TWM466367U - Dipole antenna - Google Patents

Abstract

A dipole antenna includes a dielectric substrate; a first radiating element formed on the dielectric substrate and having a first bending portion and a second bending portion; a second radiating element formed on the dielectric substrate and having a third bending portion and a fourth bending portion; a feed-in gap located between the first radiating element and the second radiating element; a first feed-in point located between the first bending portion and the second bending portion; and a second feed-in point located between the third bending portion and the fourth bending portion; wherein the first radiating element and the second radiating element are disposed in an opposite direction, and the first feed-in point and the second feed-in point are separated by the feed-in gap.

Description

Dipole antenna

The present invention relates to a dipole antenna, and more particularly to a dipole antenna that utilizes a bent structure to reduce the size of an antenna and can operate in multiple frequency bands.

With the rapid development of wireless communication technology, today's electronic products such as notebook computers, Personal Digital Assistants, wireless base stations, mobile phones, smart meters, USB dongles Most of them have wireless communication capabilities that enable technologies such as wireless local area networks (WiFi) to replace data transmission via cable. Wireless communication technology transmits or receives radio waves through an antenna to transmit or exchange radio signals to access a wireless network. Wireless local area network communication systems have multiple frequency bands, so how to develop an antenna that can operate in multiple frequency bands has also become a trend of current research. In addition, the size of the antenna needs to be developed in the direction of miniaturization to match the trend of shrinking electronic products.

Please refer to FIG. 1 , which is a schematic diagram of a conventional dipole antenna 10 . As shown in FIG. 1, the dipole antenna 10 includes a radiator 100, 102 and a coaxial transmission line 104. The radiators 100 and 102 are respectively connected to a signal source and a ground of the coaxial transmission line 104. Since the dipole antenna 10 does not require a ground plane, it is not susceptible to environmental influences. However, the antenna of the dipole antenna 10 is large in size, and the total length is about one-half wavelength (λ/2), and the smaller the frequency, the larger the size of the dipole antenna 10. Therefore, the conventional dipole antenna 10 is usually used in an external antenna, but is externally connected. The antenna is less beautiful and will reduce the user's willingness to purchase. In addition, the dipole antenna 10 can only operate in one frequency band and cannot meet the requirements of multiple frequency bands of today's wireless communication systems.

In the prior art, the two radiators of the dipole antenna can be designed to have different lengths and lengths. By adjusting the lengths of the two radiators, the fundamental frequency signal and the multiplied signal of the dipole antenna respectively conform to the two operating frequency bands. To effectively reduce the size of the antenna in a limited volume, and at the same time achieve the effect of dual frequency band. However, the high frequency band of such an antenna is a frequency doubling frequency, which causes its Radiation pattern to generate a zero point (Null), so that the application causes a dead angle of data reading, so the antenna gain and efficiency also follow reduce. In addition, the structure of such an antenna is complicated, so the difficulty, cost, and performance in production are not ideal.

Another conventional technique is to change the two radiators of the dipole antenna into a ladder-type double-sided structure, and use the ladder antennas on both sides to generate a current multipath to achieve a wide frequency effect. Then, the overlapping portions of the backplane are used to adjust the impedance matching, so that the dipole antenna can achieve good impedance matching in an operating frequency band. However, the disadvantage is that the manufacturing process is complicated, and a double-layer plate and a via hole are required, thereby increasing the manufacturing cost.

Therefore, how to design an antenna that can operate in multiple frequency bands in a limited space, while taking into account the efficiency and production cost of the antenna, has become one of the goals of the industry.

This creation mainly provides an antenna that can operate in multiple frequency bands, and has a simple structure and provides reliable antenna precision, which can reduce the implementation cost and is applied to mass production.

The present invention discloses a dipole antenna comprising a dielectric substrate; a first radiator formed on the dielectric substrate, the first radiator having a first bend and a second bend; a second a radiator formed on the dielectric substrate, the second radiator having a third bend and a fourth bend; a feed spacing between the first radiator and the second radiator; a feed point between the first bend and the second bend; and a second feed point between the third bend and the fourth bend; wherein the second radiator Opposite the first radiator, and the first feed point and the second feed point are separated by the feed pitch.

10, 20‧‧ Dipole antenna

200‧‧‧ dielectric substrate

100, 102, 202, 204‧‧‧ radiators

2020, 2022, 2024, 2040, 2042 2044‧‧‧ bend

206‧‧‧Feed spacing

208, 210‧‧‧Feeding points

A1, A2‧‧‧ upper half

B1, B2‧‧‧ lower half

104‧‧‧ coaxial transmission line

Figure 1 is a schematic diagram of a conventional dipole antenna.

2 is a schematic view of a dipole antenna according to the embodiment of the present invention.

Fig. 3A is a schematic diagram of the low frequency current resonance path of the dipole antenna shown in Fig. 2.

Fig. 3B is a schematic diagram of the high frequency current resonance path of the dipole antenna shown in Fig. 2.

