Wearable Antenna Research Articles

Miniaturized circularly polarized wearable array antenna for medical device applications

Antenna miniaturization is essential for healthcare applications, and numerous studies have tackled the challenge of presenting miniaturized, reliable designs while maintaining performance. This paper presents a small circularly polarized (CP) sequential wearable array antenna with overall dimensions of only 110 mm × 95 mm × 1.8 mm. It comprises four novel designs of circular-shaped elements arranged sequentially in an array configuration measured only 24 mm×24 mm×1 mm. It is fed by a separate cascade feeding network incorporating a single rat-race and two branch-line couplers. The antenna is designed for medical device applications within the 2.4 GHz Industrial Scientific Medical (ISM) frequency band. The proposed design is fabricated and experimentally tested, demonstrating wide impedance bandwidths of 21.24% (2.2–2.72 GHz) and an Axial Ratio (AR) bandwidth (AR < 3 dB) covering the entire 2.4 GHz ISM frequency band. At 2.43 GHz, the antenna achieves a gain of -14.9 dBi. Both simulation and experimental results confirm excellent performance in impedance matching, gain pattern, and circular polarization, making it promising for wearable wireless communication in medical applications. The link margin was calculated, and the specific absorption rate of the antenna was analyzed, the result revealing that it aligns with the safety limits of IEEE C95.1-1999 standards.

Copper Paste Printed Paper‐Based Dual‐Band Antenna for Wearable Wireless Electronics

AbstractWearable wireless electronics is becoming a significant research area because of the unique features of this technology. Within this field printed antennas are the key electrical component accomplishing the signal transmission and energy harvesting tasks and at the same these antennas need to be lightweight, environmentally friendly, safe to wear, and easy to conform. Currently, the majority of available paper‐based antennas are designed for RFID, sensing, UWB, WLAN, and medical applications, with just a few being utilized in wearable applications, particularly for wireless body area network (WBAN). Furthermore, few studies have been conducted on the usage of printable copper conductive materials and low‐temperature plasma technique for the fabrication of such antennas. This study demonstrates the realization of a dual‐band paper‐based wearable antenna by screen‐printing of a plasma‐sintered conductive copper paste. The copper paste, composed of 51 wt% solid particles, can easily produce desired conductive patterns on photo paper after printing and a subsequent plasma sintering, with a good adhesion. The antenna designed on photopaper operates in the frequency bands of 1.73–2.55 GHz and 7.66–8.89 GHz. Free‐space simulation and measurement results reveal that the antenna exhibits stable radiation performance in the targeted WBAN (2.4–2.4835 GHz) and X uplink (7.9–8.4 GHz) frequency bands, together with low profile, excellent conformality and acceptable SAR values on the body and no electronic waste formed after disposal, making it a competitive candidate for usage in wearable wireless electronics.

Radiation analysis of optimized wearable antenna sensor at 2.4GHz on human body for Wireless Body Area Network Applications

Radiation analysis of optimized wearable antenna sensor at 2.4GHz on human body for Wireless Body Area Network Applications

Robust Convergence Technique Against Multilevel Random Effects in Stochastic Modeling of Wearable Antennas’ Far Field

Robust Convergence Technique Against Multilevel Random Effects in Stochastic Modeling of Wearable Antennas’ Far Field

Embroidered textile antenna with dual‐band capability for body‐centric communication systems

AbstractThe integration of health monitoring and wearable antenna technologies has enhanced patient assessment and the provision of healthcare. Traditional health monitoring methods have evoked a surge in interest toward embroidered antennas as a viable solution for constant physiological monitoring in a noninvasive way. This study examines the performance of an embroidered wearable textile (EWT) antenna intended for breathing rate applications. The antenna is seamlessly integrated into a commercially available T‐shirt, extending the confines of “smart” textiles. The compact (45 mm × 26 mm) EWT antenna operates in 2.4 and 5.8 GHz with gains of 2.07 and 5.85 dBi, respectively. Crumpling and stretching analysis have also been investigated to ensure antenna's mechanical stability and reliability. Subsequently a specific absorption rate analysis has also been performed to quantify the radiation within specified limits.

