Microwave proximity detector
AssigneeGeneral Electric Company
InventorsSe Puan Yu, Gary H. Glover
Life of this patent
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Abstract
A non-contacting method and apparatus for proximity detection with negligible radiation loss utilizes a microwave junction essentially having propagating waves on one side and evanescent electromagnetic fields on the other. Perturbation of the evanescent fields by an object causes a variation in the reflection coefficient of the propagation mode which is dependent on the distance from the junction to the object. This variation can be detected by measuring the phase shift of the propagating reflected waves relative to a reference.
Claims12
A non-contacting method of detecting the distance from a reference position to an object comprising the steps of
- propagating incident microwave frequency electromagnetic waves through a transmission line to a microwave junction mounted at a reference position to essentially produce propagating reflected waves on one side of the junction and evanescent electromagnetic fields on the other side of the junction,
- perturbing the evanescent electromagnetic fields with a resultant variation in a selected parameter of the reflected waves dependent on the linear separation between the reference position and an object in proximity to the microwave junction, and
- detecting the variation in the selected reflected wave parameter and generating an output indicative of the distance from the reference position to the object.
A non-contacting method of detecting the distance from a reference position to an object comprising the steps of
- propagating incident microwave frequency electromagnetic waves through a transmission line to a microwave junction mounted at a reference position to essentially produce propagating reflected waves on one side of the junction and evanescent electromagnetic fields on the other side of the junction,
- perturbing the evanescent electromagnetic fields and causing a resultant variable phase shift of the reflected waves dependent upon the linear separation between the reference position and an object in proximity to the microwave junction, and
- detecting the magnitude of the phase shift of the reflected waves relative to a reference and generating a quantitative output indicative of the distance from the reference position to the object.
A microwave proximity detector comprising
- a source of microwave energy for supplying incident waves that propagate through a transmission line,
- said transmission line having at one end thereof a microwave junction capable of essentially producing propagating reflecting waves on one side of the junction and evanescent electromagnetic fields on the other side of the junction,
- detector means for detecting the magnitude of the variation in a selected parameter of the reflected waves caused by perturbation of the evanescent electromagnetic fields by an object in proximity to the microwave junction in dependence upon the linear separation therebetween, and
- output means for generating an output indicative of the distance from the microwave junction to the object.
A microwave proximity detector comprising
- a source of microwave energy for supplying incident waves that propagate through a waveguide system,
- said waveguide system having an open end at which is mounted a waveguide iris diaphragm for essentially producing propagating reflected waves at one side of the diaphragm and evanescent electromagnetic fields on the other side of the diaphragm,
- detector means for detecting the magnitude of the phase shift of the reflected waves caused by perturbation of the evanescent electromagnetic fields by an object in proximity to the waveguide diaphragm in dependence upon the linear separation therebetween, and
- output means for generating a quantitative output indicative of the distance from the waveguide diaphragm to the object.
Dependencies are inferred from the claim text.