Creating a New Schematic

Transcription

1 4 Creating a New Schematic Projects To do a linear analysis, you must first create a project, create a schematic within that project, and then run the simulation. This guide shows you how to create schematics for all three simulators: Harmonica linear simulator, Harmonica nonlinear simulator, and Symphony system simulator. If you are working with Symphony, you can skip ahead to Chapter 8, System Simulation Symphony. The Serenade Desktop operates within projects, which contain all the information necessary to build, simulate and view results for the circuit design. Each circuit you design is part of such a project. Projects contain the following files, which contain the project information..sch files.ckt files.srp files.sym files.flp or.snp files.ssp file.schematic files netlist files report files (files containing graph and table definitions) symbol files files containing component information..snp files contain only S-parameters, where N is the number of nodes, so the files appear as.s1p,.s2p, and so forth. the project file itself When you create a new design, you must first create a project (.ssp) file. The project file coordinates the various files involved in the project, and connects the appropriate simulator to the project during a design session. Creating a New Schematic 4-1

2 Projects Figure 4-1 New Project dialog We recommend creating a directory for each project so you can easily organize multiple projects. NOTE Since projects consist of a collection of linked files, it is very important that you understand the ramifications of copying, relocating, or renaming any of the files in a project. We have provided a number of functions for performing these operations. Use these functions rather than Windows Explorer or File Manager. Refer to Serenade User s Guide for more information about these operations specifically, Copy Project, Rename Project, Archive Project, and Rename Schematic. The linear simulator tutorial is a low-noise amplifier. After creating the schematic for the amplifier, you will analyze, create output reports, tune, and optimize this schematic. If you are already comfortable with building schematics, you may skip to Running the Linear Analysis in the Linear Simulation (Harmonica) chapter. The first step in designing a circuit is to create a project: If this is the first time you are using Serenade Desktop, a Quick Start dialog box appears when the desktop opens, prompting you to choose a type of file. Close this dialog and choose File > New from the main menu. Choose Project, then choose OK. The New Project dialog appears: Enter amp01 in the field labeled Project Name. Notice that amp01 is also entered automatically in the top level schematic field. Select Harmonica from the drop-down list in the Simulator field. If it is not available, you have not installed the Harmonica simulator. In the Project Location field, enter the path where you would like the project files to be stored. Select a directory for which you have read and write privileges. Notice that you can click on the ellipses ( ) button to the right of the field to display a Select Project Location browser. The default directory is the user directory, suffixed with amp01. Choose Create from the top of the dialog. Choose Yes if the following prompt appears: Directory specified does not exist. Do you want to create it? 4-2 Creating a New Schematic

3 Creating the First Stage of the Amplifier The Schematic Editor now starts, displaying a new schematic window and toolbars to work with. In addition, the Project window appears on the left side of the Serenade Desktop. You can now start building the circuit. Creating the First Stage of the Amplifier Now that you have created a project to organize your project information, the next step is to get the basic parts needed to construct the circuit. You can get these components by selecting them from the toolbars. Use the figure below as a guide to this section: Figure 4-2 Schematic following initial parts placement ¾ Placing Components The first component you need is a capacitor: Move the cursor onto the toolbar button labeled with a capacitor symbol. Leave the cursor on the button for a couple of seconds and a tooltip will appear with a brief description. Click the left mouse button on the capacitor toolbar button. A capacitor symbol is now associated with the cursor. Move the cursor into the design area. As you move into the design area, the capacitor symbol appears on the screen. Move the symbol to a position approximately halfway down the screen and near the left edge. (Don't worry about precise positioning at this point, you can move the parts later.) Creating a New Schematic 4-3

