JP2013098791A - Antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna radiating or absorbing a radio wave in a wide frequency band.SOLUTION: In a patch antenna, including a dielectric substrate 3 having a circular plane shaped ground plane layer 2 on the rear face side and a circular plane shaped antenna element 1, having a center portion C as a feeding point E, laminated on the surface 3A of the dielectric substrate 3, a plurality of arc shaped slits 5 separated by a plurality of radial bridges 4 are disposed on the circular plane shaped antenna element 1 concentrically circular with the outer peripheral edge of the circular plane shaped antenna element 1.

Description

  The present invention relates to an antenna.

  Conventionally, a patch antenna is known in which an antenna element made of a conductive material is laminated on one surface of a dielectric substrate (see Patent Document 1).

JP 2008-66979 A

  However, the conventional patch antenna can only handle a single frequency band, and the frequency range of radio waves that can be transmitted and received is limited to a narrow band. Therefore, with a conventional patch antenna, it is difficult to cover two types of radio waves for transmission and reception in frequency division duplex (FDD) with a single antenna, for example, for 2 GHz band cellular phone applications.

  Therefore, an object of the present invention is to provide an antenna that transmits or receives radio waves in a wide frequency band or a plurality of frequency bands.

  The antenna according to the present invention includes a dielectric substrate having a circular planar ground plane layer on the back side, and a patch in which a circular planar antenna element having a central point as a feeding point is laminated on the surface of the dielectric substrate. In the type antenna, the circular planar antenna element is provided with a plurality of arc-shaped slits separated by a plurality of radial bridges concentrically with the outer peripheral edge of the circular planar antenna element.

Further, the radial bridge is formed at 3 to 8 positions with the same central angle.
Further, with respect to the outer peripheral radius of the circular planar antenna element, the slit outer peripheral radius of the outer peripheral edge of the arc-shaped slit and the slit inner peripheral radius of the inner peripheral edge of the arc-shaped slit are 0.65R. ₁ ≦ R ₂ , 0.6R ₁ ≦ R ₃ , and R ₃ <R ₂ are set to satisfy the relational expression.

  According to the antenna of the present invention, it is possible to transmit and receive radio waves corresponding to two types of radio waves having different frequency ranges, and a wide band (multiband) can be achieved. Therefore, it is possible to cover two types of radio waves in two-way wireless communication of a mobile phone with one antenna.

It is the top view which showed one Embodiment of this invention. It is the cross-sectional side view which showed the antenna of this invention. It is the graph which showed the VSWR characteristic of the antenna of this invention. It is the figure which showed the gain characteristic of the antenna of this invention in 1940 MHz, Comprising: (a) is a graph figure which showed the gain characteristic in a plane perpendicular | vertical with respect to an antenna surface, (b) is perpendicular | vertical in-plane directivity. 6 is a graph showing the maximum radiation direction (about 45 ° direction indicated by a dotted arrow in (a)) with respect to the surrounding direction in the antenna plane. It is the figure which showed the gain characteristic of the antenna of this invention in 2140 MHz, Comprising: (a) is a graph figure which showed the gain characteristic in a surface perpendicular | vertical with respect to an antenna surface, (b) is perpendicular | vertical in-plane directivity. 6 is a graph showing the maximum radiation direction (about 45 ° direction indicated by a dotted arrow in (a)) with respect to the surrounding direction in the antenna plane. It is the graph which showed the VSWR characteristic of the antenna of an Example. It is the graph which showed the VSWR characteristic of the antenna of an Example. It is the graph which showed the VSWR characteristic of the antenna of an Example.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments.
As shown in FIGS. 1 and 2, the antenna of the present invention includes a dielectric substrate 3 having a circular planar ground plane layer 2 on the back surface 3B side, and a center point C on the surface 3A of the dielectric substrate 3. Is a patch type antenna in which the circular planar antenna elements 1 having a feed point E are stacked.
In the antenna of the present invention, a circular planar antenna element 1 is provided with a plurality of arc-shaped slits 5 separated by a plurality of radial bridges 4 concentrically with the outer peripheral edge of the circular planar antenna element 1.

The dielectric substrate 3 is made of a 3.2 mm thick epoxy glass plate (wavelength reduction rate: 62%).
The circular planar antenna element 1 is made of a conductive metal such as Cu, Al, Ag, or Au, and is attached to the surface 3A of the dielectric substrate 3 by printing, vapor deposition, spray film formation, etching, or the like. Formed by the method.
The circular planar ground plane layer 2 is made of a conductive metal such as Cu, Al, Ag, and Au, and is formed concentrically with the circular planar antenna element 1 on the back surface 3B side of the dielectric substrate 3. The outer peripheral radius R ₀ of the circular planar ground plane layer 2 is set larger than the outer peripheral radius R ₁ of the circular planar antenna element 1.
A coaxial connector 6 is mounted as a power supply terminal at the center of the back surface 3 </ b> B of the dielectric substrate 3. A coaxial cable for power feeding from an antenna input circuit of a wireless device (not shown) is connected to the coaxial connector 6. The coaxial connector 6 includes a center conductor 6A and a cylindrical outer conductor 6B. The center conductor 6A is electrically connected to the circular planar antenna element 1 at a feeding point E through a through hole penetrating the central portion of the dielectric substrate 3. It is connected to the. The cylindrical outer conductor 6B is electrically connected to the circular planar ground plane layer 2 in an insulated state from the central conductor 6A and the circular planar antenna element 1.

The radial bridge 4 is formed at three to eight positions with the same central angle θ.
In the illustrated example, the radial bridge 4 is formed in a four-way radial shape when viewed from the center point C, and is equally provided at four locations (center angle θ = 90 °).
In other words, the arcuate slit 5 can be said to divide the circular planar antenna element 1 into an outer ring 1A and an inner circle 1B, leaving only a plurality of radial bridges 4.

With respect to the outer peripheral radius R ₁ of the circular planar antenna element 1, the slit outer peripheral radius R _{2 of} the outer peripheral edge 5 A of the arc-shaped slit 5 and the slit inner peripheral radius R of the inner peripheral edge 5 B of the arc-shaped slit 5. ₃ is set so as to satisfy the relational expression represented by 0.65R ₁ ≦ R ₂ , 0.6R ₁ ≦ R ₃ , and R ₃ <R ₂ .
In other words, the arc-shaped slit 5 is disposed near the outer peripheral edge 1 </ b> C of the circular planar antenna element 1. If, slit outer circumferential radius R ₂ of the outer peripheral edge 5A of the arcuate slit 5, or less than 65% of the size of the outer peripheral edge radius R ₁ of the circular planar antenna element 1, the inner peripheral end of the circular slit 5 a slit inner radius R ₃ of the edge 5B, when or less than 60% the size of the outer peripheral edge radius R ₁ of the circular planar antenna element 1, obtained effect of the bandwidth of the later (multiband) There is no fear.

A method (action) of using the antenna of the present invention described above will be described.
As shown in FIG. 3, as an embodiment of the present invention, the outer peripheral radius R ₁ of the circular planar antenna element 1 shown in FIG. ₁ is 57 mm, and the outer peripheral radius R _{2 of the} outer peripheral edge 5 A of the arc-shaped slit 5 is 46 mm. , to produce an antenna which inner peripheral edge 5B slit inner radius R ₃ of the circular slit 5 is set as 42mm, installed this so that the antenna plane is horizontal shape, the analysis result of the VSWR characteristics It is shown as a graph, with the horizontal axis representing frequency (GHz) and the vertical axis representing VSWR value (voltage standing wave ratio). In addition, when it installs so that an antenna surface may become horizontal shape (parallel surface shape with the ground), a vertically polarized wave will be radiated | emitted from the antenna of this invention.

