Elastic Reactance [Microwave Bytes]

I suppose it could be regarded as appropriate, given nearly a three-year hiatus, to survey the microwave scene with my ever-more jaundiced eye. I do so, however, with brevity and the consumption of some humble pie as some (not all) of my former targets are alive, well, and going strong. One such, I have to admit, is gallium nitride (GaN) technology, which appears to be triumphing against the odds of cost and becoming the default option for gigahertz power amplifier (PA) designers. So be it; GaN certainly makes radio-frequency PAs (RFPAs) easier to design, although this respite will no doubt be short lived as the specifications adapt to keep us in the forefront of difficulty and on the edge of impossibility. Such is life, but I believe it is still a silicon world, as dramatically shown by the domination of silicon and complementary metal-oxide-semiconductor technology in the millimetric zone. If we can make complete transceivers, not to mention multi watt PAs, with decent efficiency at 100 GHz, a passing observer might question the need for the exotic compound semiconductors that still dominate the world above 1 GHz. Time will tell.