JP2021005847A - Dipole antenna - Google Patents

Abstract

To provide a compact dipole antenna which can be widened in a bandwidth.SOLUTION: A dipole antenna is provided in which radiation elements are patterned on a substrate and in a right and left direction with a feeding point 3 as a center. The dipole antenna A has a first dipole antenna set 10 and a second dipole antenna set 20 which use the feeding point 3 in common, both dipole antenna sets 10 and 20 include U-shaped radiation elements with rod-shaped elements E2 extending in pairs respectively in left and right directions, and the radiation elements are formed line-symmetrically to the left and right with the feeding point 3 as center, and the vicinity of the feeding point 3 of both dipole antennas sets 10 and 20 is formed by a common element E1, the rod-shaped elements E2 of the second dipole antenna set 20 are located above and below the rod-shaped element E2 of the first dipole antenna set 10, and are shorter than the rod-shaped element E2 of the first dipole antenna set.SELECTED DRAWING: Figure 1

Description

The present invention relates to a dipole antenna, and more particularly to a dipole antenna having a small size and a wide band frequency characteristic.

Dipole antennas used in in-vehicle communication devices and mobile devices are required to have wide-band frequency characteristics and to be compact. For example, in Patent Document 1, the radiation conductor itself is formed in a loop shape, is formed horizontally symmetrically in the left-right direction of the feeding point, and a non-feeding pattern is arranged in the vicinity of the feeding point to achieve a wide band.
Further, in Patent Document 2, by arranging a slightly smaller dipole antenna in a cavity formed inside the dipole antenna and further arranging a small dipole antenna inside the cavity, a plurality of large and small dipole antennas having a common feeding point in the center are arranged. A wide band was achieved by forming a dipole antenna.

Japanese Unexamined Patent Publication No. 2006-217511 Japanese Unexamined Patent Publication No. 2003-309417

By having two resonance frequencies, the dipole antenna of Patent Document 1 can obtain a relatively wide band characteristic of, for example, 450 MHz to 850 MHz. Further, in Patent Document 2 in which a plurality of dipole antennas are arranged so as to overlap each other, it is possible to further widen the bandwidth, for example, 0.8 GHz to 2 GHz. However, there is a demand for a smaller and wider band dipole antenna.

Therefore, in view of these problems, an object of the present invention is to provide a dipole antenna that is compact and capable of widening a wide band.

In order to solve the above problems, the invention of claim 1 is a dipole antenna in which radiating elements are patterned in the left-right direction around a feeding point on a substrate, and the first dipole antenna having a common feeding point. It has a set and a set of a second dipole antenna, and the set of both dipole antennas has a U-shaped radiating element having a rod-shaped element extending in pairs in each of the left and right directions. It is formed line-symmetrically to the left and right around the feeding point, and the vicinity of the feeding point of both dipole antenna sets is formed by a common element, while the rod-shaped element of the second dipole antenna set is the first dipole. It is characterized in that it is arranged above and below the rod-shaped elements of the antenna set and is shorter than the rod-shaped elements of the first dipole antenna set.
According to this configuration, by providing a pair of rod-shaped elements in the left-right direction and two sets of dipole antennas having different lengths, a plurality of resonance frequencies can be generated and a wide band can be achieved. Then, by arranging the second dipole antenna set outside the first dipole antenna set, that is, by arranging the two antennas so as to overlap each other, the space can be saved and the size can be reduced. Further, by arranging the feeding points line-symmetrically with respect to the center, the inclination of the directivity can be suppressed.

According to the invention of claim 2, in the configuration according to claim 1, the pair of rod-shaped elements forming the U-shape of the first dipole antenna set have different lengths from each other, and the tip of the long rod-shaped element is short. A pair of rod-shaped elements that are bent and arranged in an L-shape on the side of the rod-shaped element and form a U-shape have the same length in the left-right direction.
According to this configuration, the rod-shaped elements forming a pair of the first dipole antenna have different lengths from each other, which is effective for widening the band, and the tip of the long rod-shaped element is bent to lengthen the antenna. It can be miniaturized by shortening the direction.

In the invention of claim 3, in the configuration according to claim 1 or 2, the rod-shaped element of the second dipole antenna set and the rod-shaped element of the first dipole antenna set are arranged close to each other, and are placed between the rod-shaped elements. Is characterized in that a slit-shaped gap is formed.
According to this configuration, the set of the first dipole antenna and the set of the second dipole antenna are arranged so as to be in close contact with each other, so that the size can be reduced.