4 Creating the First Stage of the Amplifier ¾ Assigning Properties Figure 4-3 Properties window for a capacitor Click the left mouse button to place the symbol. The Capacitor, G properties window appears. The window consists of three columns (Property, Value and Visible) and an Attributes section: Property Value Visible The name of each property. The value of each property. Use these fields to enter or change property values. Whether the property name or value appears in the schematic. Possible choices are Nothing, All, or Value. Nothing indicates that neither the property name nor its value will appear in the schematic. All indicates that both the property name and its value will appear. Value indicates that only the property value will appear. Those capacitor properties that have *req* in the Value field must be given values for a successful simulation. Select the checkbox labeled Required in the lower right hand corner of the window to display only these properties. Click on the Value field for the property c. This highlights the field. Type 10pF in the field, replacing *req*. Do not put any spaces between the component value and the component units in the property definition, or your simulation will not run. Choose OK, ignoring the other fields. Select File > Save to save your work up to this point. NOTE Since Serenade tries to create a valid simulator netlist each time you save the circuit, you will receive a warning indicating substrate data not found in data block. To clear this warning, click the cursor in the warning box, then press the right mouse button. Select Clear from the popup menu. This is only a warning and can be ignored for now. 4-4 Creating a New Schematic

5 Creating the First Stage of the Amplifier Now add a transmission line to the circuit: Select the toolbar button labeled with the transmission line symbol (MS Transmission Lines (physical) on the tooltip). Once you re sure you have the correct toolbar button, click the left mouse button. Move the transmission line symbol to a position just to the right of the capacitor (not touching it) and click the mouse to place it. Click on the Value field for the property W and type 10mil in the field, replacing *req*. Again, do not put any spaces between the component value and the component units. Enter 0.25mm in the Value field for the property P. Leave sub as the property value for label. Choose OK. Next, add an inductor. Choose an inductor symbol from the toolbar, and place it just to the right of the transmission line. Enter L1 as the property value for L. L1 will be used as a variable during optimization, and will be assigned a value when you add a variables control block to the circuit. Choose OK. ¾ Using Flyouts Use the flyout toolbar feature to add the FET: Place the cursor on the toolbar button labeled with the FET symbol and the letter M. Leave the cursor on the button until the tooltip Materka FET appears. Click once on the right mouse button, bringing up the FET flyout toolbar containing all the other possible FET model selections. Creating a New Schematic 4-5

6 Creating the First Stage of the Amplifier Figure 4-4 Selecting the FET model Move the cursor onto any button to view its tooltip. Notice that all the nonlinear FET model buttons are yellow and the linear FET model buttons are gray. When the cursor is on top of the (gray) button labeled FET (Empirical Noise), click the left mouse button and move the cursor into the design area. Place the FET symbol just to the right of the inductor (not touching it). The FET model includes standard Harmonica small-signal equivalent circuit parameters such as G, C GS, and F min. Assign values to the FET as listed below: cdg: 0.001pF pgo: 80 cds: 0.05pF rd: 1 cgs: 0.4pF rg: 1 fmin: 2 ri: 5 fn: 8GHz rn: 0.5 g: 30mS rs: 1 gds: t: 2ps ls: 0.05nH tj: 25CEL mgo: 0.6 Choose OK after all values have been entered. Select File > Save, clearing the warning as before with the right mouse button menu. Now place a resistor in the circuit: Select a resistor from the toolbar: Position the resistor beneath the junction of the inductor and the FET (as shown in Figure 4-2). Press the letter R to rotate it 90 degrees, then click the mouse to place it. Enter 300 as the property value for R. Choose OK. The last component in this section is a ground: Select a ground from the toolbar: Place it beneath the FET. 4-6 Creating a New Schematic

7 Creating the First Stage of the Amplifier ¾ Selecting Components Often you will need to move, copy, rotate or delete components after you place them. In general, you need to select these components before you edit them as you did when you were moving them. Selecting Single Components Selecting a single component is a matter of simply clicking on it with the left mouse button. Click on the capacitor which you placed earlier. Notice it becomes highlighted in red to indicate that it is selected. Next, click on the transmission line. Notice that the capacitor becomes deselected and the transmission line becomes selected. Selecting Multiple Components There are two methods for selecting multiple components: Hold down the Shift key on the keyboard while clicking on the components. Click and hold the left mouse button and then drag the cursor to create a rectangle. All the components completely contained in the rectangle will become selected. If you want to select additional components using this method, simply hold down the Shift key while creating the rectangle. Deselecting Components There are two methods for deselecting components: To deselect all components, click the left mouse button in any blank area of the design area. To deselect an individual component, hold down the Shift key and then click on it. ¾ Moving Components At this point the schematic should look like the one in Figure 4-2. It may be useful to move components to line them up. To do this: Place the cursor on top of the component you want to move. Click and hold down the left mouse button. Drag the component into position and release the left mouse button. Select File > Save to save your work up to this point, clearing the warning. Creating a New Schematic 4-7

