"Design, Manufacturing and Testing of Photonic Antennas based on IR LEDs"

Abstract

Concessionaires of public lighting systems have adopted strategies and actions to replace conventional lamps with LED lamps (Light Emitting Diode) aiming at efficiency and economy. However, the potential of this technology goes well beyond the simple application in lighting, providing a communication system that is still in the development phase and that can be explored as a complementary multiple access system to the existing WiFi. Thus, with the use of VLC (Visible Light Communication) links, an innovative type of communication network can be built, supporting user mobility and multiple access, consisting of small cells (atocells), among which a handover technique must be used. be implemented. This type of network was named LiFi (Light Fidelity), since it relies on communication with visible light for its operation. More broadly, in an external environment, where public lighting points can be understood as access points, this type of network can be used with enormous advantage for applications in Smart Counties, in which a high level of communication and interaction between its elements and interfaces suitable for 5th and 6th generation wireless communication systems is required, currently under implementation and study, respectively. Among the various current challenges present, the use of LED arrays in an unconventional configuration can offer innovative solutions for systems in which lighting and communication are combined. Cartesian or periodic arrays require that the separation between the emitting elements be smaller than 1 wavelength, to avoid the appearance of so-called Bragg lobes or Gratting Lobes, which are undesirable in a wireless communication system. As LEDs have dimensions greater than 1 wavelength, they cannot be distributed in the form of periodic arrays, hence the need to use aperiodic arrays that completely eliminate Bragg lobes, in this sense, array configurations based on Vogel spirals (the Fermat spiral is a particular case), are solutions with great application potential. Therefore, we propose here to develop an array of IR (Infrared) LEDs in the form of a Vogel spiral, operating at 850 nm or 940 nm in order to develop an efficient OWC (Optical Wireless Communication) system that can operate not only in transmitter mode (down-link ), but also on the receiver (up-link). Once the proposed system has been demonstrated, it can be later integrated into the same board with a set of LED lamps operated in visible light, aiming at the implementation of a hybrid OWC and lighting system.