Dimensions for microstrip quarter wave transformer

[ebenezerabishek]

How to determine the dimensions of a quarter wave transformer for microstrip patch antenna.If any formula or any easy method to find the length and width of a quarter wave transformer is available.kindly reply in this post.thanks

 

[avadak]

Dear Friend,
the dimensions of a quarter wave transformer depend on two main paramenters: the impedence to match and the dielectric characteristics. Supposing to match an impedence Zin and the load RL, the impedence of the quarter wave transformer is Z1^2 = RL * Zin. For example if RL = 50ohm and Zin = 100 Ohm the impedence is 70.7 ohm. Established the impedence you have to design the width as function of the dielectric characteristics (dielectric constan, dielectric height, loss tangent,...) and the length as function of your wavelength.
I hope that it is useful
BR

 

[ebenezerabishek]

Dear Friend,
the dimensions of a quarter wave transformer depend on two main paramenters: the impedence to match and the dielectric characteristics. Supposing to match an impedence Zin and the load RL, the impedence of the quarter wave transformer is Z1^2 = RL * Zin. For example if RL = 50ohm and Zin = 100 Ohm the impedence is 70.7 ohm. Established the impedence you have to design the width as function of the dielectric characteristics (dielectric constant, dielectric height, loss tangent,...) and the length as function of your wavelength.
I hope that it is useful
BR

Thanks for our reply sir.It was useful.If the impedance of the quarter wave transformer is 70.7 ohm then what formula is used to obtain its length and width sir

 

[FvM]

In contrast to coaxial cable, there's no simple micro strip impedance formula, but you find many empirical formulas on the internet. E.g. PCB calculation tools like Saturn toolkit.

Propagation speed is roughly c/√Er, so you can easily calculate quarter wavelength.