Sweep Types

Select Circuit > Settings > [Analysis Plan] and click the Sweeps tab to set up Frequency sweeps and/or parameter sweeps. This topic discusses the various types of frequency and parameter sweeps available.

Frequency Sweep Types

The available frequency sweep types are described below.

Adaptive (ABS) Sweep

An Adaptive Sweep uses the Adaptive Band Synthesis (ABS) technique to provide results for a large number of frequency points by performing an EM analysis at only a small number of discrete frequencies. To learn more about ABS sweeps, see Adaptive Band Synthesis.

Linear Sweep

A Linear Sweep is used to specify evenly spaced frequencies. Enter the start and stop frequencies in the first two text entry boxes. The third text entry box is used to specify the interval between the points. You may choose either Step size or Number of points from the drop-down list.

If you select the Adaptive checkbox, Sonnet runs an Adaptive (ABS) sweep, then synthesizes the response at the requested frequencies.

If you omit the step value and the number of points value in a linear sweep, the circuit is analyzed at just two frequencies: the start and stop values.

Exponential Sweep

The Exponential Sweep is used to specify frequencies with a common ratio between each frequency value. Enter the start, stop, and number of points. For example, entering a start of 1 GHz, stop of 1000 GHz, and number of points of 4 results in 1, 10, 100, and 1000 GHz.

If you select the Adaptive checkbox, Sonnet runs an Adaptive (ABS) sweep, then synthesizes the response at the requested frequencies.

Frequency List

The Frequency List Sweep allows you to enter a list of desired analysis frequencies in the Frequency List window. This is useful if you need multiple specific frequencies that cannot be specified using any of the other sweep types. Each frequency is a floating-point number and should be separated from the other frequency values using a comma, space or new line. The frequencies do not need to be in numerical order, but you may click the Sort button to sort all the values in the list from lowest to highest frequency.

If you select the Adaptive checkbox, Sonnet runs an Adaptive (ABS) sweep, then synthesizes the response at the requested frequencies.

Single Frequency

A Single Frequency Sweep analyzes your circuit at the specified frequency entered in the text entry box.

DC Frequency

A DC Frequency Sweep may be used to obtain approximate results at DC. It should be noted that the EM solver cannot analyze exactly at DC because the coupling matrix becomes singular at DC. Sonnet provides two methods for approximating a DC analysis:

  1. You may specify an Adaptive (ABS) Sweep whose starting frequency is zero. This is the recommended method. See DC Point Extrapolation for details.
  2. If you do not wish to perform an ABS Sweep, you may specify a DC Frequency Sweep. The EM solver analyzes at a very low frequency and treats the results as the DC results. The low frequency must be chosen carefully. If the frequency is too high, then the response of the circuit could be different than the true DC value. If the frequency is too low, then precision errors may occur. You have two choices for specifying the low frequency: Auto or Manual. If you choose Auto, the software automatically calculates this frequency based on an algorithm which is approximately 95% successful. If you choose Manual, you enter a frequency and the EM solver will simulate at the specified frequency but save the results as DC results.

Parameter Sweep Types

When the Perform parameter sweeps checkbox is selected, Parameter Sweeps appear in the Sweep Sets to allow you to define Parameter Sweeps for your analysis. Each Parameter Sweep is performed at each of the frequencies defined in the Sweep Set's frequency entries. The available Parameter Sweep types are listed below.

Linear Parameter Sweep

A Linear Parameter Sweep is used to specify evenly spaced values of a variable. Enter the start and stop value in the first two text entry boxes.The third text entry box is used to specify the interval between the values. You may choose either Step size or Number of points from the drop-down list. 

Exponential Parameter Sweep

An Exponential Sweep is a sweep with a common ratio between each successive value. For example, entering a start of 1.0, a stop of 1000.0, and number of points of 4 results in 1, 10, 100, and 1000.

Value List Parameter Sweep

The Value List Sweep allows you to enter a list of values for a variable in the Value List window. This is useful if you need multiple specific values which are not related in a way which would allow you to use another sweep type. Each value is a floating-point number and should be separated from the other values using a comma, space or new line. The values do not need to be in numerical order, but you may click the Sort button to sort all the values in the list from lowest to highest.

Single Value Parameter Sweep

A Single Value Sweep analyzes your circuit at the specified variable value entered in the text entry box.

Corner Parameter Sweep

A Corner Sweep allows you to analyze the extremes of your variables by analyzing at all the combinations of the minimum and maximum values of all your independent variables. In addition, one more parameter combination is analyzed at the nominal value of all your independent variables. The number of combinations analyzed is:

Corner Sweep EquationWhere Nc is the number of combinations and Nv is the number of independent variables selected for the parameter sweep.

The example below shows all possible combinations of minimum, maximum, and nominal values for a project with two variables. The blue fill in the table indicates that the combination is analyzed when using a Corner Sweep. The circuit is analyzed at each of these five combinations of variable values.

  Lstub Min Lstub Nominal Lstub Max
Sstub Min 180, 180 180, 200 180, 220
Sstub Nominal 200, 180 200, 200 200, 220
Sstub Max 220, 180 220, 200 220,220

Sensitivity Parameter Sweep

A Sensitivity Sweep allows you to see how sensitive your circuit is to changes in any given variable. The nominal value of each variable is combined with the maximum and minimum values of the other variables as well as the nominal values. The number of combinations analyzed is:

sensitivity_swp_eqWhere Nc is the number of combinations and Nv is the number of independent variables selected for the parameter sweep.

The example below shows all possible combinations of minimum, maximum, and nominal values for a project with two variables. The blue fill in the table indicates that the combination is analyzed when using a Sensitivity Sweep. The circuit is analyzed at each of these five combinations of variable values.

  Lstub Min Lstub Nominal Lstub Max
Sstub Min 180, 180 180, 200 180, 220
Sstub Nominal 200, 180 200, 200 200, 220
Sstub Max 220, 180 220, 200 220,220