# Reflections when conjugately matched

1. ## Reflections when conjugately matched

Hi, as per Pozar's Microwave Engineering book, there is a condition
"A special case of the transducer power gain occurs when both the input and output are matched for zero reflection (in contrast to conjugate matching). Then GammaL = GammaS = 0" then GT=S21^2.
And another one is conjugate matched condition.
Does this mean ever after performing conjugate matching, there will be still reflections?. Could someone explain the difference between these two conditions.  Reply With Quote

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2. ## Re: Reflections when conjugately matched Originally Posted by circuitslave Does this mean ever after performing conjugate matching, there will be still reflections?.
Voltage wave is reflected. Originally Posted by circuitslave Could someone explain the difference between these two conditions.
Surely read and learn Power wave in Pozars Book, before EDA Tool Play.

See the followings.

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3. ## Re: Reflections when conjugately matched Originally Posted by circuitking Hi, as per Pozar's Microwave Engineering book, there is a condition
"A special case of the transducer power gain occurs when both the input and output are matched for zero reflection (in contrast to conjugate matching). Then GammaL = GammaS = 0" then GT=S21^2.
And another one is conjugate matched condition.
Does this mean ever after performing conjugate matching, there will be still reflections?. Could someone explain the difference between these two conditions.

There's a subtle distinction between travelling waves (aka voltage waves) and power waves. For travelling waves, the reflection coefficient is defined as Gamma=(ZL-Zs)/(ZL+Zs). For power waves, Gamma=(ZL-Zs*)/(ZL+Zs). So for a conjugate match, the power wave reflection coefficient will be zero, but the travelling wave reflection might not be.

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4. ## Re: Reflections when conjugately matched

Researched in my literature and found very intuitive explanation about Power Waves and Scattering
"Microwave Transistor Amplifiers-Analysis and Design"-Guillermo Gonzalez Section 1.7 pp:45-60  Reply With Quote

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