KR101067173B1 - Yagi-Uda antenna having CPS feed line - Google Patents

Abstract

A Yagi-Uda antenna with a CPS feed line is disclosed. Yagi-woo antenna according to an embodiment of the present invention, the driver is provided with a rectangular shape having a first width and a first length on one surface of the substrate for transmitting and receiving radio waves; And CPS lines, each having a second width at one end and connected at right angles to a corresponding driver, tapering a third width narrower than the second width and having a second length. Yagi-Uda antenna according to the present invention has the advantage that the structure is simple by using a CPS feeding method can be miniaturized and the radiation characteristics can be improved.

Description

Yagi-Uda antenna having CPS feed line

The present invention relates to a Yagi-Uda antenna, and more particularly, to a Yagi-Uda antenna that can improve radiation characteristics degradation by using a CPS feeding method.

The planar Yagi-Uda antenna designed on the substrate has the advantages of wide bandwidth, simple design, and low manufacturing cost. However, Yagi-Uda antennas use microstrip lines or coplanar waveguides (CPWs) as coplanar strip (CPS) lines, which limit the length and position of the reflector and ultimately the There is a problem that can limit the improvement of properties.

In addition, the MS-CPS transition structure or the CPW-CPS transition structure as described above must have a ground plane on the substrate so as to be connected to a driver disposed on the front surface of the substrate, thereby causing a problem of limiting the miniaturization of the antenna.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a Yagi-da antenna, which has a wideband characteristic and is simple in structure, which can be miniaturized and its radiation characteristics can be improved.

Yagi-Uda antenna according to an embodiment of the present invention for achieving the above technical problem, each of which is provided with a rectangular shape having a first width and a first length on one surface of the substrate for transmitting and receiving radio waves field; And CPS lines, each having a second width at one end and connected at right angles to a corresponding driver, tapering a third width narrower than the second width and having a second length.

Preferably, each of the CPS lines may be tapered so as to face each other, have a first interval at each end, and a second interval wider than the first interval at the other end.

Preferably, when one side of the CPS lines facing each other is called the inner side and the other side located opposite to the inner side is the outer side, the CPS lines are respectively from the first position to the second position, the outer side is the inner side Tapered at a first angle in a direction such that the other end has a third width that is narrower than the second width, and the inner side is tapered at a second angle in the outward direction so that a second interval at the other end is It may be wider than the first interval at one end.

Preferably, each reflector is provided in a rectangular shape of a third length, and disposed in parallel with the driver at a first distance away from the driver in a first direction to reflect reflectors radiated from the driver. Can be.

Preferably, the first director may be further provided with a rectangular shape having a fourth length and positioned at the driver by a second distance in a second direction symmetrical with the driver.

A second director may be further provided in a rectangular shape having a fourth length and positioned apart from the first director by a third distance in the second direction.

Yagi-Uda antenna according to the present invention has the advantage that the structure is simple by using a CPS feeding method can be miniaturized and the radiation characteristics can be improved.

DETAILED DESCRIPTION In order to fully understand the present invention, the operational advantages of the present invention, and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings that illustrate preferred embodiments of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals in the drawings denote like elements.

1 is a diagram illustrating a Yagi-Uda antenna according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the Yagi-Uda antenna 100 according to an exemplary embodiment of the present invention may include drivers 130, which are feeding elements, and CPS lines 120, which are feeding lines, on a substrate 200. And reflectors 140 and directors 150 and 160 which are parasitic elements.

Each of the drivers 130 has a rectangular shape having one end connected to the CPS line 120 at right angles and having a first width W1 and a first length L1 to transmit and receive radio waves. In this case, the driver 130 may be a half-wavelength dipole antenna. Although not shown in FIG. 1, signals transmitted and received by the driver 130 are transmitted to the outside or transmitted from the outside by a connector provided at the end of the substrate 200.

The Yagi-Uda antenna 100 according to an exemplary embodiment of the present invention includes a CPS line 120 as a feed line connected to the driver 130. However, in order to design the CPS lines to be impedance matched in the Yagi-Uda antenna 100, the relative dielectric constant of the substrate, the thickness of the substrate, the line width of the CPS line and the spacing between the CPS lines should be considered. In order to use the impedance-matched CPS line 120 in the Yagi-Uda antenna 100 as described above, the line width of the CPS line should be thick and the spacing between the lines should be narrow. The line width of the CPS line is different from the line width of the driver. If there is a lot of connection between the driver and the CPS line, the driver will not work properly.

Thus, when using the CPS line 120 according to an embodiment of the present invention, in order to ensure the normal operation of the driver while ensuring the line width for impedance matching, the CPS line, Taping

Specifically, referring to FIG. 1, each of the two CPS lines 120 has one end of the second width W2, while the width of the line is changed from the first position P1 to the second position P2 of the track. It is inclined at a first angle θ1 in a linearly narrowing direction and tapered so that the thickness of the other end vertically connected to the corresponding driver is provided with a third width W3 narrower than the second width. Further, the interval between the CPS lines 120 has a first distance g1 from one end of the line to the first position P1, and the line from the first position P1 to the second position P2 of the line. The interval between them is opened at a second angle θ2, and tapered to have a second interval g2 at the end of the track. At this time, the CPS line is provided with a second length (L2).

As described above, the Yagi-Uda antenna 100 according to the embodiment of the present invention includes a tapered CPS feed line, thereby ensuring the normal operation of the driver even when using the CPS line. In addition, the length and position of the reflector (reflector), which will be described later, may be used by converting a microstrip line or a coplanar waveguide (CPW) into a coplanar strip (CPS) line in the Yagi-Uda antenna 100 according to the prior art. Can solve the problem of being limited.