According to the invention of claim 4, in the configuration according to any one of claims 1 to 3, a radiation element forming a U shape and extending in the left-right direction is provided inside the first dipole antenna set, and power is supplied. It is characterized in that a set of a third dipole antenna, which is formed line-symmetrically around a point and whose rod-shaped element is shorter than that of the second dipole antenna, is arranged.
According to this configuration, by providing a set of a third dipole antenna, a larger resonance frequency can be generated and a wider band can be achieved.

According to the present invention, by providing a pair of rod-shaped elements in the left-right direction and two sets of dipole antennas having different lengths, a plurality of resonance frequencies can be generated and a wide band can be achieved. Then, by arranging the second dipole antenna set outside the first dipole antenna set, that is, by arranging the two antennas so as to overlap each other, the space can be saved and the size can be reduced. Further, by arranging the feeding points line-symmetrically with respect to the center, the inclination of the directivity can be suppressed.

It is a top view which shows an example of the dipole antenna which concerns on this invention. It is a VSWR characteristic diagram of the antenna of FIG. It is a top view which shows another example of a dipole antenna. It is a VSWR characteristic diagram of the antenna of FIG.

Hereinafter, embodiments embodying the present invention will be described in detail with reference to the drawings. FIG. 1 is a plan view showing an example of a dipole antenna according to the present invention, and shows a state in which a pattern is formed on a substrate. The dipole antenna 1 is a set of two dipole antennas formed of a metal foil on one surface of the dielectric substrate 2 and arranged so as to have a common feeding point 3 in the center (of the first dipole antenna). It is composed of a set 10 and a set 20) of a second dipole antenna.

Both the first dipole antenna set 10 (hereinafter, simply referred to as "first antenna") and the second dipole antenna set 20 (hereinafter, simply referred to as "second antenna") are U-shaped. A pattern is formed in the above, and U-shaped radiating elements are arranged on the left and right sides of the feeding point 3.
The left and right radiating elements are formed line-symmetrically around the feeding point 3, and the sets 10 and 20 of both antennas are formed in a substantially H shape as a whole. The straight line M1 arranged on the feeding point 3 in FIG. 1 indicates a center line of line symmetry.
Hereinafter, the longitudinal direction of the dipole antenna 1 will be described as the left-right direction, and the width direction will be described as the vertical direction.

The U-shaped radiating element has a bottom element E1 constituting the bottom and two rod-shaped elements E2 extending in parallel from both ends of the bottom element E1, and a set of both antennas 10, The bottom element E1 of 20 is formed in a common pattern.
A feeding point 3 is arranged at the center of the bottom element E1, the rod-shaped element E2 extends in the left-right direction, and the dipole antenna 1 of FIG. 1 is configured to include eight rod-shaped elements E2 in total.

The first element 11 (11a, 11b) as the rod-shaped element E2 of the first antenna 10 is formed longer than the second element 21 as the rod-shaped element E2 of the second antenna 20, and the second element 21 is the first element 11. It is located on the top, bottom, outside.
Further, the length L2 of the second element 21 is formed to be approximately half the length L1 of the first element 11.

The lengths of the first elements 11 differ from each other between the upper and lower two elements forming a U shape, and the first element 11b arranged on the lower side is formed longer than the first element 11a on the upper side.
However, the long first element 11b has an L-shaped portion 13 whose tip is bent at a right angle in the direction of the upper first element 11a, and the length L1 of the pattern itself in the left-right direction has the same dimensions in the upper and lower directions. There is.

Further, the width of the first element 11 is different between the base portion near the feeding point 3 and the tip portion, the base portion on which the second element 21 is arranged adjacent to each other is formed thin, and the second element is arranged close to each other. There is.
Specifically, the second element 21 is formed so as to be separated from the first element 11 by providing a slit-shaped gap 5 in an L shape on the side portion of the first element 11.
As a result, the width W2 of the tip portion of the first element 11 and the width W3 of the rod-shaped element in which the second element 21 and the base portion of the first element 11 are arranged in parallel have substantially the same dimensions.

Specifically, the rod-shaped element 11 of the first antenna 10 has a length L1 = 65 mm, and the rod-shaped element 21 of the second antenna 20 has a length L2 = 34 to 35 mm. The U-shaped radiating elements thus formed are formed on the left and right sides of the feeding point 3, and are formed so that the total length in the longitudinal direction is L3 = 140 mm and the width of the antenna 1 is W1 = 35 mm.

