Back to results
US 4,904,928 AGranted
Measurement apparatus and method utilizing multiple resonant modes of microwave energy
AssigneeE. I. Du Pont de Nemours and Company
InventorRichard W. Lewis
Life of this patent
Estimating the term…
Abstract
Measurement apparatus and method utilizing microwave energy. A symmetric microwave cavity is excited to oscillate in at least two identical resonant modes having substantially the same resonant frequencies but different field orientations relative to each other. A sample to be measured is caused to interact with the identical resonant modes and the difference in the frequencies of oscillation of the modes is determined in order to measure a property of the sample.
Claims11
Measurement apparatus utilizing microwave energy comprising:
- a. an n-fold symmetric self-oscillating microwave cavity (where n is an integer equal to or greater than 2) having at least two identical resonant modes of oscillation at substantially the same frequency, each with a different field orientation;
- b. means for exciting said cavity to oscillate simultaneously and continuously in each of said at least two identical resonant modes at substantially the same frequency;
- c. positioning means for positioning a sample of material to interact with said at least two identical resonant modes so that a property of said sample which is to be measured changes the resonant frequency of oscillation of at least one of said resonant modes from its normal resonant frequency;
- and
- d. means for measuring the difference in the simultaneously and continuously excited resonant frequencies of oscillation of said at least two identical resonant modes with said sample so positioned to measure said property of said sample.
2 more elements
A measurement method utilizing microwave energy comprising:
- a. exciting in an n-fold symmetric self-oscillating microwave cavity (where n is an integer equal to or greater than 2) in at least two identical resonant modes of simultaneous continuous microwave oscillation at substantially the same resonant frequencies;
- b. positioning a sample of material to interact with said at least two identical resonant modes to cause a property of said sample to be measured to change the resonant frequency of oscillation of at least one of said simultaneous and continuous oscillation resonant modes from its normal resonant frequency;
- and
- c. measuring the difference in the frequencies of oscillation of said at least two identical simultaneous and continuous oscillation resonant modes while so positioning said sample to measure said property of said sample.
1 more element
Dependencies are inferred from the claim text.