Multibeam half radial line slot array (RLSA) antennas

An original design of a multibeam Radial Line Slot Array (RLSA) antenna having two beams directed to the broadside and two beams directed to the backside is discussed in this research. The uniqueness of this design is the implementation of multibeam as a half-cut RLSA instead of a full-circle RLSA, which aims to make them more suitable for smaller devices. In order to produce a beam to the backside, the slots were placed on the backside ground plane. Furthermore, the use of the half-circle RLSA and the backside ground plane to generate the beam disrupted the power flow within the antenna's cavity, which caused a problem of center frequency shift. A frequency design shift technique is then proposed to overcome this problem in this research with the modeling and simulation of 120 four-beams half RLSA in order to determine the most efficient model to be fabricated. The measurements carried out to verify the accuracy of the fabricated model were in good agreement with the simulation results and proved the validity of the antenna design. The result shows the possibility and effectiveness of designing four symmetrical beam antennas with gain of 8.1 dBi, directions of 60°, 150°, 210°, and 330°, and beamwidth of 22°. The gain of 8.1 dBi is 9 dB less than the gain of a single beam antenna, which is consistent with the theory of beam splitting. Moreover, the antenna offers low reflection and broad bandwidth for Wi-Fi needs.