Industrial , Scientific And Medical Research Articles

Analysis of muscle implanted antenna performance with the variation of implantation depth

Abstract Implantation depth of Implantable Medical Devices (IMDs) is an important factor of communication quality between implantable antennas in IMDs and external devices. Therefore, it is required to study the effect of implantation depth on implantable antenna performance. In this article, dependence of resonant frequency and scattering parameters of a two-antenna system where one miniaturized meander-line antenna is placed within human muscle tissue layer operating at 2.45 GHz ISM (industrial, scientific and medical) band and a rectangular patch antenna placed outside human body, are tested. Here 15 values of implantation depth ranging over 5–35 mm inside muscle layer are taken and for each case resonant frequency and scattering parameters (S 11 and S 21) of the system are recorded. Statistical analysis has been performed to observe how these performance parameters are dependent on depth of implantation which may be varied at the time of surgery.

Genetic Algorithm for Mode Selection in Device-to-Device (D2D) Communication for 5G Cellular Networks

The widespread use of smart devices and mobile applications is leading to a massive growth of wireless data traffic. With the rapidly growing of the customers’ data traffic demand, improving the system capacity and increasing the user throughput have become essential concerns for the future fifth-generation (5G) wireless communication network. In a conventional cellular system, devices are not allowed to directly communicate with each other in the licensed cellular spectrum and all communications take place through the base stations (BS) and core network. Device-to-Device (D2D) communication refers to a technology that enables devices to communicate directly with each other, without sending data to the base station and the core network. This technology has the potential to improve system performance, enhance the user experience, increase spectral efficiency, reduce the terminal transmitting power, reduce the burden of the cellular network, and reduce end to end latency. In D2D communication user equipment’s (UEs) are enabled to select among different modes of communication which are defined based on the frequency resource sharing. Dedicated mode where D2D devices directly transmit by using dedicated resources. Reuse mode where D2D devices reuse some resources of the cellular network. Outband mode where D2D communication uses unlicensed spectrum (e.g. the free 2.4 GHz Industrial Scientific and Medical (ISM) band or the 38 GHz millimetre wave band) where cellular communication does not take place. Cellular mode where the D2D communication is relayed via gNode B (gNB) and it is treated as cellular users. In this work, the target was to reach the optimal mode selection policy and genetic algorithm method was used with the objective of maximizing the total fitness function. Optimal mode selection policy was presented and analysed amongst cellular, dedicated, reused and outband mode. In the present study of mode selection issues in D2D enabled networks, genetic algorithm was proposed for the case when the cellular user equipment (UE) moves in the network. Quality of service (QoS) parameters, mobility parameters and Analytic Hierarchy Process (AHP) method were used to define the mode selection algorithm. To evaluate the performance of the proposed genetic algorithm, a study of the convergence of the algorithm and the signal-to-interference plus noise ratio (SINR) was done.

Design and performance analysis of an L-shaped radiator and defected ground antenna for enhancing wireless connectivity in brain implants

Brain implantable wireless microsystems has potential to treat neurological diseases and maintain the quality of life. Highly efficient miniaturized antenna is the fundamental part of BID (brain implantable device) for reliable signaling of data through dissipative intracranial material. In this paper, a patch antenna with L-shaped defected ground is demonstrated. L-shaped radiator contributed to achieve the resonance at 2.45 GHz industrial scientific and medical (ISM) band. Antenna size is reduced to 10 × 10 × 0.25 mm3. The proposed L-shaped ground plane geometry is contributing in improving the radiation performance. |S11| value shifts from 15 dB to 30 dB after modifying the ground plane. Proposed structure attained the gain of −14 dBi when located between the Dura and CSF layers at the depth of 12 mm in human brain model. Full wave simulated antenna prototype is fabricated and measured for performance verification. Impedance bandwidth of 270 MHz and broadside radiation pattern (for transferring maximum electromagnetic energy away from tissue) are maintained by the proposed antenna. Brain tissue safety is ensured by specific absorption rate which is 0.709 W/kg and in compliance with the safety limits of 1.6 W/kg for 1-g averaged tissue. Proposed antenna structure is the promising candidate for medical implant technology.

