CN213717050U - Bluetooth antenna - Google Patents

Abstract

The utility model relates to a bluetooth antenna, include: the radiation plate comprises an inverted F-shaped first part and an e-shaped second part, wherein the ground plate is attached to the lower surface of the dielectric plate, a copper layer covers the lower surface of the ground plate, a through hole penetrates through the dielectric plate and the ground plate, the radiation plate is laid on the upper surface of the dielectric plate and penetrates through the through hole to be connected with the copper layer on the lower surface of the ground plate, and the radiation plate comprises the inverted F-shaped first part and the e-shaped second part. Through the design, the long-distance transmission of the Bluetooth wireless signals can be realized under the condition that the structure of the Bluetooth module is not changed.

Description

Bluetooth antenna

Technical Field

The utility model relates to a wireless signal communication field, concretely relates to remote bluetooth antenna.

Background

Bluetooth (Bluetooth) technology is mainly a short-range radio frequency connection technology for voice and data for various electronic products in a home or enterprise network environment. The bluetooth radio operates in the 2.4-2.5GHz band. With the rapid development of bluetooth wireless communication technology, more and more electronic products have the function of transmitting wireless signals through bluetooth communication technology, and a bluetooth antenna becomes a critical component that affects the transmission characteristics of bluetooth products. The types of the Bluetooth antennas adopted by different Bluetooth products are different, and the commonly used antennas of the existing Bluetooth products mainly comprise a ceramic antenna, a PCB antenna and an IPEX external antenna. The ceramic antenna is a miniaturized antenna suitable for being used in a Bluetooth product, but the gain of the antenna is not high, so that the ceramic antenna cannot transmit long-distance wireless signals, and the performance of the ceramic antenna is affected. The PCB antenna integrated on the Bluetooth module has the advantages that the radiation field intensity is uniform and limited on one plane, the field intensity distribution of the antenna is nonuniform, and positioning errors are easily caused. Meanwhile, the Bluetooth wireless communication module is easily interfered by the mainboard and is not suitable for remote transmission of Bluetooth wireless signals.

In recent years, scholars at home and abroad propose various bluetooth antennas. Documents [ T.Lin, Y.Lin, H.Chen and J.C.Hsu "," Compact UHF near-field RFID reader antipenna "," 2014International Symposium on Antennas and Propagation references Proceedings, Kaohsiung,2014, pp.629-630.]A novel miniaturized microstrip feed plane monopole antenna is provided, an Archimedes spiral groove is adopted for the antenna, WiFi, Bluetooth and LTE standards are covered, and the maximum gain of the antenna is only 2.97 dB. The documents [ B.Shrestha, A.Elsherbeni and L.Ukkonen, "UHF RFID Reader Antenna for Near-Field and Far-Field Operations," in IEEE Antennas and Wireless Propagation Letters, vol.10, pp. 1274-.]A dual-frequency printed monopole antenna is provided, the antenna comprises two rectangular patches with different sizes, the bandwidth of analog impedance is 46.25 (1.958-3.13 GHz), and the bandwidth is narrow. Documents [ J.KizhekkekkePakkathillam and M.Kanagasabai, "A Novel UHF Near-Field RFID Reader Antenna deployment CSRR Elements," in IEEE Transactions on Antennas and deployment, vol.65, No.4, pp.2047-2050, April 2017.]Provides a broadband PI working at 800-970 MHz and 1.5-5.9 GHz frequency bandFA antenna with standing-wave ratio less than 3 and antenna volume of 4 × 2 × 1cm³The size is large. The documents [ C.Cho, C.Lee, J.Ryoo and H.Choo, "Planar Near-Field RFID Reader Antenna for Item-Level Tagging," in IEEE Antennas and Wireless deployment Letters, vol.10, pp.1100-1103,2011.]A tunable antenna for integrating a Bluetooth module on a PCB is provided. The proposed tunable antenna structure is formed by integrating a curved antenna with a bluetooth module, a strip line and a chip capacitor in a PCB. By changing the capacitance value, the operating frequency can be changed without reducing the fractional input impedance, so that the input impedance is easy to match. Peak and average gain are lower due to loss of active chip capacitance. The documents [ X.Wei, B.Hu and H.Zhang, "Novel UHF Near-Field RFID Reader Antenna Based on Double-Sided Parallel-Strip Line," in IEEE Antennas and Wireless Programming Letters, vol.13, pp. 419 and 422,2014.]The small antenna with the 2.45GHz Bluetooth communication is provided, the current elimination technology is adopted, the far-field radiation efficiency is improved, the radiation efficiency of the designed antenna in the 2.45GHz Bluetooth environment is 57%, the distance between a transmitting end and a receiver is 20m, the structure of the antenna is complex, and the transmission distance is not far enough. Documents [ Y.Yao, Y.Liang, J.Yu and X.Chen "," Design of a Multipolarized RFID Reader Antenna for UHF Near-Field Applications "," in IEEE Transactions on Antennas and Propagation, vol.65, No.7, pp. 3344-.]A novel flaky ceramic dielectric antenna is formed on two sides (FR-4 with the thickness of 1.0 mm) of a ceramic dielectric and a substrate by adopting an advanced bending wire technology, and has the return loss bandwidth of 10dB (2.4-2.48GHz) and the Bluetooth radiation gain measured by 0.5 dB.

