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Novel Ultra-wideband Vivaldi Antenna and Mechanically Reconfigurable Antenna Arrays

Eichenberger, Jack Andrew
http://rave.ohiolink.edu/etdc/view?acc_num=osu1649899049589752

Abstract Details

2022, Doctor of Philosophy, Ohio State University, Electrical and Computer Engineering.
Antennas are ubiquitous in the modern world, as they underlie wireless communication. Ultra-wideband (UWB) antennas have a number of benefits, including reduced cost, minimal system footprint, resistance to jamming, and improved image quality. Vivaldis are a particularly attractive UWB candidate due to their planar shape and uncomplicated feeding structure. This dissertation implements three design characteristics to a typical antipodal Vivaldi, yielding an antenna with high gain and a wider bandwidth than the state-of-the-art. These characteristics include an elliptical pseudoelement to enhance gain, notches to reduce side-lobe levels, and corrugations to reduce back-lobe levels. The antenna achieves a peak gain of 16 dB, and is matched from 2.5 to 57 GHz. It is linearly polarized with a purity of at least 10 dB across the band. The antenna was fabricated and tested, exhibiting good agreement between measurements and simulation. While UWB antennas have a multitude of uses, some applications, such as radar, require a very narrow beamwidth for accurate target location. An antenna array is the typical solution. Phased arrays achieve beam steering by introducing a variable inter-element phase shift through devices such as PIN diodes, varactor diodes, FET switches, and more. While effective, these approaches require a bias circuit which can have unwanted effects on the system’s radiation. Alternatively, mechanically steered approaches such as physical rotation of an array or tuning screws in a feeding waveguide power divider can be used. Both of these approaches are power intensive and occupy a large footprint. This dissertation provides a novel mechanically steerable slot array that is inexpensive, reliable, scalable to arbitrary array sizes, planar, and is controlled by a singular input. A slot array is fragmented into plates then connected to accordion structures. These accordion structures allow for a uniform yet variable spacing. A microactuator is used to extend and contract the accordions. The array scans continuously from roughly 0 to -30° at 16 GHz with realized gain ranging from 20 to 24 dB. It is linearly polarized with purity over 25 dB. This approach provides a cost effective and low-profile alternative to mechanical scanning while being simple to control. The array is tested in an anechoic chamber while the beam pattern is controlled by a micromotor with a user input. Metasurfaces (MS), periodic structures composed of sub-wavelength unit cells, can be used for gain enhancement, beam steering, and filtering. Typically a metasurface is fixed, but reconfigurable structures offer more versatility. Similarly to arrays, an electrical or mechanical approach is often taken. Unit cells can be loaded PIN diodes or varactor diodes to vary performance, but this requires an increasingly large bias circuit proportional to MS size. In the mechanical realm, each element would need to be individually tuned, which becomes rapidly impractical as the surface gets larger. This dissertation makes the novel contribution of a magnetically reconfigurable metasurface filter. A substrate that is rigid at room temperature but flexible when heated is magnetically doped to allow for a two state device that can be actuated by a magnetic field then locked. This approach allows for theoretically contactless reconfiguration, as only heat and a DC magnetic field are necessary. The polymer is metallized with copper tape in such a way to reversibly switch between an all-pass and band-reject state. The structure is placed between two horn antennas and compared to a reference measurement to validate its behavior.
Nima Ghalichechian (Advisor)
Asimina Kiourti (Committee Member)
Sanjay Krishna (Advisor)
120 p.
Electrical Engineering; Electromagnetics
Antenna, Array, Mechanical, Reconfigurable, Accordion, Microactuator, Magnetic, Slot, Vivaldi

Recommended Citations

Citations

  • Eichenberger, J. A. (2022). Novel Ultra-wideband Vivaldi Antenna and Mechanically Reconfigurable Antenna Arrays [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1649899049589752

    APA Style (7th edition)

  • Eichenberger, Jack. Novel Ultra-wideband Vivaldi Antenna and Mechanically Reconfigurable Antenna Arrays. 2022. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1649899049589752.

    MLA Style (8th edition)

  • Eichenberger, Jack. "Novel Ultra-wideband Vivaldi Antenna and Mechanically Reconfigurable Antenna Arrays." Doctoral dissertation, Ohio State University, 2022. http://rave.ohiolink.edu/etdc/view?acc_num=osu1649899049589752

    Chicago Manual of Style (17th edition)

osu1649899049589752
306
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