CN104201475A - Loop antenna - Google Patents

Abstract

A loop antenna provided by the present invention includes a feeder and an antenna body, the feeder is provided with a feeder positive pole and a feeder negative pole, wherein the antenna body includes several antenna units in a ring structure, and the several antenna units surround the feeder line Symmetrically distributed around the feeder, each of the antenna elements is respectively connected to the positive pole and the negative pole of the feeder. A loop antenna provided by the invention inherits the frequency characteristics and directional characteristics of the small loop antenna, and at the same time arranges the loop elements on a three-dimensional surface according to angles, and uses the array characteristics to change the impedance and reduce the impedance, thereby improving the directivity of the small loop antenna And impedance gain, to achieve the omnidirectional effect of reducing impedance and ensuring directivity, so that the gain is not easy to decrease sharply, overcoming the impedance problem of the small loop antenna, and greatly improving the efficiency.

Description

a loop antenna

technical field

The invention relates to the technical field of antennas, in particular to a loop antenna for passive communication.

Background technique

As a component used to transmit or receive radio waves, the antenna plays a pivotal role in the wireless communication system and is an indispensable part of the wireless communication system. With the rapid development of high-frequency satellite communication systems, radar, wireless communication systems, especially the construction of global 3G and 4G networks, the requirements for antennas are getting higher and higher. On the one hand, it is necessary to enable the antenna to work in multiple frequency bands, have multiple working modes and have good transmission performance; on the other hand, it is necessary to reduce the weight of the antenna, reduce the volume of the antenna and reduce the cost. Just because of such demands, various antennas have been proposed and flourished.

Loop antennas are mainly divided into two categories, one is a small loop antenna in which the total length of the conductor and the maximum linear dimension of one circle of the loop are very small relative to the working wavelength; The wavelength is quite comparable to the loop antenna. Because of the wavelength, the antenna often has a large volume. Large loop antennas are usually composed of one-wavelength or one-half-wavelength conductors, usually formed into squares, circles, etc. The total conductor length of the small loop antenna can be less than one-tenth of a wavelength. Although the size of the small loop antenna is greatly reduced, its impedance is very large, the gain is greatly reduced, and the communication is greatly limited, so it is basically not suitable for passive communication.

Contents of the invention

The technical problem to be solved by the present invention is to provide a loop antenna, which can reduce the impedance of the small loop antenna as much as possible, improve the directivity and impedance gain of the small loop antenna, and make the gain difficult to decrease drastically.

A loop antenna provided by the present invention includes a feeder and an antenna body, the feeder is provided with a feeder positive pole and a feeder negative pole, wherein the antenna body includes several antenna units in a ring structure, and the several antenna units surround the feeder line Symmetrically distributed around the feeder, each of the antenna elements is respectively connected to the positive pole and the negative pole of the feeder.

Further, the number of the antenna units is three, and the angle θ between two adjacent antenna units is 120 degrees.

Further, the number of the antenna units is four, and the angle θ between two adjacent antenna units is 90 degrees.

Furthermore, the antenna unit includes a first arm, a second arm, and at least one third arm connecting the first arm and the second arm, the first arm is connected to the positive pole of the feeder connected, and the second arm is connected to the negative pole of the feeder.

Further, the third arm is in the shape of an arc, and the ring structure surrounded by the first arm and the second arm is fan-shaped, and the angle α between the first arm and the second arm is 75° degrees to 85 degrees.

Preferably, the included angle α is 80 degrees.

Furthermore, the ring structure surrounded by the first arm, the second arm and at least one third arm is one of triangle, rhombus or square.

Furthermore, the angle β between the first arm and the axis of the feeder line is between 15 degrees and 21 degrees.

Preferably, the included angle β is 18 degrees.

Further, the several antenna units are located at the same level.

Further, the positive electrode of the feeder is coaxial with the negative electrode of the feeder, the positive electrode of the feeder is located inside the feeder, and the negative electrode of the feeder is arranged outside the positive electrode of the feeder.

