CAL CMAD 1614, Calibration fixture for CMAD 1614

The CAL CMAD 1614 calibration fixture is used to calibrate/verify the performance of the common-mode absorption device CMAD 1614. The fixture consists of an aluminum base plate with two side plates, adjustable in height and position and each of them equipped with N-connector and inner conductor fixture. A variety of inner conductors with 4 mm diameter is part of the delivery. The calibration fixture was designed for measurements acc. to CISPR 16-1-4 sections 9.5 and 9.6.

Specifications:
Frequency Range:	30 MHz - 200 MHz
Specified in:	CISPR 16-1-4
Useable Frequency Range:	10 MHz - 1 GHz
Diameter Inner Conductor:	4 mm
Min. Inner Conductor Height:	28 mm
Max. Inner Conductor Height:	48 mm
Inner Conductor Length Reflect 1/2:	76 mm (+14)
Inner Conductor Length Through:	152 mm (+28)
Inner Conductor Length Line 1:	212 mm (+28)
Inner Conductor Length Line 2:	566 mm (+28)
Material:	Aluminum
Dimensions:	113 x 150 x 788 mm
Weight:	2.2 kg

Application

First of all it is recommended to adjust the height of the inner conductor that it is centered in the CMAD. This can be done by releasing both star knobs and moving the N-connector to the desired position. As soon as the correct height is found, tighten the star knobs and repeat the same for the opposite side. It is advisable to embed the CMAD in the calibration fixture and verify the correct height of the inner conductor, if needed, do a fine adjustment. The height shall not be changed during the TRLcalibration procedure and the following measurement to obtain meaningful results.

Calibration

The calibration of the CMAD 1614 can be done using the TRL-method. TRL means "Through", "Reflect", "Line" and is usually implemented in modern vector network analyzers. Further information about the application of the TRL-method can be found in the documentation of the network analyzer. The same applies for the data input of the calibration standards. The following table contains the data of the calibration standards to be used by the vector network analyzer. It is worth to notice that the actually measured length of the inner conductors deviates by 14 mm or 28 mm from the tabular values since the inner conductor plugs come with 14 mm length on each side.

Calibration Standards	Parameter
Reflect Port 1 An open transmission line, defines the reference plane for the S11-measurement (see Fig. 1)	90 mm Open
Reflect Port 2 An open transmission line, defines the reference plane for the S22-measurement (see Fig. 1)	90 mm Open
Through Through connection (see Fig. 2)	180 mm
Line 1 A short transmission line to extend the frequency range to higher frequencies (not mandatory to cover 30-200 MHz). (see Fig. 3)	240 mm
Line 2 A longer transmission line, includes the length of the clamp and twice the length of "Reflect" standards (see Fig. 4)	594 mm