If there is no restriction on the reflector, the reflector can be designed to improve the antenna characteristics of the Yagi-da antenna. This is described.

1, two reflectors 140 may be disposed on both sides of the CPS line 120, respectively. In addition, the two reflectors 140 are each provided in a rectangular shape having a third length L3 and positioned in parallel to the driver by being separated by the first distance S1 from the driver 130 in the negative direction of the X axis. Reflects the radio wave radiated at 130). Therefore, an improved radiation pattern can be obtained by effectively reflecting radio waves radiated to the rear of the driver 130.

The first director 150 is spaced apart from the driver 130 in the positive X-axis direction by the second distance S2 and is provided with a fourth length L4, and the second director 160 is the first director 150. It is located in the positive X-axis direction from the third distance (S3) and provided with a fifth length (). The first director 150 and the second director 160 enhance the radio wave reflected from the reflector 140. Thus, propagation proceeds in the positive X-axis direction and directivity can also be generated in this direction.

The Yagi-Uda antenna of FIG. 1 has L1 = 22 mm, L2 = 47 mm, L3 = 22 mm, L4 = 11.6 mm, L5 = 8 mm, W1 = 2 mm, W2 = 4 mm, θ1 = 4 °, θ2 = It can be optimized for 1 ° and g1 = 0.13 mm. In this case, the substrate uses a dielectric constant of 10.2 and a thickness of 0.635 mm, and Rogers RT-Duroid 6010 having a width (L) and a length (W) of 83 mm and 60 mm, respectively.

FIG. 2 is a graph illustrating return loss characteristics of the Yagi-Uda antenna of FIG. 1 optimized as described above.

Referring to FIG. 2, the Yagi-Uda antenna 100 of FIG. 1 has a bandwidth of 4.1 to 6 GHz based on a -10 dB return loss (vertical dotted line).

3 to 5 are diagrams showing the radiation pattern simulated at 4.2 GHz, 5.0 GHz, and 5.8 GHz of the Yagi-Uda antenna of FIG. 1. At 4.2 GHz, the gain of the antenna is 7.3 dBi and the half power beamwidth is 69.7 ° in the x-y plane and 114.3 ° in the x-z plane. At 5 GHz, the gain of the antenna is 8.2 dBi and the half power beamwidth is 61.8 ° in the x-y plane and 90.6 ° in the x-z plane. At 5.8 GHz, it has a gain of 8.2 dBi and the half-power beamwidth is 62 ° in the x-y plane and 86.1 ° in the x-z plane.

FIG. 6 is a diagram illustrating gain characteristics of the Yagi-Uda antenna of FIG. 1 optimized as described above. Referring to FIG. 6, the Yagi-Uda antenna 100 of FIG. 1 has a gain of 7.3 to 8.4 dBi within a bandwidth of 4.1 to 6 GHz, and thus has a small amount of gain variation compared to conventionally designed Yagi-Uda antennas.

Such a small gain change characteristic has the advantage of smoothly transmitting and receiving signals by reducing the variation of transmit and receive power according to frequency in a broadband wireless communication system. That is, the Yagi-Uda antenna according to the embodiment of the present invention has a tapered CPS line to adaptively design the reflector, thereby improving the gain change characteristic of the antenna.

As described above, an optimal embodiment has been disclosed in the drawings and specification. Although specific terms are employed herein, they are used for purposes of describing the present invention only and are not used to limit the scope of the present invention. For example, two or more reflectors of FIG. 1 may be provided, and more than one director may be provided.

Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS In order to better understand the drawings cited in the detailed description of the invention, a brief description of each drawing is provided.

1 is a diagram illustrating a Yagi-Uda antenna according to an exemplary embodiment of the present invention.

FIG. 2 is a graph illustrating return loss characteristics of the Yagi-Uda antenna of FIG.

FIG. 3 is a graph showing the radiation pattern at 4.2 GHz of the Yagi-Uda antenna of FIG. 1 optimized.

FIG. 4 is a graph showing the radiation pattern at 5 GHz of the Yagi-Uda antenna of FIG. 1 optimized.

5 is a graph showing the radiation pattern at 5.8 GHz of the Yagi-Uda antenna of FIG. 1 optimized.

FIG. 6 is a graph showing the gain characteristics of the Yagi-Uda antenna of FIG. 1 optimized.

Claims (6)

In the Yagi-Uda antenna, Drivers each having a rectangular shape having a first width and a first length on one surface of the substrate to transmit and receive radio waves; And Each having a second width and the other end connected orthogonally to the corresponding driver is tapered to have a third width narrower than the second width, and has coplanar strip (CPS) lines having a second length, Respectively provided in a rectangular shape of a third length, further comprising reflectors positioned parallel to the driver at a first distance away from the driver in a first direction, reflecting the radio waves radiated from the driver Yagi-woo antenna. The method of claim 1, wherein the CPS lines are each, Positioned opposite each other, tapered to have a first spacing at said one end and a second spacing at said other end that is wider than said first spacing. The method of claim 2, When one side of the CPS lines facing each other is called the inner side and the other side located opposite to the inner side is called the outer side, The CPS lines are each From the first position to the second position, the outer side is tapered to be inclined at a first angle in the inward direction, and the inner side is tapered to be inclined at a second angle in the outward direction, so that the other end is narrower than the second width. And the second width at the other end is wider than the first distance at the one end having the third width. delete The method of claim 1, And a first director provided in a rectangular shape of a fourth length and positioned apart from the driver by a second distance in a second direction symmetrical with the first direction. The method of claim 5, And a second director provided in a rectangular shape having a fourth length and positioned apart from the first director by a third distance in the second direction.

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