8 Creating the First Stage of the Amplifier ¾ Editing Selected Components Figure 4-5 First stage of amplifier Now that you know how to select components, you can add and position the remaining components of the first amplifier stage. Use the following figure as a guide in adding these parts: NOTE The component numbers (C1, L2, etc.) have been inserted here for reference in this guide. You may see either no numbers or numbers which are inserted automatically by the program. Use the numbers shown here when we identify elements! Copying Components First, copy the inductor you previously placed in the drawing: Press and hold down the Ctrl key. Place the cursor on the inductor labeled L1, then click and hold down the left mouse button. Move the cursor to the right and a movable copy of the inductor appears under the cursor. Move that image into position as L2 and release the left mouse button to place it. Changing Property Values Since the values for L2 are not the same as those for L1, you need to change them. Double-click on L2. Change the property value for L to 1nH. Choose OK to exit. 4-8 Creating a New Schematic

9 Creating the First Stage of the Amplifier Next, copy the transmission line, place two copies of it, rotate one copy, then place an additional copy of the rotated transmission line. Copy the transmission line: Press and hold down the Ctrl key. Place the cursor on the transmission line, then click and hold down the left mouse button. Move the cursor to the right and a movable copy of the transmission line appears under the cursor. Move it into position as TRL4 and release the left mouse button to place it. Double-click on TRL4. Change the property value for W to W2. Change the property value for P to P2. Make another copy into the vicinity of the TRL3 position using the same method (click and drag while holding down the Ctrl key). While TRL3 is still selected, click on the right mouse button anywhere in the design area to display the edit menu and then click on Rotate (alternatively, you could click on the Rotate button in the toolbar); the transmission line will rotate 90 degrees Change the property value for W to W1 and the property value for P to P1. Copy the rotated transmission line to the TRL2 position using the method outlined earlier. Change the property value for W to 10mil and the property value for P to 1.0mm. Proceed on your own to insert the remaining components by copying and rotating as necessary, using Figure 4-5 as a guide. Assign 25pF to C2, C3, and C4. Assign 10pF to C5. Select File > Save to save the circuit, ignoring the warning. ¾ Changing the View (Zooming) You'll find that the best procedure to roughly place symbols on a page is to have the whole page appear on the screen. However, to precisely place symbols and components, and to draw connecting wires, it is better to view only the small area in which you want to work. The toolbars provide you with several viewing choices: Redraw Causes the screen to redraw the circuit, eliminating any remnants of editing operations. This toolbar button is labeled with a large upper case R. Zoom Window Allows you to specify an area for zooming. This button is labeled with a pair of binoculars. After clicking on the binoculars, position the cursor at one corner of the rectangular area you wish to magnify and click (and hold) the left mouse button. Then move the mouse to drag a box around the area you wish to view. When the box is correctly defined, release the left mouse button. Creating a New Schematic 4-9

10 Creating the First Stage of the Amplifier The Zoom Window button also contains the flyout for the other view functions. To see this, click once on the binoculars with the right mouse button. Then move the left mouse button across all the flyout buttons to see the tooltips. Select a button to execute its associated command (Zoom All, Zoom In, or Zoom Out). Zoom All can also be executed by pressing the number 5 on the keyboard. Zoom in Incrementally causes the drawing to become larger, allowing you to see more detail in the circuit. When you zoom in, the grid dots which appear help you to precisely position components and draw wires neatly Zoom out Incrementally causes the drawing to become smaller, allowing you to see more of the overall circuit. Use Zoom Window to zoom in on the rectangular area from just left of the capacitor to approximately midway across the drawing. ¾ Connecting Components Figure 4-6 Wired first stage of amplifier The next step is to draw the wires which connect the symbols together. Move components into position when necessary. Use the following figure as a guide in adding these parts: 4-10 Creating a New Schematic