The antenna according to this embodiment has a VSWR value of 2.0 or less in the frequency band A _{1 of} 1920 MHz to 1980 MHz, and the first matching frequency F ₁ forming the deepest portion is substantially at the center position of the frequency band A _1. Has occurred. Further, At a frequency band _{A 2} of 2110MHz～2170MHz, shows the following VSWR value of 2.0, the second matching frequency _{F 2} which forms the deepest part, has occurred in a substantially central position of the frequency band _{A 2.} That is, the graph showing the VSWR characteristics of the antenna of the embodiment shows a bimodal locus in which the first matching frequency F ₁ and the second matching frequency F ₂ exist, and is widened (multibanded). I understand. The antenna of the present invention, for example, in a two-way wireless communication such as a mobile phone or a wireless LAN, an uplink radio wave (received radio wave; frequency 1920 MHz to 1980 MHz) and a downstream radio wave (FDD) (frequency division duplex (FDD)). It can be said that effective VSWR characteristics were obtained over a wide band corresponding to two types of radio waves (transmission radio waves; frequencies 2110 MHz to 2170 MHz).

  Next, as shown in FIGS. 4 and 5 measured at 1940 MHz and 2140 MHz, respectively, the antenna directivity at each frequency becomes a substantially circular radiation pattern in the maximum radiation direction, and the horizontal plane direction (antenna surface direction) On the other hand, it can be confirmed that uniform vertically polarized waves are radiated, and it can be seen that it has almost non-directional characteristics. That is, the antenna of the present invention transmits and receives radio waves uniformly in the horizontal direction, and has an omnidirectional characteristic for each frequency (by providing the circular-shaped antenna element 1 with the arc-shaped slit 5). Is confirmed to be intact.

Next, in the antenna device of the present invention, the response of the VSWR characteristics when various parameters constituting the circular planar antenna element 1 are changed are shown in FIGS.
First, the slit outer circumferential radius R ₂ of the outer peripheral edge 5A of the arc-shaped slit 5 shown in FIG. 1 to 40 mm, the inner peripheral edge 5B slit inner radius R ₃ of the circular slit 5 and 38mm, circular planar antenna elements The transition of the VSWR characteristic when the outer peripheral radius R1 of ₁ is changed to 42 mm, 47 mm, and 52 mm is verified.
As shown in FIG. 6, the matching frequency F _A in the low-frequency _side, F _B, F _C is, as the outer peripheral edge radius R ₁ of the circular planar antenna element 1 gradually increases, gradually decreases to a lower frequency Moving. On the other hand, the matching frequencies F _A ′, F _B ′, and F _C ′ on the high frequency side gradually move toward the low frequency side gradually as the outer peripheral radius R ₁ of the circular planar antenna element 1 gradually increases. I understand.

Next, the outer peripheral radius R ₁ of the circular planar antenna element 1 shown in FIG. 1 is set to 42 mm, the inner radius R ₃ of the inner peripheral edge 5 B of the arc-shaped slit 5 is set to 33 mm, and the outer peripheral end of the arc-shaped slit 5 is set. when the slit outer circumferential radius _{R 2} of the rim 5A 40.0 mm, 37.5 mm, is changed from 35.0 mm, as shown in FIG. 7, matching frequency _F D of the low-frequency _side, F E, _{F F} is a circle be varied as slit outer circumferential radius R ₂ of the outer peripheral edge 5A of the arcuate slits 5 gradually decreases, only slightly moved to the high frequency side, also matching frequency F _D of the high-frequency side _', F _E', F _F 'does not move very much.
The outer peripheral radius R ₁ of the circular planar antenna element 1 shown in FIG. 1 is 42 mm, the outer peripheral radius R ₂ of the outer peripheral edge 5 A of the arc-shaped slit 5 is 40 mm, and the inner peripheral edge 5 B of the arc-shaped slit 5 is set. When the inner radius R ₃ of the slit is changed to 38.0 mm, 35.5 mm, and 33.0 mm, the matching frequencies F _G , F _H , and F _I on the low frequency side are arcuate as shown in FIG. with to the slit outer circumferential radius R ₃ of the inner peripheral edge 5B of the slit 5 is reduced gradually, largely moved to the high frequency side. On the other hand, even if the inner peripheral edge 5B slit outer circumferential radius R ₃ of the circular slit 5 is changed, matching frequency F _G of the high-frequency side _{', F H', F I} ' do not substantially change.

