You make good sense. The issue is that I am a funded PhD student and I about to start my thesis in the RF or Analog circuit design field, but I do not know from where to start. Please let me know if you have any advise.
Well, while not being new topic, you may wantn to consider analog filter design. This topic is extremely wide, so you may find some underresearched area on which you may work. At least I find this topic very interesting as well as very complex and difficult (mostly from mathematic side)