Thin antenna

Abstract

To provide a compact, thin antenna consisting of a single dielectric layer.SOLUTION: A thin antenna has a metal layer, a dielectric layer on an upper surface of the metal layer, and a radiation element layer on an upper surface of the dielectric layer, and a non-contact power supply element is positioned in the notch formed by cutting out a portion of the radiation element layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an antenna using metamaterial technology, and relates to a small, thin antenna. [Background technology]

[0002] The present applicant has previously proposed a thin antenna using metamaterial technology. For example, Patent Document 1 proposes an antenna in which a radiating element layer is disposed on the upper surface of a metal layer via a dielectric layer, as shown in Figure 3(b), and a non-contact power supply element is disposed on top of that via another dielectric layer. Furthermore, Patent Document 2 proposes an antenna that is made thinner by disposing a non-contact power supply element between a metal layer and a radiation element layer, as shown in FIG. 3(c). These devices had two dielectric layers, so we investigated whether we could make them even thinner, which led to the present invention. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6452477 [Patent Document 2] Patent No. 7334936 Summary of the Invention [Problem to be solved by the invention]

[0004] SUMMARY OF THE INVENTION An object of the present invention is to provide a small, thin antenna made of a single dielectric layer. [Means for solving the problem]

[0005] The thin antenna according to the present invention is characterized in that it has a metal layer, a dielectric layer on the upper surface of the metal layer, and a radiating element layer on the upper surface of the dielectric layer, and a non-contact power supply element is arranged in a cutout portion formed by cutting out a part of the radiating element layer.

[0006] The present invention is characterized in that a part of the radiating element layer is cut out and the contactless power supply element is disposed on approximately the same surface as one of the upper surfaces (one side) of the metal layer via one dielectric layer.

[0007] In the present invention, various patterns are possible for the structure in which the radiating element layer and the non-contact power supply element are arranged flush with each other. For example, the radiating element layer may be arranged with a predetermined slit portion provided between a first radiating element layer and a second radiating element layer arranged opposite each other, the non-contact power supply element may be composed of a first non-contact power supply element and a second non-contact power supply element arranged opposite each other, the first non-contact power supply element may be arranged in a first cutout portion formed by cutting out a portion of the opposing side of the first radiating element layer, and the second non-contact power supply element may be arranged in a second cutout portion formed by cutting out a portion of the opposing side of the second radiating element layer. This pattern is the example shown in FIG. 1 and FIG. Although the pair of first and second non-contact power supply elements arranged via a slit may be directly connected for power supply, it is preferable to connect them to the drive unit via a through hole in order to achieve a thin design.

[0008] In the present invention, for example, the radiating element layer may be arranged with a predetermined slit portion provided between a first radiating element layer and a second radiating element layer arranged opposite each other, and one non-contact power supply element may be arranged in a cutout portion formed on each of the opposing sides of the first radiating element layer and the second radiating element layer. This pattern is the example shown in FIG. 7, FIG. 14, etc. Also, as shown in FIG. 15, the slits may be shaped in an interdigital structure to form capacitance on a coplanar surface, thereby achieving miniaturization.

[0009] In the present invention, the radiating element layer may be roughly rectangular, but the first radiating element layer and the second radiating element layer may have side cutouts on the sides other than the opposing side in order to divert the current path and lower the resonant frequency. This pattern is an example shown in FIG.

[0010] In the present invention, miniaturization may be achieved using the principle of mirror images, and a radiating element layer and a mirror image element layer may be provided on the upper surface of the dielectric layer, and the contactless power supply element may be arranged in a cutout portion formed by cutting out a portion of the radiating element layer. Examples of this pattern are shown in FIGS. 10, 11, 12, etc. In this case, too, as shown in FIG. 12, a notch may be provided on the side of the radiation element layer other than the portion facing the mirror image element layer. Also, as shown in FIG. 11, the radiating element layer and the mirror image element layer may be shorted to a metal layer.

[0011] In the present invention, a plurality of radiating element layers may be arranged continuously with slits interposed between them. This pattern is an example shown in FIG. 15, FIG. 22, FIG. 23, etc.

