Chris' Electronics Page

On RF Design

RF design has often been referred to as Black Magic. In many ways this is a useful analogy. Some practitioners use the wizards grimoire, more innocently named a “filter design cookbook” or similar, to conjure up their creations. More recently these rites of ancient knowledge have been entombed in commercial software, and sold at great expense, so that even the lesser mortals can fool themselves into thinking they can design an RF circuit. These mechanical minds often produce the un-producable though. But this is only the first level of RF design. Next there are the ancient lores of RF practice, handed down from generation to generation. This is still beginners stuff, but the delivery of this education, often told as yarns of projects old, hints at the route to higher enlightenment. To progress, the young RF wizard must master the true complexity of the analogue world. Here there is no ideal, all is compromise, and chaos lurks. This is where the scientific mind can penetrate the quagmire of unexpected results with the blade of reductionism, to an extent that is. The scientific mind also brings the understanding of math necessary to devise new topologies and with it the understanding of the other professions, for this too is required to move to the next level. It usually befalls the RF engineer to explain strange behaviour at equipment level and for this the understanding of many professions is required. This is where the masters of RF excel. Here the effects of RF fields and eddy currents in complex structures mixed with software and digital hardware takes the analysis beyond any CAD package. The approach to understand this becomes more holistic than reductionist. The true master of holistic design is more shaman than wizard. With a bit of Zen thrown in for good measure. It is only when the clutter of detail in today's ultra complex systems is transcended that true insight and understanding is achieved. This mind state can not be taught but just as in Zen teaching is hinted at in story telling. With practice of the mundane elements of RF these skills become automatic by slipping into the subconscious, the true powerhouse of the human mind. Combined with the experience of countless circuits built and debugged it becomes possible to visualize to flow of RF fields and eddy currents in complex structures, and with wider knowledge the functioning of mixed domain designs give up their secrets too. Thus by opening our minds and abandoning the grimoire we can paradoxically convince the word we are wizards. © C.J.Watts. 2005. Also known as G8SEK.

CAD Tools: Linear RF RFSim99, spice Simetrix, General purpose simulator Qucs.