Antennas for software defined radio handsets

The concept of software defined radio is reviewed and challenges for antennas are derived. The desire for on-chip wideband transceivers is driving the need for very wideband reconfigurable antennas, and the difficulties of on-chip filtering are indicating that integration of the filter with the antenna is desirable. Reconfiguration of antennas over the decade bandwidths envisaged is challenging and in handheld units external tuner units have been shown to be feasible. However serious problems remain particularly in the large component count and the choice of active device. This paper discusses the technical challenges involved in meeting the developing needs of this fascinating and potentially revolutionary concept.