[0012] In the present invention, a plurality of radiating element layers may be arranged in the Y direction and the Z direction with slits between them. In this specification, the Y direction and the Z direction are defined as shown in FIG. In this way, excitation can be performed with a 90° phase difference, resulting in circular polarization. This pattern is shown in the examples of FIGS. [Effects of the Invention]

[0013] While Patent Documents 1 and 2 have two dielectric layers, the antenna according to the present invention consists of a single dielectric layer, which allows for even thinner designs. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a perspective view of an antenna according to a first embodiment of the present invention; [Figure 2] 1(a) is a plan view of Example 1, and FIG. 1(b) shows the metal layer. [Figure 3] Example 1 of the present invention was compared with the antenna described in Patent Document 1 (Comparative Example 1) and the antenna described in Patent Document 2 (Comparative Example 2) for analysis. [Figure 4] A comparison of VSWR is shown, with A representing the present invention, B representing Comparative Example 1, and C representing Comparative Example 2. [Figure 5] The radiation pattern comparison results are shown below. [Figure 6] The comparison results of the current distribution are shown below. [Figure 7] 10 shows an example of an antenna structure according to a second embodiment. [Figure 8] 10 shows an example of an antenna structure according to a third embodiment. [Figure 9] 10 shows an example of an antenna structure according to a fourth embodiment. [Figure 10] 10 shows an example of an antenna structure according to a fifth embodiment. [Figure 11] This shows a modification of the fifth embodiment shown in FIG. [Figure 12] 10 shows an example of an antenna structure according to a sixth embodiment. [Figure 13] 10 shows an example of an antenna structure according to a seventh embodiment. [Figure 14] 13 shows an example of an antenna structure according to an eighth embodiment. [Figure 15] This shows a modification of the eighth embodiment shown in FIG. [Figure 16] 10 shows an example of an antenna structure according to a ninth embodiment. [Figure 17] 16 shows an example of an antenna structure according to a tenth embodiment. [Figure 18] 13 shows an example of an antenna structure according to an eleventh embodiment. [Figure 19] 12 shows an example of an antenna structure according to a twelfth embodiment. [Figure 20] 13 shows an example of an antenna structure according to a thirteenth embodiment. [Figure 21] 14 shows an example of an antenna structure according to a fourteenth embodiment. [Figure 22] 15 shows an example of an antenna structure according to a fifteenth embodiment. [Figure 23] 16 shows an example of an antenna structure according to a sixteenth embodiment. [Figure 24] 17 shows an example of an antenna structure according to a seventeenth embodiment. [Figure 25] 16 shows the VSWR characteristics and radiation characteristics of the antenna structure example of Example 17. DETAILED DESCRIPTION OF THE INVENTION

[0015] An example of the structure of an antenna according to the present invention will be described below with reference to the drawings. An example of the structure of the antenna of the first embodiment is shown in FIGS. FIG. 1 is a perspective view, FIG. 2(a) is a plan view of the antenna, and (b) shows the metal layer. The antenna has a dielectric layer 12 on the upper surface of a metal layer 11, and a radiating element layer and a non-contact power feeding element are disposed flush with the upper surface of this dielectric layer 12. In the first embodiment, a first radiating element layer 13a and a second radiating element layer 13b are disposed opposite each other with a slit portion S therebetween. A notch d1 is formed as a first notch on the side of the first radiating element layer 13a facing the second radiating element layer 13b, and a first non-contact power supply element 14a is arranged in this portion. A notch d2 is formed as a second notch on the side of the second radiating element layer 13b facing the first radiating element layer 13a, and a second non-contact power supply element 14b is arranged in this portion. Therefore, the first non-contact power feeder 14a and the second non-contact power feeder 14b are arranged opposite to each other with the slit S interposed therebetween. The first non-contact power supply element 14a and the second non-contact power supply element 14b are respectively connected to the driving section by wiring through the metal layer 11 by a first through-hole 15a and a second through-hole 15b. As a result, the pair of first and second radiating element layers 13a and 13b excite the pair of first and second non-contact power feed elements as dipoles in a balanced feed manner. In FIG. 2, the length g is approximately λ / 4 where λ is the frequency band used, and the total length L resonates at approximately λ / 2. The width of the slit portion S is preferably 0.005 to 0.01 wavelength. The dielectric layer is intended to function as a dielectric layer, and may be made of not only a resin material but also an air layer. The first and second non-contact power feeding elements 14a and 14b have a length 11 that allows them to be excited as dipoles, and are strip-shaped. In Example 1, the L dimension is longer than the W dimension, and the metal layer 11, the dielectric layer 12, and the pair of radiating element layers 13a, 13b have the same overall outer shapes, and the pair of first and second radiating element layers 13a, 13b are the same size and arranged symmetrically.

