first model corresponding to the present invention, which is ˜68 GHz, the band with a reflection loss of −10 dB or less is 55 to 73 GHz, and the band with a reflection loss of −15 dB or less is 57 to 71 GHz. I was able to confirm.

DESCRIPTION OF SYMBOLS 1 1st dielectric layer 2 2nd dielectric layer 3 3rd dielectric layer 4 4th dielectric layer 5 Strip conductor 6 Ground conductor layer 6a Slot 7 1st patch conductor 7a Short side 7b Long side 8 Second patch conductor 8a Short side 8b Long side 9 Third patch conductor 9a Short side 9b Long side

Claims (2)

  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; 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, and laminated on the second dielectric layer and the first patch conductor. A third dielectric layer; a second patch conductor disposed so as to cover a position where the first patch conductor is formed on an upper surface of the third dielectric layer; and the third dielectric layer. And a fourth dielectric layer laminated on the second patch conductor, and the fourth dielectric layer A third patch conductor disposed on the upper surface so as to cover the position where the second patch conductor is formed, and the first patch conductor, the second patch conductor, and the third patch conductor are , Each having a short side parallel to the first direction and a long side parallel to the second direction, and the area of the second patch conductor is larger than the area of the first patch conductor. An antenna substrate, wherein an area of the third patch conductor is larger than an area of the second patch conductor.   The short side of the first patch conductor is the same length as the short side of the second patch conductor, the long side of the first patch conductor is shorter than the long side of the second patch conductor, and The short side of the second patch conductor is shorter than the short side of the third patch conductor, and the long side of the second patch conductor is shorter than the long side of the third patch conductor. The antenna substrate according to claim 1.

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