Improving in‐body ultra wideband communication using near‐field coupling of the implanted antenna

Ultra wideband (UWB) signal transmission from in‐body implanted antenna to on‐body or outside body is considered for biomedical applications. The received energy density of the UWB signal in terms of the distance from the body surface of a human anatomy model is computed. Time‐domain finite integral equation (FIE) and frequency‐dependent body tissue properties are used for field calculations. Path loss factors of the UWB channel for different distances from the body surface and different implanted antenna depths are derived. It is shown that the energy coupling because of the nonradiative near‐field of the body implanted antenna is dominant for the signal transmission. The communication link quality can be significantly improved in the range of 14.5–18 dB by exploiting the near‐field components. As a result, we propose to use the nonradiative near‐field region of the implanted antenna for improving the communication link quality by designing and placing the receiving antenna close to the body surface and then by relaying the signal to the off‐body communication device.