Monitoring respiratory rate is important for assessing patients’ health in various applications. This study investigates a contactless monitoring device based on 24 GHz radar technology, which operates using Doppler detection principles. It is capable of identifying abnormal breathing events and tracking them during nighttime rest. The respiration rate is estimated by analysing phase changes caused by chest wall movement during inhalation and exhalation, which modulate the distance between the body and the radar. These variations are captured by the receiving antenna and processed to extract the breathing frequency. The sensor can accurately detect motion, speed, and distance, making it suitable for home care applications. The radar’s performance was experimentally evaluated at various distances and angles from the subject’s chest. Results show that the optimal configuration occurs when the radar is positioned at a \(0^{\circ }\) angle and a distance of approximately 1 m from the chest, ensuring accurate and reliable measurements.