CN108512564B - Wristband device applying variable frequency antenna - Google Patents

Abstract

The invention discloses a wristband device using a variable frequency antenna. According to the thickness of the wearer's wrist, the bayonet is brought into contact with the corresponding contact point, thereby determining the working frequency of the antenna. The personnel management system can determine the working frequency of the antenna according to the bound antenna working frequency information. And the wrist physical information determines the person's working area or activity range, and then realizes the binding of the wearer's wrist information, working frequency and activity range, and finally realizes the grouping of different personnel. The wristband device disclosed in the present invention does not rely on GPS, WIFI or Bluetooth positioning systems, and can realize automatic grouping of personnel according to areas or activity ranges and long-distance communication, and is especially suitable for the intelligentization of construction sites in large-scale outdoor network-free environments. Management, four-dimensional construction management system, personnel self-identification system and other large-scale management systems including personnel three-dimensional space trajectory and positioning, attendance, construction site equipment monitoring, and personnel health monitoring functions.

Description

A wristband device using variable frequency antenna

Technical field

The present invention relates to the field of wireless communication technology, and specifically to a wristband device using a variable frequency antenna.

Background technique

As an important communication device, wristband antennas are widely used in various wearable devices such as smart bracelets and smart watches. Since the design space of the wristband is small, its antenna must meet the requirements of being compact, easily conformable to the wrist, and low profile. It is difficult to achieve expansion of performance and functions such as variable frequency and high gain, especially in the sub-GHz frequency band. Promotion and application of antennas. Based on the above problems, R&D personnel develop and design various types of small antennas.

The documents "Integrated Metal-Frame Antenna for Smart watch Wearable Device" and the document "ALow-Profile Wearable Antenna Using a Miniature High Impedance Surface for Smartwatch Applications" both propose a rectangular loop antenna designed using the metal frame of smart watches. Although it can be realized It has basic communication functions, but its operating frequency band only covers 2.4GHz and cannot achieve frequency conversion; in addition, because the antenna design does not consider the impact of the human body's low specific absorption rate, it is difficult to be truly used in wearable devices. The document "Bluetoothhand Wi-Fi tri-band antenna on metal frame of smartwatch" introduces a loop-shaped multi-frequency antenna, but the antenna can only work in the high-frequency bands of GPS, Bluetooth and WIFI, making it difficult to achieve a tunable design in the low-frequency band. The document "Conformai integrated multi-layer thin-film antenna by novel LITAtechnologies for smartwatch wearable device applications" provides a multi-layer metal film antenna manufactured using a special process. The structure of the antenna is a planar inverted F antenna, and its resonant frequency is located in the 2.4GHz Bluetooth band. .

In addition, wearable antennas use flexible material media. Since the shape of the antenna changes during the wearing process, the performance of the antenna changes to a certain extent. In order to overcome such problems, researchers usually use two methods, namely The radiating unit of the antenna should be miniaturized as much as possible or adopt a new structure to reduce the antenna's sensitivity to morphological changes. The document "Research on Smart Watch Antennas" reports a multi-bending straight plate antenna that uses radiating branches to achieve the multi-band and wide-band characteristics of the antenna. The document "A novel wrist wear dual-band diversity antenna" proposes a wrist-conformal diversity microstrip antenna covering two GSM frequency bands of 850MHz-900MHz and 1.74GHz-1.85GHz. However, this antenna can only rely on circuits to tune it. The working frequency band has not been jointly tuned with human body characteristics, making it difficult to meet the needs of the personnel management system.

The existing form of antenna frequency conversion is still based on electronic module tuning. The antenna relies on its multiple physical branches to achieve frequency modulation. It is difficult to use the physical signs of the wearer, such as the wrist, as carrier information for use by a large-scale personnel management system. In addition, the design of the wristband antenna itself requires a compromise between performance and size. It requires reasonable structural design to maximize the use of available space to design an antenna that meets the needs. At the same time, existing wristband antennas are mostly concentrated above the GHz frequency band, and are affected by their own power and the body of the person wearing them, making it difficult to meet the long-distance communication and positioning needs of construction sites in large-scale outdoor network-free environments.

