Contactless Methods for Respiration Monitoring and Design of SIW-LWA for Real-Time Respiratory Rate Monitoring
Manvinder Sharma, Singh Harjinder
Abstract
With the change in lifestyles, emerging stress and physical parameters of the environment, health-related issues have affected many people worldwide. An important indicator of serious illness is the abnormality in respiration rate. This abnormality leads to asthma, obstructive sleep apnea (OSA) and heart-related diseases. This leads to having more accurate and robust healthcare monitoring and diagnosis facilities. The respiration rate and vital signs are detected through electromagnetic (EM) waves using different antennas. Different types of previous antennas (parabolic, horn, yagi-uda, helical and patch) used for respiration monitoring are studied and compared with the proposed antenna. The limitations of currently used antennas include the bulky size of setup and less directional beam, which may interfere with other devices leading to errors. Substrate integrated waveguide (SIW)-based leaky-wave antenna (LWA) is proposed with better results than current antennas available for respiration monitoring. Experimental work is carried out for the validation of simulated results. The proposed antenna has a gain of 9.72 dB with angular width or approximately HPBW 37.5°. The simulated s11 of the antenna is −16 dB, and the measured s11 is −22.97 dB. VSWR shows antenna radiation efficiency is approx 97%. An experimental setup using VNA is used to detect respiration monitoring in real-time; the system could detect the respiratory activity of the subject with a confidence interval accuracy of 93% and an average error of 7%.