Dual-coil UHF Patch Antenna with Omnidirectional Radiation Pattern for Skin-Mountable Applications

A low-cost, compact, and flexible human skin-mountable UHF tag antenna with a geometrical dimension of 28.0 mm (diameter) × 3.11 mm (height) (0.085λ × 0.0095λ) is proposed. Dual logarithmic coils are tactfully introduced on the top patch to achieve miniaturization and omnidirectional radiation pattern. The PDMS (polydimethylsiloxane) is employed as a stretchable substrate to improve the flexibility of the antenna for better conformal mounting on human body. The proposed tag antenna is found to be able to achieve a maximum realized gain of -5.65 dBi when tested on human skin phantom with an omnidirectional radiation pattern.