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# quaterwave impedance transformer

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#### danesh

##### Full Member level 3
quaterwave trasformer

Hi Guys,

I have a doubt on quater wave impedance tranformer. As i going thru a IEEE paper on inthis matter, i found out the the electrical length is defined in Θ, degree. assume given 90° for Θ=λ/4 length. How do we find the operting frequnecy of the circuit?

quaterwave vertical antennas

lamda is the angular resonance frequency (=2pif)

Î»/4 transformer

sourire said:
lamda is the angular resonance frequency (=2pif)

thanks. i cant understand... could pls jus show me the calculate the frequency at Θ=90° at λ/4 thanks alot.

quaterwave tranformer

Electrical lenght : βd=(2pi/λ)d

d=λ/4 => βd=2pi/λ * λ/4 =pi/2 (90°)

frequency : f=v/(λ)

v=c/n ; n=√εµ

λ or d=?
n=?

quaterwave

gnjus said:
Electrical lenght : βd=(2pi/λ)d

d=λ/4 => βd=2pi/λ * λ/4 =pi/2 (90°)

frequency : f=v/(λ)

v=c/n ; n=√εµ

λ or d=?
n=?

u have any document whr i can learn this..? what is λ or d=?
n=? i have gotten this information from

IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 52, NO. 12, DECEMBER 2004
Transformer With Three Reflection
Zeros Within Passband

it declares the Θ=90° to be 1Ghz

2pi/Î»

Ok look... frequency is :
f=v/λ
---------------------------------
v=velocity of el.mag. wave in material
λ=wavelenght in material...
--------------------------------

What information do you have ?

"it declares the Θ=90° to be 1Ghz"... it is immposlible to find frequency without additional info about wavelenght and characteristics of material.

You need to know λ (or λ/4),ε and µ.