However, the transmission distance of the bluetooth is limited, and data transmission can be realized only in a short space distance. Beyond a certain range, its efficiency will drop significantly, or even not be transmitted at all.

SUMMERY OF THE UTILITY MODEL

In view of this, the utility model discloses a miniaturized helical antenna of high bandwidth, high gain, but also can carry out remote bluetooth radio signal transmission has been constructed.

The utility model discloses on the basis based on Planar Inverted F Antenna (PIFA), designed a section helical antenna (Spiral PIFA), can satisfy under the condition that does not change the bluetooth module structure, realize bluetooth wireless signal's remote transmission. The spiral antenna is mainly used for a Bluetooth chip internally integrated with an IPEX adapter, and the antenna can be connected with the Bluetooth chip through an IPEX adapter wire, so that the remote transmission of wireless signals of the Bluetooth module is realized, and the Bluetooth module has the characteristics of miniaturization, wide frequency band and high gain.

In order to achieve the purpose, the following technical scheme is adopted in the application:

a bluetooth antenna, comprising:

a dielectric plate, a grounding plate and a radiation plate,

the grounding plate is attached to the lower surface of the dielectric plate, the lower surface of the grounding plate is covered with a copper layer, a through hole penetrates through the dielectric plate and the grounding plate,

the radiation plate is laid on the upper surface of the dielectric plate and penetrates through the through hole to be connected with the copper layer on the lower surface of the grounding plate,

the radiation plate includes a first portion having an inverted F-shape and a second portion having an e-shape.

In a preferred embodiment, the first portion of the radiation plate comprises: a first rectangular strip, a second rectangular strip and a third rectangular strip,

the second and third rectangular strips are respectively connected with the first rectangular strip,

in a preferred embodiment, the second rectangle is parallel to the third rectangle.

In a preferred embodiment, the second portion of the radiation plate comprises: a fourth rectangular bar of 1.8mm by 1.0mm length by width, and a helix of 1.0mm width.

In a preferred embodiment, the number of turns of the spiral line is 1-3, the gap between the inner and outer turns of the overlapping portion is 0.5mm, and one end of the spiral line close to the center is connected to one end of the fourth rectangular bar. In a preferred embodiment, the number of turns of the helix is 1.6 turns.

In a preferred embodiment, the second end of the first rectangular strip is connected to the spiral from the outside.

In a preferred embodiment, the first end of the second rectangular bar and the first end of the third rectangular bar are connected to the first rectangular bar, the second end of the second rectangular bar is a grounding point,

is connected to the ground plane and is connected to the ground plane,

the second end of the third rectangular strip is a feed point.

In a preferred embodiment, the first portion of the radiation plate is composed of a first rectangular strip with a length × width of 7.35mm × 0.7mm, a second rectangular strip with a length × width of 1.8mm × 0.9mm perpendicular to the first rectangular strip, and a third rectangular strip with a length × width of 1.5mm × 1.2mm perpendicular to the first rectangular strip, the second and third rectangular strips are both connected to the first rectangular strip, the second rectangular strip is 0.5mm away from the first end of the first rectangular strip, and the third rectangular strip is spaced from the second rectangular strip by 1.0 mm.

Advantageous effects

The application provides a bluetooth antenna structural design has following effect:

(1) can cover the ISM frequency band (2.4-2.48GHz) of Bluetooth work;

(2) the requirement of the Bluetooth module for effective communication distance of 50 meters can be met;

(3) the broadband high-gain miniaturized broadband high-gain miniaturized high-gain broadband high-gain miniaturized miniature high-gain;

(4) the antenna has simple structure and is convenient to debug and install.

