Basic Performance Characteristics of Wearable Antennas over a Wide Frequency Range

This chapter describes the basic performance characteristics of wearable antennas for body-centric wireless communications over a wide frequency range. It overviews frequency dependence of the communication channels between 3 MHz and 3 GHz for wearable antennas mounted on the human body. A static human body model which has a posture of standing in free space is employed in order to characterize various frequency channels. The chapter discusses the electric field distributions around the human body, received open voltage, and power transmission efficiency with ideal matching circuits. It describes the influence of a surrounding environment (namely a metal floor and a wall close to the human body) on the electric field distribution and received open voltages around the human body. The chapter demonstrates two different scenarios to apply the basic results to practical situations: a commercialized wall-mounted identification (ID) tag system and a human vital data acquisition system using a dual-mode antenna.