In this paper, a vehicular antenna design scheme considering the vehicular body effects is proposed. A wire antenna for GPS and LTE is implemented on the plastic plate, then it is mounted on the front glass. The outputs are commonly used to share the feed. It is necessary for GPS to increase the right hand circularly polarization (RHCP) gain near the zenith and to reduce the axis ratio while for LTE to increase the horizontal and vertical polarization (HP and VP) gain in the horizontal plane. Also for LTE, multiband characteristics are required. In order to achieve the specified performance, the antenna shape is optimized by Parato genetic algorithm (PGA). When the antenna is mounted on the body, the performance is seriously changed. To evaluate performance of the antenna mounted on the body with a complex shape, a commercial electromagnetic simulator (Ansoft HFSS) is used. To apply electromagnetic results output by HFSS to PGA algorithm operating on the MATLAB, MATLAB to HFSS linking program via Visual BASIC (VB) script was used. It is difficult to carry out the electromagnetic analysis with the whole body because of limitations of the calculating load and memory size. To overcome the limitation, we consider only a predominant part where it has an influence on the performance. It is presented that degradations caused by the body are improved through a series of optimization stages. The simulation results obtained clearly show that it is well optimized at 1.575 for GPS and 766.5 MHz and 2.135 GHz for LTE, respectively.
2. Jensen, W. K., "Concealed windshield broadband antenna,", U.S. Pat. 3,576,576, 1971.
3. Abdullah, N. and Y. Kuwahara, "VHF adaptive antenna using a rear defogger," IEEE Trans. on Antennas and Propagat., Vol. 60, No. 3, 1228-1236, 2012.
4. Wang, J. J. H. and V. K. Tripp, "Conformal multifunction shared-aperture antenna,", U.S. Patent No. 5,508,710, 1996.
5. Wang, J. J. H., "Conformal multifunction antenna for automobiles," 2007 International Symposium on Antennas and Propagation, 234-237, 2007.
6. Infantolino, J. K., M. J. Barney, and R. Haupt, "Optimal position for an antenna using a genetic algorithm," Proc. of MILCOM 2009 IEEE, 1-6, 2009.
7. Tokumaru, S. and S. Okubo, Loaded loop antennas for circular polarization, IEICE Tech. Report, AP81-33, 1981.
8. Rahmat-Samii and E. Michielssen, Electromagnetic Optimization by Genetic Algorithms, ISBN 0-471-29545-0, Wiley Interscience, 1999.
9. Kuwahra, Y., "Multiobjective optimization design of Yagi-Uda antenna," IEEE Trans. on Antennas and Propagat., Vol. 53, No. 6, 1984-1992, 2005.
10. Maruyama, T., K. Yamamori, and Y. Kuwahara, "Design of multibeam dielectric lens antennas by multi-objective optimization," IEEE Trans. Antennas and Propagat., Vol. 57, No. 1, 57-63, 2009.
11. Altshuler, E. E., "Wire-antenna designs using genetic algorithm," IEEE Antennas and Propagation Magazine, Vol. 39, No. 2, April 1997.
12. Patchaikani, S. and Y. Kuwahara, "GA optimization of transparent MIMO antenna for smartphone," IEICE Electronics Express, Vol. 10, No. 11, 1-8, 2013.
13. Patchaikani, S. and Y. Kuwahara, "Vehicular loop antenna design for GPS and LTE applications," General Conference on Electric Society Tokai Branch, K5-1, 2013.