Experiment and Spectral Analysis of a Low-Power Ka-Band Heartbeat Detector Measuring From Four Sides of a Human Body

• Published in: IEEE transactions on microwave theory and techniques Vol. 54; no. 12; pp. 4464 - 4471
• Main Authors: Changzhi Li, Yanming Xiao, Lin, J.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.12.2006; Institute of Electrical and Electronics Engineers
• Subjects: Applied sciences; Biomedical monitoring; Biomedicine; cardiopulmonary; Circuit properties; detector; Detectors; Doppler radar; double sideband; Electric, optical and optoelectronic circuits; electromagnetic wave; Electronics; Exact sciences and technology; Harmonic analysis; Heart beat; heartbeat; Humans; Ka -band; life sign; low power; Mathematical model; microwave; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; millimeter wave; noncontact; Object detection; Radar detection; Radiolocalization and radionavigation; remote sensing; respiration; sensor; Spectral analysis; Telecommunications; Telecommunications and information theory; telemedicine; vital sign; wireless; Harmonic; noncontact; heartbeat; Wireless telecommunication; double sideband; Microwave; spectral analysis; respiration; Ka-band; Remote sensing; Millimetric wave; Accuracy; Telemedicine; Spectrum analysis; Phase modulation; Microwave detectors; Human body; vital sign; Measurement sensor; life sign; Electromagnetic wave; Heart rate; millimeter wave; Biomedicine; Simulation; RF; Ka band; low power; sensor; wireless; Doppler radar; Low-power electronics; cardiopulmonary; Signal analysis; Sideband; detector; Non contact measurement
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2006.884652

The accuracy of a Ka-band physiological movement detector was tested and compared for measurements from four different body orientations and at five different distances. A rigorous spectral analysis approach is developed when previously adopted small-angle approximation model is not applicable. This theory analyzes in detail the harmonics observed in phase-modulated Ka-band Doppler radar, explaining the reason for better heart-rate accuracy when detected from the back of the body. It also explains the advantage of double-sideband transmission in avoiding the null point problem. Simulations have been performed to illustrate this theory and provide design guidelines for the system. This theory has also been verified by experiments