11 Creating the Second Stage of the Amplifier Click on the right mouse button anywhere in the schematic design area. Either choose Draw > Wire > Draw Wire or select the Wire Symbols button from the toolbar: Position the cursor on the bottom end of TRL2 and click the left mouse button. As you move the cursor down from that point, you will see a wire stretch from TRL2 to the cursor. Move the cursor to the top end of the C2 capacitor and click the left mouse button. If you were to move the cursor somewhere else, the line would continue to stretch to the new point. However, there are no additional connections between TRL2 and C2, so press the right mouse button to complete the connection. Now press the spacebar to activate the Repeat function. Click on the right end of C1, move slightly right and click again, move up and click, right and click, down and click, then right to TRL1 and click. This puts a jump in the line something that you wouldn't normally do, but it shows how to draw a line with a specific path. Click the right mouse button to complete the connection. Connect all the remaining components, using Figure 4-6 as a guide, until the first stage is fully wired. (Remember, your drawing will not have the identifying part numbers such as L2 or C5. They are shown here only for reference in the documentation.) Save your work by selecting File > Save (or typing Ctrl-S). You will receive a warning as before clear it by clicking the right mouse button in the warning box, and selecting Clear from the popup menu. HELPFUL HINT: If you move any component so that its connecting pin is on the connecting pin of another component, Serenade automatically connects the two. When you move a connected component, a wire is created which maintains the connection. Creating the Second Stage of the Amplifier You are now ready to produce the second stage of the amplifier. Since the first and second stages of the amplifier are identical, you can copy the first stage and use it to create the second. Select Zoom Out from the toolbar to create enough space for selecting and copying the first stage (this will be about twice the space the original schematic occupied). Click and hold the left mouse button, then drag the cursor to create a rectangle around all components to the right of the first capacitor (C1). This capacitor is not needed in the second stage. Release the mouse button and all of the components completely contained in the rectangle are selected. Press and hold down the Ctrl key. Click and hold the left mouse button and move the cursor to the right. A movable copy of the circuit appears. Move this copy to the right of the first stage and release the mouse button. Press the right arrow key on the keypad to page to the right if you are zoomed in too closely. Finally, wire the two stages together (C5 to TRL11). Creating a New Schematic 4-11

12 Creating the Second Stage of the Amplifier ¾ Adding External Ports To finish the schematic, add and connect the ports: Select the Microwave Port toolbar button. A port symbol appears at the cursor. Figure 4-7 Microwave Port properties window Move the symbol to the left of C1 and click the left mouse button to place it. A Microwave Port properties window appears: Enter P1 as the name for the port in the Value field of the label property, and choose OK. Place a second port at the right end of the circuit and name it P2. Wire both ports to the adjacent component. Since the values for L11 and L12 are not the same as the inductors they were copied from, you need to change them: Double-click on L11 and change the value of L from L1 to 0.5nH. Double-click on L12 and change the value of L from 1nH to L1. You should now have a complete circuit as shown in Figure 4-8: 4-12 Creating a New Schematic

13 Creating the Second Stage of the Amplifier Figure 4-8 Completed schematic ¾ Adding a Border and Title Block Figure 4-9 Title Block You can now add a border and write text in the title block. Of course, you can enter text pertinent to yourself. Zoom Out to create enough room to place the border. (The schematic should take up about one quarter of the window.) Select Parts > Border > Complete Border (with title + rev. blocks) > B Size. When the image of the B-size border appears, drag it until it surrounds the schematic. You can reposition the border just like any other component by dragging it with the mouse. Next, select Zoom Window and zoom in on the title block (bottom right corner) so that it fills as much of the screen as possible. Select Add text: A dialog appears, allowing you to enter a text string. Type in the text and choose OK. Then drag the text into position. NOTE To modify, rescale, or change text orientation, double-click on the text to display the Choose Text Style dialog. Repeat the last two steps to insert other text entries in the title block. Save your work by selecting File > Save (or typing Ctrl-S). Again, ignore the warning. Your schematic is now finished. You can plot a hard copy, then continue on to prepare it for the simulation process. Creating a New Schematic 4-13

