1. ADS – APPLICATION IN FILTER DESIGN Soh Ping Jack

2. 2 4KNOW YOUR SOFTWARE - ADVANCED Now what about if there you have a subordinate which is able to help you do all the tunings provided that: 1. You tell him all the limits of the design to be tuned 2. He will do all the tuning of the variable individually and repeatedly until the best results is obtained 3. You can still ask him to do it again if you are not satisfied with the result or u changed ur mind (and he wont mind)

3. 3 4KNOW YOUR SOFTWARE - ADVANCED Yes! There is such person! And better still, he wont lose his temper. The best thing is, you don’t even have to say “thank you” or treat him coffee His name is “THE OPTIMIZER”

4. 4 4KNOW YOUR SOFTWARE - ADV Steps to be followed when instructing the optimizer: 1. Select components to be optimized 2. Specify optimization parameters (min, max) 3. Insert OPTIM component 4. Insert GOAL component 5. Simulate to optimize 6. Update optimized values

5. 5 4KNOW YOUR SOFTWARE - ADV 1. Select components to be optimized 2. Specify optimization parameters (min, max) 3. Insert OPTIM component 4. Insert GOAL component 5. Simulate to optimize 6. Update optimized values

6. 6 4KNOW YOUR SOFTWARE - ADV As previously shown, definition of the variables can be made by double clicking the “Var Eqn” icon

7. 7 4KNOW YOUR SOFTWARE - ADV 1. Select components to be optimized 2. Specify optimization parameters (min, max) 3. Insert OPTIM component 4. Insert GOAL component 5. Simulate to optimize 6. Update optimized values

8. 8 4KNOW YOUR SOFTWARE - ADV The OPTIM icon has several important settings, which are: 1. OptimType: defines the type of optimization to be applied, either 2. Desired Error: Defines the smallest error that is tolerable in the optimization 3. MaxIters: Defines the max no of repeats for error minimization in the optimization process

9. 9 4KNOW YOUR SOFTWARE - ADV The “OPTIM” icon can be found from the drop down menu at the top tool bar. Select the “Optim/Stat/Yield/DOE” option

10. 10 4KNOW YOUR SOFTWARE - ADV Select the “OPTIM” button at the left hand side tool bar, and place it on the schematic

11. 11 4KNOW YOUR SOFTWARE - ADV 1. Select components to be optimized 2. Specify optimization parameters (min, max) 3. Insert OPTIM component 4. Insert GOAL component 5. Simulate to optimize 6. Update optimized values

12. 12 4KNOW YOUR SOFTWARE - ADV Some overview of goals Define the expression to be optimized Define simulation Define expression “target box”

13. 13 4KNOW YOUR SOFTWARE - ADV Some overview of goals (cont) Specify minimum & maximum based on “target box” Min & max can be left blank for don’t care conditions Weight: Leave blank unless want to emphasize certain goals Specify range variable, min, and max based on target box

14. 14 4KNOW YOUR SOFTWARE - ADV Setting Optimization Goals – Insertion Loss Example Expression: dB(S21) Simulation: SP1 Target box:

15. 15 4KNOW YOUR SOFTWARE - ADV Optimization Goals - Passband Symmetrical 5-element filter using same coil Insertion loss (S21) < 0.5 dB from 403 to 490 MHz (50 MHz guard band from 440 MHz) 2fc attenuation > 35 dB for freq > 750 MHz Return loss (S11) > 15 dB

16. 16 4KNOW YOUR SOFTWARE - ADV Optimization Goals - Passband Symmetrical 5-element filter using same coil Insertion loss (S21) < 0.5 dB from 403 to 490 MHz (50 MHz guard band from 440 MHz) 2fc attenuation > 35 dB for freq > 750 MHz Return loss (S11) > 15 dB

17. 17 4KNOW YOUR SOFTWARE - ADV Optimization Goals - Passband Symmetrical 5-element filter using same coil Insertion loss (S21) < 0.5 dB from 403 to 490 MHz (50 MHz guard band from 440 MHz) 2fc attenuation > 35 dB for freq > 750 MHz Return loss (S11) > 15 dB

