Electrical Balance Duplexers: Practical Performance in the Field

Electrical balance duplexers achieve high transmit-to-receive isolation, can be implemented on-chip, and utilize a shared antenna for transmitting and receiving, making this an attractive technology for low cost implementation of full-duplex transceivers . However, the transmit-to-receive isolation is sensitive to antenna impedance variation in both the frequency domain and time domain, limiting the isolation bandwidth and requiring dynamic adaptation. This presentation will review the operation of electrical balance duplexers, discussing the achievable performance of practical designs in real-world scenarios, including vehicular deployments and hand-held devices. Furthermore, electrical balance duplexers are not only relevant to in-band full-duplex, but also to frequency division duplexing, where EBD based transceivers may provide a tuneable alternative to fixed frequency duplexing filters. This presentation will also review various developments of EBDs in this application area, in particular covering architectures which combine EBDs with tunable filtering technologies and/or further self-interference cancellation techniques.