Textile-based Low-frequency RC Filter for Noise Reduction in ECG signals

Advancements in electronic textiles over the past decade have significantly transformed the field of wearable technology, with recent developments leading to the production of a wide array of textile-based sensing and actuation systems. Beyond sensors and actuators, textile-based technologies can benefit from the integration of additional electronic solutions within the framework of textilization. One such solution is filtering, which has primarily been explored in the context of high-frequency applications in e-textiles. In contrast, low-frequency filtering has received limited attention in the literature. This study investigates the design and fabrication of low-frequency textile-based Resistor-Capacitor (RC) filters, emphasizing their potential for wearability. Various materials and geometric configurations are explored for the resistive and capacitive components of the filter, evaluating their performance in terms of frequency response. Additionally, these filters are integrated with textile-based electrodes and assess their filtering efficacy at a cutoff frequency of approximately 100 Hz within the context of an electrocardiogram (ECG) application during both static and dynamic activities. The results demonstrate that textile-based filters can serve as viable alternatives to conventional electronic filters, exhibiting comparable performance in noise suppression, as evidenced by signal-to-noise ratio (SNR) improvements of 25 dB during static activities and 11 dB during dynamic activities.