TELECOMMUNICATIONS DEVICE COMPRISING AN EBD CIRCUIT, A TUNABLE IMPEDANCE NETWORK AND A METHOD FOR TUNING A TUNABLE IMPEDANCE NETWORK

摘要

Telecommunications device comprising: an electrical-balance duplexer, EBD, circuit coupled to at least one output node of a transmit path (TXin), an antenna, and at least one input node of a receive path (RXout), the EBD circuit being configured to isolate the transmit path from the receive path by signal cancellation, and a balancing network (Zbal) as part of the EBD circuit. The balancing network is an integrated tunable impedance network configured to provide an impedance that matches a target impedance (Zant) associated with the antenna at a first frequency and simultaneously at a second, different frequency. The network comprises a first portion and a second portion, the first portion reducing the influence of the tuning of the second portion at the first frequency. The network preferably comprises no explicit resistors.