TW202025554A - Yagi antenna with metamaterial guider and reflector - Google Patents

Abstract

The invention provides a Yagi antenna. The Yagi antenna includes a substrate, a dipole antenna, a reflector and a plurality of guiders. The reflector and the guiders have a metamaterial property, so that the whole length of the Yagi antenna can be shortened by about 10% while retaining the flat structure of the Yagi antenna.

Description

Yagi antenna with metamaterial guide and reflector

The present invention relates to a Yagi antenna, in particular to a Yagi antenna with a metamaterial guide and reflector.

Yagi antenna, also called directional antenna, is based on the development of ordinary dipole antenna. The Yagi antenna consists of several metal rods, one of which is a radiator, the longer one behind the radiator is a reflector, and the shorter ones in the front are a director. The radiator usually uses a folded half-wave oscillator. The maximum radiation direction of the antenna is the same as the direction of the director. The length of the director is slightly less than half the wavelength, and the length of the reflector is slightly greater than half the wavelength. The specific length depends on the actual use. It depends on the situation. The distance between the reflector and the vibrator, and the distance between the vibrator and the director is a quarter wavelength. Increasing the number of directors can enhance the directivity and gain of the antenna, but it will also reduce the bandwidth and increase the difficulty of antenna coupling.

Therefore, the advantages of the Yagi antenna are simple structure, light weight and firmness, and convenient power feeding, but the disadvantages are the narrow frequency band and poor anti-interference, especially the length of the Yagi antenna is not easy to shorten.

In order to improve the above shortcomings, it is necessary to provide an improved Yagi antenna to solve the problems of the conventional technology.

The main purpose of the present invention is to provide a Yagi antenna. Under the same gain effect, the overall length of the Yagi antenna with metamaterial characteristics can be shortened by about 10%, while maintaining the flat structure of the Yagi antenna.

To achieve the above objective, the present invention provides a Yagi antenna, which mainly includes: a substrate including an X axis along a length direction; a dipole antenna disposed on the substrate; and a metamaterial reflector located on the substrate. The +X axis side of the dipole antenna; and several metamaterial guides are located on the -X axis side of the dipole antenna; wherein each metamaterial guide includes at least one metamaterial guide single cell, Each metamaterial director unit cell includes an outer frame portion and an inner frame portion, the outer frame portion has a lower notch, the inner frame portion has an upper notch, the inner frame portion is disposed in the outer frame portion, and The left and right ends of the inner frame portion and the outer frame portion are connected by two connecting portions.

In an embodiment of the present invention, the number of the metamaterial guides is three.

In an embodiment of the present invention, the number of the metamaterial guides is five.

In an embodiment of the present invention, the number of the metamaterial guides is seven.

In an embodiment of the present invention, the substrate is a glass fiber board.

In an embodiment of the present invention, a signal feed end is connected in the middle of the dipole antenna.

In an embodiment of the present invention, the dipole antenna is used as an excitation source.

In an embodiment of the present invention, the dipole antenna is used to generate a radiation pattern in the frequency band of 2.4 to 2.5 GHz.

In an embodiment of the present invention, the reflector is used to reflect the radiation field pattern generated by the excitation source to the -X axis direction.

In an embodiment of the present invention, the directors are used to pull the radiation field generated by the excitation source to radiate in the -X direction.

100‧‧‧Yagi Antenna

100A‧‧‧Yagi antenna

100B‧‧‧Yagi antenna

10‧‧‧Substrate

20‧‧‧Dipole antenna

22‧‧‧Inlet

30‧‧‧Reflector

32‧‧‧Reflector single cell

321‧‧‧Outer frame

321a‧‧‧Upper notch

40‧‧‧Director

42‧‧‧Director single cell

421‧‧‧Outer frame

421a‧‧‧Lower notch

422‧‧‧Inner frame

422a‧‧‧Upper notch

423‧‧‧Connecting part

Figure 1: A three-dimensional schematic diagram of the Yagi antenna according to the first embodiment of the present invention.

Figure 2: A three-dimensional schematic diagram of a Yagi antenna according to a second embodiment of the present invention.

Figure 3: A three-dimensional schematic diagram of a Yagi antenna according to a third embodiment of the present invention.

Figure 4A: A schematic top view of a Yagi antenna according to a third embodiment of the present invention.

Figure 4B: A schematic top view of a single cell of a metamaterial reflector of the present invention.

Figure 4C: A schematic top view of a single cell of the metamaterial director of the present invention.

Figure 5: Simulation and measurement of the reflection loss of multiple metamaterial Yagi antennas according to the present invention.

Fig. 6: The radiation efficiency diagram of multiple metamaterial Yagi antennas simulated and measured by the present invention.

Figure 7: The present invention is a graph showing the maximum gain of multiple metamaterial Yagi antennas for simulation and measurement.

