Modeling and design of near-field antennas with periodic structures

Zeng, Yunjia

Permalink

https://hdl.handle.net/2142/98335 Copy

Description

Title

Modeling and design of near-field antennas with periodic structures

Author(s)

Zeng, Yunjia

Issue Date

2017-07-09

Director of Research (if dissertation) or Advisor (if thesis)

Jin, Jianming

Doctoral Committee Chair(s)

Jin, Jianming

Committee Member(s)

• Bernhard, Jennifer
• Schutt-Ainé, José
• Gong, Songbin

Department of Study

Electrical & Computer Eng

Discipline

Electrical & Computer Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Numerical method
• Periodic structures
• Near field
• Magnetic field
• Dispersion analysis
• Equivalent circuit
• Loop antenna
• Artificial magnetic conductor
• Radio frequency identification
• Ultrahigh frequency
• Directional antenna
• Antenna array
• Parasitic array

Abstract

In this dissertation, the one- and two-dimensional periodic structures are modelled and adopted in the design of near-field antennas. First, the discontinuous Galerkin time-domain (DGTD) method is applied to model the scattering from periodic structures. The modelling of dispersive media is incorporated into a three-dimensional DGTD scheme, which is capable of studying plasmonic periodic structures at optical frequencies. Various numerical examples are presented to demonstrate the applications of the proposed algorithm. Second, a new methodology for modelling and characterization of one-dimensional periodic structures with nonstraight geometries is developed. The one-dimensional zero-phase-shift line (ZPSL) is analyzed to obtain its dispersion characteristics. Equivalent circuit models are proposed to characterize the ZPSL structures. A design guideline is developed and demonstrated to enlarge the interrogation zone of a ZPSL loop antenna for near-field wireless systems. Third, the full dispersion characteristics, including phase and attenuation constants, of the ZPSL are analyzed in a loop configuration. Based on the dispersion characteristics, a periodic ZPSL loop antenna with uniformly distributed unit cells is studied, and a nonperiodic ZPSL loop antenna with nonuniformly arranged unit cells is designed for an improved near-field performance. Fourth, a low-profile directional ZPSL loop antenna is proposed by placing an artificial magnetic conductor (AMC) reflector behind a ZPSL grid-loop antenna. The grid-loop configuration is designed such that an enhanced magnetic field distribution can be realized on the electrically large ZPSL loop antenna with a simple feeding network. The AMC reflector with four-arm spiral unit cells is included to achieve a directional field distribution as well as to further increase the magnetic field intensity. Fifth, two low-profile ZPSL loop antennas are proposed to achieve a directional magnetic near-field distribution. The current distributions on the antennas are studied to realize the desired near-field pattern. Besides the directional distribution, both the antennas exhibit enhanced magnetic field intensities in the forward direction. All of the antennas are exemplified as a reader antenna for ultra-high frequency (UHF) near-field radio frequency identification (RFID) systems.

Graduation Semester

2017-08

Type of Resource

text

Permalink

http://hdl.handle.net/2142/98335

Copyright and License Information

Copyright 2017 Yunjia Zeng

Owning Collections