5. Monolithic sub-assemblies

5.1 Advantages of monolithic subassemblies

All microwave applications, from electronically scanned antennas to car radars, or from 24 GHz radio local loops to 60 GHz ultra-broadband links, require complex sub-assemblies combining amplification, oscillation, mixing or frequency multiplication functions. Following a trend that exists at lower frequencies, the aim is to integrate such sub-assemblies on a reduced number of chips, or even on a single chip. This integration offers several advantages, which are summarized below.

At microwave or millimeter frequencies, connections between chips introduce random variations that can be eliminated by single-chip connections perfectly calculated with CAD software.

This direct connection also eliminates...