Ultra-wide band gap metasurfaces for controlling seismic surface waves

2020 ◽  
Vol 41 ◽  
pp. 101018
Author(s):  
Wenlong Liu ◽  
Gil Ho Yoon ◽  
Bing Yi ◽  
Yue Yang ◽  
Yi Chen
2016 ◽  
Vol 109 (22) ◽  
pp. 222101 ◽  
Author(s):  
Andrew M. Armstrong ◽  
Andrew A. Allerman

A Hexagonal Microstrip Ultra Wide Band Fractal Antenna for wireless body area network applications is proposed. The Hexagonal antenna is powered through co-planar waveguide (CPW) feed structure. The proposed antenna uses a hexagonal fractal structures to achieve its Ultra Wide Band characterization. The addition of fractal elements introduces multi-resonance at different frequencies and covers a large bandwidth of 3.8GHz–10.1GHz respectively. This antenna creates a Fractal geometry inside the patch with similar in shape but difference in sizes. Electromagnetic Band Gap structures are introduced in order to improve gain and directivity of the antenna. Electromagnetic Bandgap Structure (EBG) is mainly focused on overcoming the limitation of Microstrip Patch antenna parameters such as low gain, excitation of surface waves. Electromagnetic Band Gap structures are defined as artificial periodic structures that exhibit unique electromagnetic features, such as frequency band gap for surface waves and in-phase reflection coefficient for incident plane waves, which makes them desirable for low-profile antenna designs. The Electromagnetic Band Gap structure is placed behind the antenna to suppress the propagation of surface wave and to improve gain, directivity and to reduce the side lobes of the radiation pattern. The effect of surface currents in the ground plane reduces the antennas operating bandwidth which is reduced by introducing defective ground structure. The size of the antenna is 25×25×1.588 . The proposed antenna has an average gain of 3.8dB. The radiation pattern obtained is unidirectional.


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