Now showing 1 - 2 of 2
  • Publication
    Generation Orbital Angular Momentum Modes Using Metasurfaces
    The purpose of this study is to investigate how numerous orbital angular momentum (OAM) modes may be produced by mixing acoustic plane beams with different metasurfaces. This study proposes a novel metasurface that may be simulated in order to generate OAM beams. Multi-beam and multi-mode terahertz wave incidence are produced utilizing vortex modes in the beams. The study of suitable OAM superpositions of waveguide eigenmodes is done using COMSOL Multiphysic, followed by a description of the software's usage and examples of challenges involved. With the existence of these studies, we can also prove that the mode can be produced completely with the results that have been studied. Based on the results obtained, an objective was achieved, which is to design the feature of the vortex beam modes. These results include the construction of a multi-functional vortex beam based on a theoretical model of phase gradient distribution. Also, by using metasurface mimics to specify a periodic structure specified by the user from the built-in unit cell, and the beam was attenuated and split into two paths inside the thin layer. Finally, the simulation process between 2D and 3D is very significant because the mesh and geometry in a design are very different, but generating a beam using COMSOL already has a specific module, namely the wave optic module, which can be used to predict the beam modes.
      1  37
  • Publication
    Smart embedded-analytics sensors with cloud-based measurement system for HVAC
    HVAC system is a necessary component of environment to maintain the temperature and humidity to be kept at certain levels by using air taken from outside to ensure the indoor comfort. The purpose of the study is to reduce the electricity energy usage and cost from air conditioning by using smart embedded-analytics sensors to provide the automatic thermal control in an area. In this study, we used sensors such as temperature and humidity sensors to detect and read the currently temperature and humidity of an area monitored by a microcontroller. The cloud-based system and the sensors are connected via wifi in the presence of MQTT protocol. The protocol enables publish and subscribe method which provide the communication between sensors, cloud-based system and HVAC system. This communication can serve thermal control automatically thus resulting the optimize usage of energy from air conditioning according to the external environment temperature and humidity. The control of the temperature and humidity from air conditioning can be designed through the programming embedded in the microcontroller. The monitoring result can be displayed from the control panel to ensure how the system works.
      31  2