TH-3 Microwave Radio System: Microwave Integrated Circuits

Microwave integrated circuits have been employed in the Bell System for the first time in the TH-3 radio system. These circuits, using strip transmission lines, provide numerous functions previously achieved with assemblies of individual waveguide components. By utilizing the modern technologies of photolithography, precision die casting, ceramic processing, and tantalum-gold thin films, these circuits provide advantages in size, fabrication, bay “layout,” performance, and cost.