ABSTRACT
Beam-forming systems that are used for electrical beam steering to various directions within the predefined field view have become the major solution for millimeter-wave systems, especially those operating at the unlicensed 60 GHz. Thus, systems typically utilize phased-array technique at millimeter-wave frequencies and emulate the high-gain antenna with the advantages of array gain, high directivity, and spatial coverage. The full integration of phased-array systems with digital baseband in silicon-based technologies leads to numerous improvements in cost, size, power consumption, and reliability. Meanwhile, it provides feasibility to perform fully on-chip signal processing and controlling, without any off-chip components, resulting in additional savings in cost and power. Lossy silicon substrate and poor power-handling capability have to be considered wisely in circuit designs. Variable phase shifters are commonly adopted in phased-arrays or beam-steering systems to adjust the signal phase in each antenna path and steer beam pattern.