A Contact-Less Electrically Small Antenna Sensor for Retinal Cancer Cell Detection

A new noninvasive and portable diagnostic system for detecting ocular tumors has been proposed. The system uses a contact-less electrically small antenna sensor to detect retinal cancer cells. The antenna sensor is operated in the ISM (Industrial, Scientific, and Medical) 2.413 GHz band and has electrical dimensions of 8 × 16.2 × 0.35 mm3. The antenna sensor is fabricated on a biodegradable Teslin substrate and tested in an eye-mimicking phantom to compare numerical computations with measurements. The specific absorption rate (SAR) obtained at near and far-field distances under 1 g of tissue is 1.18 W/kg and 0.353 W/kg, and that under 10 g of tissue is 0.112 W/kg and 0.313 W/kg, respectively. Furthermore, to detect the ocular tumor using the proposed antenna sensor, the resonance frequency shift, and the unsupervised machine learning technique, principle component analysis (PCA) is employed on simulated and measured results. The resonance frequency shift for a 3.5 mm radius tumor is 70 MHz for a single tumor and 120 MHz for double tumors. The PCA generates clusters with and without tumors on the positive and negative sides of the two-dimensional plot. The proposed techniques are more impactful in distinguishing between healthy and malignant tissues. The proposed systematic approach could be a portable platform for early detection of cancerous cells inside the eye.

LoRa Communication Using TVWS Frequencies: Range and Data Rate

Low power wide area network (LPWAN) is a wireless communication technology that offers large coverage, low data rates, and low power consumption, making it a suitable choice for the growing Internet of Things and machine-to-machine communication applications. Long range (LoRa), an LPWAN technology, has recently been used in the industrial, scientific and medical (ISM) band for various low-power wireless applications. The coverage and data rate supported by these devices in the ISM band is well-studied in the literature. In this paper, we study the usage of TV white spaces (TVWS) for LoRa transmissions to address the growing spectrum demand. Additionally, the range and data rate of TVWS-based LoRa, for different transmission parameter values using different path-loss models and for various scenarios such as free space, outdoor and indoor are investigated. A path-loss model for TVWS-based LoRa is also proposed and explored, and the evaluations show that TVWS offers a longer range. This range and data rate study would be useful for efficient network planning and system design for TVWS-based LoRa LPWANs.

Pattern-Reconfigurable Flexible Textile Antenna Using RF-Switch Integrated Circuits

A pattern-reconfigurable flexible textile antenna covering the 2.45 GHz Industrial, Scientific and Medical (ISM) band is presented. The design utilizes RF-switch Integrated Circuits (ICs) packaged into reconfiguration modules as switchable vias to change between the omnidirectional and broadside radiation modes of a center-shorted patch. Analytical models to calculate the resonance frequency of each mode are developed to give more physical insights into the mode resonance and assist the design optimization. An antenna prototype is experimentally characterized to further validate the concept and analysis of the proposed antenna structure. The stable performance under on-body environment and various bending test conditions demonstrates the antenna operation in wearable scenarios.

A Simple Technique for Liquid–Liquid Percentage Determination Using Single-Frequency Amplitude Measurements

This letter presents a novel technique for the liquid–liquid percentage reading based on the measurement of the transmission amplitude at a single frequency in a cavity resonator with a small pipe where the liquids flow. The proposed approach represents an alternative to the conventional technique based on the determination of the resonance frequency shift and presents a number of advantages. First of all, the proposed technique requires just an oscillator and a power meter at a fixed frequency, instead of the complex equipment needed for the broadband measurement of the scattering parameters of the circuit, as in the conventional technique. Consequently, the proposed method is well-suited for the implementation of low-cost embedded sensors. Moreover, by avoiding the frequency sweep, the reading is instantaneous and therefore the real-time determination of the characteristics of flowing liquids is possible. Experimental results have been performed with a substrate-integrated waveguide (SIW) cavity operating around the frequency of 2.48 GHz industrial scientific and medical (ISM) band, by comparing the performance of the proposed approach and the conventional one in the determination of the liquid–liquid percentage of mixtures of acetone and isopropanol.

A High Performance All-Textile Wearable Antenna for Wristband Application.

A compact, conformal, all-textile wearable antenna is proposed in this paper for the 2.45 GHz ISM (Industrial, Scientific and Medical) band. The integrated design consists of a monopole radiator backed by a 2 × 1 Electromagnetic Band Gap (EBG) array, resulting in a small form factor suitable for wristband applications. An EBG unit cell is optimized to work in the desired operating band, the results of which are further explored to achieve bandwidth maximization via floating EBG ground. A monopole radiator is made to work in association with the EBG layer to produce the resonance in the ISM band with plausible radiation characteristics. The fabricated design is tested for free space performance analysis and subjected to human body loading. The proposed antenna design achieves bandwidth of 2.39 GHz to 2.54 GHz with a compact footprint of 35.4 × 82.4 mm2. The experimental investigations reveal that the reported design adequately retains its performance while operating in close proximity to human beings. The presented Specific Absorption Rate (SAR) analysis reveals 0.297 W/kg calculated at 0.5 W input power, which certifies that the proposed antenna is safe for use in wearable devices.

