A 10-GHz Localized-LO-Phase-Shifting Phased-Array Transmitter

This work presents a phased-array architecture based on the localized LO phase-shifting technique. Each LO element consists of a digital PLL with direct phase control, which allows inherently-linear high-resolution phase shifting, in spite of the nonlinearity of the analog components. A <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$10-\text{GHz}$</tex> quadelement beamformer circuit, adopting the LO phase-shifting architecture, is implemented in a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$28-\text{nm}$</tex> CMOS process. The measured radiation pattern, when the beamformer drives an onboard patch antenna, demonstrates beam-steering capabilities and phase noise of the combined beam scaling down with the number of LO elements.