A Fern Fractal Leaf Inspired Wideband Antipodal Vivaldi Antenna for Microwave Imaging System

This communication presents a new approach to implement planar antipodal Vivaldi antenna design. A nature fern inspired fractal leaf structure is implemented here. Impedance bandwidth (−10 dB) of the proposed antenna is around 19.7 GHz starting from 1.3 to 20 GHz. The lower operating frequency of this antenna is reduced by 19% with the second iteration as compared to the first iteration of fractal leaf structure. The prototype antenna is fabricated and tested in frequency as well as in time domains to obtain various transfer characteristics along with common antenna parameters. Experimental results show that good wideband feature, stable radiation pattern, and promising group delay of less than 1 ns signatures are obtained, which agree well with the simulated data. The miniaturized proposed antenna structure becomes an attractive choice in microwave imaging applications because of its ultrawide fractional bandwidth at 175%, high directive gain of 10 dBi, and finally appreciably large fidelity factor above (>90%).

[1]  Yingzeng Yin,et al.  A Miniaturized CPW-Fed Antipodal Vivaldi Antenna With Enhanced Radiation Performance for Wideband Applications , 2016, IEEE Antennas and Wireless Propagation Letters.

[2]  Jeremie Bourqui,et al.  Balanced Antipodal Vivaldi Antenna With Dielectric Director for Near-Field Microwave Imaging , 2010, IEEE Transactions on Antennas and Propagation.

[3]  Niu Zhongxia,et al.  Analysis and Design of UWB Vivaldi Antenna , 2007, 2007 International Symposium on Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications.

[4]  E. Gazit,et al.  Improved design of the Vivaldi antenna , 1988 .

[5]  T Thayaparan,et al.  Design of an Ultrawideband Antipodal Tapered Slot Antenna Using Elliptical Strip Conductors , 2011, IEEE Antennas and Wireless Propagation Letters.

[6]  P. J. Gibson.  The Vivaldi Aerial , 1979, 1979 9th European Microwave Conference.

[7]  Rowdra Ghatak,et al.  A super wideband Chebyshev tapered antipodal Vivaldi antenna , 2015 .

[8]  Peng Fei,et al.  A Miniaturized Antipodal Vivaldi Antenna With Improved Radiation Characteristics , 2011, IEEE Antennas and Wireless Propagation Letters.

[9]  Shouyuan Shi,et al.  Modified Compact Antipodal Vivaldi Antenna for 4–50-GHz UWB Application , 2011, IEEE Transactions on Microwave Theory and Techniques.

[10]  T. Mikulášek,et al.  Design of a Compact Wideband Antenna Array for Microwave Imaging Applications , 2013 .

[11]  F. Perez-Martinez,et al.  Group delay effects on the performance of wideband CW-LFM radars , 2001 .

[12]  Ibrahim T. Nassar,et al.  A Novel Method for Improving Antipodal Vivaldi Antenna Performance , 2015, IEEE Transactions on Antennas and Propagation.

[13]  C. L. Hammond,et al.  Performance characteristics of the dual exponentially tapered slot antenna (DETSA) for wireless communications applications , 2003, IEEE Trans. Veh. Technol..