Tuan Hung Nguyen

A Multi-Level Optimization Method Using PSO for the Optimal Design of an L-Shaped Folded Monopole Antenna Array

This study presents a multi-level optimization (MLO) method applied in particle swarm optimization (PSO) to solve a 3-objective optimization problem for an antenna array design consisting of two L-shaped folded monopole antennas (LFMAs) operating in the IEEE 802.11 b/g WLAN band (2400-2484 MHz). The method incorporates a simple concept whereby three sub-objective functions, representing the reflection coefficient S 11, the mutual coupling S 21, and the entire antenna volume of the LFMA array, are minimized one by one in the PSO to obtain an optimal LFMA array configuration that provides reduced size and higher antenna performance. The advantages of the proposed method, both in terms of deriving appropriate optimization results and reducing computational cost for the optimization problem, are demonstrated by comparing its performance with that of a conventional weighted aggregation (CWA) method, and a method using the concept of Pareto dominance (PD). The optimal LFMA array configuration obtained by the proposed method has a 10% resonant bandwidth ( S 11 ≤ -10 dB for 2.32-2.57 GHz), S 21 reduced to less than -15 dB in this band, and an antenna volume that was markedly decreased, to 28.5% of that of the original design.

Basic characteristics of wideband sleeve antenna

Sleeve antenna is one typical antenna type that has a possibility of wideband characteristic. Until now, several types of sleeve antenna are introduced and investigated for obtaining a wider bandwidth than their original versions [1-5]. The most fundamental feature of sleeve antenna is that, a part of the exterior conductor with the length of λ/4 is removed from the coaxial cable, and only the thin interior conductor of this part is remained. With a sleeve added to the remained exterior surface of the coaxial cable. The operation bandwidth of a fundamental sleeve antenna is relatively narrow. In this study, we propose an effective impedance improvement technique for obtaining wideband characteristic of the fundamental sleeve antenna.

Requisite design volume of a wire inverted-F antenna inside a smartphone terminal

This study presents a concept of requisite design antenna volume to evaluate the space-saving effectiveness in the design of a wire inverted-F antennas (IFA) inside a smartphone terminal. By adjusting properly the loading position, the IFAs shape, and the deployment of other device components around the IFAs, we propose an antenna model that can both cover completely the two cellular bands and save its required design space most effectively inside the terminal. The IFA is fed by only one port, and no matching circuit is used in the design.

Bandwidth maximization of a vertical U-shaped folded dipole antenna designed for WiMAX

This study presents the method of maximizing the resonant bandwidth of a vertical U-shaped folded dipole antenna (VUFDA) that projects from a small ground plane, designed for WiMAX applications in two frequency bands of 2.3~2.7 GHz and 3.4~3.8 GHz. By applying a suitable formulation of the objective function which represents the resonant bandwidth of VUFDA in a particle swarm optimization (PSO), an optimal shape of VUFDA is derived, which has the maximum possible bandwidth that includes the two WiMAX bands (2.31~4.3 GHz for VSWR≤3).

Characteristics of vertical L-shaped folded monopole antenna designed on a ground plane

This paper presents the characteristics of a vertical L-shaped folded monopole antenna (VLFMA), which is mounted perpendicularly on a rectangular ground plane (GP) for taking into account space-saving design. By deploying the antenna element vertically to the GP, we show that it is possible to reduce the physical antenna area on GP significantly to about 21% compared to that of a conventional design, with good antenna characteristics being maintained.