Liu Zhangfa
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Publication A method of moments analysis of a microstrip phased array in three-layered structures(2001) Liu, Z.-F.; Kooi, P.-S.; Li, L.-W.; Leong, M.-S.; Yeo, T.-S.; ELECTRICAL ENGINEERING; ELECTRICAL & COMPUTER ENGINEERINGIn this paper, the scanning characteristics of an infinite stacked microstrip phased array in a three-layered structure are analyzed. In the analysis of the field distribution, the spectral-domain Galerkin Method of Moments together with the planar dyadic Green's function is applied. An attachment mode current is employed to model the singularity of currents nearby the feed point so as to facilitate the fast convergence. The currents on all patches are expanded in terms of the trigonometric basis and weighting functions in the entire domain. The normalized patterns of the infinite microstrip array are computed in this paper and the scanning features of the antenna against the scanning angle and frequency are discussed in both the E- and H-planes.Publication A Spectral-domain analysis of microstrip antenna array using method of moments: Theory & experiment(1998) Liu, Z.-F.; Kooi, P.-S.; Li, L.-W.; Leong, M.-S.; Yeo, T.-S.; ELECTRICAL ENGINEERINGThis paper presents a spectral-domain analysis of a 2 × 2 microstrip antenna array fed by a microstrip line. The Galerkin Method of Moments is employed to gain insight into the characterization and performance of such a patch array antenna system, whereas the mutual coupling is taken into account in the analysis. The VSWR and the radiation pattern of the array are calculated and compared with the data of measurements made in a frequency range from 9 to 11 GHz. As a further extension of this analysis of the 2 × 2 array, the features of a 4 × 4 microstrip patch array are also investigated in this paper and some interesting results are obtained. As shown in the comparison, reasonably good agreement between theoretical analysis and experimental data is achieved.Publication A Method for Designing Broad-Band Microstrip Antennas in Multilayered Planar Structures(1999) Liu, Z.-F.; Kooi, P.-S.; Li, L.-W.; Leong, M.-S.; Yeo, T.-S.; ELECTRICAL ENGINEERINGThe narrow bandwidth of a microstrip antenna is one of the important features that restrict its wide usage. A simple and practical method for the design of broad-band microstrip antennas is presented in this paper. Utilizing this design technique, several two-layer microstrip antennas have been proposed. To confirm the applicability of the method for the designs of antennas at L-band, experiments have been carried out. The measured results show that the proposed antennas have a bandwidth of up to 25.7%. Also, the method proposed in this paper is applicable to the design of other types of multilayered planar antennas. © 1999 IEEE.Publication Method of moments analysis of a microstrip phased array in three-layered structures(2000) Liu, Z.-F.; Kooi, P.-S.; Li, L.-W.; Leong, M.-S.; Yeo, T.-S.; ELECTRICAL ENGINEERINGIn this paper, the scanning characteristics of an infinite stacked microstrip phased array in a three-layered structure are analysed. In the analysis of the field distribution, the spectral-domain Galerkin Method of Moments together with the planar dyadic Green's function is applied. An attachment mode current is employed to model the singularity of currents nearby the feed point so as to facilitate the fast convergence. The currents on all patches are expanded in terms of the trigonometric basis and weighting functions in the entire domain. The normalized patterns of the infinite microstrip array are computed in this paper and the scanning features of the antenna against the scanning angle and frequency are discussed in both the E- and H-planes.