A wearable dual-frequency dual-polarization antenna and a wearable terminal device

Abstract

The present invention discloses a wearable dual-frequency dual-polarization antenna and a wearable terminal device, comprising a radiation patch, a flexible dielectric substrate, a grounding plate and a short-circuit probe, wherein the radiation patch is arranged on the upper surface of the flexible dielectric substrate, the grounding plate is arranged on the lower surface of the flexible dielectric substrate, and the two ends of the short-circuit probe are respectively connected to the grounding plate and the radiation patch. The antenna has dual radiation modes on the basis of having dual-frequency dual-polarization characteristics, and has the advantages of simple structure, low profile and good flexibility.

Description

Technical Field

[0001] The present invention relates to the field of antennas, and in particular to a wearable dual-frequency dual-polarization antenna and a wearable terminal device. Background Art

[0002] With the rapid development of wireless body area networks, wearable antennas play an important role in telemedicine, battlefield communications, personal entertainment, etc. Wearable antennas play a role in wireless data transmission between wearable devices and other devices, providing very promising medical care and personal entertainment solutions. Wearable antennas can be used for surface communication or external communication according to their radiation characteristics. For this reason, a wearable dual-band antenna is designed to meet two communication modes at the same time, which can reduce the space occupied and energy consumption of wearable devices, which is of great significance to wearable devices.

[0003] At present, most dual-band wearable antennas are designed with a single radiation mode and can only be used for one of the communication modes. Because on-body communication generally requires an omnidirectional radiation mode, so that it can communicate well with various sensors worn on the human body. In vitro communication generally requires a directional radiation mode to increase its gain and expand the transmission distance. And because the human body is constantly moving, there is a serious polarization mismatch between the wearable antenna and the external device, so for in vitro communication, a circularly polarized radiation mode that can resist polarization mismatch is generally required.

[0004] Currently, there are relatively few wearable antennas that can simultaneously work in dual-frequency and dual-radiation modes, and they generally require a stacked structure or multi-feed method, which undoubtedly increases the size and difficulty of the antenna. Therefore, the study of a single-layer wearable antenna with dual-frequency, dual-polarization and dual-radiation modes has important reference value and practical significance. Summary of the invention

[0005] In order to overcome the shortcomings and deficiencies of the prior art, the primary purpose of the present invention is to provide a wearable dual-frequency dual-polarization antenna, which has dual radiation modes based on the dual-frequency dual-polarization characteristics, and has the advantages of simple structure, low profile and good flexibility.

[0006] A secondary object of the present invention is to provide a wearable terminal device.

[0007] The primary purpose of the present invention is to adopt the following technical solutions:

[0008] A wearable dual-frequency dual-polarization antenna comprises a radiation patch, a flexible dielectric substrate, a ground plate and a short-circuit probe, wherein the radiation patch is arranged on the upper surface of the flexible dielectric substrate, the ground plate is arranged on the lower surface of the flexible dielectric substrate, and two ends of the short-circuit probe are respectively connected to the ground plate and the radiation patch.

[0009] The radiation patch includes two cut corners and a rectangular gap, wherein the two cut corners are respectively located at two opposite corners of the radiation patch, and the rectangular gap is symmetrical about the vertical center axis of the radiation patch.

[0010] The cut angle is an isosceles triangle or a rectangle.

[0011] Preferably, it also includes a microstrip feed line, one end of which is electrically connected to the radiation patch, and the other end of which is connected to an external feed source.

[0012] There are two pairs of short-circuit probes, and the connection points between the two pairs of short-circuit probes and the radiation patch are respectively located on two diagonal lines of the radiation patch.

[0013] The length of the right-angled side of the isosceles triangle cut corners is 7 mm to 8 mm.

[0014] The length of the rectangular gap is 23 mm to 25 mm, the width is 0.4 mm to 0.7 mm, and the distance between the center of the rectangular gap and the upper edge of the radiation patch is 5 mm to 6 mm.