Contents of the invention

In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a wristband device using a variable frequency antenna. The operating frequency of the antenna switches autonomously in the sub-GHz frequency band according to the thickness of the wearer's wrist and does not rely on GPS. , WIFI or Bluetooth positioning system, which can realize automatic grouping and long-distance communication of personnel according to area or activity range.

The technical solution of the present invention is as follows:

A wristband device using a variable frequency antenna, characterized in that it includes: a wristband base; and a plastic clamp fixed in the middle of the wristband base; one end of the plastic clamp extends out of the wristband base The first antenna radiating unit is located at the longitudinal middle position and extends in a straight line along the surface of the wristband base body to the edge of the wristband. The first antenna radiating unit extends out of the plastic clamp and is provided with an antenna feed point. The end is connected to a metal buckle; the other end of the plastic clamp extends out from the middle position of the wristband base body in the longitudinal direction and extends to the second edge of the wristband base body in a continuous and uniform "several" shape along the longitudinal direction of the wristband base body surface. Antenna radiating unit, the end of the second antenna radiating unit is provided with a first contact point, a second contact point and a third contact point respectively; the first antenna radiating unit and the second antenna radiating unit pass through the The internal circuit of the plastic clamp is connected; when in use, the contact that matches the metal buckle is selected from the first contact point, the second contact point and the third contact point according to the wearer's wrist signs for clamping.

Based on the above solution, further preferably,

The wristband base body is made of soft elastic material.

Based on the above solution, further preferably,

The plastic clamp is connected to the first antenna radiating unit and the second antenna radiating unit through plug connectors.

Based on the above solution, further preferably,

The antenna lengths of the first antenna radiating unit and the second antenna radiating unit are set according to operating frequency requirements.

Based on the above solution, further preferably,

The width of the connection portion between adjacent "ji" shapes in the second antenna radiating unit is set according to the operating gain requirements.

Based on the above solution, further preferably,

The working frequency band of the wristband device is 315MHz-915MHz and UWB frequency band.

Through the above technical solution, the present invention discloses a wristband device using a variable frequency antenna that matches the physical characteristics of the wearer's own wrist. According to the thickness of the wearer's wrist, the bayonet is brought into contact with the corresponding contact point, thereby determining the operation of the antenna. Frequency, the personnel management system can determine the working area or activity range of the person based on the bound antenna working frequency information and wrist physical signs information, and then realize the binding of the wrist information, working frequency and activity range of the wearer, and finally achieve different Personnel grouping. The wristband device disclosed in the present invention does not rely on GPS, WIFI or Bluetooth positioning systems, and can realize automatic grouping of personnel according to areas or activity ranges and long-distance communication, and is especially suitable for the intelligentization of construction sites in large-scale outdoor network-free environments. Management, four-dimensional construction management system, personnel self-identification system and other large-scale management systems including personnel three-dimensional space trajectory and positioning, attendance, construction site equipment monitoring, and personnel health monitoring functions.

Description of the drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, a brief introduction will be made below to the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description These are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a schematic structural diagram of the wristband device of the present invention;

Figure 2a is a diagram of the antenna return loss when the metal buckle is disconnected in the embodiment of the present invention;

Figure 2b is a normalized input impedance diagram of the antenna when the metal buckle is disconnected in the embodiment of the present invention;

Figure 2c is the radiation pattern of the antenna E surface when the metal buckle is disconnected in the embodiment of the present invention;

Figure 3a is a diagram of the antenna return loss when the metal buckle is in contact with the first contact point in the embodiment of the present invention;

Figure 3b is a normalized input impedance diagram of the antenna when the metal buckle is in contact with the first contact point in the embodiment of the present invention;

Figure 3c is a radiation diagram of the antenna E surface when the metal buckle is in contact with the first contact point in the embodiment of the present invention;

Figure 4a is a diagram of the antenna return loss when the metal buckle is in contact with the second contact in the embodiment of the present invention;

Figure 4b is a normalized input impedance diagram of the antenna when the metal buckle is in contact with the second contact in the embodiment of the present invention;

Figure 4c is a radiation diagram of the antenna E surface when the metal buckle is in contact with the second contact point in the embodiment of the present invention;

Figure 5a is a diagram of the antenna return loss when the metal buckle is in contact with the third contact point in the embodiment of the present invention;

Figure 5b is a normalized input impedance diagram of the antenna when the metal buckle is in contact with the third contact in the embodiment of the present invention;

Figure 5c is a radiation diagram of the antenna E surface when the metal buckle is in contact with the third contact point in the embodiment of the present invention.