Drawings

Fig. 1 is an overall view of the bluetooth antenna of the present invention.

Fig. 2 is a sectional view taken along line a-a of fig. 1.

Fig. 3 is a schematic view of the radiation plate of the present invention.

Fig. 4 is a simulation graph of the input impedance of the antenna of the present invention.

Fig. 5 is a return loss curve of the antenna simulation of the present invention.

Fig. 6 shows the antenna three-dimensional gain pattern of the present invention.

Detailed Description

The above-described scheme is further illustrated below with reference to specific examples. It should be understood that these examples are for illustrative purposes and are not intended to limit the scope of the present invention. The conditions employed in the examples may be further adjusted as determined by the particular manufacturer, and the conditions not specified are typically those used in routine experimentation.

In the present application, the terms "upper", "lower", "inside", "middle", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings. These terms are used primarily to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to a particular orientation or to be constructed and operated in a particular orientation.

As shown in fig. 1-3, the present application provides a bluetooth antenna 100, comprising: the radiation plate comprises a dielectric plate 1, a grounding plate 3 and a radiation plate 2, wherein the dielectric plate 1 is a circular plate with the thickness of 1mm and the diameter of 20mm and made of glass fiber epoxy resin (FR4), the relative dielectric constant epsilon r is 4.4, the loss tangent tan delta is 0.02, the grounding plate 3 is attached to the lower surface of the dielectric plate, the lower surface of the grounding plate is covered with a copper layer 12, and the copper layer serves as a grounding point. A through hole 11 penetrates through the dielectric plate 1 and the ground plate 3, the radiation plate 2 is laid on the upper surface 10 of the dielectric plate 1 and is connected with the copper layer 12 on the lower surface 10' of the ground plate 3 through the through hole 11, and the radiation plate comprises a first part in an inverted F shape and a second part similar to an e shape.

As shown in fig. 3, the first portion of the radiation plate is composed of a first rectangular bar 21 having a length L1 × a width H1 of 7.35mm × 0.7mm, a second rectangular bar 22 having a length H2 × a width W2 of 1.8mm × 0.9mm perpendicular to the first rectangular bar 21, and a third rectangular bar 23 having a length H3 × a width W4 of 1.5mm × 1.2mm perpendicular to the first rectangular bar 21, the second and third rectangular bars (22, 23) are both connected to the first rectangular bar 21, the second rectangular bar 22 is at a distance W1 of 0.5mm from the first end 211 of the first rectangular bar 21, and the third rectangular bar 23 is at a distance W3 of 1.0mm from the second rectangular bar 22. The second rectangular strip is parallel to the third rectangular strip.

As shown in fig. 3, the first end of the second rectangular bar 22 and the first end of the third rectangular bar 23 are connected to the first rectangular bar, the second end of the second rectangular bar 22 is a ground point and is connected to the ground plate through a ground line (not shown), and the second end of the third rectangular bar is a feeding point.

As shown in fig. 3, the second portion of the radiation plate 2 is composed of a fourth rectangular bar 24 having a length H5 × a width W3 of 1.8mm × 1.0mm, and a spiral line 25 having a width W3 of 1.0mm, a number of turns of 1.6, a gap W1 between the inner and outer turns of the overlapping portion of 0.5mm, and one end thereof near the center is connected to one end of the fourth rectangular bar. The second end of the first rectangular strip is connected to the spiral from the outside.

The IPEX patch cord is connected to the feed point from the ground plate portion of the back of the bluetooth antenna, and then is connected to the antenna of the radiation plate, the feeder usually uses 50 Ω standard impedance, when designing the antenna, need design the input impedance of the antenna as far as possible at 50 Ω, make it guarantee as small standing-wave ratio as possible in the working band.

The working principle of the antenna is as follows: the straight line trend radiation arm of the inverted F antenna is changed into the e-shaped spiral trend, so that the effective path of the radiation arm is prolonged, the size of the antenna is not increased, and the miniaturization of the antenna is ensured. The input impedance of the antenna is close to 50 omega by adjusting the e-shaped radiation arm of the antenna and the height of the antenna, namely, the impedance matching of the antenna can be completed without any additional circuit, and meanwhile, the gain of the antenna can be improved, and the antenna can transmit wireless signals at a long distance.

Fig. 4 is a graph of simulated antenna input impedance, with the input impedance of the bluetooth antenna at 2.40GHz (46.36+ i x 1.03) and 2.48GHz (53.27-i x 3.52) marked on the graph. At the 2.40GHz and 2.48GHz points, re (Z (1,1)) is above im (Z (1, 1)).