FIG. 2 shows the VSWR characteristics of the dipole antenna formed as described above. As shown in FIG. 2, for example, assuming that the frequency area where VSWR is less than 3.0 is the available frequency band, the following three used frequency bands exist, and a wide band of the frequency band can be realized.
(1) 0.697 to 0.965 GHz
(2) 1.42 to 2.81 GHz
(3) 2.93 to 3.88 GHz

As described above, by providing the pair of rod-shaped elements E2 in the left-right direction and providing two sets of dipole antennas 10 and 20 having different lengths, a plurality of resonance frequencies can be generated and a wide band can be achieved. Then, by arranging the second antenna 20 outside the first antenna 10, that is, arranging the two antennas so as to overlap each other, the antenna 20 can be formed in a small space and can be miniaturized. Further, by arranging the feeding points line-symmetrically with respect to the center, the inclination of the directivity can be suppressed.
Further, since the rod-shaped elements 11a and 11b forming a pair of the first antenna 10 have different lengths, it is effective for widening the bandwidth, and the tip of one of the long rod-shaped elements 11b is bent to lengthen the antenna 1. It can be miniaturized by shortening the direction.
In addition, since the first antenna 10 and the second antenna 20 are arranged so as to be in close contact with each other, the shape is small.

FIG. 3 is a plan view showing another example of the dipole antenna 1, and the dipole antenna 1 shown in FIG. 1 is further provided with a set 30 of a third dipole antenna (hereinafter, simply referred to as a “third antenna”). It has a structure.
The third antenna 30 is formed inside the U-shaped radiation element of the first antenna 10, and has the third element 31 as a pair of rod-shaped elements E2, and the radiation is also formed in a U shape. It has an element. Further, the center of the U-shaped bottom is connected to the center of the U-shaped bottom where the feeding point 3 of the first antenna 10 is provided, and the feeding point 3 is common. Then, it is formed line-symmetrically around the feeding point 3.
Further, the third antenna 30 is small, and the length L4 of the third element 31 is formed to have a length of 7 mm.

FIG. 4 shows the VSWR characteristics of the dipole antenna 1 of FIG. As shown in FIG. 4, looking at the frequency area where VSWR is less than 3.0, the following two frequency bands to be used exist, and a wide band of the frequency band can be realized.
(1) 0.698 to 0.966 GHz
(2) 1.42 to 3.32 GHz

In this way, the third antenna 30 may be arranged using the internal space of the first antenna 10, and a wide band can be realized.

The dimensions shown in the above embodiment are examples, and are not limited to these dimensions, and can be arbitrarily changed according to the transmission / reception frequency.
Further, of the rod-shaped elements E2 paired above and below the first antenna 10, the lower rod-shaped element E2 is formed to be long and bent, but the upper rod-shaped element may be lengthened and bent.

1 ... Dipole antenna, 2 ... Board, 3 ... Feeding point, 5 ... Gap, 10 ... 1st antenna (1st dipole antenna set), 11 ... 1st element, 13 ... L-shaped Part, 20 ... 2nd antenna (set of 2nd dipole antenna), 21 ... 2nd element, 30 ... 3rd antenna (set of 3rd dipole antenna), 31 ... 3rd element, E1 ... -Bottom element, E2 ... Rod-shaped element.

Claims (4)

It is a dipole antenna in which radiating elements are patterned in the left-right direction around the feeding point on the substrate.
It has a set of a first dipole antenna and a set of a second dipole antenna having a common feeding point.
The pair of both dipole antennas has a U-shaped radiating element having rod-shaped elements extending in pairs in the left-right direction, and the radiating elements are formed line-symmetrically to the left and right around the feeding point. It's made up
While the vicinity of the feeding point of the pair of both dipole antennas is formed by a common element,
The rod-shaped elements of the second dipole antenna set are arranged above and below the rod-shaped elements of the first dipole antenna set, and are shorter than the rod-shaped elements of the first dipole antenna set. Dipole antenna. The pair of rod-shaped elements forming the U-shape of the first dipole antenna set are different in length from each other.
The first aspect of claim 1, wherein the tip of the long rod-shaped element is bent and arranged in an L shape on the side of the short rod-shaped element, and the lengths of the pair of rod-shaped elements forming the U shape in the left-right direction are equal. Dipole antenna. The claim is characterized in that the rod-shaped element of the second dipole antenna set and the rod-shaped element of the first dipole antenna set are arranged close to each other, and a slit-shaped gap is formed between the rod-shaped elements. Item 1 or 2 The dipole antenna. Inside the set of the first dipole antenna, there is a radiation element forming a U shape and extending in the left-right direction, the rod-shaped element is formed line-symmetrically about the feeding point, and the rod-shaped element is the second. The dipole antenna according to any one of claims 1 to 3, wherein a set of a third dipole antenna shorter than the dipole antenna is arranged.

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