IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308 __________________________________________________________________________________________ Volume: 03 Special Issue: 03 | May-2014 | NCRIET-2014, Available @ http://www.ijret.org 208 COMPARATIVE STUDY OF SLOT LOADED RECTANGULAR AND TRIANGULAR MICROSTRIP ARRAY ANTENNAS G M Pushpanjali 1 , R B Konda 2 , S K Sajjan 3 1 Asst. Prof., Dept. of Physics, Central University of Karnataka, Gulbarga 2 Asst. Prof., Dept. of Electronics, Smt. V. G. Degree College for Women, Gulbarga 585 102 3 Asso. Prof., Dept. of Electronics, S.V.M, Arts, Sc. and Comm. College, Ilkal (Karnataka) 587125 Abstract In this paper we have presented the comparative study and theoretical validation of two element slot loaded rectangular microstrip array antenna (TS-RMAA) and two element slot loaded equilateral triangular microstrip array antenna (TS-ETMAA), fed by corporate feed technique illustrating wide band operation. The experimental results reveal that, the impedance bandwidth of TS- RMAA is 6.54% (i.e., 700 MHz) and the impedance bandwidth of TS-ETMAA is 7.35% (i.e., 820MHz). The impedance bandwidth of TS-ETMAA is 1.12 times more than the impedance bandwidth of TS-RMAA. The theoretical impedance bandwidth is determined to compare the experimental impedance bandwidth for validation. The theoretical and experimental impedance bandwidth is in close agreement with each other. The wide band operation of the antenna may find application in communication system. Keywords: Array antenna, wide band microstrip antenna, triangular microstrip antenna. -----------------------------------------------------------------------***---------------------------------------------------------------------- 1. INTRODUCTION With the saturation of low frequency bands, the operating frequencies of modern communication systems have risen and planar antennas have become more attractive. Among them, microstrip antennas form a special category on which considerable research work has been conducted. However microstrip antennas inherently have a narrow impedance bandwidth and its enhancement is usually demanded for practical applications. On the other hand, wide band antenna with small physical size and good performance are an oncoming challenge to meet the needs of integration, cost and efficiency of the emerging wireless world. One of the most attractive features of the equilateral triangular microstrip antenna (ETMSA) is that, the area necessary for the patch becomes about half as large as that of a nearly rectangular or square microstrip antenna designed for the same frequency [1]. In view of this an effort is made to enhance the impedance bandwidth of the antenna by reducing the area of the radiating patch. 2. DESCRIPTION OF THE ANTENNA GEOMETRY The antennas are sketched by using computer software Auto- CAD and fabricated on low cost glass epoxy substrate material of thickness h =1.66mm and permittivity  r = 4.2. The radiating elements of TS-RMAA and TS-ETMAA shown respectively in Fig.1 and Fig.2 are fed by using corporate feed technique. Fig – 1: Designed geometry of TS-RMA Fig – 2: Designed geometry of TS-ETMAA This technique has been selected because of its simplicity and it can be simultaneously fabricated along with the antenna elements. In Fig. 1 and Fig. 2 the distance between the two radiating elements D R is kept at 3 o /4 in order to add the radiated power in free space by individual elements to improve antenna parameters. However, the D R is taken in terms of multiple of half wavelength. But in this case 3 o /4 has been selected in order to accommodate corporate feed arrangements between the two radiating elements. The corporate feed arrangement consists of matching transformer, quarter wave transformer, microstrip bend and two way power