2017 Volume 14 Issue 5 Pages 20170008
A K-band four-element beamforming system-on-chip (SOC) is presented. In the SOC, the attenuators and the phase shifters, designed in the reflection topology, are realized by two types of the on-chip synthetic transmission lines. The cascode amplifier, as the first stage in the receiving path, provides a gain of 20 dB to compensate all the losses of the passive components, and use dual feedback loops to minimize the group delay variation. The SOC prototype is fabricated by using 0.13 µm CMOS technology, and characterized through the on-wafer measurements. The measured input and output return loss are less than −9.8 and −14.8 dB in the 50 Ω system. The total receiving gain and the noise figure are 5.9 dB and 7.5 dB, respectively. The prototype can continuously make 360° phase shifting with root-mean-square (RMS) errors less than 1.5° and 0.6 dB. The measured group-delay is 249.8 pico-second (ps) with a variation of ±22.8 ps from 22 to 26 GHz. The input P1dB and IIP3 are −19.8 dBm and −8.3 dBm at 24 GHz. The channel-to-channel isolation is higher than 31.6 dB in a chip area of 0.00632 λ02 at 24 GHz.