A compact low-profile substrate integrated waveguide wearable filtenna for 5G communication

We have proposed the design and synthesis of a compact, low-profile, flexible substrate integrated waveguide (SIW) wearable filtering antenna (filtenna) for 5 G communication, along with two parasitic resonator patches. We initially used a half-mode rectangular-shaped substrate-integrated (HMRSI) cavity as a resonating patch to minimize circuit size. The HMRSI cavity is located in close proximity to two parasitic truncated corner patches that serve as both the radiator and the final stage resonators, thereby optimizing filtering performance and expanding the operating bandwidth. The interaction of the parasitic patches with the HMRSI cavity produces one radiation null at the upper band-edges, while the corner truncation and notching on the parasitic patches with defected ground creates the other, enhancing the roll-off rate. Typical filter synthesis technology guides the design of the antenna. We have manufactured and measured an optimized prototype. The proposed flexible filtenna demonstrates excellent out-of-band selectivity, and its measurement aligns well with simulated ones, achieving an 8.2% fractional bandwidth (FBW), a maximum realized gain of 6.1 dBi, and a flat passband gain response. The proposed filtenna has also studied the human body and achieved a low specific absorption rate (SAR), which enables it to be an on-body wearable filtenna.

Flexible Wearable Tri-notched UWB Antenna Printed with Silver Conductive Materials.

The advancement of Internet of Things and associated technologies has led to the widespread usage of smart wearable devices, greatly boosting the demand for flexible antennas, which are critical electromagnetic components in such devices. Additive manufacturing technologies provide a feasible solution for the creation of wearable and flexible antennas. However, performance reliability under deformation and radiation safety near the human body are two issues that need to be solved for such antennas. Currently, there are few reports on compact, flexible ultrawideband (UWB) antennas with more notch numbers, reliable bendability, and radiation safety. In this paper, a UWB antenna with trinotched characteristics for wearable applications was proposed and developed using printable conductive silver materials consisting of silver microflakes or silver nanoparticles. The antenna has a compact size of 18 × 20 × 0.12 mm3 and adopts a gradient feeder and a radiation patch with three folding slots. It was fabricated on transparent and flexible poly(ethylene terephthalate) film substrates, using screen printing and inkjet printing. The measurement results demonstrated that the fabricated antennas could cover the UWB band (2.35-10.93 GHz) while efficiently filtering out interferences from the C-band downlink satellite system (3.43-4.21 GHz), wireless local area networks (4.66-5.29 GHz), and X-band uplink satellite system (6.73-8.02 GHz), which was consistent with the simulation results. The bendability and radiation safety of the antennas were evaluated, proving their feasibility for usage under bending conditions and near the human body. Additionally, it was found that the screen-printed antenna performed better after bending. The research is expected to provide guidance on designing flexible antennas that are both safe to wear and easily conformable.

Compact Ultra-Wide Band Two Element Vivaldi Non-uniform Slot MIMO Antenna for Body-Centric Applications

This work presents a novel compact two-port Vivaldi Non-uniform Slot MIMO Antenna (VNSMA) to overcome the challenges of traditional ultra-wideband (UWB) antennas, such as large size, limited bandwidth (BW), high mutual coupling, and suboptimal performance in wearable devices. Designed based on Vivaldi non-uniform slot profile antenna (VNSPA) theory, this antenna offers superior performance metrics and significantly advances wearable antenna technology. The novelty of this work is investigating different positions for the two compact UWB VNSA to get better performance with smaller sizes, wider impedance matching BW, and lower mutual coupling (MC) where side by side at an angle of 180ᵒ is determined to be the best configuration. Detailed parametric studies were performed on this configuration for better performance, where the MC was further reduced by etching the ground plane with a vertical slot between the two antennas and L slots around the Microstrip to Slot (M/S) transition, respectively. Furthermore, BW and gain enhancements were obtained by etching exponential tapered and triangular slots at its two edges. Using the Finite Integration Technique (FIT), Computer Simulation Technology (CST) software is used for the simulations in this work. The VNSMA is tested on a CST Gustav human phantom and gives excellent results with low specific absorption rate (SAR) values at several UWB frequencies. The proposed VNSMA provides good, measured outcomes of S11 < -11.08 dB with wide BW of 12.5 GHz (2.33–14.83 GHz) covering high isolation of -23 dB (for most of frequency band), moderate-high gain of 5.89 dBi, radiation efficiency of 66-90%, low Envelope Correlation Coefficient (ECC) of 0.002 and high diversity gain (DG) of 9.99 dBi, stable radiation patterns, and average group delay of 1.2 ns. This innovative design, which optimizes antenna positioning and incorporates ground plane modifications, achieves remarkable improvements in BW, which covers multiple bands, including WLAN (2.4–2.485 GHz), X-band (8-12 GHz), and part of Ku band (12-18 GHz). The findings demonstrate the antenna's potential for various high-resolution microwave imaging applications, particularly in medical diagnostics like breast and brain cancer detection, showcasing its impact in wearable technology and healthcare.