Beneficial effects of the present invention: a loop antenna provided by the present invention inherits the frequency characteristics and directional characteristics of the small loop antenna, and at the same time arranges the loop elements on a three-dimensional surface according to angles, and uses the array characteristics to change the impedance, thereby improving the small loop antenna The directivity and impedance gain of the antenna achieve the omnidirectional effect of reducing the impedance and ensuring the directivity, so that the gain is not easy to decrease sharply, overcome the impedance problem of the small loop antenna, and greatly improve the efficiency.

Description of drawings

FIG. 1 is a front view of a loop antenna structure according to an embodiment of the present invention.

Fig. 2 is a bottom view of the structure of the loop antenna according to the embodiment of the present invention.

Fig. 3 is an antenna pattern calculated by simulation at 1.5 GHz for the loop antenna according to the embodiment of the present invention.

Detailed ways

In order to better illustrate the technical characteristics and structure of the present invention, the following is a detailed description in conjunction with preferred embodiments of the present invention and accompanying drawings.

1 and 2, the loop antenna provided by the present invention includes a feeder 100 and an antenna body 200, wherein the feeder 110 is provided with a feeder positive pole 110 and a feeder negative pole 120, the feeder positive pole 110 and the feeder negative pole 120 are coaxial, and the feeder positive pole 110 is located at Inside the feeder 100 , the negative feeder 120 is a dielectric surrounding the positive feeder 110 , and forms the feeder 100 with the positive feeder 110 . The antenna body 200 includes a plurality of antenna units 210 in a ring structure, and the plurality of antenna units 210 are symmetrically distributed around the feeder line 100 around the feeder line 100, wherein each antenna unit 210 is connected to the feeder line positive pole 110 and the feeder line The negative pole 120 is connected, and all antenna elements 210 are located at the same level.

Specifically, considering that the size of the antenna unit 210 has a different response to the frequency points, as the number of loops (the number of antenna units 210) increases, the frequency will increase. In this embodiment, three antenna units 210 are selected. , wherein, the angle θ between each antenna unit 210 is 120 degrees, the total length of each antenna unit 210 is about a quarter wavelength, and the circular vertical array is on the antenna body, so that the radiation surface of the overall antenna is no longer It is a unidirectional axial plane, and the entire horizontal plane, such as the yz plane in Figure 2. In other embodiments, the number of antenna units 210 may be selected to be more, for example, 4, and at this time, the angle θ between each antenna unit 210 is 90 degrees.

Wherein, each antenna unit 210 is a ring structure, and this ring structure at least includes a first arm 211, a second arm 212, and at least one third arm connecting the first arm 211 and the second arm 212. An arm 213 , the first arm 211 is connected to the positive electrode 110 of the feeder, and the second arm 212 is connected to the negative electrode 120 of the feeder. In this embodiment, as shown in FIG. 1 , the antenna unit 210 of the ring structure includes a first arm 211, a second arm 212 and a third arm connecting the first arm 211 and the second arm 212. The arm 213 and the third arm 213 are arc-shaped, and the ring structure formed by surrounding the first arm 211 and the second arm 212 is fan-shaped, and the angle α between the first arm 211 and the second arm 212 is 80° degrees, in some other embodiments, the included angle α can be selected between 75 degrees and 85 degrees. In other embodiments, the third arm 213 can be in other shapes, and its number can be set to more. The ring structure formed by one arm 211 and the second arm 212 is triangular; or, the third arm 213 is linear, and the number is two. At this time, the two third arms 213 and the first arm 211 , The ring structure formed by the second arm 212 is a rhombus or a square. The examples mentioned above are only for optimizing the structural form, and should not be regarded as a limitation to the specific structural form.