[0016] A comparative analysis was carried out using the antenna according to the present invention in Example 1 and the antennas in Patent Document 1 (Comparative Example 1) and Patent Document 2 (Comparative Example 2). The analytical model used in the analysis is shown in Figure 3. Each was set to match at 2.45 GHz. t is the thickness of the dielectric layer, and the dielectric constant εr is 2.58 and the dielectric loss tangent tanδ is 0.0014. FIG. 4 shows the results of a comparison of VSWR, where A is the present invention, B is comparative example 1, and C is comparative example 2, where "free" indicates the value in a free space arrangement and "metal" indicates the value on a conductor. There was no significant difference between A, B, and C. Figure 5 compares the radiation patterns, and almost no difference was observed between A, B, and C. In addition, when comparing the radiation patterns, A, B, and C were almost overlapping in the on-metal state. Figure 6 shows the results of comparing the current distribution. There was no significant difference in the current distribution between A, B, and C.

[0017] FIG. 7 shows an example of the structure of the antenna according to the second embodiment. In this embodiment, the non-contact power supply element 14c is excited by unbalanced power supply in an inverted L shape relative to the radiating element layer. Specifically, a notch is formed on the opposing side of the first radiating element layer 13a and the second radiating element layer 13b, and a non-contact power feeding element 14c is disposed in the notch, and power is fed via a through hole 15c. In FIG. 7(a), l1=21, W=30, W1=0.8, g=37, s=0.5, and the dielectric layer was the same as in Example 1. The analysis results are shown in FIGS. 7(c) and 7(d). This antenna was analyzed in both the on-metal state and the free-space state, and hereafter the on-metal state will be represented as m and the free-space state as f. In this case, too, resonance occurs when the length of g is approximately λ / 4 and the total length L is approximately λ / 2.

[0018] FIG. 8 shows Example 3. The third embodiment is an example in which the first and second non-contact power feeding elements 14a and 14b are arranged offset from the first embodiment. This makes it possible to achieve a wider bandwidth.

[0019] FIG. 9 shows Example 4. In this Example 4, a notch e is formed in the other side (other side) of the radiating element layer other than the opposing side (opposing portion) to divert the current path of the radiating element layer, thereby lowering the resonant frequency and achieving miniaturization. In FIG. 9(a), W=30, W1=1, g=30.6, s=0.5, e1 width: 1, length: 6.5, and the dielectric layer was the same as in Example 1. The analysis results are shown in FIGS. 9(c) and 9(d).

[0020] FIG. 10 shows Example 5. In Example 5, in contrast to Example 1, a mirror image layer 16a is formed instead of the second radiating element layer 13b, and is connected to the metal layer 11 at the connection portion 17 via a through-hole, thereby achieving miniaturization using the principle of mirror image compared to the first radiating element layer 13e. The length of g resonates at approximately λ / 4. The results of analysis using W=31, W1=1, 11=8.8, g=35.4, s=0.5, sg=2 and the same dielectric layer as in Example 1 are shown in FIGS. 10(c) and 10(d). FIG. 11 shows a modified example of the embodiment of FIG. 10. The difference from FIG. 10 is that the mirror image layer 16a is connected to the metal layer 11 at a connection portion 17a made of a through-hole, and the radiation element layer 13e is also connected to the metal layer 11 at a connection portion 17b made of a through-hole. The analysis results are shown in Figures 11(d) and (e).

[0021] FIG. 12 shows Example 6. A notch is formed in the corner of the radiation element layer 13f, and the non-contact power supply element 14d is arranged at an angle of 45 degrees. In FIG. 11, short-circuit plates 16b are arranged to the left and below. This allows the antenna to emit linearly polarized waves with an electric field component in a 45-degree diagonal direction. Moreover, by moving the non-contact power feeding element 14d leftward or downward, or by making a notch e in one side of the radiation element layer, it is also possible to radiate a circularly polarized wave.