Textile omnidirectional antenna for wearable WiFi-7 applications using higher order modes

In WiFi 7 (IEEE 802.11be), Multiple Input Multiple Output (MIMO) technology plays a crucial role in enhancing throughput. This combination enables numerous applications for wearable WiFi devices. For instance, WiFi can be utilized for tracking and fall detection purposes. Additionally, wearable devices used in gaming, vital signal monitoring, and tracking can benefit from the implementation of wearable MIMO antennas. Despite the demand for wearable WiFi antennas, specifically in the new 6 GHz band, a significant gap exists in the investigation of antennas that are completely made of textile, are low profile, and provide vertical polarization and omnidirectional patterns. Addressing this gap, in this paper, a wearable planar antenna is introduced, which is specifically designed to offer an omnidirectional pattern and linear polarization. To ensure its practicality and ease of use, the antenna utilizes lightweight and wearable textile material. The design details and performance of the proposed antenna are presented. The antenna covers all three bands of WiFi, namely, 2.4 GHz, 5 GHz, and 6 GHz bands. The 10-dB return loss bandwidth is 2.4 GHz–2.5 GHz, and 4.6 GHz–7.2 GHz. The maximum Specific Absorption Rate (SAR) for an input power of 500 mW is calculated at 1.053 W/Kg for a 2 mm air gap between the antenna and tissue surface. The size of the antenna is given by a circular area of π × (50 mm)2, and a thickness of 6 mm.

A novel dual-band defected ground structure wearable microstrip patch antenna for breast tumor detection in biomedical applications

This paper presents a dual-band, low-profile wearable antenna for detecting breast tumors in biomedical applications. The antenna is designed on the FR4 substrate with an optimized dimension of 32 × 27.5 × 0.61 mm3. The compact rectangular patch is miniaturized by cutting the rectangular slots on the front side. The partial ground structure is used for moving the resonance frequency in the ISM band region and for giving the tripping result of the return loss. A breast phantom is created between the transmitter and receiver for detecting the tumor in the phantom model. The different sizes and positions of the tumor in the breast phantom provide different values of the return loss. The final optimized design of the antenna is operated at 2.43 GHz and 3.32 GHz with −35 and −24 return losses respectively. It has been observed from the simulated and measured results that the antenna has a negligible difference between the reflected coefficient, radiation pattern and gain. Afterward, the antenna is also checked for biocompatibility, which represents its good performance. The on-body analysis of the antenna represents a minor variation in the results. The Specific Absorption Ratio (SAR) value of the antenna is in the acceptable range as defined for the wearable device. It is a promising compact wearable antenna that can be used in biomedical applications.

A Miniaturized Wearable Annular Slot Antenna Based on Designer LSPs for Telemedicine Communication

A Miniaturized Wearable Annular Slot Antenna Based on Designer LSPs for Telemedicine Communication

Green Wearable Sensors and Antennas for Bio-Medicine, Green Internet of Things, Energy Harvesting, and Communication Systems.