18. 18 4KNOW YOUR SOFTWARE - ADV Optimization Goals - Stopband Symmetrical 5-element filter using same coil Insertion loss (S21) < 0.5 dB from 403 to 490 MHz (50 MHz guard band from 440 MHz) 2fc attenuation > 35 dB for freq > 750 MHz Return loss (S11) > 15 dB

19. 19 4KNOW YOUR SOFTWARE - ADV Optimization Goals - Stopband Symmetrical 5-element filter using same coil Insertion loss (S21) < 0.5 dB from 403 to 490 MHz (50 MHz guard band from 440 MHz) 2fc attenuation > 35 dB for freq > 750 MHz Return loss (S11) > 15 dB

20. 20 4KNOW YOUR SOFTWARE - ADV Optimization Goals – passband RL Symmetrical 5-element filter using same coil Insertion loss (S21) < 0.5 dB from 403 to 490 MHz (50 MHz guard band from 440 MHz) 2fc attenuation > 35 dB for freq > 750 MHz Return loss (S11) > 15 dB

21. 21 4KNOW YOUR SOFTWARE - ADV Optimization Goals – passband RL Symmetrical 5-element filter using same coil Insertion loss (S21) < 0.5 dB from 403 to 490 MHz (50 MHz guard band from 440 MHz) 2fc attenuation > 35 dB for freq > 750 MHz Return loss (S11) > 15 dB

22. 22 4.0KNOW YOUR SOFTWARE - ADV 4.1Selecting & Setting Variables To edit the property of variables for optimization purposes, click on “Simulate” button at the top of window. Select “Optimize” option, OR press “F7” button

23. 23 4.0KNOW YOUR SOFTWARE - ADV Optimization Optimizer will try to reduce the current error function (CurrentEF in the dialogue box) to reach 0

24. 24 4.0KNOW YOUR SOFTWARE - ADV Changing the limits to cater for EF = 0 (Cap) CurrentEF has not reached 0 after optimization has stopped due to the limitations that we have set for the components. A new limit has to be set for both C

25. 25 4.0KNOW YOUR SOFTWARE - ADV Changing the limits to cater for EF = 0 (Cap) Both Cmid and Cend optimization limits are changed to have a limit of 50 instead of the previous 20

26. 26 4.0KNOW YOUR SOFTWARE - ADV Changing the limits to cater for EF = 0 (Ind) CurrentEF has not reached 0 after optimization has stopped due to the limitations that we have set for the components. A new limit has to be set for L

27. 27 4.0KNOW YOUR SOFTWARE - ADV Changing the limits to cater for EF = 0 (Ind) LCoil optimization limit is changed to have a limit of 2 instead of the previous lower limit of 12 Optimization limits have to be repeatedly modified to reduce the error function to a minimal level

28. 28 4.0KNOW YOUR SOFTWARE - ADV Are the results good enough? Forward transmission (S21) between 403 MHz to 440 MHz is less than 0.5 dB. Have a rolloff margin of > 50 MHz. But response look like a BPF?

29. 29 4.0KNOW YOUR SOFTWARE - ADV Are the results good enough? Forward transmission (S21) should have an attenuation of 35 dB at 750 MHz. In this case, this is failing

30. 30 4.0KNOW YOUR SOFTWARE - ADV Are the results good enough? Forward transmission (S21) should have an attenuation of 35 dB at 750 MHz. In this case, this is failing

31. 31 4.0KNOW YOUR SOFTWARE - ADV Are the results good enough? Return Loss (S11) should have an attenuation of > 15 dB at passband. In this case, this is failing as at 440 MHz, S11 = -14.706

32. 32 4.0KNOW YOUR SOFTWARE - ADV How about trying out our skills? Design a three-section bandstop lumped element filter with a 0.5 dB equal-ripple response, a bandwidth of 10% centered at 3 GHz, and impedance of 50 Ω. Tune or optimize to get the best response.