Generation of Orbital Angular Momentum beams using Leaky Wave Substrate Integrated Waveguide Antenna

Abstract

Recently, the demand for research on vortex electromagnetic waves has been on the rise due to the lack of channel capacity and spectrum congestion. In this aspect, a cutting-edge technology known as Orbital Angular Momentum (OAM) provides a new degree of freedom and has a tremendous potential to increase the channel capacity and spectral efficiency of wireless communications. It is a well-known fact that light carries angular momentum, and electromagnetic waves carry both linear and angular momentum. The vortex electromagnetic wave is characterized by the structure and distribution of the electromagnetic wave in space. OAM,ontheotherhand,isaspatialcoordinatedimensionthat describes the transverse rotation of the vortex electromagnetic beam energy, which is perpendicular to the propagation direction of the electromagnetic wave. Beams carrying OAM have a helical phase front and a field strength with an amplitude null, which can be used for information transmission, imaging, and particle manipulation. The number of orthogonal OAM modes in a single beam is theoretically infinite and each mode is an element of a complete orthogonal basis that can be employed for multiplexing different signals, thus greatly improving the transmission rate and efficiency. Generating orbital angular beams presents a number of challenges including issues related to the design of the OAM generator, as well as difficulties in controlling the properties of the beams themselves. This includes controlling the polarization, phase, and amplitude of the beams, as well as ensuring that they are properly focused and aligned. Despite these challenges, significant progress has been made in recent years in the generation of orbital angular beams. The solution to this challenge lies in Substrate Integrated Waveguide (SIW) technology, which enables the implementation of active and passive components, antennas, and the integration of a complete system into a single dielectric substrate. SIW technology is a promising contender for the future of microwave and millimeter wave components and antennas. Its potential is particularly evident in the rapidly growing field of wireless sensor networks and the Internet of Things wherein this technology offers an ideal solution for the creation of low-cost and environmentally friendly wireless nodes. By leveraging these innovative approaches, we can create a more sustainable future for wireless communication technology. In my thesis report, I have comprehensively summarized and compared the methods for generation and detection of radio OAM especially using a uniform circular array and subsequently a slotted SIW by successfully generating first order OAM beams. The potential applications of this promising technology in future wireless systems and wearable devices are also discussed.