Patent Application
20240021975
The present invention relates to a flexible wearable antenna intended for wireless communications applicable to medical telemetry.
It is known and made available to the public domain from patent application AU 2021 100 926 A4, published on 29 Apr. 2021, a coplanar waveguide antenna implanted in the human body intended for medical diagnosis of illnesses at an early stage. The antenna has a modified hexagonal structure with a ring placed in the center and radiating edges. The modified hexagonal shaped structure is made of metal raw material and is mounted on a substrate containing epoxy resin.
Patent application U.S. Pat. No. 2,015,048 981 A1, published on 19 Feb. 2015, discloses a wearable dual-band antenna implanted in the human body which consists of: a zeroth-order resonant antenna formed at the bottom of a substrate to receive a signal from a wireless device that is implanted in the human body and a coplanar waveguide antenna formed at the top of the substrate to transmit the signal to a wireless device that is external with respect to the human body.
It is known and made available to the public domain from patent application CN 109 904 602 A, published on 18 Jun. 2019 a flat coplanar waveguide antenna intended for wireless communication with respect to the human body, which is inclusive of two dielectric plates made of epoxy resin.
Patent application JP 2009 106 307 A, published on 21 May 2009, discloses an antenna embedded in the human body, which transmits and receives electromagnetic waves toward and from it, respectively. The antenna is of dielectric type and is made of two copper conductors and dielectric substrates, and the signal transmitted to or received from an external communication device is within the band range from 402 through 405 MHz.
From utility model CN 212 908 060 U, published on 6 Apr. 2021, a wearable antenna based on organic polymeric materials is disclosed and made available to the public domain, which is used for wireless communication with respect to the human body. The antenna mechanism is made of layers of fabric of conductive organic polymers, which replace the metal conductive materials, which makes the antenna lightweight, comfortable, and unnoticeable part of the clothing.
Patent application CN 104 269 615 A, published on 7 Jan. 2015, describes a dual band monopole antenna with the possibility of mounting on the human body, which includes an antenna radiating device, a coplanar waveguide feeding structure and a flexible dielectric substrate. The waveguide feeding structure is equipped with a 50Ω coplanar waveguide center line, and the dielectric substrate constitutes a flexible vinyl polymer. When the antenna is placed on the human body, The structure of the antenna of patent CN 104 269 615 A contains three radiating elements. The antenna substrate of patent CN 104 269 615 A has dimensions of 47.5 mm×28.5 mm and has a frequency band range from 2.40 GHz to 2.51 GHz, the bandwidth is 110 MHz. When placed on a human body model, the efficiency of the antenna is not specified.
The purpose of the invention is to create a flexible antenna that is small in terms of a size, that consists of only one radiating element, which is placed (attached) on the skin surface of a person or animal without causing allergic reactions and without changing the parameters of the antenna, which has a non-directional pattern of directional action that allows communication with respect to one or more communication devices placed on the human body, as well as with a medical device implanted in the human body and/or a remote external communication device.
The object is fulfilled by means of a flexible wearable antenna 1 intended for wireless communications attached to the human body, which consists of a radiating element which constitutes fractal-based monopole 2, composed of electrically mechanically connected fractal-based monopole 2a and 2b, which is connected to a modified coplanar waveguide (CPW) transmission line 3 with a conductor element 3a connecting the coplanar waveguide ground planes 3b and 3c of a coplanar waveguide (CPW) transmission line 3. The coplanar waveguide center line 3d is connected to the radiating element fractal-based monopole antenna 2 and is located between the two coplanar waveguide ground planes 3b and 3c, and the small gaps 3e are located between 3d, 3a 3c. The feed point 4 is located between the coplanar waveguide center line 3d and the conductor element 3a. The fractal-based monopole 2, the coplanar waveguide (CPW) transmission line 3 and the feed point 4 are mounted on the flexible substrate 5. The antenna 1 attached to the human body 6 is connected on both points by means of wireless connection to an implanted medical device 7 and/or is connected to a wearable communication device 9 and/or is connected to an external communication device 8.
The antenna 1 is connected on both points to the implanted medical device 7 by means of a wireless connection 10, is connected on both points to a wearable communication device 9 by means of a wireless communication 11 and is connected on both points to an external communication device 8 by means of a wireless connection 12.
According to an embodiment of the invention, the antenna 1 is connected on both points by means of a wireless connection 10 to the implanted medical device 7.
According to another embodiment of the invention, the antenna 1 is connected on both points by means of wireless connection 12 to the external communication device 8.
The fractal-based monopol 2 has dimensions of 16.5 mm×10.0 mm.
Flexible substrate 5 has the following qualitative and quantitative composition Natural rubber STR 10—100; Zinc oxide—3.0; Stearic acid—2.0; Titanium dioxide—70.0; N-Isopropyl-N′-phenyl-1,4-phenylenediamine—1.0; N-tert-butyl-benzothiasole-sulphenamide—1.5 and Sulfur—2.0.
