Over the last three weeks, you have been incrementally developing some basic modeling and simulation skills by completing a software orientation and by building and simulating two basic RF/microwave components in the Microwave Office software. This week, you will examine the behavior of a parallel line coupler.
First, read this linked article on the basic definitions of RF directional couplers. Here you will see that the directional coupler is treated as a four-port device and that there are specific names given to the amount of power transmitted between the various ports, i.e. S21 = mainline loss, S31 = coupling loss, S41 = directivity, etc.
Next, review the Microstrip Edge Coupled Directional Coupler Design that starts on page 24 of the linked file. It was written for a software tool called ADS, but it shows you the general setup of a directional coupler simulation. (Note: ADS (Advanced Design System) is a software tool that competes with NI’s AWR Microwave Office.) This article from Microwaves 101 may also be helpful because it has a section that is AWR specific.
Once you have familiarized yourself with these materials, build the circuit on page 26 of the ADS example in MWO. Simulate and verify that your results are similar to those on page 27. (Note: in MWO the coupled line schematic element is called MCLIN)
These steps verify that you know how to setup and simulate a directional coupler properly.
For your assignment, modify the line length and spacing to produce a coupler with a 20 dB coupling factor at 10 GHz. (Note: To help you calculate the required spacing, try the built in calculator in MWO: TOOLs -> TXLine ->Coupled MS Line tab.)
Submit the documents:
A copy your microwave office design file (*.emp)
I need the answer designed in microwave office and the file attached. This is the only requirement that’s needed to be done. Thanks.