Materials Measurement Phil Bartley Shelley Begley

TRL CalibrationThruReflectMove the antenna away tocompensate for the thicknessof the short. Move it backfor the next step.LineMove the antenna away on aquarter-wavelength and thenback in the original position.Precise positioning fixtures are expensiveA second widely used technique is TRL. TRL uses a thru, reflect and linestandard to determine the error coefficients. However, to measure thereflect, the port two antenna must be moved back by the thickness of themetal plate. The line standard is then realized by precisely moving the porttwo antenna on quarter wavelength. After the calibration the antenna needsto be precisely moved back to its original position. In order to do thisaccurately enough to get a good calibration, expensive positioning fixturingis required like optical table.For both TRM and TRL calibration the main problem is the third standard(Match or Line). The GRL calibration avoids using the third standard as itwill be explained next.62