011/100 Example 1.5-1 Single Layer Capacitor

100 ADS Design Examples Based on the Textbook: RF and Microwave Circuit Design
Michael Benker
Example 1.5-1 Consider the design of a single layer capacitor from a dielectric that is 0.010 inches thick and has a dielectric constant of three. Each plate is cut to 0.040 inches square. Calculate the capacitor value and its Q factor.

Capacitance formed by a dielectric material between two parallel plate conductors:

C = (N-1)(KAεr/t)(FF) pF

A: plate area
εr: relative dielectric constant
t: separation
K: unit conversion factor; 0.885 for cm, 0.225 for inches
FF: fringing factor; 1.2 when mounted on microstrip
N: number of parallel plates



004/100 Example 1.3-1B Parasitic Elements of a Physical Resistor vs. Frequency

100 ADS Design Examples Based on the Textbook: RF and Microwave Circuit Design
Michael Benker
Example 1.3-1B: Plot the impedance of a 5 Ω leaded resistor in ADS over a frequency range of 0 to 2 GHz.


This indicates a resonance at 500 MHz. This is due to the parasitic iductance and capacitance that exists on a real resistor. The resistor behaves as a combination of series parasitic inductance and resistance, in parallel with a parasitic capacitance.

The impedance of an inductor is reduced as the frequency increases, while the impedance of a capacitor increases as the frequency increases. The intersection frequency of these two patters meet is the resonant frequency.

The resonance frequency can be found from equating XL and XC. The formula is:

Resonant frequency fR = 1/(2*pi*sqrt(LC))

002/100 Example 1.2-4 Skin Effect and Flat Ribbons

100 ADS Design Examples Based on the Textbook: RF and Microwave Circuit Design
Michael Benker
Example 1.2-4 Calculate the inductance of the 3 inch Ribbon at 60 Hz, 500 MHz, and 1 GHz. Make the ribbon 100 mils wide and 2 mils thick.


The flat ribbon inductance is calculated with the following equation:

L = K*l*[ ln((2*l)/(W+T))+0.223*(W+T)/l + 0.5 ] nH

l: length of the wire
K: 2 for dimensions in cm and K=5.08 for dimensions in inches
W: the width of the conductor
T: the thickness of conductor


001/100 Example 1.2-1 Reactance and Inductance with respect to Frequency

100 ADS Design Examples Based on the Textbook: RF and Microwave Circuit Design
Michael Benker
Example 1.2-1: Calculate the reactance and inductance of a three inch length of AWG #28 copper wire in free space at 60 Hz, 500 MHz, and 1 GHz.



> The increase in reactance with respect to frequency represents the skin effect property, in which, as the frequency increases, the current density begins to be concentrated on the surface of a conductor.

OrCAD Tutorial/Study Guide

This post outlines the steps needed to create a schematic using OrCAD and then prepare it for manufacture as a PCB board. Writing this post helps me to learn OrCAD better and this will serve as a guide for review later. I will be using the free version, OrCAD Lite.


Opening a new project

1. First, start a new project.



2. Give the project a name and create the folder that you want for the project files. Select PSpice Analog or Mixed A/D.



3. Select “Create a blank project” if starting from scratch.



Building the Schematic

4. Select the “Place Part” button or press P to open the parts menu.



5. This next part requires a bit of knowledge about where which libraries the components are found under. Here, I want to place a resistor, so I typed R and selected the library “Analog”. If the libraries are not added, you can find them in the OrCAD folder on the PC and add them using the “Add libraries” button shown on the screen.



6. Double-click on the part in the menu to place it on the schematic page. I also added a VDC, which is found in the Source library. Finish placing parts.



7. In this case, I will add an LED, but I am unable to find it in the Place Part menu. To find what I am looking for, I chose “Place”, “PSpice Component…” and “Search…” to open a new menu shown below. Further components can be found here if you are unable to find what you need. Under part name and description, select one from the list to add it to the schematic.



8. Press G on the keyboard to add a ground. I chose “0/CAPSYM”. Now select the “Place Wire” button or W to put down the wires.



9. Double-click on the voltage and resistor values to change them as necessary.




10. To run a simulation, on the drop down menu, select “PSpice”, “New Simulation Profile”. Give this simulation a name.




11. Define the parameters for this simulation, click apply and Ok.



12. Select the voltage probe and add it to the circuit.



13. Select “Run” and open the new simulation window to view results.




PCB Design

14. First, a folder will be created for the PCB. Rename the schematic folder in the main project folder., then rename the default “PAGE1” page name.




