Method of testing dielectric materials

Claim 1

A method of accurately measuring the phase delay of microwave energy passing along a path through a dielectric material by selection of the frequency of the microwave energy, the method comprising: providing first and second microwave transducers, a microwave signal source, and means for connecting the signal source to either one of the transducers, each of the transducers having an aperture through which it can radiate and receive microwave energy, each aperture being adapted for positioning adjacent the dielectric material; determining a frequency at which S 11 and S 22 for the transducers are both less than a selected level, S 11 being a measure of the amount of microwave energy reflected when the transducers are positioned with their apertures abutting, the first transducer is connected to the signal source, and a microwave signal is sent from the signal source to the first transducer, and S 22 being a measure of the amount of microwave energy reflected when the transducers are positioned with their apertures abutting, the second transducer is connected to the signal source, and a microwave signal is sent from the signal source to the second transducer; positioning the tranducers adjacent different surfaces of the dielectric material and injecting microwave energy at said frequency along said path from the first transducer to the second transducer; and determining the phase delay of the microwave energy at said frequency along said path.

Claim 2

A method of accurately measuring the phase delay of microwave energy passing along a path through a dielectric material by selection of the frequency of the microwave energy, the method comprising: providing first and second microwave transducers, a microwave signal source, and means for connecting the signal source to either one of the transducers, each of the transducers having an aperture through which it can radiate and receive microwave energy, each aperture being adapted for positioning adjacent the dielectric material; determining a frequency at which S 11 and S 22 for the transducers are both less than a selected level, S 11 being a measure of the amount of microwave energy reflected when the transducers are positioned with their apertures abutting, the first transducer is connected to the signal source, and a microwave signal is sent from the signal source to the first transducer, and S 22 being a measure of the amount of microwave energy reflected when the transducers are positioned with their apertures abutting, the second transducer is connected to the signal source, and a microwave signal is sent from the signal source to the second transducer; positioning the tranducers adjacent different surfaces of the dielectric material and injecting microwave energy at said frequency along said path from the first transducer to the second transducer; and determining the phase delay of the microwave energy at said frequency along said path.

Claim 7

A method of accurately measuring a value related to the average dielectric constant along a path through a sheet of dielectric material having opposite faces conductively surfaced and edges of exposed dielectric by means of microwave energy having a preselected frequency, comprising: providing first and second microwave transducers, a microwave signal source, and means for connecting the signal source to either one of the transducers, each of the transducers having an aperture through which it can radiate and receive microwave energy, each aperture being adapted for positioning adjacent an edge of the sheet; determining a frequency at which S 11 and S 22 for the transducers are both less than a selected level, S 11 being a measure of the amount of microwave energy reflected when the transducers are positioned with their apertures abutting, the first transducer is connected to the signal source, and a microwave signal is sent from the signal to the first transducer, and S 22 being a measure of the amount of microwave energy reflected when the transducers are positioned with their apertures abutting, the second transducer is connected to the signal source, and a microwave signal is sent from the signal source to the second transducer; positioning the transducers adjacent different edges of the sheet and injecting microwave energy at said frequency along said path from the first transducer to the second transducer, and, determining the phase delay of the microwave energy at said frequency along said path.

Claim 8

A method of accurately measuring a value related to the average dielectric constant along a path through a sheet of dielectric material having opposite faces conductively surfaced and edges of exposed dielectric by means of microwave energy having a preselected frequency, comprising: providing first and second microwave transducers, a microwave signal source, and means for connecting the signal source to either one of the transducers, each of the transducers having an aperture through which it can radiate and receive microwave energy, each aperture being adapted for positioning adjacent an edge of the sheet; determining a frequency at which S 11 and S 22 for the transducers are both less than a selected level, S 11 being a measure of the amount of microwave energy reflected when the transducers are positioned with their apertures abutting, the first transducer is connected to the signal source, and a microwave signal is sent from the signal to the first transducer, and S 22 being a measure of the amount of microwave energy reflected when the transducers are positioned with their apertures abutting, the second transducer is connected to the signal source, and a microwave signal is sent from the signal source to the second transducer; positioning the transducers adjacent different edges of the sheet and injecting microwave energy at said frequency along said path from the first transducer to the second transducer, and, determining the phase delay of the microwave energy at said frequency along said path.