Explanation of reference symbols:

1. Wristband base; 2. Plastic fixture; 3. First antenna radiating unit; 4. Second antenna radiating unit; 5. First contact; 6. Second contact; 7. Third contact; 8 , metal buckle; 9. Antenna feed point.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the drawings in the embodiments of the present invention:

As shown in Figure 1: a wristband device using a variable frequency antenna, including: a wristband base 1; and a plastic clamp 2 fixed in the middle of the wristband base 1; one end of the plastic clamp 2 extends There is a first antenna radiating unit 3 disposed at the longitudinal middle position of the wristband base 1 and extending in a straight line along the surface of the wristband base 1 to the edge of the wristband. The first antenna radiating unit 3 extends out of the plastic The clamp 2 is provided with an antenna feed point 9 and its end is connected to a metal buckle 8; the other end of the plastic clamp 2 extends out and is arranged at the longitudinal middle position of the wristband base 1, extending longitudinally along the surface of the wristband base 1 The second antenna radiating unit 4 extends continuously and uniformly in a "severe" shape to the edge of the wristband base 1. The ends of the second antenna radiating unit 4 are respectively provided with first contacts 5, second contacts 6 and third contacts. Contact 7; the first antenna radiating unit 3 and the second antenna radiating unit 4 are electrically connected inside the plastic fixture 2 through a plug connector and a circuit board; during use, according to the physical signs of the wearer's wrist Select the contact point matching the metal buckle 8 among the first contact point 5, the second contact point 6 and the third contact point 7 to clamp, and the effective length of the antenna is changed by the metal buckle 8 contacting different contacts. Change of working frequency band.

Furthermore, the wristband base 1 is made of soft elastic material. Flexible materials can be silicone, rubber, soft plastic, etc. When making the wristband, the antenna is placed into the slot inside the mold to ensure the relative position of the antenna is accurate, and then the shape is shaped by pouring silicone and other materials.

Furthermore, the plastic clamp 2 is connected to the first antenna radiating unit 3 and the second antenna radiating unit 4 through plug connectors, and the plastic clamp 2 is provided with male and female heads corresponding to the plug connectors inside.

Further, the antenna lengths of the first antenna radiating unit 3 and the second antenna radiating unit 4 are set according to the operating frequency requirements and calculated according to the well-known conventional antenna formula. The longer the antenna length, the more usable operating frequency points. The antenna 8 The length depends on the minimum operating frequency requirement. At the same time, the layout of the antenna is related to the gain, so the width of the connection between adjacent "ji" shapes in the second antenna radiating unit 4 is set according to the working gain requirements. The wider the width of the connection, the gain of the microstrip antenna increases, and The width range between each turn of the second antenna radiating unit 4 is the total length of the antenna/the number of turns, and the total length is determined by the working frequency point.

The working frequency band of the wristband device is 315MHz-915MHz and UWB frequency band.

In the low-frequency stage (sub-GHz), the present invention can select the contact point in contact with the metal buckle according to the thickness of the wearer's wrist, thereby changing the effective length of the access antenna and thereby adjusting the operating frequency of the antenna, thereby realizing the connection between the wearer and the operating frequency. Binding facilitates personnel identification. Due to different access points and corresponding changes in the operating frequency, the invention has a frequency conversion function. The number of contacts can be increased or decreased according to the needs of the wristband operating frequency. In this way, the system can determine the working area or activity range of the person based on the bound antenna working frequency information. Finally, the wearer's wrist information, working frequency and activity range are bound to realize grouping of different people.

The following analyzes the working status of the wristband device when operating at different operating frequencies as a further explanation of the technical solution of the present invention:

When the metal buckle 8 remains disconnected, under the excitation of the feed source, the antenna works at f1 frequency, the input impedance is close to 50 ohms, and it is an omnidirectional antenna with a bandwidth of 82MHz (830MHz~913MHz), as shown in Figures 2a to 2c. are shown, respectively, their return loss schematic diagram, normalized input impedance schematic diagram and E-plane radiation schematic diagram.

