jianke wrote on Mar 1st, 2011, 12:40pm:Hi, rfidea. Thank you for your reply. The idea of using CC and CB to as a current and gain device, respectively, is from the low-frequency analogy circuit. To be honest, I am not sure whether it can work or not at RF. The problem of a CE (or CG) amplifier is that the current and voltage will be amplified simultaneously, and it is not what I want. For a CE (or CG) amplifier, do you know whether it can mainly amplify current or voltage, while has low gain for the other one.
Could you suggest a BJT device (and a FET device) ? If I want my amplification circuit to work at 2GHz, whether the device’s maxFt should be higher than 25GHz as you suggested first ? I am sorry I don’t have much experience in RF circuit design. Cloud you give me a hand ? Thanks and Best Regards!
A suggestion -
Please tell us what you are trying to do, and perhaps we can offer suggestions.
Not the circuit you are trying to create, but rather what you are trying to do. (example, you have a 2.5GHz signal with XX amplitude, coming from a 50 ohm cable and you need to amplify it to XX amplitude, and feed it into another cable at 50 ohms, you need a linearity of IP3 = XXdb, and your Noise Figure has to be XX)
At these frequencies, you have to know what you are doing and parasitics and many other factors will effect what you are doing.