Comparative study of radial line slot array antenna with different dielectric substrates

Abstract

Radial Line Slot Array Antenna (RLSA) is the legendary types of communication device due to its low profile, high gain, and durable antenna for point to point. From the existing RLSA antenna, most researcher designed their antenna with a huge size indirectly make antenna become weight. Hence, this dissertation focus on enhancement performance of antenna in compact size and at the same time retain a frequency operation which is at 5.8 GHz. By reducing the size of antenna, the overlapping of slots will be occurred and subsequently decrease the gain. Thus, the attachment technique with another substrate is one of the options to overcome this problem. Hence, the research presents the antenna designed with three different structures: Spider-Radial Line Slot Array (SRLSA) antennas which are Single Layer of RLSA, an Air-Gap RLSA and Compact Sandwich Polypropylene Antenna (CSPA). The design construction is started with a single layer of SRLSA antenna with a dimension of (100x100) mm. The number of slots and degree angles of radiating element are significantly affected the overall performance of SRLSA antenna. Parameter sweeps study on the number of slots and degree angles are executed to obtain an optimum gain of SRLSA antenna. The maximum gain obtained of single layer SRLSA antenna is only 3.42 dBi which is consider average for point to point application. Thus, air-gap structure is investigated. The similar number of slots and degree angles is used. After simulation, the gain of 7.68 dBi is achieved. This improvement gain is due to the changes of permittivity, ?. The lower value of ? increased the fringing field at the patch periphery and thus radiated power. Further research has been done on polypropylene (PP) substrate even though the gain of air gap antenna is better than single layer of SRLSA. The deployment of PP has successfully boost the gain up to 10.52 dB within the frequency range of 5.49 GHz to 5.89 GHz. It is found that the incorporation of PP filler improved the dielectric constant and inclined the dielectric loss of the CSPA antenna thus generating an optimum gain. With all capabilities mentioned, this CSPA antenna is highly potential to be deployed for point to point application