Embroidered Annular Elliptical E-Textile Antenna Sensor for Knee Effusion Diagnosis

This article presents the design of a wearable textile antenna sensor for knee effusion diagnosis application. According to human anatomy, effusion is the collection of synovial fluid in a specific anatomic space. Knee effusion, often known as water on the knee, is a condition in which excess fluid collects around the knee joint. The antenna sensing patch region is embroidered using an automated computerized embroidery machine, while the design parameters were optimized using machine learning (ML) algorithms, including deep neural network (DNN). For the best fit on a knee joint, an annular elliptical structure of electronic textile (E-textile) antenna sensor is developed. Pure silver-coated highly conductive thread with improved flexibility is used for embroidering the patchwork in order to enhance the feasibility of the proposed device. The fabricated antenna sensor has the operating resonance frequency at 2.19 GHz and performs diagnosis based on the concept of reflection coefficient parameter. Furthermore, the specific absorption rate (SAR) level of a proposed sensor device is being evaluated on the knee joint and has been kept below the safety limit value of 1.6 W/kg averaged over 1 g of tissue model.