Adaptive Sweep (ABS) - Adaptive Band Synthesis

Project Editor - Analysis Setup Dialog Box - Analysis Control

An Adaptive sweep uses the Adaptive Band Synthesis (ABS) technique to perform a fine resolution analysis of a specified frequency band. You enter the desired frequency band by entering the beginning frequency in the Start text entry box and the ending frequency in the Stop text entry box. Em analyzes the circuit at the beginning and end frequencies. Using an iterative process, em then analyzes at other discrete frequencies and determines a rational polynomial fit to the S-parameter data within the frequency band. Once a rational polynomial fit is achieved with an acceptable error, the frequency response across the specified bandwidth is calculated.

The output data consists of the discrete data points, frequencies at which the analysis engine, em, performs an electromagnetic analysis, and the adaptive data, which is data calculated using the rational polynomial.

Note            If you select None for the ABS caching level, and an ABS sweep is stopped before the adaptive data has been calculated, you will have to start the analysis over from the beginning. Any processing time invested in the analysis is lost.

Please note that when the value of the S-parameters is close to 1 (0 dB) over the entire band you may have small ripples or oscillations in the S-parameter values. This is due to the rational fitting model having too many degrees of freedom when trying to fit a straight line. If this is a problem, it is recommended that you analyze the frequency band in which this occurs with another type of sweep.

If you only input a Start frequency or if the Start and Stop frequency are the same value, em will perform an analysis at that discrete point.

For a detailed discussion of Adaptive Band Synthesis, see Chapter 9, Adaptive Band Synthesis (ABS) in the Sonnet User's Guide.