FIG. 5 is a graph showing the return loss S of an antenna simulation, and it can be seen from the graph that the return loss S is obtained when the antenna is operated at a center frequency of 2.44GHz₁₁The-10 dB bandwidth is 230MHz, the frequency range is from 2.32GHz to 2.55GHz, and the relative bandwidth BW is 9.4%. The measured bandwidth is 220MHz and the measured maximum gain is 4.6 dB. When the antenna is used for the wireless signal communication of the Bluetooth module, the communication distance of the antenna can reach more than 60 meters, which is 2 times of the transmission distance of the folding antenna of the same type.

Helical antenna gain	Folding antenna actual measurement transmission distance	Actually measured transmission distance of helical antenna
			4.6dB	30m	60m

Fig. 6 is a three-dimensional gain pattern of the bluetooth antenna of the present application.

According to the structure and the principle of the antenna described in the technical scheme, HFSS is used for modeling simulation, after a simulation result reaches the standard, a simulation model of the antenna is led out for processing and manufacturing, the dielectric plate is made of glass fiber epoxy resin, the dielectric constant is 4.4, the loss tangent is 0.02, and the thickness is 1 mm. When the antenna is welded with the IPEX patch cord, attention needs to be paid to not melting an insulating layer, so that an inner conductor and an outer conductor of the patch cord are connected to cause short circuit and influence the performance of the antenna.

And a testing step, namely connecting the 2 spiral antennas to IPEX end seats of the 2 wireless modules through IPEX patch cords respectively, connecting the wireless receiving module to a computer serial port, and continuously moving the wireless sending module to a long distance until the computer serial port cannot receive the wireless signal data, namely the farthest transmission distance of the spiral antennas. In the process of testing the farthest transmission distance of the antenna, attention is paid to the directivity of the antenna and the placement position of the antenna, and the antenna connected with the wireless module is adjusted to be placed in the same horizontal plane, so that the sensing surface for transmitting and receiving wireless signals is the largest, the strength of transmitted and received electromagnetic wave signals is the strongest, and the wireless transmission distance is further.

The above description is only a preferred embodiment of the present invention, and the present invention is not limited to the above description, and although the present invention has been disclosed by the preferred embodiment, it is not limited to the present invention, and any person skilled in the art can make modifications or changes equivalent to the equivalent embodiments by utilizing the above disclosed technical contents without departing from the technical scope of the present invention, but all the modifications, changes and changes of the technical spirit of the present invention made to the above embodiments are also within the scope of the technical solution of the present invention.

Claims (8)

1. A bluetooth antenna, comprising:

a dielectric plate, a grounding plate and a radiation plate,

the grounding plate is attached to the lower surface of the dielectric plate, the lower surface of the grounding plate is covered with a copper layer, a through hole penetrates through the dielectric plate and the grounding plate,

the radiation plate is laid on the upper surface of the dielectric plate and penetrates through the through hole to be connected with the copper layer on the lower surface of the grounding plate,

the radiation plate includes a first portion having an inverted F-shape and a second portion having an e-shape.

2. A bluetooth antenna according to claim 1, characterized in that:

the first portion of the radiation plate includes: a first rectangular strip, a second rectangular strip and a third rectangular strip,

the second and third rectangular strips are respectively connected with the first rectangular strip,

the second rectangular bar is perpendicular to the first rectangular bar.

3. A bluetooth antenna according to claim 2, characterized in that:

the second rectangle is parallel to the third rectangle.

4. A bluetooth antenna according to claim 1, characterized in that:

the second portion of the radiation plate includes: a fourth rectangular bar of 1.8mm by 1.0mm length by width, and a helix of 1.0mm width.

5. A Bluetooth antenna according to claim 4, characterized in that:

the number of turns of the spiral line is 1-3, the gap between the inner circle and the outer circle of the overlapped part is 0.5mm, and one end, close to the center, of the spiral line is connected to one end of the fourth rectangular strip.

6. A Bluetooth antenna according to claim 4, characterized in that: the number of turns of the spiral is 1.6.

7. A bluetooth antenna according to claim 2, characterized in that: the second end of the first rectangular strip is connected to the spiral line from the outside.

8. A bluetooth antenna according to claim 2, characterized in that:

the first end of the second rectangular strip and the first end of the third rectangular strip are connected to the first rectangular strip, the second end of the second rectangular strip is a grounding point and is connected to a grounding plate, and the second end of the third rectangular strip is a feeding point.

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