The conductor radiating element 2 consists of a modified rectangular monopole having a fractal geometric shape formed by means of a Minkowski curve 2a, which is connected to an inverted Minkowski curve 2b, whereby a modified Minkowski curve is created tuned to broadcast in a wide frequency band and covering at least four frequency bands connected to a modified coplanar waveguide (CPW) transmission line 3, intended to match the impedance of the conductor radiating element 2 with the impedance of the coaxial cable. By adjusting the geometric dimensions by changing the length and width of the fractal-based monopole, the length and width of each of the elements of the coplanar line and the small gaps of the coplanar line of the fractal-based monopole 2 and the modified coplanar waveguide transmission line 3, the input impedance of the antenna is matched to the source at the maximum radiation efficiency of the antenna within the desired frequency ranges. The optimal dimensions are selected based on the following criteria, minimum antenna size, maximum transmission efficiency, minimum SAR, maximum bandwidth at the specified input impedance.
Advantages of the antenna according to the invention are:
Radiation efficiency from 4.60% to 4.83% in the frequency range from 2.36 GHz to 2.50 GHz.
The fractal-based monopole 2 has dimensions of 16.5 mm×10.0 mm. The antenna represents only one radiating element; it can be placed (attached) on the skin surface of a person or animal without causing allergic reactions and without changing the parameters of the antenna.
There is a non-directional pattern of directed action, which allows communication with an implanted medical device, inside the human body being suitable for the purposes of a medical telemetry.
Flexible wearable antenna for wireless communications, capable to broadcast in the following frequency bands, namely MBAN (2.36 GHz-2.40 GHz), ISM (2.40 GHz-2.50 GHz), and LTE band 7 (2.50 GHz-2.69 GHz), as well as WLAN frequency band appropriate for indoor use and installations (5.15 GHz-5.35 GHz) Another advantage is that the antenna subject to patent claim has a substrate made of raw materials derived from renewable sources and is environmentally friendly.
The attached examples illustrate preferred embodiments on an illustrative basis with respect to the invention but do not limit to the embodiments described herein.
As a result, small dimensions of the radiating element 16.5 mm×10.0 mm were achieved.
The radiating element 2 is fed by means of a modified coplanar waveguide (CPW) transmission line 3 in order for the conductor elements of the antenna structure to be implemented only on one side of the supporting structure. The modified coplanar waveguide (CPW) transmission line 3 contains a conductor element 3a connecting the coplanar waveguide ground planes 3b and 3c of a coplanar line, and the coplanar waveguide center line 3d connected to a fractal-based monopole 2, which is located between 3b and 3c. The small gaps 3e are located between 3d, 3a 3c. Feed point 4 is located between the coplanar waveguide center line 3d and 3a. Elements 2,3,4 are mounted on a flexible substrate 5 by means of gluing.
According to the invention, a sufficient in terms of extent wideband bandwidth has been achieved to cover three frequency ranges, namely MBAN (2.36 GHz-2.40 GHz), ISM (2.40 GHz-2.50 GHz), and LTE band 7 (2.50 GHz-2.69 GHz), as well as to cover the WLAN frequency band intended for indoor use and installations (5.15 GHz-5.35 GHz) by means of numerical simulations with the finite-difference time-domain method. As a result of the dimensions of the coplanar waveguide, the geometric dimensions of the coplanar waveguide center line 3d and the width of the small gaps 3e, the best combination of small dimensions of the coplanar waveguide 7.5 mm×9 mm is achieved with a characteristic impedance approaching 50Ω (±10%) in respect of the four frequency bands. By means of the feed point 4, an external transmission line connection is provided to the modified coplanar waveguide (CPW) transmission line 3 and the radiating element 2 to transmit a signal from or to the transceiver module of the communication device. The conductor elements of the antenna are mounted on the upper part of a flexible polymer substrate 5 with dimensions of 26 mm×12 mm and thickness of 2 mm. The substrate is specially developed from a mixture of natural rubber with TiO2 filler with electromagnetic parameters, ε′r=3.16, tan δ=0.0018, σ=0.0008, at 2.565 GHz. By means of the involvement of natural rubber, an easy-to-fabricate flexible wearable antenna with high elasticity and low cost is achieved. The substrate developed does not cause allergic reactions and can be placed on the surface of the skin of a person, and also is composed of products derived from renewable sources and is environmentally friendly. The main function of the antenna substrate relates to its use in terms of a supporting structure, but also its electromagnetic parameters contribute to reducing the size of the antenna. The radiating element and the coplanar waveguide (CPW) can be made of conductive material with a small thickness amounting to of tens or hundreds of microns, such as copper, brass, conductive fabric, conductive ink.
According to the invention, the antenna 1 can transmit and receive information from the implanted medical device 7 by means of a two-way wireless connection 10. The disclosed embodiment can be used for real-time monitoring and tracking of vital physiological status signs with respect to a person.
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The diagrams represented under
In the diagram represented under
The flexible substrate according to the invention has the following qualitative and quantitative composition Natural rubber STR 10—100; Zinc oxide—3.0; Stearic acid—2.0; Titanium dioxide—70.0; IPPD—N-Isopropyl-N′-phenyl-1,4-phenylenediamine—1.0 and is an anti-aging agent; TBBS—N-tert-butyl-benzothiazole-sulphenamide—1.5 and is a Vulcanization accelerator and Sulfur which constitutes a vulcanizing agent)—2.0.
Flexible substrate 5 has the following electromagnetic parameters ε′r=3.16, tan δ=0.0018, σ=0,0008 at 2.565 GHz. And is characterized with following dimensions 26 mm×12 mm and thickness amounting to 2 mm.
