Miniaturization of a Dual-Band Wearable Antenna for WBAN Applications

A planar, compact, dual-band antenna on a semiflexible substrate is proposed for 2.45/5.85 GHz wireless body-area network applications. The proposed antenna is comprised of an I-shaped monopole embedded with an inverted L-shaped slit and an inductive meander line on the front side of the substrate, which excites the higher resonant mode at 5.85 GHz. On the backside, an inverted U-shaped stripline embedded with another inductive meander line is attached to the ground plane to excite the lower resonant mode at 2.45 GHz. The key to the miniaturization procedure is increasing the inductance and the capacitance by loading the inductive meander lines and slit line. The overall size of the proposed antenna is 0.15λ × 0.1λ × 0.004λ at 2.45 GHz. The measured results of the proposed antenna show the impedance bandwidths of 5.7% (2.4-2.54 GHz) and 3.78% (5.72-5.94 GHz) and the maximum peak gains of 2.1 dBi and 3.5 dBi, respectively. The simulated specific absorption rate values satisfy both the U.S. and EUR standards of under 1 g average and under 10 g average, respectively.