JP2001339233A - Characteristics adjusting method for circularly polarized wave antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it easy to finely adjust characteristics of a circularly polarized wave antenna and to suppress variations in the characteristics. SOLUTION: When the characteristics of the circularly polarized wave antenna 1 are adjusted, a radiation element 3 is trimmed and a ground pattern 4 is trimmed. A fine error which can not be adjusted only by the trimming of the radiation element 3 can be eliminated by trimming the ground pattern and variations in the characteristics can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for adjusting the characteristics of a circularly polarized antenna, and more particularly to a method for adjusting the characteristics of a circularly polarized antenna which facilitates fine adjustment.

[0002]

2. Description of the Related Art A planar circularly polarized patch antenna is used as a receiving antenna of a GPS type car navigation device or a portable navigation device. FIG. 5 shows a GPS circularly polarized antenna 1 in which a rectangular radiating element 3 is formed on the surface of a dielectric substrate 2 made of ceramic or the like, and a ground pattern 4 is provided on the entire back surface.

The circularly polarized antenna 1 is formed with pin holes 5 penetrating from front to back at positions slightly displaced from the center.
The feed pin 6 is inserted into the pin hole 5 from above, and the head of the feed pin 6 and the radiation element 3 are soldered. As shown in FIG. 5C, a notch 4a having a diameter larger than that of the pin hole 5 is formed in the ground pattern 4, and the feeding pin 6 projecting downward and the ground pattern 4 are insulated.

The circularly polarized antenna 1 is superimposed on the LNA substrate 7, and the power supply pins 6 are inserted into the pin holes of the LNA substrate 7 and soldered to connect the LNA substrate 7 and the radiating element 3. . The LNA board 7 and the radiating element 3 are housed in a waterproof case (not shown), and the LNA board 7 is connected to a GPS receiver by an antenna cable.

When adjusting the characteristics such as the reception frequency and impedance of the circularly polarized antenna 1, the horizontal and / or vertical sides of the radiating element 3 are uniformly trimmed (hatched portions) with a trimmer as shown in FIG. ) Then go.

[0006]

In the conventional characteristic adjusting method for uniformly trimming the horizontal and / or vertical sides of the radiating element, errors in the trimming width and errors in the parallelism of each side of the radiating element are reduced. Since the characteristics easily occur, the characteristics after the adjustment are likely to vary, and a more precise adjustment method is desired.

Therefore, there arises a technical problem to be solved in order to facilitate the fine adjustment of the antenna characteristics and to suppress the variation in the characteristics, and the present invention has an object to solve the above problems. I do.

[0008]

SUMMARY OF THE INVENTION The present invention proposes to achieve the above-mentioned object, and provides a characteristic of a circularly polarized antenna having a radiating element provided on a surface of a dielectric substrate and a ground pattern provided on a back surface. An object of the present invention is to provide a method for adjusting the characteristics of a circularly polarized antenna, wherein the characteristic is adjusted by trimming a ground pattern.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. The GPS circularly polarized antenna 1 shown in FIG. 1 is the same as the GPS circularly polarized antenna 1 shown in FIG. 5, 2 is a dielectric substrate made of ceramic or the like, 3 is a radiating element, and 4 is the entire ground on the back surface. Pattern 5, power supply pin 6
This is a pin hole for inserting

The radiating element 3 has a substantially quadrangular shape, and is formed by obliquely removing two corners at rotationally symmetric positions.
a is formed, and a corner 3b having a different shape from the hypotenuse 3a acts as a perturbation element for generating a circularly polarized wave.

In adjusting the antenna characteristics, FIG.
As shown in (a), the horizontal side 3 of the radiating element is
c or the vertical side 3d is trimmed by a trimmer to bring the characteristic closer to the design value, and further, as shown in FIG. I do.

FIG. 2 is a Smith chart showing the characteristics of the circularly polarized antenna. In general, the frequency fc at the tip (marker 1) of the central closed loop portion indicates the center frequency as circularly polarized waves. The center frequency fc is 1.
The design characteristic of the circularly polarized antenna for GPS of 57542 GHz is shown.

