ADS – APPLICATION IN FILTER DESIGN

1. ADS – APPLICATION IN FILTER DESIGN Soh Ping Jack

2. 1.0 FILTER DESIGN PROCESS Low-pass Prototype Design Filter Specification Scaling & Conversion Done using ADS Optimization & Tuning Filter Implementation

3. 1.2 GENERAL STEPS IN FILTER DESIGN • Know your filter specifications • Max Flat/Equal Ripple, • LPF/HPF/BPF/BSF • Desired freq of operation • Passband & stopband range • Max allowed attenuation (for Equal Ripple) • Design your LPF Prototype • Min Insertion Loss level, No of Filter Order/Elements • Determine whether shunt cap model or series inductance model to use • Determine elements’ values from Prototype Table

4. 1.3 FILTER DESIGN PROCESS Low-pass Prototype Design Filter Specification Scaling & Conversion Done using MWO Optimization & Tuning Filter Implementation

5. 1.4 GENERAL STEPS IN FILTER DESIGN • Scaling & Conversion • Draw LPF filter prototype • Determine if there are any conversion to HPF/BPF/BSF required • If yes, convert the LPF to the desired HPF/BPF/BSF filter prototype. If no, move on to step 4. • Use equations to de-normalize cap & inductance values • Re-draw de-normalized filter prototype

6. 1.5 FILTER DESIGN PROCESS Low-pass Prototype Design Filter Specification Scaling & Conversion Done using ADS Optimization & Tuning Filter Implementation

7. 1.4 GENERAL STEPS IN FILTER DESIGN • Filter Implementation & Optimization • Draw de-normalized LPF filter prototype with elements’ values • Implement filter prototype on software • Optimize & tune filter to get best response To do this you have to be familiar with ADS

8. 2.0 KNOW YOUR SOFTWARE - BASIC 2.1 Working in the Circuit Schematic Environment 2.2 Selecting & placing elements 2.3 Setting project frequency range 2.4 Changing elements’ values 2.5 Adding result Graphs & Charts

9. 2.0 KNOW YOUR SOFTWARE - BASIC 2.1 Working in the Circuit Schematic Environment 2.2 Selecting & placing elements 2.3 Setting project frequency range 2.4 Changing elements’ values 2.5 Adding result Graphs & Charts

10. 2.0 KNOW YOUR SOFTWARE - BASIC 2.1 Working in the ADS Environment To open up the program, double click on the ADS icon

11. 2.0 KNOW YOUR SOFTWARE - BASIC 2.1 Working in the ADS Environment A pop-up window like this will appear after clicking “New Project”, name your project as “Filter” (or any other names) andclick on “OK” button after entering the desired name

12. 2.0 KNOW YOUR SOFTWARE - BASIC 2.1 Working in the ADS Environment A blank schematic like this will appear. It is used for the placement of components/elements

13. 2.0 KNOW YOUR SOFTWARE - BASIC 2.1 Working in the Circuit Schematic Environment 2.2 Selecting & placing elements 2.3 Setting project frequency range 2.4 Changing elements’ values 2.5 Adding result Graphs & Charts

14. 2.0 KNOW YOUR SOFTWARE - BASIC 2.2 Selecting and Placing Elements To select a specific element, ensure that the “Lumped Components” tab is selected. Specific element are sorted into these categories as shown in the box below

15. 2.0 KNOW YOUR SOFTWARE - BASIC 2.2 Selecting and Placing Elements For example, to select a inductor, select “Lumped elements” category on the top drop down menu. A specific lumped element (inductor) then can be selected from the box at the bottom

16. 2.0 KNOW YOUR SOFTWARE - BASIC 2.2 Selecting and Placing Elements To insert the desired element into the schematic, click on the specific element in the bottom box and drag till an outline of the element appear as shown. Click again to place the element

17. 2.0 KNOW YOUR SOFTWARE - BASIC 2.2 Rotating Elements To rotate the element after placing it on the schematic, right click on the element and select “rotate” function.

18. 2.0 KNOW YOUR SOFTWARE - BASIC 2.2 Rotating Elements The rotated element will be rotated 90 degrees after this function is applied

19. 2.0 KNOW YOUR SOFTWARE - BASIC 2.1 Working in the Circuit Schematic Environment 2.2 Selecting & placing elements 2.3 Wiring, grounding, adding ports 2.4 Setting project frequency range 2.5 Changing elements’ values 2.6 Adding result Graphs & Charts

20. 2.0 KNOW YOUR SOFTWARE - BASIC 2.3 Wiring and grounding To start wiring the components together, click on the wire icon and start creating connections from node to node

21. 2.0 KNOW YOUR SOFTWARE - BASIC 2.3 Wiring and grounding All connection from node to node between components will be created

22. 2.0 KNOW YOUR SOFTWARE - BASIC 2.3 Wiring and grounding To insert a ground node, click on the “Insert Ground” icon at the top tool bar

23. 2.0 KNOW YOUR SOFTWARE - BASIC 2.3 Wiring and grounding The ground is then placed at the desired nodes

24. 2.0 KNOW YOUR SOFTWARE - BASIC 2.3 Adding S-parm simulator A termination must be added to continue with the S parameter simulation. Click on the “Term” icon on the right tool bar. The termination network components are actually sinusoidal voltage components with an ideal series resistor

25. 2.0 KNOW YOUR SOFTWARE - BASIC 2.3 Adding S-parm simulator Click to wire all the “Term” components as shown and ground it

