A compact, scalable 60GHz active phase shifter and combiner in 28nm CMOS

Recent development in wireless technologies has brought us ubiquitous connectivity. Moving forward, emerging applications requiring multi-Gb/s data rate make the 7GHz unlicensed band at 60GHz band more uniquely attractive. Much effort has been made to implement integrated 60GHz phased-array transceivers on silicon, but they usually suffer from high power consumption and cost due to large die area. One of the key challenges is to implement low loss phase shifters with a small footprint. This paper therefore proposes to use a Cartesian phase shifter to improve the performance. Power combining functionality is incorporated to balance the impedance variation of phase shifter as well as provide the combining naturally. Hence, the proposed phase shifter/combiner demonstrates minimal gain variation across the phase settings. Sharing the passive networks between elements has significantly reduced the physical size of the proposed design. Sample designs with different number of elements in 28nm CMOS technology are presented to demonstrate the working front-end and its excellent scalability.