Nikolaou, Symeon; Vryonides, Photos (Frederick University, 7, Y. Frederickou Str. Pallouriotisa, Nicosia, 1036, Cyprus)
Kim, Boyon (Samsung Electronics, Yongin 446-711, Korea)
Cognitive radios seem to provide an answer to the problem aroused from the continuously increasing wireless applications that result in the congestion of the spectrum and the increase of interference. Cognitive radios require agile components and therefore antennas with reconfigurable characteristics. The current paper presents three antennas that use PIN diodes to achieve frequency, pattern and polarization reconfigurability respectively. An annular slot microstrip-fed antenna (ASA) is matched at three different frequencies and the reconfigurable matching network results in a reconfigurable operation frequency. The same radiator is used to achieve radiation pattern reconfigurability by integrating two PIN diodes on the slot circumference. Lastly a microstrip-fed circular patch antenna is presented which with the appropriate use of PIN diodes it can switch between left hand circular polarization (LHCP) and right hand circular polarization (RHCP).