Recent Advances in Fabrication Methods for Flexible Antennas in Wearable Devices: State of the Art

Abstract

Antennas are a vital component of the wireless body sensor networks devices. A wearable antenna in this system can be used as a communication component or energy harvester. This paper presents a detailed review to recent advances fabrication methods for flexible antennas. Such antennas, for any applications in wireless body sensor networks, have specific considerations such as flexibility, conformability, robustness, and ease of integration, as opposed to conventional antennas. In recent years, intriguing approaches have demonstrated antennas embroidered on fabrics, encapsulated in polymer composites, printed using inkjets on flexible laminates and a 3-D printer and, more interestingly, by injecting liquid metal in microchannels. This article presents an operational perspective of such advanced approaches and beyond, while analyzing the strengths and limitations of each in the microwave as well as millimeter-wave regions. Navigating through recent developments in each area, mechanical and electrical constitutive parameters are reviewed, and finally, some open challenges are presented as well for future research directions.

Washing Durability of PDMS-Conductive Fabric Composite: Realizing Washable UHF RFID Tags

“…Nevertheless, such topology allows for a better integration between the two classes of material, thanks to PDMS-PDMS bonding created through the fabric pores. At the same time, owing to the unique characteristics of PDMS, its combination with conductive fabric provides physical robustness from harsh wearable environments, which might not be achieved by the conductive fabric itself [3], [15]. The length and width of the PDMS layers are slightly larger than those of the conductive fabric to allow PDMS-PDMS sealing at the edge of the antenna, maximizing the antenna protection.…”

“…T HE ubiquity of wireless wearable technologies over the last decade has created an ever-growing research interest in the utilization of textiles for wearable antenna realization [1]- [3]. Current research efforts in this area towards the realization of truly wearable wireless platforms include achieving the antenna durability against recurrent machine washings.…”

Mutual Coupling Reduction in Microstrip Array Antenna by Employing Cut Side Patches and Ebg Structures

“…In addition, unlike [12] our proposed EBG consists of only four cells arranged in one column, resulting in smaller distance between the patches. This low profile antenna, like other low profile planar antennas, has a potential to be fabricated with flexible materials such as antenna based on polydimethylsiloxane and conductive fabric due to its high gain, high efficiency, and low profile [13,14].…”

A Conformal Band-Notched Ultrawideband Antenna With Monopole-Like Radiation Characteristics

“…By loading the patch with two rectangular slots, two parasitic rings, and vias, an ultra-wide bandwidth of 3.8-8.3 GHz with 5-6 GHz notched band has been achieved. The proposed antenna was fabricated based on the polydimethilsiloxane (PDMS)-conductive fabric composite technique, in which all antenna parts including radiators and ground plane are embedded inside the PDMS, making it flexible and resilient to the harsh environment [20]- [22]. The mentioned antenna characteristics along side its low profile and flexibility make the proposed antenna a suitable candidate for any applications with the need for wide coverage in all directions, particularly in which the antenna has to be placed on the non-flat surface, near to the ground.…”