1. ADS – APPLICATION IN FILTER DESIGN - Layout
Nurul Husna Mohd Rais
Soh Ping Jack

2. Presentation Outline Filter Design Process & Implementation
Filter Design Example
Implementation using Distributed Elements
Lumped Element to Stubs Conversion
Selecting & Placing Components
Description of Components
Board Parameters

3. Filter using Distributed Elements
Filter Design Process & Implementation
Remember this process?
Low-pass Prototype Design
Filter Specification
Scaling & Conversion
Done using ADS
Optimization & Tuning
Filter Implementation
Etc etc….
Filter using Distributed Elements
Filters using stubs

4. Filter Design Example
Example Design a low pass filter for fabrication using microstrip lines. The specifications are: cutoff freq of 4 GHz, third order, impedance of 50 ohms and a 3dB equal ripple characteristics g1 = = L1 g2 = = C2 g3 = = L3 g4 = = RL

5. Implementation using Distributed Elements

6. Lumped Element to Stubs Conversion

7. Selecting and Placing Elements
To select a specific element, ensure that the “Tlines Microstrip Components” tab is selected. Specific element are sorted into these categories as shown in the box below

8. Selecting and Placing Elements - MLIN
To insert the MLIN component 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

9. Selecting and Placing Elements - MLOC
To insert the MLOC 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

10. Description of Components
MSUB component
General substrate characteristic of printed
circuit board
MLIN component
Represents short lengths of microstrip
transmission line used in LPF.
MLIN1
Correspond to transmission line section 1.

11. Board Parameters
Set the characteristics of the substrate “MSUB1” as to H = 0.813mm, T = 0.035, Er =3.8, and Cond = 5.8E+07 (conductivity of copper). The rest of the parameters leave as default. The parameters dialog box for MSUB can be invoked by doubling clicking on the MSUB component.
Set the characteristic W and L of each MLIN components.
The filter specification, physical parameters, and the even and odd mode line must be enter into LineCalc.

12. Board Parameters
To design a low pass filter on a RT/Duroid 6002 board with the following parameters:
tanδ = 0.019
εr = 3.38
Metallization Layer Thickness (t) = 35 um
Substrate Height (h) = mm
Desired Freq Range (f) = 4 GHz

13. Board Parameters Board Cross Section & Substrate Definition
tanδ = 0.019
εr = 3.38
Metallization Layer Thickness (t) = 35 um
Substrate Height (h) = mm
Conductivity = 5.8e+07

14. W and L from LineCalc Tool
To obtain the value of physical dimension (W & L) of component, LineCalc from ADS tool.
Click Tools>LineCalc>Start LineCalc

15. Presentation Outline Filter Design Process & Implementation
Filter Design Example
Implementation using Distributed Elements
Lumped Element to Stubs Conversion
Selecting & Placing Components
Description of Components
Board Parameters
Dimensions from LineCalc
Inserting

16. Dimensions from LineCalc Tool

17. Dimensions from LineCalc Tool
Substrate Parameters εr = 3.38 Miur = 1mm H = 0.813mm Hu = 0.813mm T = Cond=5.8E7 TanD = Component parameters Freq = 4GHz
Electrical Z0 = 50Ω E_eff = 90degres

18. Dimensions from LineCalc ToolZ0 L W 50
64.9
70.3
217.5

19. Inserting Dimensions
Doble click the MLIN component and insert the L and W value obtain from the LineCalc.

20. Filter Implementation

21. Generating Layout

22. Generating Layout