Full-Wave Modal Dispersion Analysis and Broadside Optimization for a Class of Microstrip CRLH Leaky-Wave Antennas

• Published in: IEEE transactions on microwave theory and techniques Vol. 56; no. 12; pp. 2826 - 2837
• Main Authors: Paulotto, S., Baccarelli, P., Frezza, F., Jackson, D.R.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.12.2008; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Analytical models; Antennas; Applied sciences; Attenuation; Balancing; Beams (radiation); Broadside radiation; Circuit properties; Composite right/left-handed (CRLH); Design engineering; Design optimization; Dispersions; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; Leaky wave antennas; Materials; Metamaterials; Microstrip antennas; Microstrip components; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Microwaves; Parametric study; Periodic structures; Radiocommunications; Studies; Telecommunications; Telecommunications and information theory; Transmission lines; Unit cell; Performance evaluation; Harmonic; Modal analysis; Parametric analysis; Bloch wave; Leaky wave antennas; Numerical method; Composite material; Optimization; Wave dispersion; Transmission line; leaky-wave antennas; Microstrip antennas; Shunt; metamaterials; Composite right/left-handed (CRLH); Green function; Stratified medium; Simulation; Attenuation coefficient; Periodic medium; Equivalent circuit; Modal dispersion; Broadside radiation; Metamaterial; Planar technology
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2008.2007333

In this paper, a planar microstrip composite right/left-handed leaky-wave antenna is analyzed and designed as an infinite 1-D periodic microstrip leaky-wave antenna. A parametric study, based on a full-wave numerical modal approach that analyzes a unit cell using a periodic layered-medium Green's function, is shown to be an efficient approach to accurately design the structure, completely eliminating open-stopband effects and achieving an almost constant radiation efficiency when the beam is scanned through broadside. Results obtained by the proposed approach are compared with those obtained by means of both an artificial transmission-line analysis and a Bloch-wave analysis, which use the full-wave simulation of a finite-length structure. The balanced condition is interpreted in terms of the behavior of the phase and attenuation constants relevant to the radiating harmonic. Furthermore, it is shown how radiation at broadside is guaranteed by the presence of two radiating elements (one series and one shunt) within the equivalent circuit of the unit cell. The effectiveness of the analysis is demonstrated through the design of a finite-length antenna excited by a source at one end.