EELE 461561 Digital System Design ADS Mo Mentum

EELE 461/561 – Digital System Design ADS Mo. Mentum EE 461 – Digital System Design Spring 2010 Page 1

Momentum • Objectives 1) Create a Microstrip Layout in ADS with a custom substrate stackup 2) View the layout using the 3 D Preview 3) Run a Field Simulation and view the S-parameters 4) Run a transient SPICE Simulation using the field-simulation data EE 461 – Digital System Design Spring 2010 Page 2

Momentum • Part 1: Create a Microstrip transmission line layout - create a new design - enter the MLIN and MSUB components from the T-lines – Microstrip library - enter the desired parameters for the substrate and microstrip EE 461 – Digital System Design Spring 2010 Page 3

Momentum • Part 1: Create a Microstrip transmission line layout - Using the pull-down menu in the schematic, perform: - Layout – Update/Generate Layout - In the layout, use the pull-down menus to perform: - Momentum - Substrate –Update from Schematic EE 461 – Digital System Design Spring 2010 Page 4

Momentum • Part 1: Create a Microstrip transmission line layout - Enter two ports to your microstrip structure using the pull-down menus: - Insert – Port (accept defaults) - Rotate and attach to the microstrip as in the following figure: EE 461 – Digital System Design Spring 2010 Page 5

Momentum • Part 2: View the structure using the 3 D Previewer - Using the pull-down menus, perform: - EMDS – 3 D EM Preview EE 461 – Digital System Design Spring 2010 Page 6

Momentum • Part 3: Run a field simulation - Using the pull-down menus, perform: - Momentum – Substrate – Precompute - Set the frequency range to (100 MHz to 10 GHz) and click OK - Using the pull-down menus, perform: - Momentum – Simulation – S-parameters - On the right of the screen, enter: - Sweep Type - Start - Stop - Points/Decade = Log = 100 MHz = 10 GHz =5 - Click “Update” to add to Frequency Plan - Click “Simulate” EE 461 – Digital System Design Spring 2010 Page 7

Momentum • Part 3: View the S-parameter Results - The S-parameters for all ports will automatically appear when the field simulation completes. - You should change the frequency axis to LOG EE 461 – Digital System Design Spring 2010 Page 8

Momentum • Part 4: Run a transient simulation using the field-solver data - Back in the schematic, enter a full schematic using your Gaussian 35 ps step (the figure below shows an ideal step) EE 461 – Digital System Design Spring 2010 Page 9

Momentum • Part 4: Run a transient simulation using the field-solver data - Run the transient simulation and observe the performance of the microstrip line - notice the impedance discontinuity on the TDR - notice the frequency dependant loss on the TDT (i. e. , the slow tail) EE 461 – Digital System Design Spring 2010 Page 10