A Spirally Slotted Microstrip Antenna with Improved Bandwidth for Lower C Band Applications

In this paper a spirally slotted micro strip antenna with improved bandwidth for lower C band (4-6 GHz) applications was designed and fabricated. The reflection coefficient at the determined position of the proposed antenna was well below −10 dB for the whole frequency band. The size of the antenna was thus reduced by about 62% when compared to a conventional micro strip patch antenna. The bandwidth of the spiral slot antenna was approximately 38% from 4.1 to 6 GHz, while the antenna without slots was approximately 1 % from 4.5 to 4.55 GHz. For the simulation process IE3D version 14.62 electromagnetic software had been used. The effect of antenna dimensions and substrate parameters on the performance of antenna was investigated. Different substrate heights were taken and based on their performance analysis; substrate with height 1.5 mm was chosen for the antenna design. It was found that the proposed antenna bandwidth was almost thirty eight times to that of the antenna without the slots.VSWR analyzed was well below 1.5 which is almost near to the ideal value. The antenna was tested on Rohde and Schwarz network analyzer to obtain experimental results. The experimental and simulation results exhibited good agreement with each other.