Thus, in the antenna of the present invention, the outer peripheral radius R _{1 of} the circular planar antenna element 1, the slit outer peripheral radius R _{2 of} the outer peripheral edge 5 A of the arc-shaped slit 5, and the inner peripheral edge of the arc-shaped slit 5 by setting 5B slit inner radius R ₃ of the appropriate two matching frequencies corresponding to two types of radio waves, it is possible to control each independently. In other words, the antenna of the present invention can easily adjust the matching frequency in addition to having a wider band (multiband).

  In the present invention, the design can be changed. For example, in the illustrated example, the radial bridges 4 are provided at four locations, but can be increased or decreased without changing the gist. Moreover, although the power supply terminal is the coaxial connector 6, it can be replaced with another terminal.

  As described above, the antenna according to the present invention includes the dielectric substrate 3 having the circular planar ground plane layer 2 on the back surface 3B side, and the center point C is placed on the surface 3A of the dielectric substrate 3 with the feeding point E. In the patch-type antenna in which the circular planar antenna elements 1 are laminated, a plurality of arc-shaped slits 5 separated by the plurality of radial bridges 4 are provided on the circular planar antenna element 1 outside the circular planar antenna element 1. Since it is provided concentrically with the peripheral edge, it is possible to transmit and receive radio waves corresponding to two types of radio waves having different frequency ranges, and a wide band (multiband) can be achieved. Therefore, it is possible to cover two types of radio waves in two-way wireless communication of a mobile phone with one antenna.

  Further, since the radial bridge 4 is formed at three to eight positions with the same central angle θ, the radio waves can be transmitted and received substantially evenly in the horizontal direction without impairing the non-directionality.

Further, with respect to the outer peripheral radius R ₁ of the circular planar antenna element 1, the slit outer peripheral radius R _{2 of} the outer peripheral edge 5 A of the arc-shaped slit 5 and the slit inner periphery of the inner peripheral edge 5 B of the arc-shaped slit 5. Since the radius R ₃ is set so as to satisfy the relational expression represented by 0.65R ₁ ≦ R ₂ , 0.6R ₁ ≦ R ₃ , and R ₃ <R ₂ , the first matching frequency F _The frequency bands A ₁ and A _{2 in} which the _first and second matching frequencies F ₂ exist are separated from each other to form a VSWR characteristic having a bimodal trajectory, and a wide band (multi-band) can be ensured.

DESCRIPTION OF SYMBOLS 1 Circular planar antenna element 2 Circular planar ground plane layer 3 Dielectric substrate 3A Front surface 3B Back surface 4 Radial bridge 5 Arc-shaped slit 5A Outer edge 5B Inner edge C Center point E Feed point θ Center angle R ₁ Outer peripheral radius R ₂ Slit outer radius R ₃ Slit inner radius

Claims (3)

A dielectric substrate (3) having a circular planar ground plane layer (2) on the back surface (3B) side is provided, and a center point (C) is fed to the front surface (3A) of the dielectric substrate (3). In the patch type antenna in which the circular planar antenna element (1) as (E) is laminated,
The circular planar antenna element (1) is provided with a plurality of arc-shaped slits (5) separated by a plurality of radial bridges (4) concentrically with the outer peripheral edge of the circular planar antenna element (1). An antenna characterized by.   The antenna according to claim 1, wherein the radial bridge (4) is formed at three to eight positions with equal central angles (θ). The outer peripheral radius (R ₁ ) of the circular planar antenna element (1), the outer peripheral radius (R ₂ ) of the outer peripheral edge (5A) of the arc-shaped slit (5), and the arc-shaped slit The inner peripheral radius (R ₃ ) of the inner peripheral edge (5B) of (5) is represented by 0.65R ₁ ≦ R ₂ , 0.6R ₁ ≦ R ₃ , and R ₃ <R _2. The antenna according to claim 1, wherein the antenna is set to satisfy a relational expression.

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