Non-invasive respiration and/or heartbeat monitor or the like
US4991585A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 13, 1990 |
| Grant date | Feb 12, 1991 |
| Priority date | — |
| Expiry date | Mar 13, 2010 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/113
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A microwave carrier signal is transmitted into certain tissue (such as the thorax) of a patient from an outer one of three linearly-arranged independent elements of an antenna assembly. Back-scatter portions of the carrier signal are received by both the middle and the other outer ones of the elements of the antenna assembly. The back-scatter portion received by the middle element is phase-modulated by a modulation frequency and retransmitted into the tissue of the patient, and the other outer element also receives a back-scatter portion of this retransmitted phase-modulated signal. The total signal received by this other outer element is beat against the original microwave signal in a mixer and the output of the mixer is applied as an input to a bandpass filter, which passes only the phase-modulated signal. The envelope of the bandpass filter output is indicative of motion (e.g., breathing rate) of the patient. The detection of spurious motions of objects located outside of the target area of interest of the patient is minimized in the disclosed monitor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.