Double-Balanced Graphene Integrated Mixer with OutstandingLinearity.

A monolithicdouble-balanced graphene mixer integrated circuit (IC) has been successfullydesigned and fabricated. The IC adopted the cross-coupled resistivemixer topology, integrating four 500 nm-gate-length graphene field-effecttransistors (GFETs), four on-chip inductors, and four on-chip capacitors.Passive-first-active-last fabrication flow was developed on 200 mmCMOS wafers. CMOS back-end-of-line processes were utilized to realizemost fabrication steps followed by GFET-customized processes. Testresults show excellent output spectrum purity with suppressed radiofrequency (RF) and local oscillation (LO) signals feedthroughs, andthird-order input intercept (IIP3) reaches as high as 21 dBm. Theresults are compared with a fabricated single-GEFT mixer, which generatesIIP3 of 16.5 dBm. Stand-alone 500 nm-gate-length GFETs feature cutofffrequency 22 GHz and maximum oscillation frequency 20.7 GHz RF performance.The double-balanced mixer IC operated with off-chip baluns realizinga print-circuit-board level electronic system. It demonstrates graphene’spotential to compete with other semiconductor technologies in RF front-endapplications. [ABSTRACT FROM AUTHOR]