Wideband impedance matching

[tlz]

I'm using an antenna that works in the range from 1 GHz to 3 GHz. I want to match impedances between a cable from the transmitter and the input amplifier and from the output amplifier and the cable to the receiver to get the maximum power and the lossless.

I found that there are some techniques called Bode-Fano equations, five λ/4 impedance transformer and stub tuner when you use a wide range of frequencies (1GHz to 3GHz) instead only one frequency, but I don't understand it how could I used it. Can you help me?

 

[vfone]

I am not familiar with the method you mentioned, but the most effective broadband matching topology that I used (using lumped components) was a cascaded L, High-Pass-T, L, network.
The frequency range was between 900MHz and 2.5GHz, but might work up to 3GHz with careful consideration of the parasitics of the components and layout.
The component values must be optimized by a simulator.

 

[tlz]

Thank you vfone, do you know a good page for the equations of L, hight pass t and l networl?

 

[volker@muehlhaus]

If commercial matching synthesis software is an option, have a look here:
https://www.optenni.com/optenni-lab/overview

This is the most efficient and most comprehensive matching network synthesis package I have seen so far. Highly recommended!

 

[Dan Mills]

Build it up on a bit of copper clad and make some measurements!
That is how you learn about this stuff....

Regards, Dan.

 

[volker@muehlhaus]

Build it up on a bit of copper clad and make some measurements!
That is how you learn about this stuff....

I don't agree. Trial and error by pushing metal pieces works for narrow band cases. It is not very efficient for wide band matching and does not help at all to understand the matching procedure.

 

[vfone]

Yes, don't even think to get good performances for this wideband matching circuit without using the "optimize" option of an RF simulator.
Because the maximum frequency is relative high, very important is how to set all the parasitics in the optimization process.
In this broadband match circuit the main goal is related to a huge impedance transformation between input/output ports and central T network, which can get very low loaded-Q (below 1).

 

[tlz]

Thanks for the idea of the simulator, but I need to create .sp1 and all my data for inut and output are in pdf.
How can create .sp1?

 

[volker@muehlhaus]

The Touchstone file name for 1-port files is .s1p
It should be easy to create the file from your document. Here is the file format description.
**broken link removed**