Quasi-Differential Operation of Capacitive Tuners for Aperture Tuning Applications

A method of operating a switch-based series capacitive tuner in quasi-differential mode is proposed. The method suggests to split the applied RF voltage between the terminals of the tuner such that the terminals see the out-of-phase voltage waveforms with reduced amplitudes. The proposed approach allows minimizing power losses in the parasitic shunt resistive elements of the capacitive tuner. The same approach may be applied to antenna tuning switches as well.The method is evaluated on a capacitive tuner integrated circuit fabricated in bulk-CMOS RF-switch technology. The network based on the prototype operating in quasi-differential mode demonstrated a potential to reduce power losses by up to 15% when operating at high-ohmic aperture tuning plane.