On-board Printed Handset Antenna with Coupled Monopoles M.A.B. Abbasi 1 , S. Shahid 1 , M. Rizwan 1 , M.A. Tarar 1 , S.M. Abbas 2 1 Department of Electrical Engineering, School of Electrical Engineering and Computer Science (SEECS), National University of Sciences and Technology (NUST), Islamabad, Pakistan 2 Department of Electrical Engineering, COMSATS Institute of Information Technology, Islamabad, Pakistan {11mseemabbasi, saleem.shahid, 11mseemrizwan, munir.tarar}@seecs.edu.pk, muzahir_abbas@comsats.edu.pk Abstract—A multiband coupled on-board printed handset antenna capable of providing wideband operation for GSM 1800/1900, UMTS and LTE 2300/2500 is presented. Antenna consists of coupling monopole resonators which are extended from the feed and main ground plan to accommodate integration with circuit board of mobile handset. Antenna can easily be fabricated with the help of extended line and ground without disturbing main circuit board of handset, considering the presence of protruded components over circuit board. The antenna design uses fork-shaped monopole coupling resonators extended from active element and ground plane. These resonators along with prolonged length from patch and ground, as a function of resonating wavelength, control the bandwidth of antenna. Monopoles driven from patch and ground contribute the lowest and higher order resonant modes to form three wide operating bands centered at about 1800, 2500 and 5200MHz to cover GSM1800/1900/UMTS/LTE2300/2500. The results of this study confirmed that extended planner monopoles couple to form lower and higher resonant modes. This study provides new understanding on coupling monopole resonators and their application in handset antenna designing. I. INTRODUCTION Printed planar antennas on circuit board are the suitable candidates for low profile smart mobile phones due to negligible thickness of antennas. Some of the promising handset antennas operating at LTE700/GSM850/900 and GSM1800/1900/UMTS/LTE2300/2500 have been reported earlier [1-2]. Spiral monopole with parasitic shorted strip are used to achieve wide band operations with compact size [3], implantable zeroth-order resonance antennas or use of multiband helical and PIFA has been demonstrated [4-5]. Antennas designed using printed monopole resonators help in integration of the antenna with mobile circuit board. Another technique in which antennas comprising of two monopole slots operated at their quarter-wavelength modes for GSM- 850/900/1800/1900 and UMTS (1920–2170 MHz) has been presented [6]. A number of techniques like shorting pin with ground [7-8], entrenching slots and slits in radiating patch and ground plane [7, 9-11] and tuning stubs [7, 12-13] has been used extensively by antenna designers. To the best of author’s knowledge, no work has been done in capacity of optimizing coupled resonating element such as planar monopoles, dipoles and stubs. This paper presents a multiband antenna with fork-shaped monopole coupling resonators having maximum length of 30mm. Antenna covers bands of GSM-1800 (1710–1880 MHz), GSM-1900 (1850–1990 MHz), UMTS (1920–2170 MHz), LTE (2300–2400 MHz) and LTE (2500–2690 MHz) bands that are widely demanded for next generation cellular phones [2-3] in near future. Rest of the paper is organized as; Section-II explains proposed antenna design; Section-III presents parametric analysis of antenna design and discussion on results whereas Section-IV concludes the paper. (a) (b) Fig. 1. Geometry of proposed handset antenna a) Antenna integrated with mobile circuit board (b) Dimensions of monopole coupling resonators II. PROPOSED DESIGN Fig. 1 shows the geometry of proposed antenna with coupled resonating monopoles. Antenna has been designed on FR4-epoxy sheet having size 55x115x1.6mm 3 , relative permittivity (İ r ) 4.4 and loss tangent (tanį) 0.02. This FR4- epoxy sheet has been treated as one-sided copper-coated circuit board used for mobile handset. Detailed dimensions of coupled resonating monopoles are shown in Fig. 1 (b). The dimensions of main circuit board and monopole resonators are balanced to ensure practical implantation in manufacturing of 3489