A frequency doubler and frequency divider network for quadrature LO phase generation in a 5--6 GHz WLAN transmitter

This thesis studies the design of a quadrature phase generator using a novel differential pair frequency doubler, and a quadrature regenerative frequency halver. The frequency doubler and frequency halver are cascaded to form the quadrature phase generator for a monolithic 5–6 GHz band transmitter. Details of a new differential pair frequency doubling circuit using passive loads are presented. The doubler is shown to have good harmonic suppression and a potential for low voltage/low power operation. The regenerative frequency halver incorporates an external voltage phase-tuning mechanism in its design. The halver has a wide locking range that is >80% of its free-running frequency. The cascaded doubler and halver has a wide operating range spanning 4–7 GHz. The proposed quadrature phase generation network is validated by integration in an fully differential transmitter intended for 5–6 GHz WLAN applications.