Next, an example of a characteristic change due to the trimming of the ground pattern 4 will be described. FIG. 3 shows a characteristic change when the vertical side 4d of the ground pattern 4 shown in FIG. 1C is trimmed. The impedance pattern of the circularly polarized fc rotates counterclockwise according to the trimming area while the center frequency is changed. There is almost no change in the degenerate separation (the length before and after the closed loop), which is a factor causing fc to rise slightly.

Therefore, when the original characteristic pattern of the circularly polarized antenna is rotated clockwise, the vertical side 4d is trimmed to rotate the characteristic pattern counterclockwise as shown in FIG. 1C. Thus, the ideal characteristics shown in FIG. 2 can be obtained.

FIG. 4 shows a characteristic change when the oblique corner 4a of the ground pattern 4 is trimmed, and the degenerate separation is enlarged according to the trimming area. If the degenerate separation of the original characteristic pattern of the circularly polarized antenna is too small, the degenerate separation can be expanded by trimming the corner 4a.

The above example is merely an example, and the characteristic pattern changes variously depending on which side or corner of the ground pattern is to be trimmed, and the trimming location is selected according to the characteristics of the original circularly polarized antenna element. By doing so, it is possible to approach the ideal characteristics, and it is possible to perform highly accurate adjustment. If the characteristic deviation of the original antenna element is small and fine adjustment is sufficient, the characteristic may be finely adjusted by trimming only the ground pattern.

The present invention is not limited to the above-described embodiment, and various modifications are possible within the technical scope of the present invention, and it goes without saying that the present invention extends to those modifications. is there.

[0018]

As described above, the method for adjusting the characteristics of the circularly polarized antenna according to the present invention finely adjusts the characteristics by trimming the ground pattern on the back surface of the circularly polarized antenna.
It is possible to perform adjustment with higher accuracy than the conventional characteristic adjustment method in which only the radiating element is trimmed, thereby suppressing variation in characteristics and improving the quality of the circularly polarized antenna.

[Brief description of the drawings]

1A and 1B show a method for adjusting the characteristics of a circularly polarized antenna according to the present invention, wherein FIG. 1A is a plan view of the circularly polarized antenna, FIG. 1B is a side view, and FIG.

FIG. 2 is a Smith chart showing design characteristics of a circularly polarized antenna.

FIG. 3 is a Smith chart showing a characteristic change when a horizontal side of a ground pattern is trimmed by the characteristic adjustment method of the present invention.

FIG. 4 is a Smith chart showing a characteristic change when a corner of a ground pattern is trimmed by the characteristic adjusting method of the present invention.

FIG. 5 shows a circularly polarized antenna, wherein (a) is a plan view,
(B) is a side view, and (c) is a bottom view.

FIG. 6 is a plan view of a circularly polarized antenna showing a conventional characteristic adjustment method.

[Explanation of symbols]

 Reference Signs List 1 circularly polarized antenna for GPS 2 dielectric substrate 3 radiating element 3a oblique side 3b corner 3c side 3d vertical side 4 ground pattern 4a side 4b corner 5 pin hole 6 feeding pin

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor, Koharu Saito 95, Iizuka-cho, Iidagawa-cho, Minamiakita-gun, Akita 95-2, Inside Akita Mitsumi Co., Ltd. (72) Inventor, Nobuo Tamura Upper Tsutsujiki 95 No. 2 Akita Mitsumi Co., Ltd. F-term (reference) 5J045 AA01 AA02 AB06 CA04 DA10 EA07 NA01

Claims (1)

[Claims] 1. A method for adjusting the characteristics of a circularly polarized antenna in which a radiating element is provided on a front surface of a dielectric substrate and a ground pattern is provided on a back surface, wherein the characteristic is adjusted by trimming the ground pattern. How to adjust the characteristics of a wave antenna.