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akb11
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I read that conventional (low frequency) circuit parameters - voltage gain and power gain are not applicable for RF circuits but I didn't understand why?
Can anyone please explain.
Can anyone please explain.
I was going to come back and stress some points relate to what you brought up here.akb11 said:Hi ,
Thanks for your reply. I went through Smith Chart and also tried a couple of impedance matching exercises. I have understood when to use a series L or C and when to use a parallel L or C.
So just to check if i have understood it right.
In RF circuits we use insertion voltage gain instead of the usual voltage gain. In low frequency circuits, the source voltage is always equal to voltage at the device (2 port network) input. In RF circuits, the voltage transfer from source to device input depends on the impedance match and in the best possible case ( i.e. reflection coefficient is 0 ) only half of the source voltage appears as device input voltage or half of the power is transferred from source to input (Maximum power transfer theorem).
Have I understood it correctly ?
Thanks for your help.
In RF circuits, voltage gain refers to the ratio of the output voltage to the input voltage, while power gain refers to the ratio of the output power to the input power. These two measures are used to quantify the amplification capabilities of a circuit.
Unlike in DC circuits, where voltage and power are directly related, RF circuits operate at high frequencies where the concept of voltage and power becomes more complex. The behavior of RF signals is influenced by factors such as impedance, phase, and frequency, making voltage and power gain less meaningful measures of performance.
In RF circuits, measures such as return loss, insertion loss, and S-parameters are used to evaluate performance. These measures take into account the complex nature of RF signals and provide a more accurate representation of the circuit's behavior.
Technically, voltage and power gain can still be calculated for RF circuits, but they may not accurately reflect the circuit's performance. It is more useful to use other measures, such as S-parameters, to analyze and design RF circuits.
In some cases, voltage and power gain may still be useful for comparing the performance of RF circuits that operate at similar frequencies and have similar impedance levels. However, it is important to keep in mind that these measures may not provide a complete understanding of the circuit's behavior.