14 Creating the Second Stage of the Amplifier ¾ Plotting the Schematic Figure 4-10 Print Setup and Print buttons To plot (print) a schematic, you need to first set up the printing criteria (such as which printer to use), then choose File > Print to actually access the printer. Printer Setup To set up the print criteria, either select Print Setup from the toolbar, or File > Print Setup from the main menu. A dialog appears, allowing you to select from your installed printers and specify certain other print criteria. Refer to the Microsoft Windows documentation if you are unfamiliar with these print setup procedures. Print To go ahead with printing, either select File > Print from the main menu, or choose Print from the toolbar. A dialog appears, asking how many copies you want and which pages are to be printed. It will also provide access to options and the Print Setup dialog Creating a New Schematic

15 5 Linear Simulation (Harmonica) In order to simulate a circuit using Harmonica, you need to add control blocks to the circuit symbols that define the simulation parameters. The two control blocks used here are the Substrate Media and the Frequency control blocks. The Substrate Media control block defines the substrate thickness, the dielectric constant, metal type and thickness, and other properties associated with the circuit board. The Frequency control block defines the frequency or range of frequencies at which the circuit will be simulated. Substrate Media Control Block To add the Substrate Media control block: Either select the Substrate Media (Microstrip) toolbar button or select Parts > Substrate Media > Microstrip. Place the symbol that appears in an empty spot in the schematic. When the Substrate Media (Microstrip) property window appears, enter the following values: H:25mil ER:9.8 HU:2500mil label:sub Met2:Cu 50um TAND: Met1:Ni 10um Linear Simulation (Harmonica) 5-1

16 Frequency Control Block Figure 5-1 Substrate Media symbol Choose OK. The symbol should look like the following figure: Frequency Control Block To add the Frequency control block: Figure 5-2 Linear Frequency symbol Either select the Linear Frequency toolbar button or select Parts > Control Blocks > Linear Frequency. Place the symbol that appears in an empty spot in the schematic. When the Linear Frequency property window appears, type the following line in the Value field to specify the frequency range (5 12 GHz) and the step size (0.25 GHz) for the Freq property: STEP 5GHz 12GHz 0.25GHz Choose OK. The symbol should look like the following figure: Save your work up to this point. At this point, you should not get any errors. You now have a schematic suitable for linear simulation by Harmonica. 5-2 Linear Simulation (Harmonica)

17 Preparing for Circuit Optimization Preparing for Circuit Optimization In order for optimization to work, you must define which values can be adjusted by the program. This requires two more control blocks. The Variable control block defines the starting values and ranges of the variables referenced by the circuit components. The Optimization control block defines the parameters which will be optimized, and the range where optimization will be done. ¾ Variable Control Block The Variable control block defines variables used when you created the schematic L1, P1, P2, W1, and W2. To add the Variable control block, Select Parts > Control Blocks > Variables (at the bottom of the menu) or click the Variable Block button on the Linear frequency flyout: Figure 5-3 Variable Block icon Place the symbol that appears in an empty spot in the schematic. The Variable Block properties dialog has no pre-assigned properties. You will have to add five new properties, which will be the variables. W1 and W2 are assigned to a range of values; these parameters will be optimized over that range, starting with the middle value. Click in each field and fill them in as shown in the following figure: Figure 5-4 Variable Block properties window Choose OK after all values have been entered. Linear Simulation (Harmonica) 5-3

18 Preparing for Circuit Optimization ¾ Optimization Control Block The Optimization control block specifies optimization goals. This block tells the simulator that the input and output return losses are to be optimized only over the 7.5 GHz to 8.5 GHz band, and that the output match is weighted fivefold over the input match. To add the Optimization control block: Either select the Linear Optimization toolbar button or select Parts > Control Blocks > Linear Optimization Info (at the top of the menu). Place the symbol that appears in an empty spot in the schematic. When the Properties dialog appears, set FSTART to 7.5GHz and FSTOP to 8.5GHz for the optimization by entering them in the Value fields. Next, add two properties that tell the simulator that the input and output return losses of the circuit are going to be optimized, and that the output match is weighted fivefold over the input match by entering them in the Value fields as follows: Set MS11 value to 15dB LT Set MS22 value to 10dB LT W=5 The Properties dialog should appear as shown in Figure 5-5: Figure 5-5 Optimization properties window Choose OK, and select File > Save to save your work up to this point. 5-4 Linear Simulation (Harmonica)

