Wearable Antennas for Body-Centric Communications: Design and Characterization Aspects
Keywords:Antenna characterization, antenna design, optimization, radiation efficiency, SAR, wearable antenna
Wearable antennas exhibit numerous challenges in terms of design and optimization due to the specific environment in which they operate. Therefore, the design of such antennas is a non-trivial task, as multiple constraints have to be satisfied. We present an algorithm for design-and-optimization of flexible wearable antennas with high radiation efficiency and low specific absorption rate, that takes into account the dielectric loading of the human body. It provides a list of feasible antenna designs, not just a single solution, and identifies the optimal wearable antenna design. Numerical examples on the design and optimization of a wearable antenna (based on a dipole structure with a reflector) to demonstrate the validity and efficiency of the proposed algorithm are given. The optimal antenna design shows robust on-body performance and provides a suitable balance between small antenna size (antenna surface is 2214 mm2), high radiation efficiency (57.73%), and low value of the maximum 10 g average SAR (0.112 W/kg) on a homogeneous semisolid phantom. Finally, the optimal antenna design is fabricated. The antenna performance is studied under different conditions: on a homogeneous semisolid phantom, on a liquid phantom, on a three-layer semisolid phantom, on a human arm and in the free space. A good agreement between simulated and measured antenna performance is observed.
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