International Journal of Enhanced Research in Science Technology & Engineering, ISSN: 2319-7463 Vol. 2 Issue 12, December -2013, pp: (85-90), Available online at: www.erpublications.com Page | 85 A single layer multi-resonant 1×4 series fed high gain microstrip patch array antenna for L-Band and C-Band applications Brajlata Chauhan 1 , Sandip Vijay 2 , S. C. Gupta 3 1 Uttarakhand Technical University, Dehradun UK India 2,3 Dept. of Electronics & Comm., Engineering Dehradun Institute of Technology, Dehradun, UK. India Abstract: This paper describes a design of 1×4 series fed Microstrip Patch Antenna Array for multi-resonance applications such as GPS devices, WCDMA (1910–2190 MHz) and WLAN. This antenna array consists of patch elements using a single layer RT/Duroid 5880 substrate with transformer coupled impedance matching network, which provides high gain of 9.583dB and efficiency 96.08%. This antenna array has good performance in terms of antenna gain, directivity, return losses ,VSWR, Characteristics impedance, liner polarization, Band width and efficiency over the frequency range for L band C band applications. WLAN working at IEEE 802.11a employ 5.15-5.35 GHz for lower WLAN and 5.725-5.825GHz for higher band WLAN. Index Terms: RMPA, High gain, Multiband antennas, Method of moment ADS-2009, Impedance matching, WLAN. 1: Introduction Micro-strip patch antenna (MPAs) has attractive and widespread features due to its low profile, small size, light weight, low cost as well as to the fact these are very simple to design, suited to planer and non-planer surfaces. It is mechanically robust, easily integrated with circuits, and allow multi-frequency operation to be achieved [1]. However their further use in specific systems is limited of their relatively narrow bandwidth. The principle of wide bandwidth or bandwidth enhancement of MPAs may be achieved by several efficient approaches as : Increasing the substrate thickness ,Optimizing impedance matching ,Reduce substrate effective permittivity , Incorporating multiple resonance. The miniaturization of conventional MPA size [1] has been accomplished by using various form such as using high permittivity substrate, shorting ports and modifying basic patch shape. MPAs required to be extremely small and compact size that is basic need of mobile cellular handsets, card-less phones and Bluetooth devices. In this paper, a line fed rectangular patch is developed to has resonant frequency for 5.15-5.35GHz and 5.725-5.825 GHz for lower and higher band WLAN with edge fed is connected to the radiating patch. This fed is also easy to match. 2.1: IEEE802.11a Wi-Fi system using 802.11a specification operates in Unlicensed National Information Infrastructure (UNII) band, which enables system using this exacting network to operate not only at higher speeds but also at higher power .The 802.11aoperate the UNII band at 5Ghz.It is designed to provide data rate of up to 54 Mbps [13]. Design for an antenna (usually, linearly polarized) operating at DCS-1800 (1710–1880 MHz), IMT-2000 at (1885– 2200MHz) , global positioning system (GPS) at (1570–1580 MHz) receiver WLAN-IEEE 802.11b (2400–2483 MHz) bands. 2.3: Microstrip Lines A microstrip line consists of a single ground plane and a thin strip conductor on a low loss dielectric substrate [1] above the ground plate. Due to the absence of the top ground plate and the dielectric substrate above the strip, the electric field lines remain partially in the air and partially in the lower dielectric substrate. This makes the mode of propagation not pure TEM but that is quasi-TEM. Due to the open structure and any presence in discontinuity, the microstrip line radiates electromagnetic energy. The use of thin and high dielectric materials reduces the radiation loss of the open structure where the fields are mostly confined inside the dielectric.