title: On the design and assessment of a 2.45 GHz radio telecommand system for remote patient monitoring.
abstract: This paper discusses the design and operational assessment of a minimum-power, 2.45 GHz portable pulse receiver and associated base transmitter comprising the interrogation link in a duplex, cross-band RF transponder designed for short-range, remote patient monitoring. A tangential receiver sensitivity of - 53 dBm was achieved using a 50 ohms microstrip stub-matched zero-bias diode detector and a CMOS baseband amplifier consuming 20 microA from + 3 V. The base transmitter generated an on-off keyed peak output of 0.5 W into 50 ohms. Both linear and right-hand circularly-polarised antennas were employed in system evaluations carried out within an operational Coronary Care Unit ward. For transmitting antenna heights of between 0.3 and 2.2 m above floor level. transponder interrogations were 95% reliable within the 82 m2 area of the ward, falling to an average of 46% in the surrounding rooms and corridors. Separating the polarisation modes, using the circular antenna set gave the higher overall reliability.
authors.affiliation: The Northern Ireland Bioengineering Centre and School of Electrical and Mechanical Engineering, University of Ulster, Co Antrim, UK.
authors.forename: G C
authors.initials: GC
authors.lastname: Crumley
authors.forename: N E
authors.initials: NE
authors.lastname: Evans
authors.forename: J B
authors.initials: JB
authors.lastname: Burns
authors.forename: T G
authors.initials: TG
authors.lastname: Trouton
mesh_terms: D004867:Equipment Design; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods; D011846:Radio Waves; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D013686:Telemetry / Q000295:instrumentation*