Design of Hexa-Band Planar Inverted-F Antenna Using Hybrid BSO-NM Algorithm for Mobile Phone Communications K. R. Mahmoud, 1 A. M. Montaser, 2 H. A. Elmikati 3 1 Faculty of Engineering, Department of Electronics and Communications Engineering, Helwan University, Cairo, Egypt 2 Electrical Engineering Department, Sohag University, Sohag, Egypt 3 Department of Electronics and Communications Engineering, Mansoura University, Mansoura, Egypt Received 10 November 2011; accepted 14 March 2012 ABSTRACT: This article presents a new design of multiband planar inverted-F antenna with slotted ground plane and S-etched slot on the radiation patch. The proposed antenna is optimized using an efficient global hybrid optimization method combining bacterial swarm optimization and Nelder-Mead (BSO-NM) algorithm to cover a very important six service bands including GSM900, GPS1575, DCS1800, PCS1900, ISM2450, and 4G5000 MHz with enhanced bandwidths. The BSO-NM algorithm in Matlab code is linked to the CST Micro- wave studio software to simulate the antenna. To validate the results, the antenna is ana- lyzed using the finite difference time domain (FDTD) method. A good agreement is achieved between the results of EM simulation and that produced from the FDTD method. V C 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE 00:000–000, 2012. Keywords: planar inverted-F antenna; multiband; hybrid BSO-NM algorithm; FDTD method I. INTRODUCTION Nowadays, multisystem applications have been used explosively. Owing to this, it has been a necessity to design antennas with the characteristics of multiband for mobile terminals. The planar inverted-F antenna (PIFA) is being adopted extensively as handset antennas because of its advantages [1]. However, a major disadvantage of the PIFA antenna is its narrow impedance bandwidth. So, there are several methods demonstrated to broaden the bandwidth [2, 3]. In addition, many multiband designs based on PIFA concepts for achieving operation at two or more of the GSM900, DCS1800, PCS1900, UMTS2000, and ISM2450 bands have been reported in the open litera- ture [3–10]. In Ref. [3], parasitic patches are placed around the main radiation element to increase the antenna bandwidth. The bandwidth of the PIFA antenna described in Ref. [4] is broadened by using a tapered-type radiating patch at 1800 MHz. In Ref. [5], multilayer patches and a folded stub are introduced into the internal PIFA to improve its bandwidth. The bandwidth enhancement approaches mentioned above both focus on making modi- fications on the radiating elements of PIFA antennas. There are also other bandwidth improvement methods concentrating on making modifications on the system ground plane of mobile terminals. A slotted ground plane for handset devices is described to lower the profile and improve the bandwidth of PIFA antennas [6, 7]. In Ref. [8], a T-shaped ground plane is reported to broaden the bandwidth of the PIFA antenna. By etching a U-shaped slot in company with an L-shaped slot on a rectangular patch, triple bands (GSM900/DCS1800/ISM2450) were easy to be realized [9], but their bandwidths did not sat- isfy the demands in mobile communication. It has been demonstrated that in Ref. [10], by introducing a rectangu- lar slot with an appropriate location and a proper size on the mobile chassis, the bandwidths of the PIFA antenna in both the low and high bands can be significantly broad- ened. In Ref. [11], a novel multiband and broadband PIFA has been designed by etching T-shaped slot on the ground plane and radiation patch simultaneously. In Ref. [12], a small-size PIFA for penta-band opera- tion in the folder-type mobile phone is presented. The Correspondence to: K. R. Mahmoud; e-mail: KURANY_ HAMEDA@h-eng.helwan.edu.eg V C 2012 Wiley Periodicals, Inc. DOI 10.1002/mmce.20656 Published online in Wiley Online Library (wileyonlinelibrary.com). 1