Design and analysis of super wideband microstrip antennas for parameter optimization

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] In this work, two super wideband microstrip antennas have been proposed, studied, and analyzed through industry standard simulation suite. The first design is a directional super wideband microstrip antenna with an FR-4 substrate of dielectric constant equal to 4.3 and dimensions of 60 mm x 38.5 mm x 16.5 mm. The feed location, the ground plane, and the edges were optimized through simulations. To our knowledge, the proposed antenna has the widest operational bandwidth of 196.42 GHz (2.38 GHz to 197.8 GHz) reported so far. The VSWR for this design is < 2 and the impedance bandwidth ratio (IBR) is 82.77:1, which is, to our best knowledge, also higher than any reported values. The antenna has a directional behavior and a radiation pattern both starting from about 30 GHz and up. With a return loss of -14 dB or less, the proposed design can be used for outdoor applications for most of the operational bandwidth [1]. The second proposed structure, which was a fractal antenna, was compact in size with FR-4 substrate having dimensions of 17.2 mm x 18.25 mm x 3 mm. The thicknesses of the copper annealed patch and the copper annealed ground plane for both antennas were 0.1 mm. The design of the patch has simply a circular shape with four iterations of engraved notches described in chapter 4. The fractal antenna is more compact than the first design, but its radiation pattern smoothness and directivity were less than the first design. The obtained bandwidth of the fractal antenna was (7.7 GHz -- 197.4 GHz) with IBR of 25.6363:1.