CST2013: Filter Analysis / Smith Chart - Phase Rotation

Home: MacrosMacrosFilter AnalysisSmith Chart - Phase Rotation

The macro performs a simple graphical rotation of the Smith-Chart data curve. (Note, that this is not a deembedding operation) As user input only the rotation angle is required, a negative angle rotates the curve counter clockwise. Additional markers automatically indicate crossing points at (+/-j1) and (+/-1.), respectively. The macro is useful if e.g. the focal point of the flat phase regime for a band pass needs to be rotated into the short or open point of the Smith chart for a latter estimation of coupling bandwidths (calibration).

The rotated smith chart is stored in an extra folder and might be used for comparison reasons to the un-rotated Smith Chart:

Example:

a) Original Smith-chart data prior to the rotation:

b) Smith Chart data after the rotation. The markers 1 and 2 are rotated onto (-1/j0):

As additional output crossing points at (+/-j1) can be displayed by deactivating the ”Skip Markers at +/- 90 deg” option. The markers indicate the coupling bandwidth of a bandpass filter for the first resonator.

c) Example of coupling bandwidth estimation by checking the markers Nr.1 and 3:

For the computation of the coupling bandwidth for additional resonators the zero crossings are of interest and are alternately positioned at (+/-1.,j0). From the displayed markers the coupling bandwidth can be computed.

d) Zero crossing markers are displayed, imaginary markers are ignored: