JPH07231217A - Cross loop antenna - Google Patents

Abstract

PURPOSE:To prevent an offset in the radiation characteristic from being produced by differentiating the size of elements on one side and other side of a printed circuit board in two loops integrated on the printed circuit board to generate both horizontally and vertically polarized waves CONSTITUTION:The printed circuit board 10 is composed of elements 11a, 11b, 12a, 12b, a loop surrounded by the elements 11a, 11b forms a horizontally polarized wave loop antenna and a loop surrounded by the elements 12a, 12b forms a vertically polarized wave loop antenna. In this case, the elements 12a, 12b are folded to be integrated, an end of the element 12a is connected to an end of the elements 11a, 11b and the connecting point is used for a feeding point 13. Through the constitution above, the width of the elements 12a, 12b, that is, the size D2 is set larger than the width, that is, the size D1 of the elements 11a, 11b and a power distribution ratio is controlled to increase the power fed to the elements 12a, 12b more than the power supplied to the elements 11a, 11b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cross loop antenna for generating both horizontal and vertical polarized waves, and more particularly to a cross loop antenna incorporated in a circuit board.

[0002]

2. Description of the Related Art FIG. 3 is a diagram showing the principle configuration of a cross-loop antenna for generating both horizontal and vertical polarizations. In the figure, 101 is a horizontal polarization loop (element), and 102 is a vertical polarization. A loop 103 for feeding is a feeding point, and as shown in the figure, has a structure in which the loop 101 for horizontal polarization and the loop 102 for vertical polarization are crossed and integrated. It is known that the loop antenna can be widely used for long wave to ultra short wave and for reception and transmission.
In addition to the loop formed by winding the electric wire into a coil,
In some cases, the loop is composed of strip lines as shown in FIG. In recent years, cross-loop antennas have been used as remote control key antennas for locking and unlocking keys in automobiles and the like by remote control using radio. In this case, it is necessary to make them as convenient as possible to carry. Since it is integrated into the circuit board and incorporated into the key chain, it is necessary to make it compact and flat.

FIG. 4A is a perspective view showing an example of the structure of a conventional cross-loop antenna incorporated in the above-mentioned circuit board. In the figure, 200 is a circuit board, and 201 is for horizontal polarization, for example. The first loop, 202 is a second loop for vertical polarization, and 203 is a feeding point. Figure 4
The cross loop antenna shown in FIG.
First loop 201 and second loop 20 across the front and back of the
2 are held so as to be orthogonal to each other on the plane of the circuit board 200, and have a structure for generating two orthogonal polarized waves, horizontal and vertical. However, in this structure, the first loop 201 and the second loop 202 are completely independent,
Two sets of feeding points must be provided. FIG. 4 (B) is a perspective view showing another example of the structure of the conventional cross loop antenna incorporated in the above-mentioned circuit board.
201a and 201b are, for example, half of the elements that form the horizontal polarization loop, 202a and 202b are half of the elements that form the vertical polarization loop, and 203 is the feeding point. As shown in FIG. 4 (B), this cross-loop antenna connects the first loop and the second loop, and has one feeding point 203, and is provided on the surface (upper surface) of the circuit board 200. Is element 2
A horizontal polarization loop is formed by 01a and 201b, a vertical polarization loop is formed by the elements 202a and 202b over the front and back surfaces, and a feeding point 203 is provided on each of the front and back surfaces. Note that the elements 202a and 202b
The area surrounded by the vertical polarization loop constituted by is smaller than the area enclosed by the electronic components (not shown) on the circuit board 200, and the strip lines (elements) 202a and 202b are laid on it. Even if it can be used, it is because it is required to be as thin and compact as possible when it is used as a remote control key or the like.

[0004]

The above-described cross-loop antenna incorporated in the conventional circuit board shown in FIG. 4 is configured as described above, and the cross-loop antenna shown in FIG. 4 (A) has two loops. Is completely independent,
Since two sets of power feeding points must be provided, there is much structural waste, which hinders miniaturization. In the cross loop antenna shown in FIG. 4B, the electric field strength received from the loop formed on the surface of the circuit board (horizontal polarization loop in the example shown in FIG. 4B) due to the influence of the shape of the circuit board. Is stronger than the loop formed over the front and back surfaces of the circuit board (the vertical polarization loop in the example shown in FIG. 4B), and the radiation characteristic is biased. In addition, the size of the loop formed over the front and back surfaces of the circuit board is inevitably smaller than that of the loop formed on the front surface of the circuit board for flattening and miniaturization, and the deviation of the above radiation characteristics is further increased. There was a problem that it would grow.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a cross loop antenna in which the radiation characteristics are prevented from being biased due to the difference in the circuit board shape and the loop shape. .