19 Running the Linear Analysis Running the Linear Analysis Before running a simulation, a netlist has to be created (extracted) to be used by the simulator. A netlist is a text (ASCII) representation of the electrical, physical, and simulation characteristics of the components in a schematic. The netlist is saved as a.ckt file, which can then be used as input to the simulator or the layout tool. The software which extracts the netlist from the schematic is called a netlister. Component properties are very important to the netlister because the schematic s electrical, physical, and simulation characteristics are passed to the netlister through the assigned property values. Therefore, if you are going to create a netlist, you must be aware of which property values that particular netlister requires and which are optional. Serenade automatically extracts a netlist from the schematic as a part of the analysis. You can view the netlist in a separate window by selecting Window > Show > Netlist. You cannot edit the netlist of an open project, since the netlist would no longer accurately describe the project. To generate a netlist for and simulate the schematic: Select the Linear (linear analysis) button from the Serenade Desktop toolbar. To run the analysis, select the Analysis button. Serenade generates a netlist, then runs the simulation. A progress bar indicates the analysis status. If any errors occur, the progress bar displays the message An Analysis Error has Occurred, and the error log provides details. To highlight the error in your schematic window, double-click on the line in the error log. Check the properties of any highlighted components for errors or inconsistencies, such as spaces between the property values and the units. Linear Simulation (Harmonica) 5-5

20 Displaying Results Displaying Results ¾ Rectangular Plot Once you ve finished your schematic and run the simulation, you can display the results of the simulation. You can look at information using a rectangular plot, a table, or a Smith chart. To generate a rectangular plot: Select Edit Reports (Reports > Report Editor) to display the Linear Analysis Reports dialog. This dialog is used to build graphs and tables of simulation results. Notice that the Domain list is set to Frequency and the Output Type list at the top of the dialog is set to Rectangular Plot. In the Report Title field enter: LNA Noise Figure, Input Match and Gain. Select the circuit responses to display. There are three lists at the bottom of the dialog: Circuit, Function and Response. You only have one choice in the Circuit list; leave it set to amp01. Select db() from the Function list. Click anywhere in the Response list and then press the N key on your keyboard. The cursor jumps to the NF response. Choose Add. A line is added to the Response subwindow. Highlight S11 and S21 in the response list (hold down the Ctrl key to select multiple options). Choose Add. Another line is added to the Response subwindow. 5-6 Linear Simulation (Harmonica)

21 Displaying Results Figure 5-6 Setting up a rectangular plot Figure 5-7 Rectangular Plot for amp01 Choose Display to create the rectangular plot. The program generates a new window containing a rectangular plot of Noise Figure, S21, and S11 versus frequency for the amplifier. Note that the status bar displays the cursor position. Choose Close to exit the dialog box and view the plot. Linear Simulation (Harmonica) 5-7

22 Displaying Results Zoom Zooming works very similarly to zooming in the Schematic Editor. Zoom in to view the plot more closely: Click the right mouse button within the rectangular graph window. A popup menu appears. Select Zoom In. The cursor changes to a plotter zoom cursor: Position the cursor at one corner of the rectangular area you wish to magnify and click (and hold) the left mouse button. Then move the mouse to drag a box around the area you wish to view. When the box is correctly defined, release the left mouse button To zoom out, select Zoom Out from the right mouse button menu. 5-8 Linear Simulation (Harmonica)

