Application of Orthogonal Array for the Design of Inverted L Antenna

• Main Authors: Chih-Hung Weng, 翁志宏
• Other Authors: Ching-Lieh Li
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/24783229039173486924

碩士 === 淡江大學 === 電機工程學系碩士班 === 100 === In this thesis, the application of Orthogonal Array (OA) to design an offset-fed inverted L antenna through a novel iterative procedure is investigated. The objective is to design a planar dual-band antenna. A coaxial-fed inverted L antenna structure and its extension is optimized through the proposed novel procedure. It is expected that within a certain limited small iterations the S11 characteristics of the antenna can satisfy the required specification. The offset-fed inverted L antenna associated with a coupled strip exhibit dual-band structure. Moreover, it is found that the bandwidth at the low band can be widened by suitable extending the inverted L shape to un-symmetric T shape. The goal is to design a dual-band antenna with frequency range covering the WLAN (802.11a/b/g/n) application. The antenna is fed by a IPEX coaxial line, in practice. The antenna concerned is assumed to reside on an FR4 substrate (of thickness of 0.8mm, and with relative dielectric constant of 4.4 and loss tangent~0.02), and. For the above conditions, the antenna simulation and the iteratively optimized design are carried out, and finally the novel antennas are fabricated and verified by measurement. For the novel iterative design procedure, the parameters of the inverted L antenna with coupled strip are first choice, and their ranges are suitably set, then a corresponding OA can be established. Next, the fractional factorial experiments of the OA are carried out by using the commercial electromagnetic simulation software. Based on the simulation results, the fitness of the fractional factorial experiments are calculated such that the limited small number of iterations is conducted to optimize the antenna parameters. The objective is to test that whether the proposed novel antenna design procedure work to have the convergent antenna meet the pre-set frequency requirement or not, As compared to other design method, the most important feature of the proposed novel method is the utilization of the OA, which exhibits the uniformity for the occurrence of each level of the parameters. The inclusion of OA is expected to accelerate the design process, reduce the search time. When the OA is combined with the range reduction technique, it is found quite suitable to serve as an alternative for antenna design. In this study, we test two kinds of design procedure with one phase and two phases, respectively, in order to utilize OAs within a limited number of iterations. For the one-phase case, 5 iterations or 10 iterations are tested, while for the two-phase case, there are 5 iterations for each phase. The test results show that the proposed novel methods utilizing consecutive OAs are able to obtain good results in a fast way.