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

摘要

A system having a tunable impedance network and a method of tuning a tunable impedance network are disclosed. In one aspect, a telecommunications device comprises 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), wherein the EBD circuit is configured to isolate the transmit path from the receive path by signal cancellation, and a balancing network (Zbal) as part of the EBD circuit. In one embodiment, 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. In some embodiments, the network preferably comprises no explicit resistors.

主权项

1. A 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; wherein 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 frequency, the first and second frequencies being different from each other; and wherein the integrated tunable impedance network comprises an input port and at least one impedance branch with a plurality of reactive elements and associated tuning components connected to the input port, wherein the number of reactive elements and associated tuning components, their topology and their reactance values are such that the respective impedance branch is tunable to match the target impedance at the first frequency via mainly a first portion of the impedance branch and to match the target impedance at the second frequency via mainly a second portion of the impedance branch, the first portion being closer to the input port than the second portion and reducing the influence of the tuning of the second portion at the first frequency.