23 Displaying Results Customizing Graphs Serenade Desktop allows you to customize virtually all the attributes of graphs and tables. In general, any item in a graph window can be selected (highlighted) by clicking on it. For example, place the cursor on top of any one of the numbers which mark the scale for the x axis and click the left mouse button (such as on the above the phrase Freq [GHz]. The x axis is now selected. By double-clicking on an item in the graph, you can access a dialog to help you customize that item. For example, to customize the x axis: Double-click on any of the numbers which mark the scale for the x axis. A dialog box appears, allowing you to customize the color, fonts, or scale of the x axis. You cannot change the line style for the x axis. Figure 5-8 X-Axis Properties dialog Select the Rescale tab to move it to the top. Click on the Autoscale checkbox (in the lower left of the dialog) to turn off autoscaling Enter 9.0 in the Min field and 11.0 in the Max field. Choose Apply and the x axis rescales to reflect the settings in the dialog box. HELPFUL HINT: You can customize another part of the graph without closing down the dialog simply click on the next item to be customized. For instance, you can click on the y-axis Y1 label and give the y axis a more informative name, such as NF, S21, S11 [db]. Click anywhere outside the grid area and the dialog title changes to Background Properties and the Color tab will move to the top. Select another color from the palette, then choose Apply. Choose Close to exit the dialog. Linear Simulation (Harmonica) 5-9

24 Displaying Results ¾ Tables Figure 5-9 Data table for amp01 To generate a data table: Select Edit Reports (Reports > Report Editor) to display the Linear Analysis Reports dialog. Select Data Table from the Output Type pull-down menu. In the Report Title field enter: LNA S parameters. Select the circuit responses to display. You only have one choice in the Circuit list; leave it set to amp01. Leave None selected in the Function list. Click anywhere in the Response list and then press the S key on your keyboard. Select S11, then hold the Shift key down and select S22. The four responses S11, S12, S21, and S22 are selected. Choose Add to create four entries in the Response subwindow. Choose Display to create the table, then choose Close to exit the dialog box. The table appears in a separate window consisting of all four 2-port S parameters for the amplifier. Click on the header section of any column of data to highlight the entire column, and doubleclick on any column header to display the Table Unit Format dialog, which allows you to change the format of the data for that column. To reformat multiple columns, click, hold, and drag across the headers of the columns you want to reformat Linear Simulation (Harmonica)

25 Displaying Results ¾ Smith Chart To generate a Smith chart: Select Edit Reports (Reports > Report Editor) to display the Linear Analysis Reports dialog. Select Polar Plot from the Output Type pull-down menu. In the Report Title field enter: LNA S11 and S22. Select the circuit responses to display. You only have one choice in the Circuit list; leave it set to amp01. Leave None selected in the Function list. Click anywhere in the Response list and then press the S key on your keyboard. Select S11, then scroll down, hold the Ctrl key down, and select S22. HELPFUL HINT: The simulators are very prolific in generating analysis responses, which can result in a very long Response list. Use the Filter button to select the responses you want to have displayed in the list, and to eliminate those responses you don t often use. Choose the Filter button to display the Linear Response Filter dialog. Those items that are checked in the dialog will appear in the Response list. Choose Add to create two entries in the Response subwindow. Choose Display to create the polar plot, then choose Close to exit the dialog box. A polar plot appears in a separate window, showing S 11 and S 22 as a function of frequency. Note that the status bar displays the position where the cursor was last clicked in the graph. Figure 5-10 Polar Plot for amp01 Linear Simulation (Harmonica) 5-11

26 Displaying Results Place the cursor directly on top of either data trace and click the left mouse button to select it. Click the right mouse button within the plot window. A popup menu appears. Select Data Marker. A data marker appears, moving along the data trace as you move the cursor along the trace. You can also move the marker using the left and right arrows on your keyboard. Move the marker from trace to trace using the up and down arrows on your keyboard. Finally, create a permanent marker. Click with the left mouse button anywhere on the data trace. A permanent marker is placed on the trace and a legend box appears, showing the values associated with the marker. Figure 5-11 Polar Plot with data marker Select Exit Marker Mode from the right mouse button menu Linear Simulation (Harmonica)

27 Displaying Results ¾ Tune Mode Figure 5-12 Tune dialog box Tune mode allows you to select a component from the circuit and sweep its value across a range of values while simultaneously viewing output responses. In this example you will select an inductor and sweep its value from 0.5nH to 2nH while viewing the response at each step on the rectangular plot. Close the table and polar plot created earlier. Select Window > Tile Vertically to view the schematic and the rectangular plot simultaneously. Select Tune from the toolbar: The Tune dialog box appears move it so that it doesn t cover the plot or the schematic. In the schematic, double-click on the 1nh inductor connected to the drain of the first FET. The selected element s parameters are entered into the Tune dialog. Select Sweep from the Type list. Enter the sweep range: Enter 0.5 in the Start field. Enter 2 in the End field. Enter 0.5 in the Step field. Clear the % checkbox. This causes the steps to be swept by 0.5nH rather than 0.5%. Choose Tune from the bottom of the dialog box to begin the tune parameter sweep. Linear Simulation (Harmonica) 5-13

