Plantar pressure sensing using loop antenna sensors

Foot complications associated with diabetes might lead to foot ulcers. Foot ulcers if neglected can cause foot infection and subsequent amputation. Ulceration is believed to be contributed by stresses acting over the foot. Therefore, measurement of plantar pressures is important in diagnosis and foot ulcer evaluation. However, current plantar pressure measurement systems are either expensive or have a low resolution. This paper investigates the feasibility of employing a loop antenna sensor printed on a dielectric substrate (Rogers 4350B) to detect plantar pressure distribution. This flexible, low profile, inexpensive, high resolution sensor can be easily embedded in shoes to measure the plantar pressures in real-time. The most important advantages of the antenna sensor are they can be multiplexed and wirelessly interrogated. The principal of operation, sensor fabrication, experimental setup, experimental procedure and results are presented. Preliminary results show that the loop antenna sensors have a very low hysteresis loss and respond to pressure with good repeatability. Finally, a technique to wirelessly interrogate the loop antenna sensor is proposed.