A dual-frequency 0.7-to-1GHz balance network for electrical balance duplexers
 
A dual-frequency 0.7-to-1GHz balance network for electrical balance duplexers ■
 
Benjamin Hershberg, Benjamin Hershberg, Benjamin Hershberg, Barend Van Liempd, Barend Van Liempd, Barend Van Liempd, Xiaoqiang Zhang, Xiaoqiang Zhang, Xiaoqiang Zhang, Piet Wambacq, Piet Wambacq, Piet Wambacq, Jan Craninckx, Jan Craninckx, Jan Craninckx
 
Abstract ■

An electrical-balance duplexer (EBD) is a tunable RF front-end concept that seeks to address several key challenges of 4G and 5G mobile systems [1]. The basic principle is shown in Fig. 20.8.1. Duplexer isolation is achieved when the signals in paths 1 and 2 cancel and prevent the TX signal from appearing at the RX port. This cancellation is achieved by {"}balancing{"} the antenna impedance ZANT with an on-chip tunable impedance ZBAL.