cpw microstrip transition

Hi Guys,
Is there anybody out there having some experience how to simulate in HFSS a rectangular waveguide to microstrip/CPW transition?

I tried to simulated a probe already widely published, but I am having some problems how to set up my model......


One of my problems is how to plot the probe's impedance when I dembeed the port until the probe feed point.

Any help?

plz reply

Regards

I've done WG-to-microstrip transition for TE10 mode in HFSS a couple of years ago, which directly converts the transmisison line from WG to microstrip on PCB using substrate intergrated technique. If the details on how help, I may look up in my files.

Hey thanks for the reply,
I tried to simulate the probe presented in the paper:

Y. Leong, S. Weinreb, "Full band waveguide-to-microstrip probe transitions", IEEE MTT-S, pp. 1435-1438, 1999

I hope you can give a look at.

I have a problem on how to figure out the impedance seenfrom the probe side when I dembeed frpm the transmission line to the three different section.
The microstrip probe, coming from the WR, is composed of: probe, high impedance element (just a narrower segment of microstrip), and a quarter wavelength transformer (other segment of microstrip). Well I would like to know what effect the other two elements induce on the transition, maybe on a Smith chart.

a Question....when you worked on the project, what were you trying to optimize?....I mean what type of behaviour of S11 and S21 were you looking for?

Hope you can help me a bit because I feel a bit lost...

Regards

I'll take a look at the paper to see the detailed structure.

I have done both quarter wave transformer transition and taper type in microstrip form. The former has narrower bandwidth response and the latter wider.

I only optimized the return loss for goal, so the insertion loss get optimized also.

Hi there,
from that publication, it is understandable that each element of the probe plays a role in the impedance matching.
The width of the probe needs to couple the E field from the WR, the inductive element (short and narrow trans line segment) should bring up the characteristic of the curve in the Smith chart because gives an overall inductive effect, and then the lambda/4 transformer brings the the inpedance to 50 ohm.
I am working on a single transition, and I have then S11 and S21 shapes.
I am trying to correlate the single transition smith chart graph and the back-to-back configuration smith chart graph.
Any Idea of their relationship?

This is because if I am going to measure the transition I have got to do it in the back to back config. Afterwards I can operate a reverse engineering to go back to the single transition and compare the results from measurements with the simulated ones.

any help?

regards