To those actively engaged in microwave and RF design and manufacture the relative merits of solid state versus vacuum tube technology is, remarkably, still open to lively discussion. 

Some forty or so years ago anyone would be forgiven for assuming that the then new, ubiquitous solid state technology would rapidly make the ‘old and faithful’ vacuum tube well and truly redundant. Has that happened? Well, not quite! The fact is that although solid state technology in the microwave industry has made tremendous strides forward, the vacuum tube can still offer the designer some significant advantages.