When the metal buckle 8 is in contact with the first contact 5, the antenna can work in the f2 and f3 frequency bands, and the f3 frequency is greater than f2. When the antenna works in the f2 frequency band, the effective length of the antenna is the largest and the frequency band is the lowest. The return loss S11 value is -26.56dB and the bandwidth is 18MHz. The radiation characteristics of the antenna are similar to those of the monopole antenna, both are omnidirectional radiation. Figures 3a to 3c are respectively the return loss diagram, the normalized input impedance diagram and the E-plane radiation diagram at this time.

When the metal buckle comes into contact with the second contact 6, the resonant frequency of the antenna will increase because the effective length of the antenna is reduced. The antenna can work in f4 and f5 frequency bands, and f5 is higher than f4. At this time, in the f4 band, the antenna S11 is -33dB, the bandwidth is 18MHz, the input impedance is close to 50 ohms, and the antenna also radiates omnidirectionally. Figures 4a to 4c are respectively the return loss diagram, the normalized input impedance diagram and the E-plane radiation diagram at this time.

When the metal buckle 8 comes into contact with the third contact 7, the length is further reduced and the resonant frequency is increased. At this time, the resonant frequencies of the antenna are f6 and f7. At the f6 frequency, the return loss value of the antenna is -38.96dB, the effective bandwidth is 20MHz, and the normalized input impedance is very close to 50 ohms. The radiation direction is omnidirectional. Figures 5a to 5c are respectively the return loss diagram, the normalized input impedance diagram and the E-plane radiation diagram at this time.

The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person familiar with the technical field can, within the technical scope disclosed in the present invention, implement the technical solutions of the present invention. Equivalent substitutions or changes of the inventive concept thereof shall be included in the protection scope of the present invention.

Claims (6)

1. A wristband device employing a variable frequency antenna, comprising: a wristband base (1);

and a plastic clamp (2) fixed in the middle of the wrist strap matrix;

one end of the plastic fixture (2) extends out of a first antenna radiation unit (3) arranged at the longitudinal middle position of the wristband substrate (1) and extends to the edge part of the wristband substrate (1) along the surface of the wristband substrate (1) in a longitudinal linear mode, an antenna feed point (9) is arranged at the position of the first antenna radiation unit (3) extending out of the plastic fixture (2), and the tail end of the first antenna radiation unit is connected with a metal buckle (8);

the other end of the plastic fixture (2) extends out of a second antenna radiation unit (4) which is arranged at the longitudinal middle position of the wrist strap base body (1) and extends to the edge part of the wrist strap base body (1) in a continuous and uniform shape along the surface of the wrist strap base body (1), and the tail end of the second antenna radiation unit (4) is respectively provided with a first contact (5), a second contact (6) and a third contact (7);

the first antenna radiating unit (3) and the second antenna radiating unit (4) are connected inside the plastic fixture (5) through a circuit;

when the metal buckle is used, the contact matched with the metal buckle (8) is selected from the first contact (5), the second contact (6) and the third contact (7) according to wrist signs of a wearer to clamp;

according to the wrist thickness of the wearer, the bayonet is contacted with the corresponding contact, so that the working frequency of the antenna is determined, the personnel management system can determine the working area or the moving range of the wearer according to the information of the working frequency of the antenna and the information of the wrist sign, and further the binding of the wrist information, the working frequency and the moving range of the wearer is realized, and finally the grouping of different persons is realized.

2. Wristband device according to claim 1, characterized in that the wristband base (1) is of soft elastic material.

3. Wristband device according to claim 1, characterized in that the plastic clamp (2) is connected with the first antenna radiating element (3) and the second antenna radiating element (4) by means of connectors.

4. Wristband device according to claim 1, characterized in that the antenna length of the first antenna radiating element (3) and the second antenna radiating element (4) is set according to the operating frequency requirement.

5. Wristband device according to claim 4, characterized in that the width of the connection between adjacent "several" shapes in the second antenna radiating element (4) is set according to the operational gain requirement.

6. A wristband device according to any one of claims 4 or 5, wherein the wristband device is operated in the 315MHz to 915MHz and UWB bands.