26. 2.0 KNOW YOUR SOFTWARE - BASIC 2.3 Adding S-parm simulator To proceed with an S parameter simulation, a simulator must be added into the schematic. The “Simulation-S_param” palette is selected from the drop down menu

27. 2.0 KNOW YOUR SOFTWARE - BASIC 2.3 Adding S-parm simulator Select the “S P” icon and click on anywhere on the schematic to place the S-parameter simulator

28. 2.0 KNOW YOUR SOFTWARE - BASIC 2.3 Setting project frequency range Define desired “Start Freq”,“Stop Freq” & “Freq Step”. In this case, it should be from 1.5 GHz till 4.0 GHz with steps of 0.01 GHz

29. 2.0 KNOW YOUR SOFTWARE - BASIC 2.1 Working in the Circuit Schematic Environment 2.2 Selecting & placing elements 2.3 Setting project frequency range 2.4 Changing elements’ values 2.5 Adding result Graphs & Charts

30. 2.0 KNOW YOUR SOFTWARE - BASIC 2.4 Changing elements’ values To edit an element’s value, double-click on the element’s default value and enter a desired value

31. 2.0 KNOW YOUR SOFTWARE - BASIC 2.4 Elements’ Values Before starting the simulation, ensure that all the capacitor and inductor values are as shown in this figure.

32. 2.0 KNOW YOUR SOFTWARE - BASIC 2.4 Starting the simulation To start the simulation, click on the “Simulate” button at the top toolbar.

33. 2.0 KNOW YOUR SOFTWARE - BASIC 2.1 Working in the Circuit Schematic Environment 2.2 Selecting & placing elements 2.3 Setting project frequency range 2.4 Changing elements’ values 2.5 Adding result Graphs & Charts

34. 2.0 KNOW YOUR SOFTWARE - BASIC 2.5 Adding result Graphs & Charts – Add Graph After clicking the “Simulate” button, a pop up window like this will appear, showing the progress of the simulation

35. 2.0 KNOW YOUR SOFTWARE - BASIC 2.5 Adding result Graphs & Charts – Graph Types Rename the graph as preferred After simulation completion, a “Data Display Window” will appear.

36. 2.0 KNOW YOUR SOFTWARE - BASIC 2.5 Adding result Graphs & Charts – Add Graph To display the S parameters of this simulation, a “rectangular plot” graph type is selected. Drag and drop the graph onto the display area.

37. 2.0 KNOW YOUR SOFTWARE - BASIC 2.5 Adding result Graphs & Charts – Select Meas After inserting the appropriate graph type, it still does not know what type of parameters that is to be plotted on it. To define this, double click on the parameters “S11” and “S21”. Choose the display units (in dB) A pop-up window like this will appear, select the appropriate parameters to be displayed in rectangular form

38. 2.0 KNOW YOUR SOFTWARE - BASIC 2.5 Adding result Graphs & Charts – Simulate The graph will show the results as displayed here.

39. 2.0 KNOW YOUR SOFTWARE - BASIC 2.5 Adding result Graphs & Charts – Results Filter Design Criteria A good S11 will have a response at the desired design freq with < -10dB value in pass band A good S21 will have almost 0dB response in pass band, & infinite response in stop band

40. 3.0 D.I.Y No. 1 Simulate the following design in ADS. Save the file.

41. 3.1 KNOW YOUR SOFTWARE - INTERMEDIATE 3.1.1 Selecting & Setting Variables 3.1.2 Analyzing & Tuning

42. 3.1 KNOW YOUR SOFTWARE - INTERMEDIATE Re-open the file that was saved earlier in DIY No 1.

43. 3.1 KNOW YOUR SOFTWARE - INTERMEDIATE 3.1.1 Selecting & Setting Variables To start manual tuning of certain parameters in a schematic, the “Tune Parameter” in the schematic should be selected

44. 3.1 KNOW YOUR SOFTWARE - INTERMEDIATE 3.1.1 Selecting & Setting Variables Immediately after the “Tune” button is clicked, a Status Window and a Tuning Controller window will appear

45. 3.1 KNOW YOUR SOFTWARE - INTERMEDIATE 3.1.1 Selecting & Setting Variables Add another rectangular plot to see the changes on S11 and S21 when the Tuner is tuned.

46. 3.1 KNOW YOUR SOFTWARE - INTERMEDIATE 3.1.1 Selecting & Setting Variables The parameters values that are to be tuned can be selected from the schematic. Once selected effectively, it will appear in the tuning controller as shown on the left

47. 3.1 KNOW YOUR SOFTWARE - INTERMEDIATE 3.1.1 Selecting & Setting Variables The parameters values that are to be tuned can be selected from the schematic. Once selected effectively, it will appear in the tuning controller as shown on the left

48. 3.1 KNOW YOUR SOFTWARE - INTERMEDIATE 3.1.1 Selecting & Setting Variables A variable tuning toolbar like this will appear before you. The nominal, max, min and step of tunable values/range can be set here by users

49. 3.1 KNOW YOUR SOFTWARE - INTERMEDIATE 3.1.2 Analyzing & Tuning Ensure that the variable tuner controller slider bar is also easily accessible. Notice the difference of S11 and S21 values when sliding the values of the capacitance up and down

50. 3.1 KNOW YOUR SOFTWARE - INTERMEDIATE 3.1.2 Analyzing & Tuning To further observe the effect of capacitance values, the “Store” button can be pressed to hold the initial (old) values before tuning