Enhanced surface acoustic wave (SAW) sensors and SAW sensor-tag wireless interface devices, including low loss devices, devices that enable enhanced use of time diversity for device identification, and devices suitable for use in band-limited environments (such as ISM band) and for use in ultra-wideband applications are disclosed. Antennas for use with both SAW sensors and/or tags, and wireless transceiver systems also are disclosed, including antennas suitable for operation in conductive media and in highly metallic environments, said antennas being used to activate and read said SAW sensors and/or tags. SAW sensors and sensor-tags and related methods for measuring scaled voltage and current in electrical conductors via measurements of the electric and magnetic fields thereof are disclosed.