Two quadrature generation architectures, optimized for low power consumption in the 2.4?GHz frequency range, have been presented: a QVCO and a VCO with divider. Measurement results confirm that the QVCO achieves lower power consumption and better phase noise performance thanks to passive RC phase shifters in the coupling path.

The described models consisting of several resistors and capacitors approximate an ideal constant phase element. Their input impedance phase is reasonably constant over several decades of frequency and can have any value between ?90° and 0°. The models are much simpler and at the same time much more accurate than any other models of constant phase elements described so far.