1. Field of Invention
The field of the present invention relates in general to transceivers and particularly to baluns for half-duplexed wireless and wired communications transceivers.
2. Description of the Related Art
Baluns are transformer like devices for converting an unbalanced signal to a balanced signal and vice-versa. Typical applications involve wire line and wireless transceivers. In these communications transceivers the balun couples an unbalanced signal from an antenna in the case of wireless communications or a coaxial or optical cable in the case of wire line communications with the balanced signals processed by the transmit and receive path components of the transceiver. In communications transceivers the balun typically also matches the impedances of the transmit and receive path components, i.e. the system, to the impedances of the load, e.g. the antenna or the coaxial of optical cable. In receive mode a balun takes the received signal and converts it to a balanced signal, typically expressed as two signals, a phase and anti-phase signal, on which receive operations such as noise cancellation can be performed. In transmit mode a balun takes a differential signal from the transmit path components and converts it to an unbalanced signal to drive the load, e.g. antenna, coaxial or optical cable. One of the most challenging balun designs is identified as a half-duplexing balun. A half-duplexing balun switches back and forth between transmit and receive communications. Such baluns are used even in very high speed communications, where switch performance is a major impediment to efficient balun performance.
What is needed in half-duplexing balun design with improved high speed transmit and receive switching performance characteristics.