This paper presents innovations in green electronic and computing technologies. The importance and the status of the main subjects in green electronic and computing technologies are presented in this paper. In the last semicentennial, the planet suffered from rapid changes in climate. The planet is suffering from increasingly wild storms, hurricanes, typhoons, hard droughts, increases in seawater height, floods, seawater acidification, decreases in groundwater reserves, and increases in global temperatures. These climate changes may be irreversible if companies, organizations, governments, and individuals do not act daily and rapidly to save the planet. Unfortunately, the continuous growth in the number of computing devices, cellular devices, smartphones, and other smart devices over the last fifty years has resulted in a rapid increase in climate change. It is severely crucial to design energy-efficient "green" technologies and devices. Toxic waste from computing and cellular devices is rapidly filling up landfills and increasing air and water pollution. This electronic waste contains hazardous and toxic materials that pollute the environment and affect our health. Green computing and electronic engineering are employed to address this climate disaster. The development of green materials, green energy, waste, and recycling are the major objectives in innovation and research in green computing and electronics technologies. Energy-harvesting technologies can be used to produce and store green energy. Wearable active sensors and metamaterial antennas with circular split ring resonators (CSSRs) containing energy-harvesting units are presented in this paper. The measured bandwidth of the matched sensor is around 65% for VSWR, which is better than 3:1. The sensor gain is 14.1 dB at 2.62 GHz. A wideband 0.4 GHz to 6.4 GHz slot antenna with an RF energy-harvesting unit is presented in this paper. The Skyworks Schottky diode, SMS-7630, was used as the rectifier diode in the harvesting unit. If we transmit 20 dBm of RF power from a transmitting antenna that is located 0.2 m from the harvesting slot antenna at 2.4 GHz, the output voltage at the output port of the harvesting unit will be around 1 V. The power conversion efficiency of the metamaterial antenna dipole with metallic strips is around 75%. Wearable sensors with energy-harvesting units provide efficient, low-cost healthcare services that contribute to a green environment and minimize energy consumption. The measurement process and setups of wearable sensors are presented in this paper.

A low‐profile, wideband, circularly polarized, slotted, U‐shaped textile antenna for W‐BAN applications

AbstractWe propose a compact, wideband, U‐shaped, circularly polarized textile antenna (UCPTA) resonating at 2.45 GHz for wireless body area network (W‐BAN) applications. The radiator of the antenna is printed on the top of the substrate (size of mm3; ) and has a full ground plane on the other side. The proposed antenna's substrate consists of a single layer of denim (), and conductive copper tape was used to fabricate the patch. The antenna has a low‐profile design that is suitable for wearable applications. A small slot was introduced at the center of the U‐shaped patch to enhance the 3 dB axial ratio bandwidth (ARBW) up to 55.17%. The proposed antenna radiates with a 10 dB return loss (RL), impedance bandwidth (IBW) of 64.40%, and a simulated gain of 5.1 dBi. The wearable textile antenna with broadside radiation response is appropriate for off‐body communications. The prototype of UCPTA is fabricated for experimental validation. The measured results for the fabricated antenna were in good agreement with the simulated results. Further, it has been demonstrated that the antenna's performance is stable during structural deformation and human body loading. This textile antenna covers an ARBW in the frequency band of 2.1 GHz–3.72 GHz and has a broad IBW (2 GHz–3.9 GHz) for LTE (2.17 GHz), MBAN (2.360 GHz–2.4 GHz), WPAN (2.395 GHz–2.4 GHz), and WLAN (2.4 GHz–2.482 GHz) applications.

Unveiling the Potential of Wearable Antennas and Microwave Technology in Kidney Cancer Detection

Unveiling the Potential of Wearable Antennas and Microwave Technology in Kidney Cancer Detection

