A Low-Profile Ultrawideband Antenna Based on Flexible Graphite Films for On-Body Wearable Applications

New Advances in Antenna Design toward Wearable Devices Based on Nanomaterials

Wearable antennas have recently garnered significant attention due to their attractive properties and potential for creating lightweight, compact, low-cost, and multifunctional wireless communication systems. With the breakthrough progress in nanomaterial research, the use of lightweight materials has paved the way for the widespread application of wearable antennas. Compared with traditional metallic materials like copper, aluminum, and nickel, nanoscale entities including zero-dimensional (0-D) nanoparticles, one-dimensional (1-D) nanofibers or nanotubes, and two-dimensional (2-D) nanosheets exhibit superior physical, electrochemical, and performance characteristics. These properties significantly enhance the potential for constructing durable electronic composites. Furthermore, the antenna exhibits compact size and high deformation stability, accompanied by greater portability and wear resistance, owing to the high surface-to-volume ratio and flexibility of nanomaterials. This paper systematically discusses the latest advancements in wearable antennas based on 0-D, 1-D, and 2-D nanomaterials, providing a comprehensive overview of their development and future prospects in the field.

Flexible UWB and MIMO Antennas for Wireless Body Area Network: A Review

In recent years, there has been a surge of interest in the field of wireless communication for designing a monitoring system to observe the activity of the human body remotely. With the use of wireless body area networks (WBAN), chronic health and physical activity may be tracked without interfering with routine lifestyle. This crucial real-time data transmission requires low power, high speed, and broader bandwidth communication. Ultrawideband (UWB) technology has been explored for short-range and high-speed applications to cater to these demands over the last decades. The antenna is a crucial component of the WBAN system, which lowers the overall system's performance. The human body's morphology necessitates a flexible antenna. In this article, we comprehensively survey the relevant flexible materials and their qualities utilized to develop the flexible antenna. Further, we retrospectively investigate the design issues and the strategies employed in designing the flexible UWB antenna, such as incorporating the modified ground layer, including the parasitic elements, coplanar waveguide, metamaterial loading, etc. To improve isolation and channel capacity in WBAN applications, the most recent decoupling structures proven in UWB MIMO technology are presented.

Compact Dual-Band Antenna with Paired L-Shape Slots for On- and Off-Body Wireless Communication

A simple dual-band patch antenna with paired L-shap slots for on- and off-body communications has been presented in this article. The proposed antenna resonates in the industrial, scientific, and medical (ISM) band at two different frequencies, at 2.45 GHz and 5.8 GHz. At the lower frequency band, the antenna’s radiation pattern is broadsided directional, whereas it is omni-directional at the higher frequency band. The efficiency and performance of the proposed antenna under the influence of the physical body are improved, and the specific absorption rate (SAR) value is significantly reduced by creating a full ground plane behind the substrate. The substrate’s material is FR-4, the thickness of which is 1.6 mm and it has a loss tangent of tanδ = 0.02. The overall size of the proposed design is 40 mm × 30 mm × 1.6 mm. Physical phantoms, such as skin, fat and muscle, are used to evaluate the impact of physical layers at 2.45 GHz and 5.8 GHz. The SAR values are assessed and found to be 0.19 W/kg and 1.18 W/kg at 2.45 GHz and 5.8 GHz, respectively, over 1 gram of mass tissue. The acquired results indicate that this antenna can be used for future on- and off-body communications and wireless services.