Title :
Study on tunable electrically small antennas
Author :
Liu, Luyi ; Langley, Richard
Author_Institution :
EEE Dept., Univ. of Sheffield, Sheffield
Abstract :
Cognitive Radio systems require antennas and microwave components to be actively tuned for different parts of the frequency spectrum. In this paper results of a study of two antenna tuning techniques are presented here. The first tunable antenna is a liquid crystal (LC) tuned microstrip patch antenna operating in the 5 GHz range. The simulated tuning range is 8% while the measurements showed a range of 4%. Losses in the LC material at these frequencies give rise to antenna efficiencies ranging from 40% to around 20% when the LC is in the unbiased state. The second antenna is a reconfigurable PIFA which is able to cover 7 frequency bands by changing the combination of 4 MEMS switches.
Keywords :
cognitive radio; microstrip antennas; MEMS switches; antenna tuning; cognitive radio systems; frequency spectrum; liquid crystal; microstrip patch antenna; microwave components; tunable electrically small antennas; Antenna accessories; Antenna measurements; Cognitive radio; Crystalline materials; Frequency; Liquid crystals; Microstrip antennas; Microwave antennas; Patch antennas; Tuning;
Conference_Titel :
Antennas and Propagation, 2009. EuCAP 2009. 3rd European Conference on
Conference_Location :
Berlin
Print_ISBN :
978-1-4244-4753-4
Electronic_ISBN :
978-3-00-024573-2