[0015] The radiation patch, microstrip feed line and ground plane are all made of conductive nylon fabric. The thickness of the conductive nylon fabric is 0.13 mm, and the surface resistivity is less than 0.009 ohm per square meter.

[0016] The flexible dielectric substrate is made of wool felt material, the wool felt material has a thickness of 2 mm, a dielectric constant of 1.2, and a loss tangent of 0.02.

[0017] The secondary purpose of the present invention is achieved by the following technical solutions:

[0018] A wearable terminal device comprises the wearable dual-frequency dual-polarization antenna.

[0019] Beneficial effects of this antenna:

[0020] 1. The antenna of the present invention adopts all-textile materials, the radiation patch and the ground plate are conductive nylon fabrics, and the dielectric substrate is a felt material, all of which are bendable, so that the radiation patch can be deformed with the deformation of the dielectric substrate in a complex environment and the working performance of the antenna can be maintained normally.

[0021] 2. The antenna of the present invention adopts a single-layer dielectric substrate and has a complete floor structure. The antenna conforms well to the human body and can reduce the coupling effect between the human body and the antenna, so that the antenna performance is not affected.

[0022] 3. The antenna of the present invention realizes dual-frequency dual-radiation mode operation by using probe loading technology, and also realizes dual-polarization operation by using angle cutting technology. Compared with stacking technology or multi-feed technology, the antenna has a simple structure, is easy to process and has low cost.

[0023] 4. The antenna of the present invention can be used for both on-body communication and off-body communication. It can realize a vertically polarized omnidirectional radiation mode in a low-frequency band for on-body communication and a circularly polarized directional radiation mode in a high-frequency band for off-body communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A side structural diagram of the wearable dual-frequency dual-polarization antenna provided by the present invention;

[0025] Figure 2 A top view of the wearable dual-frequency dual-polarization antenna provided by the present invention;

[0026] Figure 3 A comparison diagram of the measured and simulated reflection coefficients of the wearable dual-frequency dual-polarization antenna provided by the present invention;

[0027] Figure 4 A comparison diagram of the gain and axial ratio of the wearable dual-frequency dual-polarization antenna provided by the present invention;

[0028] Figure 5 A comparison diagram of the normalized radiation characteristics of the wearable dual-frequency dual-polarization antenna provided by the present invention at 2.4 GHz;

[0029] Figure 6 This is a comparison diagram of the normalized radiation characteristics of the wearable dual-frequency dual-polarization antenna provided by the present invention at 3.5 GHz;

[0030] Figure 7 A reflection coefficient diagram of the wearable dual-band dual-polarized antenna provided by the present invention under different bending conditions;

[0031] Figure 8 The normalized radiation characteristic diagram of the wearable dual-frequency dual-polarization antenna provided by the present invention under different bending conditions at 2.4GHz;

[0032] Fig. 9 The normalized radiation characteristic diagram of the wearable dual-band dual-polarization antenna provided by the present invention under different bending conditions at 3.5 GHz. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0034] Example 1

[0035] like Figure 1 and Figure 2As shown, a wearable dual-frequency dual-polarization antenna for a wireless body area network, which can be well applied to wearable terminal devices, comprises a radiation patch 1, a flexible dielectric substrate 2, a ground plate 3, two pairs of short-circuit probes 4 and a microstrip feeder 7, wherein the flexible dielectric substrate is a single layer.

[0036] The radiation patch 1, the flexible dielectric substrate 2 and the grounding plate 3 are arranged in sequence from top to bottom. Specifically, the radiation patch 1 is attached to the upper surface of the flexible dielectric substrate 2, and the grounding plate is attached to the lower surface of the flexible dielectric substrate 2; one end of the two pairs of short-circuit probes 4 is connected to the grounding plate 3, and the other end of the short-circuit probes 4 is connected to the radiation patch 1 through the flexible dielectric substrate 2; the upper end of the microstrip feed line 7 is electrically connected to the radiation patch 1, and feeding by the microstrip feed line 7 can better conform to the human body, and the width of the microstrip feed line is 5mm to 6mm.

