Previous: ADS Tutorial (Part 3) S-Parameter Simulation

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In this tutorial, we will learn how to use Data Display in ADS  of simulation.

In the previous section, we performed an S parameter simulation, and the following window popped up automatically after the simulation (click “New to ADS” when ADS is just opened, and an introduction to some operations will appear):

In the Palette on the left side of the page, there are many plot options. We first select (Rectangle Plot, a rectangular plot used to display frequency response characteristics such as S parameters, gain, insertion loss, return loss, etc.), then click the left mouse button in the window to display the “Plot Traces & Attributes” window, which is used to set and manage plots. We can see all the data obtained from the simulation under Dataset and Equations. We first select S(2 ,1), then click Add, and the following window will pop up:

This window shows the display mode for processing complex data. It has the following options:

• dB: Converts complex data to decibel (dB). Usually used to express gain or insertion loss, the formula is :
• dBm: Converts complex data to decibel milliwatt (dBm), commonly used for power measurement, with the formula :
• Magnitude: Displays the amplitude (absolute value) of complex data, that is, the modulus of the complex number, and the formula is .
• Phase (Phase Frequency): Displays the phase (angle) of complex data, that is, the phase angle of the complex number, and the formula is .
• Real part: Displays the real part of complex data.
• Imaginary part: Displays the imaginary part of complex data.
• Time domain signal: A time domain signal representation showing complex data, usually used for time domain analysis.

Since we are analyzing the frequency response of the S parameter, we select “dB” this time. After clicking “OK”, we can see that S(2,1) is added to the Traces in dB form:

Then click “OK”, and we get the relationship between S(2,1) (expressed in dB) and freq (frequency, in MHz):

Similarly, we can also plot the frequency response of S(1,1):

We can also plot multiple curves in one table. For example, if we want to plot S(1,1) in the graph of S(2,1), we can double-click the graph of S(2,1), then use the same steps to add dB(S(1,1)), and click “OK”:

As you can see, the two are presented in the same plot with different colors, and there are also color labels on the left. Double-click to pop up the property box and highlight the trace. At this point, we can use the toolbar (if there is no toolbar, right-click in the toolbar to add a marker) to the graph ( marker, you can put the mouse cursor on the icon to view the specific function). For example, if we click the first one, the following window will pop up:

At this point, we select a Trace location and can add a Marker:

If we want to view the values ​​​​of multiple curves at the same frequency, we can select and then select a position. The corresponding frequency position can be modified by directly clicking the schematic box above the plot, or by pressing and holding the added Marker triangle to drag it:

Next, we can select (List, list data in tabular form) to draw a table.

Similarly, we add S(2,1) and S(1,1), then click “OK” and adjust the size of the table appropriately:

We can intuitively see the relationship between the amplitude frequency and phase frequency of S(2,1) and S(1,1) and freq in the table. At this point, we can see that the frequency range in the table is smaller than the range we set during simulation, and the mouse wheel is invalid at this time. We can select the table to highlight it, and then use the toolbar (if there is no toolbar, right-click the mouse to add it) to view it by row or page.

If we want to change the data format in the table, we can first double-click the table to open the table settings window:

Then double-click S(2,1) on the right (take it as an example) to modify the data format:

The default data format is “Mag/Degrees”, we change it to “dB/Degrees”:

At this time, the data format of S(2,1) in the table is “dB/Degrees”, and the data format of S(1,1) is “Mag/Degrees”.

We can put multiple plots in one Page, or we can put plots in different Pages (similar to different Sheets) like EXCEL. At the top of the window, click “Page – New Page”:

Then name the newly created Page (for example, “SmithChart”). After creation, we can switch between different Pages at the bottom of the window (you can also right-click in the toolbar above, add different tools, and use them to switch Pages).

Then in the new Page, we select (Smith Chart, which is a very important tool in RF engineering and microwave engineering, used to graphically represent and analyze impedance, admittance, and S parameters, etc.), and then we draw two Smith Charts , the contents of which are S(1,1) and S(2,2):

Then save the design.

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Next article: ADS Tutorial (V) Real Time Tuning