International Journal on Recent and Innovation Trends in Computing and Communication ISSN: 2321-8169 Volume: 3 Issue: 3 1507 - 1509 _______________________________________________________________________________________________ 1507 IJRITCC | March 2015, Available @ http://www.ijritcc.org _______________________________________________________________________________________ Bandwidth Enhancement in Microstrip Patch Antenna Using Rhombus Shape Slot Pritika Bhatt MTech student, RF &Microwave Engineering, GITAM University, Visakhapatnam,AP, India pritikabhatt1818@gmail.com Dr. T. Venkata Ramana Associate Professor, Dept of ECE, GITAM University, Visakhapatnam, AP, India, teppala@gmail.com. P. Saleem Akram Asst. Professor, Dept of ECE, KL University (KLEF) Vaddeswaram, Guntur (D.T), AP, India, saleemakramp@gmail.com. Abstract—The Microstrip antennas are the low profile radiators. It is so because of their numerous features such as low volume, compactness, low fabrication cost and mechanical robustness. Numerous techniques have been suggested to improve the Microstrip patch antenna characteristics. In this paper we discuss the slot coupled patch antenna, one with a rectangular patch and other one with a rhombus shaped patch. And study the antenna characteristics of both the antenna such as bandwidth, radiation loss and gain. The results indicate the impact of changing patch on the antenna performance. To excite the structure the microstrip line is placed below the slot. The slot is made between the feed line and the radiating patch substrate. Fields from the microstrip line will be coupled to the patch through this narrow slot. ANSYS HFSS is used to carry out the procedure Keywords—slot antenna, rectangular slot patch, rhombus slot patch, bandwidth, radiation pattern __________________________________________________*****_____________________________________________ I. INTRODUCTION All manuscripts must be in English. Advancements in printed circuit fabrication bought a revolutionary change in the way antennas were fabricated. It’s now possible to fabricate extremely useful low profile antennas; such antennas are either called as printed circuit antennas or simple the microstrip antennas. Microstrip antenna has two parallel conductors and a dielectric substrate sandwiched between the two. The lower conductor serves as ground plane and the upper conductor as a patch. This is how microstrip antennas got the name patch antennas. The patch can be of any shape, circular, square, rectangular, triangular, elliptical , dipole etc. in this paper we discuss two different patch antennas, first a rectangular slot patch antenna and second a rhombus slot patch antenna.[1-6] The various advantages of patch antennas prompted us to carry out research in this field. The advantages of patch antennas are Ease of fabrication, compactness, high reliability, low initial costs and light weight. Applications where high performances, size, low installation cost, cheap and integral antennas are required, patch antennas are always the first choice. The field of application are very wide-ranging from satellites, spacecrafts, missiles and wireless communication. The wireless communication demands for high capacity and small size. Thus small sized antenna were required as the devices became small themselves. This need led to development in patch antennas [8].The patch antennas also compensate for the coupling effects due to various nearby objects acting as scatters. But Microstrip antennas suffer from some disadvantages also. They lack polarization clarity, low power, less efficient, low scanning ability, narrow bandwidth, and spurious feed radiation. But these disadvantages can be overcome using various techniques, including feeding techniques, stack configuration, changing height of substrate and using different patch. In the present work we compare two slot coupled antennas having different patches. Various performance metrics are studies such as radiation loss, gain and bandwidth. This would help us to enhance the antenna performance. Slot couple patch antennas are designed to achieve the higher bandwidth with better radiation efficiency and less return losses so that said disadvantages can be eliminated [7]. II. RESEARCH METHODOLOGY In this section we discuss the antenna design. The antennas are fed using coax probe feed. First antenna has a rectangular patch whereas the second antenna under study has a rhombus shaped patch. The antennas have a narrow slot located on the ground plane, sandwiched between the feed line and radiating patch substrate. The structure would be excited from the Microstrip line present at the bottom. Fields would be coupled from