[0037] In this embodiment, the flexible dielectric substrate is made of wool felt material with a thickness of 2 mm, a dielectric constant of 1.2, a loss tangent of 0.02, and an overall size of 70 mm×70 mm×2 mm.

[0038] like Figure 2 As shown, the radiation patch 1 includes two isosceles triangle cut corners and a rectangular gap. The isosceles triangle cut corners can also be rectangular cut corners. The connection points of the two pairs of short-circuit probes and the radiation patch are located on two diagonals respectively. The dual-frequency dual-radiation mode operation is realized through the technology of reactance loading. The two pairs of short-circuit probes have the same structure, with a radius of 0.5mm and a spacing of 42mm. The rectangular gap is symmetrical about the vertical center axis of the radiation patch. Under the action of the rectangular gap, the antenna achieves good impedance matching.

[0039] The dual-frequency dual-radiation mode operation is achieved through the technology of reactance loading. Specifically, two pairs of short-circuit probes are used as reactance loading. The loading of the short-circuit probes will first cause the fundamental mode (TM10) of the microstrip antenna to shift to a high frequency, thereby simultaneously generating a dipole-like radiation mode in the low frequency band. The required two modes can be obtained by adjusting the spacing and radius of the short-circuit probes.

[0040] In this embodiment, the length of the rectangular slot is 24 mm, the width is 0.5 mm, and the distance between the center of the rectangular slot and the upper edge of the radiation patch is 5 mm. The rectangular slot 5 is loaded mainly to obtain a pair of mutually orthogonal degenerate modes, thereby achieving circular polarization performance.

[0041] The two isosceles triangle cut corners 6 are respectively located at two opposite corners of the radiation patch 1, wherein the length of the right angle side of the isosceles triangle is 7 mm.

[0042] In the above embodiment, the radiation patch 1 and the ground plate 3 are both made of conductive nylon fabric material, and the size of the radiation patch is 51 mm*51 mm.

[0043] like Figure 3 As shown in the figure, the antenna of this embodiment works in two frequency bands. It can be seen from the figure that the results of antenna simulation and test are very consistent, and the slight frequency deviation mainly comes from the processing error. The measured -10-dB impedance bandwidth of the antenna in the low frequency band is 2.368GHz~2.467GHz; the measured -10dB impedance bandwidth in the high frequency band is 3.395GHz~3.645GHz. The impedance bandwidths of the two frequency bands of this embodiment meet the working indicators, and the antenna has good performance in the above frequency bands.

[0044] like Figure 4 As shown in the figure, the axial ratio characteristics and gain characteristics of the simulation and test of this embodiment are shown. It can be seen from the figure that the minimum axial ratio of the antenna simulation and test is less than 3dB in the high frequency band, and the circular polarization performance is good. The gain in the two passbands is relatively stable, with peak gains of 1.38dBi and 7.7dBi respectively.

[0045] like Figure 5 As shown in the figure, the simulation and test radiation characteristic curves of this embodiment in the 2.4-GHz medical human area network frequency band are shown. It can be seen from the figure that the antenna simulation and test results are very consistent. In this frequency band, a good omnidirectional radiation pattern is achieved, and the cross-plan ratio in the horizontal plane is greater than 18dB, which can be well applied to body surface communication.

[0046] like Figure 6 As shown in the figure, the simulation and test radiation characteristic curves of this embodiment in the 3.5-GHz WiMAX frequency band are very consistent with each other. In this frequency band, a good circular polarization directional radiation pattern is achieved, and the cross-plan ratio in the main direction is greater than 19dB, which can be well applied to in vitro communication.

