With the development of multi-band wireless communication and the increasing data transmission rate,the circulator as an antenna interface must be able to work in multiple frequency bands and provides large bandwidth....With the development of multi-band wireless communication and the increasing data transmission rate,the circulator as an antenna interface must be able to work in multiple frequency bands and provides large bandwidth.It presents a high challenge to the design of circulators,especially the active quasi-circulators.In this survey,we review the representative active quasi-circulators and summarize three different techniques and the corresponding structures to show an incremental improvement of the isolation and bandwidth of the active quasi-circulators.In addition,we also compare the performance of several state-of-art active circulators,and analyze their advantages and disadvantages.Finally,we conclude the future trend of the active quasi-circulators.展开更多
文摘With the development of multi-band wireless communication and the increasing data transmission rate,the circulator as an antenna interface must be able to work in multiple frequency bands and provides large bandwidth.It presents a high challenge to the design of circulators,especially the active quasi-circulators.In this survey,we review the representative active quasi-circulators and summarize three different techniques and the corresponding structures to show an incremental improvement of the isolation and bandwidth of the active quasi-circulators.In addition,we also compare the performance of several state-of-art active circulators,and analyze their advantages and disadvantages.Finally,we conclude the future trend of the active quasi-circulators.
