Compact multi-band reconfigurable antenna for Cognitive Radio

This paper presents a selective frequency reconfigurable antenna, suitable for Cognitive Radio systems. The proposed antenna with 18×16 mm² dimensions is capable of switching between three different frequency bands, which allows using it for sensing between these bands and then adjusting its bandwidth to select the suitable band and pre-filter-out the other ones. The antenna is composed of a radiating element in the form of a triangle and three non-symmetrical arms that is fed with a microstrip feed-line on its top layer. In order to achieve a selective frequency reconfiguration, two switches are incorporated on the two lateral arms to act as reconfigurable filter. By changing the mode of the switches, three bands can be obtained. Although, in each case one of them is observed. These modes are Bluetooth, WiMAX and WLAN frequency band.