Shape Memory Alloy-Based Frequency Reconfigurable Ultrawideband Antenna for Cognitive Radio Systems
L. Sumana, Esther Florence Sundarsingh, S. Priyadharshini
Abstract
The present work demonstrates a frequency reconfigurable planar antenna with narrowband and ultra-wideband (UWB) characteristics for cognitive radio systems. The designed antenna has a dimension of 60 × 58 × 1.6 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> with a ground plane made of nickel-titanium (Ni-Ti) shape memory alloy (SMA). The antenna operates at a flat condition with frequency 1.46 GHz. Bending the SMA ground plane at an angle of 200° with a transformation temperature of 66 °C. The same antenna operates over 3.4-10.2-GHz UWB range. This is due to the SMA phase transformation between martensite and austenite via resistive heating/cooling. The insertion of rectangular slits in the antenna creates dual band-notched characteristics 4.7-5.1 and 5.3-6.0 GHz with VSWR <; 2 and S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> <; -10 dB. This creates a different working frequency leading to frequency reconfiguration. Details about the proposed antenna have been discussed along with measured and simulation results.