Among them, the first arm 211 of the antenna unit 210 connected to the positive pole 110 of the feeder line, the first arm 211 between each antenna unit 210 cannot overlap or interfere with each other, that is, the first arm 211 of each antenna unit 210 There needs to be a gap between them, and the included angle β between the first arm and the axis of the feeder line is between 15 degrees and 21 degrees. In this embodiment, the included angle β is preferably 18 degrees. The second straight line 212 of the antenna unit 210 is connected to the negative pole 120 of the feeder line, and the negative pole 120 of the feeder line is used for grounding.

The loop antenna provided by the above embodiments inherits the frequency characteristics and directional characteristics of the small loop antenna; at the same time, the antenna elements are arranged and combined at a certain angle on a three-dimensional surface, and the impedance is changed by using the array characteristics, thereby improving the directivity and directional characteristics of the small loop antenna. Impedance gain achieves the omnidirectional effect of reducing impedance and ensuring directivity, so that the gain is not easy to decrease sharply, overcomes the impedance problem of the small loop antenna, and greatly improves the efficiency.

Fig. 3 is a graphical representation of the numerical verification of the loop antenna provided by the above embodiment using the method of simulation calculation. When the frequency of the loop antenna is 1.5GHz, the gain can reach -6dBi, and the half-power angle can reach more than 100°, which shows that the loop antenna At the same time, the directivity of the antenna is omnidirectional, which overcomes the impedance problem of the small loop antenna and greatly improves the efficiency.

It should be noted that in this article, relational terms such as first and second etc. are only used to distinguish one entity from another, and do not necessarily require or imply any actual relationship between these entities or order.

The above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, rather than limiting the implementation of the present invention. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. All modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (11)

1. a loop aerial, comprise feeder line (100) and antenna body (200), described feeder line (100) is provided with feeder line positive pole (110) and feeder line negative pole (120), it is characterized in that, described antenna body (200) comprises the antenna element (210) of some structures ringwise, described some antenna elements (210) are symmetrically distributed in the surrounding of described feeder line (100) around described feeder line (100), described each antenna element (210) is connected with feeder line negative pole (120) with described feeder line anodal (110) respectively.

2. loop aerial according to claim 1, is characterized in that, the quantity of described antenna element (210) is three, and the angle theta between adjacent two antenna elements (210) is 120 degree.

3. loop aerial according to claim 1, is characterized in that, the quantity of described antenna element (210) is four, and the angle theta between adjacent two antenna elements (210) is 90 degree.

4. according to arbitrary described loop aerial in claims 1 to 3, it is characterized in that, described antenna element (210) comprises the first support arm (211), the second support arm (212) and connects described the first support arm (212) and at least one the 3rd support arm (213) of the second support arm (212), described the first support arm (211) is connected with described feeder line anodal (110), and described the second support arm (212) is connected with described feeder line negative pole (120).

5. loop aerial according to claim 4, it is characterized in that, described the 3rd support arm (213) is circular-arc, it is fan-shaped surrounding with described the first support arm (211), the second support arm (212) loop configuration forming, and the angle α of the first support arm (211) and the second support arm (212) is between 75 degree to 85 degree.

6. loop aerial according to claim 5, is characterized in that, described angle α is 80 degree.

7. loop aerial according to claim 4, is characterized in that, described the first support arm (211), the second support arm (212) and at least one the 3rd support arm (213) surround the loop configuration forming be triangle, rhombus or square in a kind of.

8. loop aerial according to claim 4, is characterized in that, the angle β of described the first support arm (211) and feeder line (100) axis is between 15 degree to 21 degree.

9. loop aerial according to claim 8, is characterized in that, described angle β is 18 degree.

10. loop aerial according to claim 1, is characterized in that, described several antenna elements (210) are positioned at same level height.

11. loop aerials according to claim 1, it is characterized in that, described feeder line anodal (110) is coaxial with described feeder line negative pole (120), feeder line anodal (110) is positioned at the inside of described feeder line (100), and anodal (110) outside of feeder line is provided with feeder line negative pole (120).