Reconfigurable antennas for very wide spectrum monitoring

Two different reconfigurable techniques for spectrum-monitoring antenna are presented. The first method inserts high-performance RF-MEMS switches along the microstrip feed line and back slot of a Vivaldi antenna for switching between three frequency bands centered at 2, 3.5 and 5.25 GHz. The second method collocates three different excitations in the defined space and utilise a common aperture for the bands from 500 MHz to 8GHz. The radiation patterns of the two proposed antennas are maintained in the broadside direction. The proposed antennas offer improved performance over multiple antennas, wideband and multiband application and are suitable for wide RF spectrum monitoring.