Radio waves are widely used in the fields of communication and sensing, and technologies for sending wireless power are currently being put to practical use. The barriers that have so far limited these technologies are about to disappear completely. In the present study, we examine waveguides, which are a key component of the next-generation wireless technologies. A waveguide is a metal pipe through which radio waves transfer. Although a waveguide is a very heavy component, due to technological innovations, waveguides will undergo drastic modifications in the near future. This chapter introduces trends in innovative waveguide technologies and the latest wireless systems, including communication and power transfer system, that use waveguides.
Part of the book: Surface Waves
Wireless LAN usage is also increasing at construction and civil engineering sites, and the efficiency of ICT construction has increased due to the use of tablet PCs and network cameras. When constructing a wireless LAN environment, for example, a LAN cable may be laid from outside the tunnel, and a number of wireless access points (APs) may be installed. However, it is not advantageous to use a large number of APs because the system price increases significantly. We consider using a long leaky-wave antenna to provide one AP. The reason for using a leaky-wave antenna is that, since the total tunnel length is on the order of km, it is necessary to reduce the power radiated by the antenna as much as possible to provide a functional communication area over a long distance. To reduce such transmission losses, we used a waveguide. A waveguide is a low-loss line and can function as a low-loss and low-radiation leaky-wave antenna which is suitable for long-distance communications; this is accomplished by combining a waveguide with a low-radiation antenna mechanism. In this chapter, we report the development of a waveguide-type leaky-wave antenna and the development of a wireless LAN environment in a tunnel.