[0006]

A cross-loop antenna according to the present invention is held on one surface of a circuit board or the like of two loops for generating both horizontal and vertical polarized waves which are incorporated in the circuit board or the like. The thickness of the element that constitutes one loop and the thickness of the element that constitutes the other loop that is held over the front and back surfaces of the circuit board etc. are made different to adjust the balance of radiation intensity. . In addition, the width of the element forming the other one loop is made wider than the width of the element forming the one loop to adjust the balance of the radiation intensity. Further, the element forming the one loop, which is held on one surface of the circuit board or the like, is positioned at the outer peripheral end of the circuit board or the like.

[0007]

In the cross-loop antenna of the present invention, one of two loops, which is installed on a circuit board or the like and generates both horizontal and vertical polarized waves, is held on one surface of the circuit board or the like. The thickness of the element to
The thickness of the element that constitutes the other loop, which is held over the front and back surfaces of the circuit board, etc., is made different, so that the power distribution ratio to the two loops can be adjusted while downsizing and flattening. It is possible to prevent the radiation characteristics from being biased.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of the present invention, in which 10 is a circuit board, 11a, 11b, 12a, 1
Reference numerals 2b respectively denote elements. In the present embodiment, a loop surrounded by the elements 11a and 11b constitutes a loop antenna for horizontal polarization, and a loop surrounded by the elements 12a and 12b constitutes a loop antenna for vertical polarization. 13 is a feeding point. And the elements 12a,
The width (thickness) D2 of 12b is made wider (thicker) than the width (thickness) D1 of the elements 11a and 11b.
Element element 1 from the electric power sent to a and 11b
The power distribution ratio is set so that the power sent to 2a and 12b becomes stronger.

Therefore, when the power distribution ratio is the same, the deviation of the radiation characteristic due to the asymmetry of the shape of the circuit board 10 and the loop shape, that is, the elements 11a, 11
The electric field strength radiated from b is the element 12a, 1
It is possible to construct an antenna capable of canceling the radiation characteristic of being stronger than the electric field intensity radiated from 2b and uniformly radiating two orthogonal polarization components.

FIG. 2 is a perspective view showing another embodiment of the present invention. This embodiment shows a horizontal polarization element 11a,
11b is provided at the outer peripheral end of the circuit board 10. In the present embodiment, the elements 11a and 11b can be made relatively thin, and such a configuration is also possible. By adopting such a configuration, The structure can easily hold the element. In the above embodiment, the circuit board 1
Although the case where it is incorporated into 0 has been described, it goes without saying that it can be implemented in all cases where it is incorporated into a similar shape.

[0011]

As described above, the cross-roof antenna of the present invention is held on one surface of the circuit board or the like of the two loops for generating both horizontal and vertical polarized waves which are incorporated in the circuit board or the like. The thickness of the element that constitutes one loop and the thickness of the element that constitutes the other loop that is held over the front and back surfaces of the circuit board etc. are made different to adjust the balance of radiation intensity. So
By using an asymmetrical cross loop built in the circuit board, it is possible to obtain an antenna that is compact and planar, and that has uniform radiation characteristics of two orthogonal polarization components. Further, by forming the inside of the case by etching or the like, there is an effect that the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing another embodiment of the present invention.

FIG. 3 is a diagram showing a principle configuration of a loop antenna that generates both horizontal and vertical polarized waves.

FIG. 4 is a perspective view showing a structure of a cross loop antenna incorporated in a conventional circuit board.

[Explanation of symbols]

 10 circuit board 11a, 11b, 12a, 12b element 13 feeding point

Claims (3)

[Claims] 1. A thickness of an element constituting one loop, which is held on one surface of a circuit board or the like, of two loops for generating both horizontal and vertical polarized waves which are incorporated in the circuit board or the like, and a circuit. A cross-loop antenna characterized by a structure that adjusts the balance of radiation intensity by changing the thickness of the element that constitutes the other loop that is held across the front and back surfaces of the substrate and the like. 2. The width (thickness) of the element forming the other one of the loops which is held over the front and back surfaces of the circuit board or the like, and the width of one of the elements which is held by the one surface of the circuit board or the like. The cross-loop antenna is characterized in that it is wider (thicker) than the width (thickness) of the elements that make up the loop. 3. A cross-loop antenna, wherein elements constituting the one loop held on one surface of the circuit board or the like are located at an outer peripheral end portion of the circuit board or the like.