Figure 8: The 2D radiation pattern at 2.45GHz of the Yagi antenna of the present invention with 3 layers of metamaterial directors.

Figure 9: The 2D radiation pattern of the Yagi antenna of the present invention at 2.45GHz with 5 layers of metamaterial director.

Figure 10: The 2D radiation pattern of the Yagi antenna of the present invention with 7 layers of metamaterial director at 2.45GHz.

In order to make the above and other objectives, features, and advantages of the present invention more obvious and understandable, the following will specifically cite the preferred embodiments of the present invention, together with the accompanying drawings, and describe in detail as follows. Furthermore, the directional terms mentioned in the present invention, such as up, down, top, bottom, front, back, left, right, inside, outside, side, surrounding, center, horizontal, horizontal, vertical, vertical, axial, Radial, most The upper layer or the lowermost layer, etc., are only for reference in the direction of the attached drawings. Therefore, the directional terms used are used to describe and understand the present invention, rather than to limit the present invention.

Please refer to Figure 1. Figure 1 is a perspective view of the Yagi antenna according to the first embodiment of the present invention. A Yagi antenna 100 according to the first embodiment of the present invention includes a substrate 10, a dipole antenna 20, a reflector 30 and three guides 40. The substrate 10 includes an X-Y-Z coordinate, where a length direction of the substrate 10 is an X axis (the downward direction of the X axis in the figure is the positive direction of the X axis). The dipole antenna 20 is disposed on the substrate 10 and serves as an excitation source for generating a radiation pattern of Wi-FI 2.4GH (2.4 to 2.5GHz) frequency band. The reflector 30 is disposed on the substrate 10 and is located on the +X axis side of the dipole antenna 20 (that is, below the dipole antenna 20 in the figure) to reflect the radiation field pattern generated by the excitation source to the -X axis Direction (the direction on the X axis in the figure). The director 40 is disposed on the substrate 10, located on the -X axis side of the dipole antenna 20 (that is, above the dipole antenna 20 in the figure), and is used to pull the radiation field generated by the excitation source to radiate in the -X direction ( The direction of the X axis in the figure).

In the embodiment of the present invention, the reflector 30 and the guides 40 are made of metamaterials. Therefore, the Yagi antenna 100 of the embodiment of the present invention is a Yagi antenna with a metamaterial guide and reflector. 100. In addition, in the embodiment of the present invention, the substrate 10 is a glass fiber board, and a signal feeding end 22 is connected in the middle of the dipole antenna 20.

Please refer to Figure 2. Figure 2 is a perspective view of a Yagi antenna according to a second embodiment of the present invention. The Yagi antenna 100A of the second embodiment of the present invention is roughly similar to the Yagi antenna 100 of the first embodiment of the present invention. Therefore, the same component names are used, but the difference between the two is: in this embodiment, the metamaterial The number of guides 40 is increased to five.

Please refer to Fig. 3, which is a perspective view of a Yagi antenna according to a third embodiment of the present invention. The Yagi antenna 100B of the third embodiment of the present invention and the Yagiten antenna of the first embodiment of the present invention The lines 100 are roughly similar, so the same component names are used, but the difference between the two is that: in this embodiment, the number of metamaterial guides 40 is increased to seven.

In the present invention, the number of the metamaterial guides 40 is not specifically limited, and the user can set according to actual needs.

Please refer to FIGS. 4A to 4C, where FIG. 4A is a schematic top view of a Yagi antenna according to a third embodiment of the present invention; FIG. 4B is a schematic top view of a single cell of a metamaterial reflector of the present invention; And Figure 4C is a schematic top view of a single cell of the metamaterial director of the present invention.

As shown in Figure 4A, the size of the Yagi antenna 100B of this embodiment is, for example, 150mm (length)×70mm (width)×0.8mm (thickness), and each metamaterial reflector 30 includes two metamaterial reflectors. The single cell 32, each metamaterial guide 40 includes three metamaterial guide single cell 42, but the user can design the number of these single cells according to actual needs.

Specifically, as shown in FIG. 4B, each metamaterial reflector unit cell 32 includes an outer frame portion 321 having an upper notch 321a (approximately forming a C-shaped notch upward). The size of this metamaterial reflector unit cell 32 is, for example, 25 mm (length)×5 mm (width)×0.8 mm (thickness).

In addition, as shown in Figure 4C, each metamaterial director unit cell 42 includes an outer frame portion 421 and an inner frame portion 422. The outer frame portion 421 has a lower notch 421a (approximately forming a notch downward C-shaped), the inner frame portion 422 has an upper notch 422a (approximately forming a C-shaped notch upward), the inner frame portion 422 is provided in the outer frame portion 421, and is connected to the inner frame portion 422 by two connecting portions 423 The inner frame portion 422 and the left and right ends of the outer frame portion 421. The size of the metamaterial guide unit cell 42 is, for example, 21 mm (length)×3.5 mm (width)×0.8 mm (thickness).

