Precise beam shaping and positioning by using non-symmetrical array feed technique / Amirul Farid Amir Shapuddin

The array antenna technology nowadays is very popular in terms of easy of fabrication, light weight characteristic, inexpensive, simple structure and its very accurate to get simulation results through various electromagnetic simulators. Apart from that, the combination of techniques between array feed antenna and reflector antenna can generate the precise beam shape and coverage, which is very important and high in demand for commercial and also military used. In this research, the critical element of the array feed design and feed network have been emphasized on getting the right or precise dimension for the desired beam shaping. In order to get the desired results, certain method was considered to be used. At the first place, the arrangement of the single array element were calculated and tested via a programme named Ray Tracing technique using MATLAB software. The results from that simulation determined the best positions of the patch element to be placed on the substrate. Normally, the position or range between the elements is based on Lamda/2 (A/2) and Lamda (X) in order for the fields at the aperture of the two slots to have opposite polarization. Another criterion to design the array feed with a good VSWR and return loss (SI 1) is impedance matching for feed line network. From the previous research, to get a good impedance matching between patch and feedline for allowing the maximum power transfer, the 35Q quarter-wave transformer is used to match the 50Q coaxial feedline with the equivalence of 100Q. for each feed line. In this research, the suggested frequency or reference frequency,^ is 8.144 GHz. The thickness of substrate is 1.6mm by using FR-4 substrate and substrate permittivity, s=4.3. From the calculation using single patch element to get good VSWR and return loss (SI 1), the dimension of the single element antenna is 7.550mm in width, 6.547mm in length, while the thickness of the patch is 0.0035mm. The positioning of the proposed non-symmetrical arrangement of eight elements based on the ray tracing method for West Malaysia beam and the characteristics of the array feed have been verified through CST Studio Suite electromagnetic simulations.