Full-Duplex RF Front Ends : From Antennas and Circulators to Leakage Cancellation

Abstract

With the increasing demands of wireless communication and sensing such as mobile cellular networks and the Internet of Things, radio spectrum is becoming a scarcer resource more than ever. The electromagnetic waves emitted from a radio transmitter typically occupy a certain information channel that is divided into either time [e.g., time division duplex (TDD)] or frequency [e.g. frequency division duplex (FDD)], and, within this channel, all of the receivers or sensors colocated with the transmitter are normally paralyzed.