Antenna94
Junior Member level 3
Hi!
This may be a really rookie question. I am designing a mixer, and was wondering how I should choose the input powers in dBm if I know the wanted input voltage magnitude. So the input impedance at the drain or the gate of a FET is not 50ohm, hence I guess I should calculate the apparent power on the input impedance (calculated from S-parameters) by the known voltage. My guess would be that this is correct, even if I match the port to 50ohms. So if the amplitude of the voltage is 1V and the input impedance is (100-j*50)ohms (totally made up value for the question), then the power is (1V)^2 / (2*111.8ohm)=4.47mW->6.5dBm. Am I right, or for example if the amplitude of the voltage is 1V, then the power is (1V)^2 / (2*50ohm) = 10mW->10dBm and it is as simple as that?
Thanks!
This may be a really rookie question. I am designing a mixer, and was wondering how I should choose the input powers in dBm if I know the wanted input voltage magnitude. So the input impedance at the drain or the gate of a FET is not 50ohm, hence I guess I should calculate the apparent power on the input impedance (calculated from S-parameters) by the known voltage. My guess would be that this is correct, even if I match the port to 50ohms. So if the amplitude of the voltage is 1V and the input impedance is (100-j*50)ohms (totally made up value for the question), then the power is (1V)^2 / (2*111.8ohm)=4.47mW->6.5dBm. Am I right, or for example if the amplitude of the voltage is 1V, then the power is (1V)^2 / (2*50ohm) = 10mW->10dBm and it is as simple as that?
Thanks!