28 Displaying Results The program updates the rectangular plot to show the data for each step in the sweep. The legends on the right-hand side of the plot list the traces corresponding to each sweep step. Figure 5-13 Accumulated traces on rectangular plot after tuning When the sweep is completed the message Tune Analysis for 2NH is completed appears. To back-annotate a value to the schematic, select the trace from the plot. The legend associated with that trace is highlighted at the right of the plot. Read the value of the component from the legend. Conversely, you can select the legend that has the component value in which you are interested. The trace associated with the legend is highlighted. Choose Apply from the Tune dialog. The Tune Sweep Values dialog appears, allowing you to select the value associated with the legend or trace you want to back-annotate. Click on the value you want to back-annotate. If you have applied a tuned value and want to return to the original value, choose Revert. Choose Done to exit the Tune dialog. In addition to the Sweep tune method you can use the Step and Single Point/List methods. Experiment these methods to find which ones are the most useful for your applications. The Step method allows you to set a start value and a step size. The Incr and Decr buttons are then activated, so you can adjust the start value by the step amount. Any open graphs or tables are immediately updated. The Single Point/List method allows you to discretely adjust component values Linear Simulation (Harmonica)

29 Displaying Results ¾ Optimization Note that the original circuit gives a result with poor gain and input and output VSWR match from 7.5 GHz to 8.5 GHz. Optimization automatically adjusts the values of certain circuit parameters to produce improved performance performance which is closer to or meets the optimization goals you specified when you placed the OPT control block in the schematic. Optimization adjusts specified circuit parameters, holding all other parameters constant. The optimization process repeats until the performance goals are met, or until the specified number of iterations are completed. The results, in the form of updated circuit parameter values, can then be back-annotated into the schematic. Figure 5-14 The results of analyzing amp01 In this example, you will use the random optimizer to select component values, then the gradient optimizer to narrow the search. Close the original rectangular plot. Create a rectangular plot of S11, S22, and S21 in db. Linear Simulation (Harmonica) 5-15

30 Displaying Results Figure 5-15 Linear Optimization dialog Select the Optimization toolbar button. The Linear Optimization dialog appears. Select Random from the top of the dialog. Enter 100 into the Iterations field. Enter 10 into the Update reports every x iterations field (at the bottom of the dialog). Clear the Apply Manual Scaling to graphs checkbox. Choose Optimize from the lower-left corner of the dialog. Serenade now performs 100 random iterations. The Linear Optimization dialog displays the objective function as it decreases. Click on No More Iterations when the Optimization Iterations dialog appears. Select Gradient and do 30 iterations. NOTE The optimization objective function, also referred to as the error function, is derived from the difference between computed and specified optimization goals. The smaller the error function, the closer the optimizer has come to meeting the optimization goals. During optimization, the variables set up in the schematic (L1, P1, P2, W1, and W2) are optimized in order to meet the performance goals specified in the OPT control block. Select No More Iterations if the Optimization Iterations dialog appears. Choose Analyze, then choose Close to dismiss the Linear Optimization dialog. Choose Window > Tile Horizontally to view all windows Linear Simulation (Harmonica)

31 Displaying Results Notice the improvement in results that is displayed in the rectangular plot which you generated earlier. Your plot may differ slightly due to the way the optimizer randomly selects component values. For more information on optimization, refer to the Linear Optimization chapter in the Reference Volume and Linear Optimization Examples in the Examples Volume. Figure 5-16 The results of optimizing amp01 The simulator automatically modifies the schematic to reflect the results from the optimization. Double-click on the VAR control block in the schematic to display the VAR properties page. Notice that the values for L1, P1, W1, P2, and W2 have all been updated to the optimized values. Linear Simulation (Harmonica) 5-17

32 Displaying Results 5-18 Linear Simulation (Harmonica)