15. Right-click on the main project folder and create a new schematic. This will be for the PCB board. Now, copy the schematic from the schematic folder and paste it to the new PCB folder. Rename the copied schematic to indicate it is for PCB and not the schematic.





16. Make the PCB folder the root folder. Click and open the PCB schematic file.



17. For the PCB board, the DC voltage needs to be replaced with connectors. Select the VDC and delete it. Select “Place Part” and choose to add a new library. The connectors are found in the library folder shown below.





18. Select CON1 from the part list and place the parts where the VDC was connected. Remember to save.



19. Select all the components and go to “Edit”, “Properties”.  Select the “Parts” tab on the lower left.




20. Scroll to the right to view the PCB Footprint tab. The footprint names here are then changed to the footprint names found in the libraries. Save.



21. Now, open the OrCAD PCB Designer program and create a new drawing in the main project folder. I put it in a separate folder inside the project folder. Selecting the board wizard will take you through a series of prompts.



22. Continue through the wizard (in this case using only default settings until Spacing Constraints). At Spacing Constraints, change the Minimum line width from the default 0 (this default setting can be problematic). Then select the default via padstack. I chose “Via”. Select ok. Continue through the wizard. In this case, choose a rectangular board. After finishing the wizard, you will see an empty square. Now, save and close the PCB designer.




23. Go back to Capture CIS, open the project tab and select the PCB schematic file. Select “Tools”, “Create Netlist…” to begin transferring the schematic to a printed circuit board. Select Create of Update PCB Editor Board and choose the file created using OrCAD PCB Designer. For the output file, I chose to output the board to the same file, since I won’t be needing the empty board file. Now, select Open Board in OrCAD PCB Editor and select OK.




24. Now, go to “Place”, “Components Manually…” to add the parts from the schematic to the PCB. Select the components you need to place (or select all if you will place all of them) and hide the menu.




25. Place the parts on the board. Parts may need to be rearranged to fit nicely. When satisfied,, right-click and select “Done”. Save and “overwrite”.



26. Now select in the menu, “Route”, “Connect” to place wires connecting the components. When finished, right-click and select “Done”. Once again, save and “overwrite”.




Generating Gerber and Drill files and Online Check


20 GHz RF Amplifier Design – ADS

ECE336 – Electromagnetic Theory II, Professor Dr. Yifei Li
April 2019
Michael Benker
20 GHz RF Amplifier Design – ADS

This is a 20 GHz amplifier circuit, made using smith chart impedance matching in ADS. This circuit is one of the first times I have used this powerful software. Glad to be putting my emag theory to work to build something real. The report should be helpful for me to jog my memory to do it again. With the notes I have, a similar circuit should be possible.

For the impedance matching, I considered using an inductor, though using only caps and t-lines, the result seemed to be cleaner.



See the following for the full report:



[1]B. E. A. Saleh and M. C. Teich, Fundamentals of photonics. Hoboken: Wiley, 2019.


[3]Barton Zwiebach. 8.04 Quantum Physics I. Spring 2016. Massachusetts Institute of Technology: MIT OpenCourseWare, https://ocw.mit.edu. License: Creative Commons BY-NC-SA.

[4]R. Hunsperger, Integrated optics. Berlin: Springer, 2002.

[5]K. Ng, Complete guide to semiconductor devices. New York: Wiley-Interscience, 2002.

[6]J. Wilson and J. Hawkes, Optoelectronics. Prentice Hall, 1998.

[7]D. Pozar, Microwave engineering. .

[8]D. Neamen, Semiconductor physics and devices. New York: McGraw-Hill, 2012.

[9]S. Haykin and M. Moher, Introduction to analog and digital communications. Hoboken, N.J.: J. Wiley & Sons, 2007.

[10]SILVACO, ATLAS User’s Manual. 1998.

[11]2.3.1 III-V Semiconductors and Optoelectronics. (n.d.). Retrieved March 08, 2020, from https://www.tf.uni-kiel.de/matwis/amat/semitech_en/kap_2/backbone/r2_3_1.html


Electrical Engineering Students at University of Massachusetts Dartmouth