A doubly balanced transceiver system having a transmit terminal, a receive terminal, and an an antenna terminal, 180\xb0 hybrids, 90\xb0 hybrids, a power amplifier and a RXTX switch for disabling the power amplifier so that signals received at the transmitter are reflected to the receive terminal. A method of forming the fabric is also described. The variation in the domain wall energy along the racetrack can be provided by continuous variations of the racetrack’s width andor cross-sectional area. Gravity separation of air and liquid to be dispensed is used to replace liquid with air in the reservoir and to selectively place air and liquid into communication with passageways for ejection. The \u201cslit\u201d valve allows access to wires or catheters for the purpose of any type of graft maintenance. The invention provides for a new type of vertical memory where each layer encodes information in two degrees of freedom, which has the potential to increase the theoretical storage capacity by factor 4n.