Fig. 4 is a view showing the reflection coefficient of the antenna of the dipole antenna shown in Fig. 2.

Fig. 5 is a radiation pattern diagram of the dipole antenna shown in Fig. 2 operating at 2.45 GHz.

Fig. 6 is a radiation pattern diagram of the dipole antenna shown in Fig. 2 operating at 5.15 GHz.

Figure 7 is a radiation pattern diagram of the dipole antenna operating at 5.55 GHz as shown in Figure 2.

Figure 8 is a radiation pattern diagram of the dipole antenna operating at 5.85 GHz as shown in Figure 2.

Figure 9 is a diagram showing the antenna gain and radiation efficiency of the dipole antenna operating at 2.4 GHz to 5.85 GHz as shown in Fig. 2.

Fig. 10 is a schematic diagram showing the attenuation power of the antenna when the dipole antenna is operated at 2.4 GHz and 5 GHz with respect to the data throughput (Throughput) of the wireless local area network communication system.

Please refer to FIG. 2, which is a schematic diagram of a dipole antenna 20 according to an embodiment of the present invention. The dipole antenna 20 includes a dielectric substrate 200, radiators 202 and 204, a feed pitch 206, and feed points 208, 210. The radiators 202, 204 are formed on the dielectric substrate 200 and have bending portions respectively 2020, 2022 and bend 2040, 2042. The radiator 202 is disposed opposite the radiator 204, and a feed pitch 206 is formed therebetween. Feeding points 208, 210 are formed on the radiators 202, 204, respectively, and connected to the center conductor and the outer ground conductor of a coaxial transmission line. The feed point 208 is located substantially at a midpoint between the bend 2020 and the bend 2022, and the feed point 210 is located substantially at a midpoint between the bend 2040 and the bend 2042. The feed point 208, 210 is substantially equal to the feed gap 206.

As shown in FIG. 2, the upper half A1 of the radiator 202 is asymmetrical with the lower half B1, and the upper half A2 and the lower half B2 of the radiator 204 are also asymmetric, that is, the radiators 202, 204 are not up and down or The left and right symmetrical structure, therefore, can generate a plurality of current resonant paths of different lengths. Please refer to FIG. 3A and FIG. 3B. FIG. 3A and FIG. 3B are respectively schematic diagrams of the low frequency and high frequency current resonance paths of the dipole antenna 20 shown in FIG. 2 . As shown in FIGS. 3A and 3B, the dipole antenna 20 can have at least two current resonant paths of different lengths. One of the paths from the upper half A1 of the radiator 202 to the lower half B2 of the radiator 204 via the feed pitch 206, by appropriately selecting the positions of the bend 2022 and the bend 2042, allows the dipole antenna 20 to resonate with one Lower frequency band. For example, when the total length of this path is 64 mm (about 0.51 λ), the dipole antenna 20 can resonate in the 2.4 GHz band. The other path from the upper half A2 of the radiator 204 via the feed pitch 206 to the lower half B1 of the radiator 202 allows the dipole antenna 20 to resonate by appropriately selecting the positions of the bend 2020 and the bend 2040. A higher frequency band. For example, when the total length of the path is 26 mm (about 0.46 λ), the dipole antenna 20 can resonate in the 5 GHz band. Therefore, the dipole antenna 20 can be applied to an antenna of a built-in Wireless Local Area Network (WLAN) band for transmitting and receiving RF signals in the 2.4 GHz and 5 GHz bands, and supporting multiple wireless communication protocols (IEEE 802.11a). /b/g/ac/Bluetooth/HiperLAN), and the dipole antenna 20 operating in this band can be placed in a narrow space of 45 x 13 mm ² .

It should be noted that the dipole antenna 20 of the present invention utilizes the bends 2020, 2022, 2040, and 2042 to combine a plurality of current resonance paths, thereby reducing the antenna size and forming a plurality of operation frequencies. segment. Those skilled in the art can make different changes as they are based on, and are not limited to. For example, the radiator 202 and the radiator 204 may be formed on the dielectric substrate 200 by a printing or etching technique. The dielectric substrate 200 may be a fiberglass board conforming to an FR4 board specification, and other dielectric substrates may be used as needed. Moreover, as is well known to those of ordinary skill in the art, the size of the radiator 202 and the radiator 204 can be adapted to the needs of the operating frequency.

The corners of the bends 2020, 2022 and the bends 2040, 2042 can form all oblique angles to reduce the influence of the discontinuous surface and reduce the parasitic capacitance effect. In addition, the number of bends is not limited. As shown in FIG. 2, the radiators 202, 204 can be further formed with bends 2024, 2044, respectively, to further reduce the overall length of the dipole antenna 20. Furthermore, as shown in FIG. 2, the angles of the bends 2020, 2022, 2024, 2040, 2042, 2044 of the dipole antenna 20 are 90 degrees, but are not limited thereto, and may be any between 90 degrees and 180 degrees. The value between them is as long as the designed shape does not affect the formation of a plurality of current resonance paths. Both the radiator 202 and the radiator 204 may be point-symmetric with the center of the feeding point 208 and the feeding point 210 as the axis (ie, the relative direction and relative position of the bending body 202 and the radiator 204, bending) Consistently, it can also be designed as a non-point symmetrical structure according to the actual antenna setting requirements.