Please refer to Figure 5. Figure 5 is the simulation and measurement of the reflection loss of multiple metamaterial Yagi antennas. These metamaterial Yagi antennas are added with 3 layers, 5 layers and 7 layers of metamaterial guides. The curve after 40 is the first to third embodiments of the present invention. It can be seen from the figure that the impedance bandwidth of the antenna falls within Wi-FI2.4GH (2.4 to 2.5GHz).

Please refer to Figure 6. Figure 6 is the simulation and measurement of the radiation efficiency of multiple metamaterials Yagi antennas. These metamaterials Yagi antennas are added with 3, 5 and 7 layers of metamaterial guides. For the curve after 40, the radiation efficiency obtained through a full-wave simulation software analysis falls between 75% and 85%, and the measured value is 55% to 80%.

Please refer to Figure 7. Figure 7 is the maximum gain diagram of simulation and measurement of multiple metamaterial Yagi antennas. These metamaterial Yagi antennas are added with 3, 5 and 7 layers of metamaterial guides respectively. The curve after 40. It can be seen from the figure that the maximum gain values analyzed by the simulation software are 8.23dBi, 9.48dBi and 10.16dBi, while the actual measurement results are 7.91dBi, 9.09dBi and 9.76dBi respectively.

Please refer to Figures 8 to 10. Figures 8 to 10 show the 2D radiation pattern of a Yagi antenna with metamaterials with 3, 5 and 7 layers of metamaterial director 40 at 2.45GHz. (XY plane), which contains simulation and measured values. From the figure, it can be seen that the radiation pattern of the antenna does increase in the direction of the metamaterial guide 40, and the back radiation is reduced due to the influence of the metamaterial reflector 30 , Forming a high gain, high directivity antenna.

As mentioned above, the present invention uses the design concept of metamaterials to change the dielectric characteristics of the reflector and director itself, and combines the dipole antenna to form a new type of metamaterial Yagi antenna, which not only retains its high gain characteristics, but also has better overall performance. Generally, the Yagi antenna is 10% shorter. For example, the length of the general Yagi antenna is 167mm. The length of the metamaterial Yagi antenna of the present invention can be shortened to 150mm. The Yagi antenna with metamaterial guide and reflector of the present invention can effectively design the refractive index of the metamaterial guide, so that the guide has the effect of concentrating radiation beams, and can focus the electromagnetic waves emitted by the excitation source, thereby increasing the antenna gain ; And adjust the reflection phase of the reflector itself and shorten the distance with the excitation source to improve the radiation pattern of the back radiation and reflection in its direction, so that the antenna gain is concentrated in the direction of the director, achieving the effect of increasing the gain.

Although the present invention has been disclosed in the preferred embodiments, it is not intended to limit the present invention. Anyone familiar with the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection shall be subject to the scope of the attached patent application.

100B‧‧‧Yagi antenna

10‧‧‧Substrate

20‧‧‧Dipole antenna

22‧‧‧Inlet

30‧‧‧Reflector

40‧‧‧Director

Claims (10)

A Yagi antenna, comprising: a substrate including an X axis along a length direction; a dipole antenna disposed on the substrate; a metamaterial reflector located on the +X axis side of the dipole antenna; and Several metamaterial directors are located on the -X axis side of the dipole antenna; among them, each metamaterial director includes at least one metamaterial director single cell, and each metamaterial director single cell It includes an outer frame portion and an inner frame portion, the outer frame portion has a lower notch, the inner frame portion has an upper notch, the inner frame portion is provided in the outer frame portion, and the inner frame portion is connected by two connecting portions. The frame and the left and right ends of the outer frame. For the Yagi antenna described in item 1 of the scope of patent application, the number of these metamaterial guides is three. For the Yagi antenna described in item 1 of the scope of patent application, the number of the metamaterial guides is five. Such as the Yagi antenna described in item 1 of the scope of patent application, in which the number of the metamaterial guides is 7. The Yagi antenna described in the first item of the scope of patent application, wherein the substrate is a glass fiber board. Such as the Yagi antenna described in item 1 of the scope of patent application, wherein the dipole antenna is connected with a signal feed end in the middle. The Yagi antenna described in item 1 of the scope of patent application, wherein the dipole antenna is used as an excitation source. The Yagi antenna described in item 7 of the scope of patent application, wherein the dipole antenna is used to generate a radiation pattern in the frequency band of 2.4 to 2.5 GHz. Such as the Yagi antenna described in item 7 of the scope of patent application, wherein the reflector is used to reflect the radiation field pattern generated by the excitation source to the -X axis direction. Such as the Yagi antenna described in item 7 of the scope of patent application, wherein the directors are used to pull the radiation field generated by the excitation source to radiate in the -X direction.

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