Dual-band low profile antennas for body-centric communications

Dual-band operation is highly desirable for wearable devices that need to connect with a range of wireless systems. We present a series of microstrip-line fed, dual-band compact patch antennas designed to operate in the common 2.45 GHz and 5.8 GHz bands for body-centric communications. All of the designs are low-profile and, with further study, may be suitably implemented in flexible or fabric materials. Our best performance was obtained with a shorted parasitic patch element close to a rectangular patch operating at the TM₁₀ mode. This design, with an overall height of less than ¿/24, had a radiation efficiency of 91% at 2.45 GHz and 95% at 5.8 GHz in free space. When placed 2 mm above a muscle tissue phantom at 2.45 GHz, an efficiency of 52% and a 2:1 impedance bandwidth of 95 MHz was obtained. The bandwidth at the 5.8 GHz band was 400 MHz in free space.