RF Choke Operation: Unable to track energy flow!
时间：04-05
整理：3721RD
点击：
Hi friends, I'm confused about operation of an RF amplifier(MMIC or single transistor) biased through an RF choke.
I know the two basic functions of the RF chokes. An appropriately chosen RF choke helps DC biasing by filtering the supply and it also prevents the RF signal from leaking into the supply which causes reduction in the gain. It is necessary, no doubt.
A typical amplifier biasing with an RFC:
However, I can not track the energy flow from a DC source to AC output which are (ideally) isolated by the choke at the operating frequency.
In other words, the amplifier continuously sources AC current to the load(say 50 ohm) while it sinks DC current only. There should be some reservoir(capacitor) somehwere in the system for this transition? Could you tell me the energy flow?
I know the two basic functions of the RF chokes. An appropriately chosen RF choke helps DC biasing by filtering the supply and it also prevents the RF signal from leaking into the supply which causes reduction in the gain. It is necessary, no doubt.
A typical amplifier biasing with an RFC:
However, I can not track the energy flow from a DC source to AC output which are (ideally) isolated by the choke at the operating frequency.
In other words, the amplifier continuously sources AC current to the load(say 50 ohm) while it sinks DC current only. There should be some reservoir(capacitor) somehwere in the system for this transition? Could you tell me the energy flow?
The "store" for this energy is in the magnetic flux of the RFC. Hence if it too small, the losses increase.
Frank