[0022] FIG. 13 shows Example 7. The seventh embodiment is a type in which the vertical width W of the dielectric layer 12a is made larger than the vertical width Wg of the radiating element layer, thereby improving the robustness when the antenna is placed on a conductor. The results of analysis using W=37, Wg=30, W1=1, 111=2.4, g=33.95, s=0.5 and the same dielectric layer as in Example 1 are shown in FIGS. 13(c) and 13(d).

[0023] FIG. 14 shows Example 8. In the eighth embodiment, the non-contact power feeding element 14c is used to provide an inverted L-type power feeding, resulting in two resonances and enabling a wider bandwidth. FIG. 15 shows an inverted L-type feeding configuration similar to FIG. 7, but the slit section 5 formed between the first radiating element layer 13a and the second radiating element layer 13b has a zigzag interdigital structure, which configures the capacitance in a coplanar manner and allows for miniaturization. The analysis results are shown in Figures 15(d) and (e).

[0024] FIG. 16 shows Example 9. In contrast to Example 1, Example 9 is an example in which a plurality of sets of radiating element layers are continuously arranged. This allows for compatibility with a variety of frequency modes.

[0025] FIG. 17 shows Example 10. This Example 10 is an example in which the radiating element layer is arranged with slits in the Y and Z directions, and the non-contact power supply element is arranged at right angles to create a 90° phase difference, making it a circularly polarized antenna. As circularly polarized wave models, Example 11 is shown in FIG. 18, Example 12 in FIG. 19, Example 13 in FIG. 20, and Example 14 in FIG. 21, respectively. The structures of the non-contact power feed element, the slit portion, and the notch portion of the radiating element layer are the same as those in FIG. 1, and therefore the explanation will be omitted.

[0026] Example 15 is shown in FIG. The fifteenth embodiment is an example in which the lengths in the Z direction of a pair of combined radiating element layers are different from those of the first embodiment, such as g1 and g2. This allows operation in different frequency modes, enabling multi-frequency sharing and broadband operation. As examples of arranging radiating element layers for the same purpose, Example 16 is shown in FIG. 23 and Example 17 is shown in FIG. In Example 17 of FIG. 22, W=30, W1=0.8, g2=15.3, g1=38.1, s=0.5, and the dielectric layer was the same as in Example 1. The analysis results are shown in FIG. It can be seen that it operates in frequency modes of 2.45GHz, 5.25GHz, and 6.60ZHz. [Explanation of symbols]

[0027] 11 Metal tank 12 Dielectric layer 13a First radiating element layer 13b Second radiating element layer 14a First non-contact power supply element 14b Second non-contact power supply element 15a 1st through hole 15b Second through hole

Claims

1. A thin antenna comprising a metal layer, a dielectric layer on the upper surface of the metal layer, and a radiating element layer on the upper surface of the dielectric layer, wherein a non-contact power supply element is disposed in a cutout portion formed by cutting out a portion of the radiating element layer.

2. the radiating element layer is arranged with a predetermined slit portion provided between a first radiating element layer and a second radiating element layer arranged opposite to each other, 2. The thin antenna according to claim 1, wherein the non-contact power supply element comprises a first non-contact power supply element and a second non-contact power supply element arranged opposite each other, the first non-contact power supply element being arranged in a first cutout portion formed by partially cutting out the opposing side of the first radiating element layer, and the second non-contact power supply element being arranged in a second cutout portion formed by partially cutting out the opposing side of the second radiating element layer.

3. the radiating element layer is arranged with a predetermined slit portion provided between a first radiating element layer and a second radiating element layer arranged opposite to each other, 2. The thin antenna according to claim 1, wherein one non-contact power supply element is disposed in a cutout formed in each of the opposing sides of the first radiation element layer and the second radiation element layer.

4. 4. The thin antenna according to claim 2, wherein the first radiation element layer and the second radiation element layer have side cutouts on the sides other than the opposing side.

5. 2. The thin antenna according to claim 1, wherein a radiating element layer and a mirror image element layer are provided on the upper surface of the dielectric layer, and the non-contact power supply element is disposed in a cutout portion formed by cutting out a portion of the radiating element layer.

6. 2. The thin antenna according to claim 1, wherein a plurality of radiating element layers are arranged successively with slits interposed therebetween.

7. 2. The thin antenna according to claim 1, wherein a plurality of radiating element layers are arranged in the Y direction and the Z direction with slits between them.

Images