Dual-Band Antenna on 3D-Printed Substrate for 2.4/5.8 GHz ISM-Band Applications

In this paper, we present a dual-band antenna working at 2.45 GHz and 5.8 GHz. The design is based on two radiating rectangular slots with one upper Split Ring Resonator (SRR) to enhance the radiation pattern at 5.8 GHz, one Complementary Split Ring Resonator (CSRR), and three Split Rings (SR) to improve the input reflection coefficient. The dual-band antenna covers the 2.45 GHz and 5.8 GHz Industrial, Scientific and Medical (ISM) bands. The total size of the proposed antenna is 31 × 70 × 70 mm3. The proposed antenna was manufactured and tested. The attained gain is better than 7.5 dBi, and 6.5 dBi at 2.4 GHz and 5.8 GHz, respectively. The measured gain and input reflection coefficient have good correlation with the simulated results, covering the ISM bands around 2.45 GHz and 5.8 GHz. The performance of the proposed antenna is remarkable and suitable for applications where the size is not a severe limitation, such as sensors, LPWAN/WLAN modules, health care devices, base stations, IoT, and control applications.

A planar microwave sensor for noninvasive detection of glucose concentration using regression analysis

AbstractThis paper presents a planar microwave sensor for the noninvasive detection of glucose concentration in diabetic patients. The designed sensor operates from the 3.8 to 6.2 GHz frequency band, which covers the 5.8 GHz Industrial Scientific and Medical (ISM) band. The designed sensor shows a percentage bandwidth of 23.8% with a reflection coefficient (S11) of −50 dB at the resonance frequency of 5.7 GHz. The detection was carried out by varying the relative permittivity of the blood in accordance with the glucose concentration based on the Cole–Cole model. The measured result is calculated in terms of varying resonance frequency with variation in the reflection coefficient |S11| of the designed sensor. The observed frequency shift and corresponding sensitivity of the sensor are found at 1.7 GHz and 0.089 MHz/mg dL−1, respectively. An experimental validation has also been performed, and the frequency shift is analyzed by interacting the human thumb with the sensor. The simulated and experimental results of the designed sensor suggest that it can be useful for detecting glucose concentration noninvasively for diabetic patients.

Snipped Triple Band Microstrip Antenna for ISM Band and Wi-MAX Applications

The work suggests a snipped shaped patch antenna design and its analysis which will work in the microwave frequency in the low spectrum. Here the patch is introduced which is made up of denim cotton material. This type of antenna is relatively new device used for medical applications. This antenna is light in weight, compact in size, and inexpensive. This antenna resonates at 1.18 GHz, 2.45 GHz, 3.1 GHz, and 7.9 GHz to 10.6 GHz. As a result, it is used in Industrial Scientific and Medical (ISM) band and Wi-MAX applications. There are different types of patch antenna here a microstrip is used as wearable antenna. As a result, the patient’s condition can be diagnosed by using this antenna after studying the radiation pattern, return loss. Ansoft HFSS can be used to emulate them.

ISM Band 2.4 GHz Wearable Textile Antenna for Glucose Level Monitoring

Wearable technology has recently attracted much interest for various uses. An essential component of the wearable system is the wearable antenna. Textile and non-textile materials have both been used to create wearable antennas. Textile antennas are very useful and widely used nowadays, particularly in body-worn applications monitoring health parameters. Fabricated using microstrip technology, textile antennas have various benefits, including small size, lightweight, simple fabrication, and ease of wear. In this study, a microstrip antenna is created utilizing a substrate made of jeans. It works between 2.4 to 2.5 GHz in the ISM (industrial, scientific, and medical) band. High-frequency structure simulator (HFSS) software was used to simulate two antennas, one with an incomplete and the other with a complete ground plane. Wearable antennas can protect the body from the impacts of RF radiation by utilizing the entire ground plane principle. Results from a vector network analyzer were obtained for the fabricated antenna (VNA). This antenna's main function is to track blood glucose levels. Blood's dielectric characteristics change when blood sugar levels fluctuate, affecting the antenna’s output frequency. There are two ways to monitor glucose levels. One method requires placing a finger on an antenna patch, while the other involves fixing an antenna to a person's arm and detecting the output frequency fluctuation. The antenna's resonant frequency raises in reaction to increased blood glucose levels. Therefore, these textile antennas are a great choice for non-blood sample monitoring of blood glucose levels.

