Pavel Hamouz

Design of a Dual-Band Orthogonally Polarized L-Probe-Fed Fractal Patch Antenna Using Modal Methods

Modal methods are used to effectively design a dual-band orthogonally polarized fractal patch antenna. This letter summarizes the workflow from generating a fractal motif through modal analysis to feeding design and full-wave analysis. As the antennas feeding and matching structure, a dual L-probe was proposed to widen its bandwidth. The full-wave simulation is in very good agreement with the measurement. The motif size is 50 × 50 mm2, and the antenna operates at 1.25 and 2.1 GHz. The relative bandwidths are 4.18% and 11.4%, respectively.

Implementation of the Theory of Characteristic Modes in MATLAB

This paper describes the implementation of a complex MATLAB tool to calculate the characteristic modes and associated antenna parameters. The first code, written in FORTRAN, was presented in the early seventieths by Harrington and Mautz. Here, we utilize MATLAB, which is widely known and used in the antenna community these days. Because eigen-decomposition is time consuming, parallel and distributed computing is used. Thanks to the hundreds of built-in functions in MATLAB, computation of the surface currents from the eigenvectors obtained, as well as other important characteristics, are very easy and effective. The practical features are discussed with two examples.

Efficiency Treatment of Composite Right/Left-Handed TL Zeroth-Order Resonator Antenna

Antenna efficiency of zeroth-order resonator (ZOR) antenna implemented in composite right/left-handed transmission line (CRLH TL) microstrip structure is treated by method of moment simulator IE3D. Radiation is investigated from individual portions of the antenna structure according to calculated amplitude of surface current density. Dominantly radiating regions are identified, geometrically emphasized, and efficiency improved version of CRLH ZOR antenna is designed, realized, measured and compared with initial design. Improvement of simulation antenna efficiency from 10 to 75% and 4x increased measured gain at design ZOR frequency has been found.

Theory of Characteristic Modes: Getting More Insight into Linear Antenna Behavior

The theory of characteristic modes is a very useful tool to get physical insight into antenna behavior. It is possible to easily obtain resonant frequencies, modal radiation Q or bandwidth, modal currents and modal radiation patterns. The paper is intended to study well known linear antennas under this new point of view.

Efficiency Treatment of Two Closely Spaced Dipoles by Characteristic Mode Theory

The two closely spaced dipoles exhibit frequency narrow deep decline of radiation efficiency. This phenomenon is treated by theory of characteristic modes (TCM). Modal currents excited close to the resonant frequencies are determined, antenna and transmission line modes are identified, comparison of their relative amplitudes, and corresponding modal fields and radiated power are provided. Radiation efficiency calculated from TCM approach is compared with the results acquired by MoM software IE3D.