JP2003008337A - Microstrip antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make uniform transmission and reception areas by matching half- angle characteristics in a direction where a linearly polarized wave crosses orthogonally. SOLUTION: A square plate-shaped ground conductor 1 is arranged upright. A radiating element 2 being smaller than the ground conductor 1 is arranged while being overlapped to the center of one side of the ground conductor 1. Two parasitic conductors 4 are provided in parallel adjacent to the left and right sides of the ground conductor 1, and, two parasitic conductors 5 are provided in parallel adjacent to upper and lower sides. In the parasitic conductors 4 and 5, the length is set to 1/2 of radiation wavelength, and the width and clearance are set to 1/10 of the radiation wavelength.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microstrip antenna, and more particularly to improvement of directivity of a microstrip antenna that radiates linearly polarized waves in the orthogonal direction.

[0002]

2. Description of the Related Art A microstrip antenna called a patch antenna is a PHS base station antenna or a wireless LAN.
It is used as an antenna. FIG. 5 shows a schematic view of such a microstrip antenna, in which 11 is a ground conductor and 12 is a radiating conductor, which has a horizontal polarization feed point 13a and a vertical polarization feed point 13b, and two types of linear polarization. Can be sent and received.

[0003]

However, the linearly polarized wave radiated from the microstrip antenna shown in FIG. 5 has a different directivity in the same direction as the electric field and a directivity in a direction orthogonal to the electric field, and as shown in FIG. The vertical plane half-value angle and the horizontal plane half-value angle of the polarization had different values. Therefore, there is a difference between the transmission / reception area for horizontal polarization and the transmission / reception area for vertical polarization. This is not a desirable characteristic, because the sensitivity differs between when the PHS mobile phone is used upright and when it is laid down, for example. Therefore, for example, it is conceivable to change the aspect ratio of the ground conductor to expand the horizontal width and align the half-value angles of the vertical plane and the horizontal plane of the vertically polarized wave.However, in this case, there is a problem that the characteristics of the horizontally polarized wave are deteriorated. Was. Therefore, in view of the above problems, it is an object of the present invention to provide a microstrip antenna capable of uniforming the transmission / reception area by matching the half-value angle characteristics of linearly polarized waves in orthogonal directions.

[0004]

In order to solve the above-mentioned problems, the present invention according to claim 1 is arranged such that a ground conductor having a substantially square shape and a plane shape is erected so that four sides are arranged horizontally or vertically. In a microstrip antenna in which a planar radiating element is arranged via a dielectric so as to overlap with one side of a ground conductor, and which can radiate at least one of vertical polarization and horizontal polarization At least one linear parasitic conductor is provided adjacent to at least a pair of opposing sides of the upper and lower sides or the left and right sides of the ground conductor.

According to a second aspect of the present invention, in the first aspect of the present invention, when the radiated wave is vertically polarized, the parasitic conductor is provided at least adjacent to the left and right sides of the ground conductor and parallel to the vertical direction. It is characterized by being formed. The invention of claim 3 is
In the invention of claim 2, the length of the parasitic conductor is 0.4 to 1.1 times the radiation wavelength.

According to a fourth aspect of the present invention, in the first aspect of the present invention, when the radiated wave is a horizontally polarized wave, the parasitic conductor is provided adjacent to at least the upper and lower sides of the ground conductor and parallel to the horizontal direction. It is characterized by being formed. The invention of claim 5 is
The microstrip antenna according to claim 4, wherein the length of the parasitic conductor is 0.4 to 1.1 times the radiation wavelength.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the width of the parasitic conductor is 0.2 of a radiation wavelength.
It is characterized by being 5 times or less.

According to a seventh aspect of the present invention, in the invention according to any one of the first to sixth aspects, in which a plurality of parasitic elements are arranged adjacent to each other, the gap between the parasitic elements is radiated. It is characterized in that the wavelength is 0.5 times or less.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a front explanatory view showing an example of a microstrip antenna according to the present invention, in which a square plate-shaped ground conductor 1 and a ground conductor 1 having a square shape are also formed so as to overlap with the center of one side surface (front surface in the drawing) of the ground conductor 1. A radiating element 2 formed to be smaller than 1 is arranged and formed via a dielectric. In addition, 3a is a horizontal polarization feeding point, 3b is a vertical polarization feeding point,
The sides are arranged horizontally and vertically, respectively. If the dielectric is a resin plate, both sides of which can be used to easily form the installed conductor and the radiating element, but it may be simply air.

Two parasitic conductors 4 are provided in parallel in the vertical direction so as to be adjacent to the left and right sides of the ground conductor 1. The length L1 of the parasitic conductor 4 is 0.5λ when the radiation wavelength of the antenna is λ, and the width W1.
The conductor spacing P1 is 0.1λ. The half-value angles of the vertical plane and the horizontal plane of the vertically polarized wave and the horizontally polarized wave of this antenna are the values shown in FIG. 2, and the half-value angle of the horizontal plane of the vertically polarized wave is the same value as the half-value angle of the vertical plane.

