Flexible transparent antennas: advancements, challenges, and prospects

Optically transparent electronic devices have attracted enormous interests in recent years. The development of transparent electronics emerges a lot of new industrial applications in variety of fields, such as displays, glasses, solar panels, satellite communications, terrestrial communications, integrated circuits, and sensors where optical transparency is required for unobtrusive placement of electronic devices on the surface. Over the last couple of years, there have been notable advancements in the development of transparent wireless electronics due to the emerge of new materials and fabrication technologies. Among transparent electronic devices, transparent antennas attract tremendous interests due to their widespread applications in healthcare industry, security sector, defence, sports, smart city, Internet of Things (IoTs) and many more. Many of these applications require antennas that are concurrently transparent and flexible. A transparent and flexible antenna can be easily integrated with displays, windows, solar cells and optoelectronic modules, thus, reducing the space in the integrated circuits. However, still the development of flexible-transparent electronics is associated with some challenges which continue to impede the progress of this emerging field. Among them are the contradictory relationship between the electrical conductivity and optical transparency of the transparent conductors, costly and complex processing of the transparent materials and unavailability of the appropriate materials. In this paper, we discuss current advancements in the development of flexible transparent antennas, including potential applications, various enabling materials and manufacturing approaches, technical hurdles, as well as prospects.