Claim 16

A method for the nondestructive testing of a sheet of dielectric material having opposite faces conductively surfaced and edges of exposed dielectric by measuring the phase delay of microwave energy of a selected frequency along paths through the dielectric material, the method comprising: (a) determining, by means of injected microwave energy passed through the dielectric sheet, respective values related to the average dielectric constant of the sheet along a plurality of paths in the plane of the sheet, said paths comprising a first group of mutually parallel paths and a second group of mutually parallel paths oriented to intersect the paths of the first group, the step of determining said respective values comprising: (i) providing first and second microwave transducers, a microwave signal source, and means for connecting the signal source to either one of the transducers, each of the transducers having an aperture through which it can radiate and receive microwave energy, each aperture being adapted for positioning adjacent an edge of the sheet; (ii) determining a frequency at which S 11 and S 22 for the transducers are both less than a selected level, S 11 being a measure of the amount of microwave energy reflected when the transducers are positioned with their apertures abutting, the first transducer is connectd to the signal source, and a microwave signal is sent from the signal source to the first transducer, and S 22 being a measure of the amount of mircrowave energy reflected when the transducers are positioned with their apertures abutting, the second transducer is connected to the signal source, and a microwave signal is sent from the signal source to the second transducer; and (iii) successively positioning the transducers adjacent edges of the sheet such that microwave energy can be injected along said paths from the first transducer to the second transducer, and injecting microwave energy at said frequency along each path from the first transducer to the second transducer; and (b) comparing said values with one another, thereby identifying variations in said values within the sheet.

Claim 17

A method for the nondestructive testing of a sheet of dielectric material having opposite faces conductively surfaced and edges of exposed dielectric by measuring the phase delay of microwave energy of a selected frequency along paths through the dielectric material, the method comprising: (a) determining, by means of injected microwave energy passed through the dielectric sheet, respective values related to the average dielectric constant of the sheet along a plurality of paths in the plane of the sheet, said paths comprising a first group of mutually parallel paths and a second group of mutually parallel paths oriented to intersect the paths of the first group, the step of determining said respective values comprising: (i) providing first and second microwave transducers, a microwave signal source, and means for connecting the signal source to either one of the transducers, each of the transducers having an aperture through which it can radiate and receive microwave energy, each aperture being adapted for positioning adjacent an edge of the sheet; (ii) determining a frequency at which S 11 and S 22 for the transducers are both less than a selected level, S 11 being a measure of the amount of microwave energy reflected when the transducers are positioned with their apertures abutting, the first transducer is connectd to the signal source, and a microwave signal is sent from the signal source to the first transducer, and S 22 being a measure of the amount of mircrowave energy reflected when the transducers are positioned with their apertures abutting, the second transducer is connected to the signal source, and a microwave signal is sent from the signal source to the second transducer; and (iii) successively positioning the transducers adjacent edges of the sheet such that microwave energy can be injected along said paths from the first transducer to the second transducer, and injecting microwave energy at said frequency along each path from the first transducer to the second transducer; and (b) comparing said values with one another, thereby identifying variations in said values within the sheet.

Claim 27

A method for the nondestructive testing of a sheet of dielectric material having opposite faces conductively surfaced and edges of exposed dielectric, comprising: (a) determining, by means of injected microwave energy passed through the dielectric sheet, respective values related to the average dielectric constant of the sheet along a plurality of paths in the plane of the sheet, said paths comprising a first group of mutually parallel paths and a second group of mutually parallel paths oriented to intersect the paths of the first group; (b) estimating, for each area of the sheet consisting of the intersection of a path selected from the first group and a path selected from the second group, a value related to the mean dielectric constant for said area, the estimating step comprising: (i) assigning an estimated value to each area; (ii) for each path in succession, adjusting the estimated values for the areas making up that path by an amount proportional to the difference between the average estimated value for areas making up that path and the value determined along that path; and (iii) repeating step (ii) one or more times until the amounts of the adjustments become insignificant in comparison to the estimated values.

Claim 28

A method for the nondestructive testing of a sheet of dielectric material having opposite faces conductively surfaced and edges of exposed dielectric, comprising: (a) determining, by means of injected microwave energy passed through the dielectric sheet, respective values related to the average dielectric constant of the sheet along a plurality of paths in the plane of the sheet, said paths comprising a first group of mutually parallel paths and a second group of mutually parallel paths oriented to intersect the paths of the first group; (b) estimating, for each area of the sheet consisting of the intersection of a path selected from the first group and a path selected from the second group, a value related to the mean dielectric constant for said area, the estimating step comprising: (i) assigning an estimated value to each area; (ii) for each path in succession, adjusting the estimated values for the areas making up that path by an amount proportional to the difference between the average estimated value for areas making up that path and the value determined along that path; and (iii) repeating step (ii) one or more times until the amounts of the adjustments become insignificant in comparison to the estimated values.