Wearable coupled-quarter-mode SIW antenna platform with hybrid kinetic and ambient-light energy harvesting

As key enablers for smart fabric interactive textile (SFIT) systems, textile antenna systems and platforms need to be energy-efficient, low-profile and should guarantee a stable wireless body-centric communication link. Using multiple energy harvesters on and in the antenna platform is highly recommended to enable autonomous SFIT systems. Different sensors could be added to the system for monitoring the environmental and/or biophysical parameters of rescue workers, military personnel, and other safety workers. Therefore, a wearable coupled-quarter-mode (coupled-QM) substrate-integrated waveguide (SIW) antenna with optimally, seamlessly integrated hybrid kinetic and ambient-light energy harvesters is proposed. Two QM cavities are coupled via a non-resonant slot to create a compact antenna covering the [2.4; 2.4835] GHz Industrial, Scientific and Medical (ISM) band. The antenna platform fully consists of textile materials, being protective rubber foam and copper taffeta, enabling its unobtrusive integration into protective clothing. A novel, compact way of deploying a kinetic energy harvester inside the substrate, combined with flexible power management electronics on the antenna feed plane and a flexible ambient-light photovoltaic cell on the antenna plane, is proposed. The integrated antenna platform exhibits a measured impedance bandwidth of 307 MHz, a radiation efficiency of 88.57% and maximum gain of 3.74 dBi at 2.45 GHz. Wearing the antenna platform around a person’s wrist resulted in an average harvested power of 229.8 µW when walking in an illuminated room.

Design of wearable antenna for ISM band application

A crescent-shaped wearable antenna is designed at 5.4 GHz for ISM (Industrial, Scientific, and Medical) band application and it is presented in this paper. The crescent shape is a combination of two circles and then the inner circle is removed from the outer circle for achieving a crescent shape. The crescent-shaped wearable antenna used jeans fabric as a substrate and it provides comfort and greater flexibility to wear on the human body. The proposed wearable antenna has a small thickness. The measured radiation parameters of wearable antenna-like return loss and VSWR are agreed well with performance evaluation simulations. It is simulated using HFSS software.

Impedance Matching at Skin–Air Interface for Transmission-Range Improvement of Implantable Antennas

This article presents a novel impedance matching layer (IML) placed on skin tissue to enhance the transmission ability for implantable antenna. The IML is designed with a particular dielectric constant to mitigate the reflection occurred at skin–air interface at 2.45 GHz Industrial Scientific and Medical (ISM) band. To obtain this targeted effective dielectric constant, periodic posts are inserted into a 3-D printed substrate to increase its shunt capacitance, forming an IML with a height of 17 mm for enhancement of transmission ability. Furthermore, a slow wave structure is adopted to lower the profile of IML further to 7 mm, making it more comfortable for routine wearing. To testify the property of the proposed IML, a slot implantable antenna is designed, and its gains with and without IML are comparatively studied. The simulated results exhibit a gain enhancement of over 5 dB with IML loaded, providing a promising solution for a typical communication link for implantable application.

A Dual-Band Differential Intraoral Antenna and System for Wireless Data and Radiative Near-Field Power Transfer

Intraoral tongue drive system (iTDS) is a promising assistive technology for rehabilitating disabled persons. This article proposes a radiative near field power transfer (RNF-PT) system comprising an intraoral differential rectenna (rectifying antenna) and external power transmitter (RNF-Tx). A dual-band compact differential intraoral antenna operating in the Industrial, Scientific and Medical (ISM) band (2.45 GHz) and midfield band (1.9 GHz) is proposed for the data and power transmission modes, respectively. The proposed differential antenna and rectifier were designed and fabricated individually using a Rogers RT/duroid 6010 substrate. The differential rectifier shows a simulated conversion efficiency of 89.3% for a radio frequency (RF) input power of 14.78 dBm at 1.9 GHz with a 2 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{k}\Omega $ </tex-math></inline-formula> load. The maximum transmission coefficient of −25.95 and −24.93 dB was achieved at a separation of 22 mm for the closed and opened mouth conditions, respectively. The measured impedance bandwidths of the proposed antenna in both the closed and open mouth of the test subject are around 10% in the midfield band and around 9.5% in the ISM band, respectively. The measured peak gain in the minced pork and saline solution was −20.48 dBic, −18.25 dBic at the frequency of 1.9 GHz and −18.54 dBi, and −16.88 dBi at the frequency of 2.45 GHz, respectively. The specific absorption rate (SAR) values have also been analyzed through simulations for both data and power transmission modes and are found acceptable in the closed and open mouth placements. Based on these acceptable SAR values, the link margin was theoretically calculated where it could communicate over a reasonable distance. Thus, the proposed intraoral differential antenna with a rectifier is ideal for data and PT support in iTDS-based applications.

