A Wearable Flexible Loop Antenna for In-Body Beamforming

This paper presents a wearable flexible loop antenna array for use on the anterior and posterior torso. The antenna array that has been developed to assist in the detection of excess fluid in the lungs operates in the Medical Implant Communication System frequency Band. The antenna elements use a novel high-permittivity flexible substrate with dimensions of 70.5 mm x 59 mm x 2 mm. We investigate a simple beamforming technique to enable focusing the transmitted energy toward a specific lobe of the lung and also improve the low signal power at the receiver. In-body beamforming is achieved by adding proper phase shifts to the transmitter antennas. Both the return loss values of anterior antennas and the transmission coefficients between the anterior and posterior antennas are presented.