Orbital Angular Momentum Vortex Waves Generation Using Textile Antenna Array for 5G Wearable Applications

Abstract

The development of wireless systems for fifth-generation technology (5G) has enabled the use of textile antennas for a wide range of applications, and it has now become one of the world's most in-demand technology. As the number of wireless devices and users increase, operators would need higher channel capacity to deliver better possible service to their customers. This paper presents the generation of Orbital Angular Momentum (OAM) vortex waves with mode 1 using a wearable textile antenna. OAM introduces a new scheme called Mode Domain Multiple Access (MDMA). OAM mode is an orthogonal mode with each mode carrying individual signals. Therefore, multiple signals can be sent using the same carrier frequency without additional resources. This allows the channel capacity and spectrum efficiency to be enhanced. The proposed antenna array comprises rectangular microstrip patch elements with an inset fed technique. Felt textile fabric was used as an antenna substrate. A carefully planned feeding phase shift network was used to excite the elements by supplying similar output energy at output ports with the required phase shift value. The generated OAM waves were confirmed by measuring the null in the boresight direction of their 2D radiation patterns as well as simulated phase distribution, intensity distribution and mode purity. The antenna covered portions of the 5G n77 band with a bandwidth of 81.7 MHz and an overall gain of 2.9 dBi. This is, to the best of our knowledge, the first work on generating OAM waves using a flexible textile material.