Low Power Body Worn Antenna Systems

Future tele-medicine and communications systems will increasingly be worn on the human body with wireless links to external systems. Radio channels will propagate around the body and it is very important to be able to understand and characterize exactly how this energy is distributed about the surface of a human subject. There remains a concern among the public and users in general that exposure to radio frequency (RF) energy should be minimized to avoid possible health issues and reducing transmit powers will also improve battery life. Research has been done to assess how electromagnetic waves are guided by animated human models wearing radio devices, but this work does not include the effect of gaps caused by loose fitting clothing and how this causes the radio device to tilt with time. The position of a radio antenna will have a significant effect on how much energy is directed towards the surface of the skin and therefore on the wireless channel. This project is a collaboration between two established UK centres of wearable antenna and flexible screening research. The project will investigate new techniques for integrating antenna systems and screens into clothing for worn applications. The novelty of the proposal is to reduce RF powers by utilizing diversity between disguised and low profile antennas realizing the potential for low interference and improved reliability. New design philosophies will be created for worn wireless systems where movement data and worn antenna tilting will be captured from real humans and used to find propagation paths around the body while switchable periodic screens will select between magnetic reflection and surface guided modes. Antennas for medical applications mounted on disposable paper clothing will be explored as well as auto-tuning of antennas on different body types using varactor diodes, liquid crystal mixtures and MEMs switches. The outcomes of this research will well place the UK as a leader in, and an exploiter of, future wireless systems such as tele-medicine and pervasive computing.