Method for comparing the quality of rf absorbers

Claim 1

A method for comparing the quality of RF absorbers by means of a TEM cell, wherein the TEM cell expands in the form of a pyramid from a point, an absorber wall is located at the widened end of the TEM cell and has the form of a spherical cap, a metal wall is located behind the absorber well, the TEM cell is provided with a low-reflection line termination, means for generating TEM pulses and means for evaluating a scattered wave are provided; comprising the steps of performing a first calibration measurement wherein the reflection of the absorber wall entirely equipped with reference absorbers is determined; performing a second calibration measurement wherein the reference absorbers are removed in a test area of the absorber wall such that the reflection of the metal wall lying behind the absorber wall is determined in said test area; performing a third measurement wherein the test absorbers are arranged in the place of the test area such that the reflection of the absorber wall with the test absorbers arranged in the test area is determined; and determining the quality of the test absorbers based on a predetermined comparison of results of the first, second and third measurements performed.

Claim 2

A method for comparing the quality of RF absorbers by means of a TEM cell, wherein the TEM cell expands in the form of a pyramid from a point, an absorber wall is located at the widened end of the TEM cell and has the form of a spherical cap, a metal wall is located behind the absorber well, the TEM cell is provided with a low-reflection line termination, means for generating TEM pulses and means for evaluating a scattered wave are provided; comprising the steps of performing a first calibration measurement wherein the reflection of the absorber wall entirely equipped with reference absorbers is determined; performing a second calibration measurement wherein the reference absorbers are removed in a test area of the absorber wall such that the reflection of the metal wall lying behind the absorber wall is determined in said test area; performing a third measurement wherein the test absorbers are arranged in the place of the test area such that the reflection of the absorber wall with the test absorbers arranged in the test area is determined; and determining the quality of the test absorbers based on a predetermined comparison of results of the first, second and third measurements performed.

Claim 7

A device for carrying out a comparison of the quality of RF absorbers, comprising: (a) a TEM cell in which a TEM wave is conducted by an inner conductor and an outer conductor and is absorbed at one end of the TEM cell by an absorber wall for absorbing a field-guided energy and by an ohmic line termination for absorbing a conductor-bound energy of the TEM wave; (b) the termination located in a place determined by the inner conductor and located in the wave direction, the line termination designed as an ohmic resistance which produces a gradual serial attenuation in the inner conductor and locally compensates a capacitance loading additionally caused on the line termination by the RF absorber; (c) a pulse generator for generating steep-edged pulse waves; (d) a sensor which is arranged in front of the absorber wall at a distance D of about one third of a total length of the TEM cell; (e) means for producing a first signal based on a detection by the sensor during a first calibration measurement wherein the reflection of the absorber wall entirely equipped with reference absorbers is determined; (f) means for producing a second signal based on a detection by the sensor during a second calibration measurement wherein the reference absorbers are removed in a test area of the absorber wall such that the reflection of the absorber wall outside the test area and the metal wall lying behind the absorber wall is determined; (g) means for producing a third signal based on a detection by the sensor during a third measurement wherein test absorbers are arranged in the place of the test area such that the reflection of the absorber wall with the test absorbers arranged in the test area is determined; and (h) means for determining the quality of the test absorbers based on a predetermined comparison of the first, second and third signals.

Claim 8

A device for carrying out a comparison of the quality of RF absorbers, comprising: (a) a TEM cell in which a TEM wave is conducted by an inner conductor and an outer conductor and is absorbed at one end of the TEM cell by an absorber wall for absorbing a field-guided energy and by an ohmic line termination for absorbing a conductor-bound energy of the TEM wave; (b) the termination located in a place determined by the inner conductor and located in the wave direction, the line termination designed as an ohmic resistance which produces a gradual serial attenuation in the inner conductor and locally compensates a capacitance loading additionally caused on the line termination by the RF absorber; (c) a pulse generator for generating steep-edged pulse waves; (d) a sensor which is arranged in front of the absorber wall at a distance D of about one third of a total length of the TEM cell; (e) means for producing a first signal based on a detection by the sensor during a first calibration measurement wherein the reflection of the absorber wall entirely equipped with reference absorbers is determined; (f) means for producing a second signal based on a detection by the sensor during a second calibration measurement wherein the reference absorbers are removed in a test area of the absorber wall such that the reflection of the absorber wall outside the test area and the metal wall lying behind the absorber wall is determined; (g) means for producing a third signal based on a detection by the sensor during a third measurement wherein test absorbers are arranged in the place of the test area such that the reflection of the absorber wall with the test absorbers arranged in the test area is determined; and (h) means for determining the quality of the test absorbers based on a predetermined comparison of the first, second and third signals.