MINIATURIZATION OF STACKED WEARABLE ANTENNA FOR 5G APPLICATIONS

Wearable antennas have significantly expanded the capabilities of electronic devices, as they can now be seamlessly integrated into clothing for user convenience. The advent of 5G has opened up possibilities for enhanced functionality, necessitating compact antennas with high gain for efficient data transmission. In this paper, a sub-6GHz 5G stacked wearable antenna is proposed. The choice of a rectangular patch structure was made for its simplicity and ease of fabrication. A comprehensive analysis of antenna design, progressing from a single layer to a multilayer configuration is explained. The antenna was designed using 1mm felt and Shieldit Super conductor, with a 50 Ω coaxial feed. The proposed stacked three-layer antenna, with substrate dimensions of 44 x 44 mm², achieves a gain of 2.7 dBi. Stacking the substrate and patch layer improves the antennas’ performance, especially the impedance bandwidth and gain. On top of that, the antenna dimensions were reduced to 57% while maintaining its performance. Bending tests conducted in both X- and Y-axes demonstrate that the antenna's performance remains within an acceptable range. Although the resonating frequency shifted to 3.4 GHz in 3 layers during bending in Y-axis, the gain was kept to 1.8dBi. Both measured and simulated results exhibit good consistency, with a slight shift observed in the case of the three-layer structure.

Bending Effects on Polyvinyl Alcohol Thin Film for Flexible Wearable Antenna Substrate

Polyvinyl Alcohol (PVA) has been used in various applications, including the medical health industry and electronics. It is a synthetic polymer with advantages such as being transparent, flexible, biocompatible, biodegradable, and a simpler synthesis process. These advantages make PVA a very promising material for human wearable antennae. In this research, the bending effect of an antenna using a PVA substrate is studied to analyze its durability in the wearable application. Firstly, the thin film substrate synthesis is performed using PVA 2488 with the measured average dielectric constant and tangent loss of 1.24 and 0.066, respectively, across S-Band frequency. Later, a 5G antenna is designed and fabricated using the PVA substrate. Finally, the bending effects of the fabricated antenna are measured at different bending radii. Four different antenna-bending radii are selected to represent different curvatures of human body parts. Results show that bending does not have a significant effect on the reflection coefficient of the antenna, where the frequency shifts from 2.2% up to 7.4% only for all bending conditions. Hence, in that aspect of finding, the PVA thin film is a potential candidate for flexible and wearable antenna material in various human body parts in biomedical applications.

Dual band half-hexagonal shape with additional slot wearable microstrip antenna

Dual band half-hexagonal shape with additional slot wearable microstrip antenna

Analysis of tumor detection using polydimethylsiloxane based wearable antenna

Abstract A Polydimethylsiloxane (PDMS) based antenna is designed for skin tumor detection. The antenna functions at 2.45 GHz with a bandwidth of 2.30–2.64 GHz working in the ISM (Industrial, Scientific, and Medical) band. The size of the antenna is 40 × 40 × 1 mm3. This antenna detects tumors in the skin by considering the variations in values of the E-field, J-surf, and H-field. Various analyses such as the distance between the patch and stacked layer skin phantom for different tumor sizes and input power to the antenna are changed and antenna performance is observed. A significant amount of changes is attained which denotes the presence of the tumor. The proposed antenna is fabricated and the corresponding results are analyzed in the Anechoic Chamber. The antenna has an efficiency of 99 % with a Specific Absorption Rate of 1.3846 W/kg which is lower than 1.6 W/kg as per the recommendations of FCC standard.

Designing of Textile-based Wearable Antennas at 2.45 GHz

In the recent times, there are a continuous development and distinctive growth in the implementation of wearable sensors and flexible devices in real lifes. These devices are exploited to monitor signals in healthcase applications, for the intents of geo‐positioning of the rescue, and in military personnel. There are abundant of frequency bands have been introduced worldwide such for the narrow-band versions 2.36–2.40 GHz for the medical body area network, 2.40–2.48 GHz as the industrial, scientific, and medical band, and 3.1–10.6 GHz for the ultra‐wideband applications. In designing of wearable antennas, we find many challenges due to the practical implementation of antennas next to human body. The human body presents as very loss structures and its presence affects the form of the radiation pattern of the antenna and also can shift its operational frequency. Moreover, placement of the antenna on convex structures with different curvature radii also affects its performance due to overall change in electrical length. In this study, we analyze wearable antennas based on textile flexible materials for WBAN implementation. The type of the antennas is a metasurface implementation of microstrip antennas. In this way, we can reduce the thickness of the material significantly to prevent the radiation efficiency of the antennas. We will observe the bending effect on the radiation patterns of the antenna.

Flexible Wearable Antenna for IoT-Based Plant Health Monitoring

Flexible Wearable Antenna for IoT-Based Plant Health Monitoring