A Review of Miniaturized Advanced IC Rectenna for Energy Harvesting Applications

This article presents a review of different types of miniaturized rectenna integrated circuits IC used for energy harvesting applications such as medical applications. The rectenna design consists of two basic components: an embedded antenna that collects radio-frequency RF energy from the surrounding environment, and the rectifier circuit that converts AC-RF energy values into DC voltage for usage in low-power electronics devices such as implantable medical devices (IMDs). Microwave Schottky diodes HSMS-285x and SMS-763x series are used as a voltage doubler rectifier with an implanted antenna to improve conversion efficiency and the output voltage at a given input power and appropriate load. There are many challenges in the implantable rectenna IC design such as biocompatibility, miniaturization, patient safety, compact size, resonant frequency, bandwidth, radiation efficiency, and insensitivity to detuning. This review article summarizes the overall rectenna research carried out for new different design strategies in implant medical applications that operated at industrial scientific, and medical (ISM) bands such as 2.45GHz and 5.8GHz.

Design and Analysis of Smart Antenna for Mobile Application

There is a growing desire for digitalization in today's world. Digitization aims to improve people's lives by creating smart homes and businesses. The primary goal of this research is to increase the communication efficiency of these modules by redesigning or replacing existing antennas with others of a different kind. A communication module antenna is presented in this paper. With four distinct PCB antenna designs, we were able to get more accurate simulations of gain, reflection coefficient, VSWR, and bandwidth. Design of antennas for GPS L1, ISM (Industrial, Scientific, and Medical) 2.45 and 5.8 GHz bands is a constant in antenna development for mobile devices.

Energy Harvesting Rectenna Using High-Gain Triple-Band Antenna for Powering Internet-of-Things (IoT) Devices in a Smart Office

A new rectenna that can be utilized for sending/receiving data and scavenging radio frequency (RF) waves for linking and powering the Internet-of-Things (IoT) devices is proposed. The rectenna has three operating frequency bands; the lower frequency band is used for energy harvesting, and the other two frequency bands are assigned for data communication. It comprises a stacked four-layer antenna integrated with a voltage doubler rectifier. The antenna consists of a driven element, a planar reflector, and a planar director composed of a periodic structure of a square patch with a hexagonal slot in its center. The measurement results show that the proposed antenna covers 1.86–2.65, 2.84–3.64, and 5.34–6 GHz with an impedance bandwidth of 35%, 24.7%, and 11.64%, respectively. The antenna exhibits a high measured gain of 8.1, 8.9, and 9 dBi at 2.3, 3.5, and 5.7 GHz, respectively. The Industrial, Scientific and Medical (ISM) 2.45-GHz frequency band is selected for energy harvesting. Moreover, specific absorption rate (SAR) calculations are done for the antenna using the Hugo model to ensure lower absorption operation. The proposed antenna provides acceptable values of SAR; the values are under the safety standard limits for RF exposure. Then, a rectifier circuit is designed, fabricated, and tested separately. Finally, the rectifier is integrated with the proposed enhanced-gain antenna to produce a rectenna system. The rectenna presents a power conversion efficiency (PCE) of 69.7% and a dc output voltage of 1.9 V at an input power of 2 dBm. The PCE of the proposed rectenna is over 50% at a range of input power from −6.5 to 4.7 dBm.

A Compact Penta-Band Low-SAR Antenna Loaded with Split-Ring Resonator for Mobile Applications

A compact rectangular patch with dual-ring SRR (split-ring resonator) is presented in this article. An antenna is designed on FR4 substrate with an overall footprint size of 26 mm × 30 mm × 1.6 mm. The antenna presented operates in five bands from 2.95 to 3.06 GHz, 3.79 to 3.87 GHz, 4.11 to 4.19 GHz, 5.39 to 5.51 GHz, and 5.97 to 6.11 GHz. Mobile and fixed voice communication, WiMAX (Worldwide Interoperability for Microwave Access), 5G (5th generation), WLAN (Wireless Local Area Network), and ISM (Industrial Scientific and Medical) are some applications that utilized the above resonating bands. The penta-band operation is due to the inclusion of dual-ring SRR. The optimum values of the critical parameter of the SRR are identified using parametric analysis, and the results are presented. The antenna is also analyzed for the SAR (specific absorption rate) values, and it was found to be less than 2 W/kg for 10 g volume of tissue. The designed antenna is fabricated and tested, and the presented results show that there is good agreement between the simulated and measured results. Penta-band operation with simple structure, stable radiation pattern, and low SAR makes this antenna more intelligent and suitable for the mobile application.