Since the feeding pitch 206 of the dipole antenna 20 can be equivalent to a capacitor, the impedance matching of the dipole antenna 20 can be effectively improved by appropriately adjusting the feeding pitch 206 to improve the radiation efficiency. Fig. 4 is a view showing the antenna reflection coefficient of the dipole antenna 20 shown in Fig. 2. The triangle point line segment represents the reflection coefficient of the conventional dipole antenna 10, the square point line segment represents the simulation result of the reflection coefficient of the dipole antenna 20, and the dot line segment represents the measurement result of the reflection coefficient of the dipole antenna 20. As can be seen from Fig. 4, by adjusting the size of the feed pitch 206, the dipole antenna 20 of the present invention can have a large reflection coefficient, so that a better radiation efficiency can be obtained.

It is worth noting that the left and right halves of the dipole antenna 20 (ie, the radiator 202, 204) The dipole antenna radiators are mutually opposite to each other, so that an Omni-directional radiation pattern can be formed on the XZ plane without generating a null (Null). Fig. 5 to Fig. 8 are radiation pattern diagrams of the dipole antenna 20 shown in Fig. 2 operating at 2.45 GHz, 5.15 GHz, 5.55 GHz, and 5.85 GHz, respectively. Due to the asymmetric structure of the dipole antenna 20, the current distribution is affected, resulting in a slight asymmetry in the radiation pattern of the YZ plane.

Fig. 9 is a view showing the antenna gain and radiation efficiency when the dipole antenna 20 operates at 2.4 GHz to 5.85 GHz as shown in Fig. 2. As can be seen from Fig. 9, when operating near the 2.4 GHz band, the antenna gain of the dipole antenna 20 is about 1.85 dBi, and the radiation efficiency is about 97%. When operating near the 5 GHz band, the antenna gain of the dipole antenna 20 is about 2.3dBi, the radiation efficiency is about 96%. Fig. 10 is a schematic diagram showing the attenuation power of the antenna when the dipole antenna 20 operates at 2.4 GHz and 5 GHz with respect to the data throughput of the wireless local area network communication system. As can be seen from Fig. 10, the wireless local area network communication system equipped with the dipole antenna 20 can have good data throughput.

In summary, this creation is based on the design of the bending direction and position of the radiator, plus When the feeding pitch is combined to form a plurality of current resonance paths, the dipole antenna can be operated in a plurality of frequency bands, and the setting space of the dipole antenna can be effectively reduced, and then applied to the built-in antenna. The dipole antenna of the present invention has a simple structure, does not require an additional Via, and can be accurately fabricated using a common circuit board process (such as a FR4 single-layer board) to achieve good antenna performance, so the manufacturing cost Low cost, suitable for industrial applications.

The above descriptions are only preferred embodiments of the present invention, and all changes and modifications made by the scope of the patent application of the present invention should be covered by the present invention.

20‧‧‧ Dipole antenna

200‧‧‧ dielectric substrate

202, 204‧‧‧ radiator

2020, 2022, 2024, 2040, 2042 2044‧‧‧ bend

206‧‧‧Feed spacing

208, 210‧‧‧Feeding points

A1, A2‧‧‧ upper half

B1, B2‧‧‧ lower half

Claims (9)

A dipole antenna includes: a dielectric substrate; a first radiator formed on the dielectric substrate, the first radiator has a first bend and a second bend; and a second radiator forms On the dielectric substrate, the second radiator has a third bend and a fourth bend; a feed pitch is between the first radiator and the second radiator; a first feed point Between the first bend and the second bend; and a second feed point between the third bend and the fourth bend; wherein the second radiator and the first The radiator is oppositely disposed, and the first feed point and the second feed point are separated by the feed pitch. The dipole antenna of claim 1, wherein the first bend, the second bend, the third bend, and the fourth bend are at right angles, and the outer corners are all oblique. The dipole antenna of claim 1, wherein the first radiator and the upper half of the second radiator are asymmetrical to the lower half. The dipole antenna according to claim 1, wherein the first radiator and the second radiator are mutually opposite radiators. The dipole antenna of claim 1, wherein the first radiator further has a fifth bend, and the second radiator further has a sixth bend. The dipole antenna of claim 1, wherein the dielectric substrate conforms to an FR4 sheet size. The dipole antenna of claim 1, wherein the dipole antenna does not have a consistent aperture (Via). The dipole antenna of claim 1, wherein the first feed point and the second feed point are respectively connected to a center conductor and an outer ground conductor of a coaxial transmission line. The dipole antenna of claim 1, wherein the first radiator and the second radiation system are formed on a dielectric substrate by a printing or etching technique.