Stretchable dipole antenna for body area networks at 2.45 GHz

A stretchable antenna is proposed for body area networks operating at 2.45 GHz. The topology of the antenna is based on a meandered dipole with a parasitic arm, which has an impedance with a dual-resonance behaviour. The antenna impedance is optimised for the specific radio-frequency integrated circuit where it will be connected to. This topology has been implemented on two stretchable technologies using thermoplastic poly-urethane and silicone as substrates. A simple stretching model has also been proposed for design purposes and it has been validated through measurements. Simulations based on this model and real stretching measurements have shown the potential of the structure for obtaining a wideband match in stretched conditions, with optimised designs achieving a reflection coefficient lower than 210 dB up to 20% stretching. On-body simulations and measurements have also been done, which indicate that practical values of reflection coefficient and radiation efficiency can be achieved with a separation of few millimetres between the antenna and the human body.