As described above, with respect to an antenna that radiates vertically polarized waves, it is possible to match the half-value angle of the horizontal plane with the half-value angle of the vertical plane with a simple structure in which parasitic conductors are provided adjacent to the left and right sides of the ground conductor. Yes, the service area in both directions can be made uniform. Since this parasitic conductor is arranged in the same direction as the electric field of vertical polarization, it is orthogonal to the electric field direction of horizontal polarization, and does not affect the characteristics of horizontal polarization. The length L1 of the parasitic conductor is 0.4λ-1.
The width W1 is preferably 0.25λ or less, and the gap P1 between adjacent parasitic conductors is preferably 0.5λ or less.

In FIG. 3, in addition to the structure of FIG. 1, two parasitic conductors 5 are provided in the left-right direction adjacent to the upper and lower sides of the ground conductor. The length L of the parasitic conductor 5 in the left-right direction
2 is formed with a length of 0.5λ, and the width W2 and the conductor interval P2 are formed with 0.1λ. The vertical plane half-value angle and the horizontal plane half-value angle of each of the vertical polarization and the horizontal polarization of this antenna are the values shown in Fig. 4, and the horizontal plane half-value angle and the vertical plane half-value angle of both the vertical polarization and the horizontal polarization are the same. It is a value.

By thus providing the parasitic conductors adjacent to the upper and lower sides of the grounding conductor, the horizontal plane half-value angle and the vertical plane half-value angle of horizontal polarization can be matched. Also, since the parasitic conductors arranged above and below are in the same direction as the electric field of horizontal polarization, they are orthogonal to the electric field direction of vertical polarization and do not affect the characteristics of vertical polarization. The horizontal plane half-value angle and the vertical plane half-value angle of both the horizontal polarization and the vertical polarization can be matched with the provided parasitic conductor, and even when both polarizations are radiated, both service areas can be made uniform.
The length L2 of the parasitic conductor provided above and below the ground conductor
Is preferably 0.5λ or less, the width W2 is 0.25λ or less, and the gap P2 is 0.5λ or less. Further, two parasitic conductors are formed on each of the two parasitic conductors, but one parasitic conductor may be formed, or a plurality of parasitic conductors may be arranged adjacent to each other.

[0014]

As described in detail above, according to the present invention,
It becomes possible to match the half-value angle in the horizontal plane and the vertical plane direction with a simple configuration for the vertical or horizontal radiated polarized wave. Particularly, according to the inventions of claims 2 and 3, the half-value angles of the vertically polarized horizontal plane and the vertical plane can be matched, and according to the inventions of claims 4 and 5, the horizontally polarized horizontal plane and the vertical plane can be aligned. The half-value angles can be adjusted, and the service areas of both vertically polarized waves and horizontally polarized waves can be made uniform.

[Brief description of drawings]

FIG. 1 is a front view of a microstrip antenna showing an example of an embodiment of the present invention.

FIG. 2 is a table showing half-value angle characteristics of the antenna of FIG.

FIG. 3 is a front view of a microstrip antenna showing another embodiment of the present invention.

FIG. 4 is a table showing half-value angle characteristics of the antenna of FIG.

FIG. 5 is a front view of a conventional microstrip antenna.

6 is a table showing half-value angle characteristics of the antenna of FIG.

[Explanation of symbols]

1 ... Grounding conductor, 2 ... Radiating element, 3a ... Horizontal polarization feed point, 3b ... Vertical polarization feed point, 4, 5 ... Parasitic conductor.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5J021 AA01 AB06 BA01 CA05 FA23                       GA04 HA05 JA05                 5J045 AA12 AA13 AA21 CA01 DA10                       FA08 GA01 NA03

Claims (7)

[Claims] 1. A substantially square and planar grounding conductor is erected so that four sides are arranged horizontally or vertically, and a planar radiating element is provided as a dielectric so as to be superposed on one side surface of the grounding conductor. In a microstrip antenna capable of radiating at least one of a vertically polarized wave and a horizontally polarized wave, the grounded conductor has at least a pair of opposite sides of the upper and lower sides or the left and right sides thereof. At least one linear parasitic conductor is provided adjacent to the microstrip antenna. 2. The microstrip antenna according to claim 1, wherein when the radiated wave is vertically polarized, a parasitic conductor is provided adjacent to at least the left and right sides of the ground conductor and parallel to the vertical direction. 3. The length of the parasitic conductor is set to 0.4 of the emission wavelength.
The microstrip antenna according to claim 2, wherein the multiplication factor is about 1.1 times. 4. The microstrip antenna according to claim 1, wherein when the radiated wave is horizontally polarized, the parasitic conductor is provided adjacent to at least the upper and lower sides of the ground conductor and parallel to the left and right direction. 5. The length of the parasitic conductor is set to 0.4 of the emission wavelength.
The microstrip antenna according to claim 4, wherein the ratio is about 1.1 times. 6. The microstrip antenna according to claim 1, wherein the width of the parasitic conductor is 0.25 times the radiation wavelength or less. 7. When a plurality of parasitic elements are arranged adjacent to each other, a gap between the parasitic elements is set to 0.
The microstrip antenna according to any one of claims 1 to 6, which is 5 times or less.