Microwave reflection resonator sensors
US5334941A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 14, 1992 |
| Grant date | Aug 2, 1994 |
| Priority date | — |
| Expiry date | Sep 14, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R27/2664
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A highly sensitive, direct-contact, in situ sensor for nondestructively measuring or monitoring the complex dielectric and conductive properties of solids, liquids, or gasses at microwave frequencies. A metal microstrip dipole resonator (11) is etched on the surface of a dielectric substrate (12) which is bonded to a copper ground plane (14). The dipole resonator is electromagnetically driven by mutual inductive coupling to a short nonresonant feed slot (13) formed in the ground plane (14). The slot (13) is driven by a coaxial feed line (7) or a microstrip feed line (16) extending from a swept microwave frequency source (2) which excites the incident wave (17). Alternatively, the metal resonator is omitted and the length of the slot (15) is increased so that it becomes the resonator. In use, the sensor is placed in close physical contact with the test material (9) having complex dielectric constant .epsilon.* (=.epsilon.'-j.epsilon.") or conductivity .sigma.. As the frequency of the microwave source (2) is swept, a sharp dip in the reflected wave (18) occurs at the resonant frequency, provided that the coaxial feed line (7) or microstrip feed line (16) is nearly critically coupled …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.