[0047] like Figure 7 As shown, it is the reflection coefficient curve of this embodiment under different bending conditions. It can be seen from the figure that under the bending conditions of different directions and different radii, the impedance characteristics of the antenna are well maintained in two frequency bands, and the antenna has very good robustness.

[0048] like Figure 8 As shown, this is a radiation characteristic curve diagram of different bending conditions of this embodiment in the 2.4-GHz medical human body local area network frequency band. It can be seen from the figure that the radiation characteristics of the antenna remain consistent under structural deformation. All situations achieve a good omnidirectional radiation pattern and can be well applied to body surface communication.

[0049] like Fig. 9As shown, it is a radiation characteristic curve diagram of different bending conditions of this embodiment in the 3.5-GHz WiMAX frequency band. It can be seen from the figure that the radiation characteristics of the antenna change slightly under structural deformation, but in all cases a good directional radiation pattern is achieved, which can be well applied to in vitro communication.

[0050] Example 2

[0051] A wearable terminal device includes the wearable dual-frequency dual-polarization antenna in Example 1, wherein the antenna includes a radiation patch 1, a flexible dielectric substrate 2, a ground plate 3, two pairs of short-circuit probes 4 and a microstrip feed line 7.

[0052] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A wearable dual-frequency dual-polarization antenna, characterized in that: It comprises a radiation patch, a flexible dielectric substrate, a grounding plate and a short-circuit probe, wherein the radiation patch is arranged on the upper surface of the flexible dielectric substrate, the grounding plate is arranged on the lower surface of the flexible dielectric substrate, and two ends of the short-circuit probe are respectively connected to the grounding plate and the radiation patch; The radiation patch includes two cut corners and a rectangular gap, the two cut corners are respectively located at two opposite corners of the radiation patch, and the rectangular gap is symmetrical about the vertical center axis of the radiation patch; The cut angle is an isosceles triangle or a rectangle; It also includes a microstrip feed line, one end of which is electrically connected to the radiation patch, and the other end of which is connected to an external feed source; There are two pairs of short-circuit probes, and the connection points of the two pairs of short-circuit probes and the radiation patch are respectively located on two diagonal lines of the radiation patch; The connection points of the two pairs of short-circuit probes and the radiation patch are located on two diagonals respectively, and the dual-frequency dual-radiation mode operation is realized through the technology of reactance loading, specifically: Two pairs of short-circuit probes are used as reactance loading. The loading of the short-circuit probes will first shift the fundamental mode of the microstrip antenna to the high frequency, thereby generating a dipole-like radiation mode in the low frequency band. The required two modes can be obtained by adjusting the spacing and radius of the short-circuit probes. A pair of mutually orthogonal degenerate modes are obtained by loading the rectangular slot, achieving circular polarization performance.

2. The wearable dual-frequency dual-polarization antenna according to claim 1, characterized in that: The length of the right-angled side of the isosceles triangle cut corners is 7 mm to 8 mm.

3. The wearable dual-frequency dual-polarization antenna according to claim 1, characterized in that: The length of the rectangular gap is 23 mm to 25 mm, the width is 0.4 mm to 0.7 mm, and the distance between the center of the rectangular gap and the upper edge of the radiation patch is 5 mm to 6 mm.

4. The wearable dual-frequency dual-polarization antenna according to claim 1, characterized in that: The radiation patch, microstrip feed line and ground plane are all made of conductive nylon fabric. The thickness of the conductive nylon fabric is 0.13 mm, and the surface resistivity is less than 0.009 ohm per square meter.

5. The wearable dual-frequency dual-polarization antenna according to claim 1, characterized in that: The flexible dielectric substrate is made of wool felt material, the wool felt material has a thickness of 2 mm, a dielectric constant of 1.2, and a loss tangent of 0.

02.

6. A wearable terminal device, characterized in that: It comprises a wearable dual-frequency dual-polarization antenna as described in any one of claims 1 to 5.

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