DESIGN AND IMPLEMENTATION OF RECTENNA FOR ON- AIR DRONE CHARGING

• Main Author: Iqbal Arrachman, Muhammad
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/82194
• Institution: Institut Teknologi Bandung

A drone, also called a UAV (Unmanned Aerial Vehicle), is a flying machine that functions without a crew on board. In the 21st century, drones have been used for military and non-military functions such as photography, agriculture, monitoring, delivery of goods, and entertainment. One of the problems in using drones is the low flight duration. To overcome this, a wireless power transmission system was designed. Wireless power transmission is a method of sending power without using cables, but instead using magnetic fields, electric fields, electromagnetic waves, visible light and other energy carriers. Implementing an electromagnetic wave- based WPT system to charge batteries on drones operating in the air is promising because its distance capability is longer than induction-based WPT systems, and its implementation is easier and not as expensive as laser-based WPT systems. In this final assignment book, the design and implementation of a WPT receiver sub-system using 2.45 GHz electromagnetic waves to charge the battery on a drone in the air is discussed. The 2.45 GHz frequency is used because it is unlicensed so it does not require costs to use and the frequency signal attenuation in the air is relatively low. Making a WPT system at this frequency also uses relatively small components, and it is easy to design a power transmitter using an antenna that is supplied to a magnetron which can be found in microwave ovens which are capable of emitting a typical power of 900 W. The WPT system includes three sub-systems, namely the sub-system a transmitter that emits electromagnetic waves towards the receiver, a receiver sub-system that captures electromagnetic waves and converts them to DC signals, and an application sub-system that controls the transmission of power to drones that have been verified only. The receiving sub-system includes a receiving antenna whose function is to receive electromagnetic waves and then transmit them to a rectifier circuit, and a rectifier circuit which functions to convert electromagnetic waves to DC signals. The receiving antenna uses a modified patch design to have circular polarization using truncation and slots, wide beamwidth. The combination of wide beamwidth and circular polarization allows the antenna to receive electromagnetic waves from many directions and orientations. The rectifier circuit is designed based on a two- stage Dickson rectifier circuit to increase the output voltage of the circuit. An impedance matching design is used to minimize reflections in the rectifier circuit. iv Plus, a filter on the output side uses inductors and capacitors to minimize ripple due to remaining RF signals. The results of testing the receiving antenna show that the antenna is capable of operating at a frequency of 2.45 GHz with a S11 of -16.7 dB, and is able to receive electromagnetic waves well in many directions. The receiving antenna also has circular polarization with a low axial ratio for most measurement angles. The results of testing the rectifier circuit show that the circuit is capable of converting electromagnetic waves into DC signals, with a maximum output voltage of 14.7 V at an input power of 26 dBm, but with a relatively large return loss at 2.45 GHz. The results of testing the entire receiver sub-system show that the sub-system is capable of capturing the emitted electromagnetic waves and converting them into a DC signal which has sufficient voltage to charge the battery on the drone, with an output voltage reaching 22.9 V at a distance of 4 m from the transmitter. The receiver is also capable of turning on LED lights which are arranged so that they have a forward voltage of 8.6 V at a distance of 4.5 m from the transmitter. The weakness of the designed sub-system is the low efficiency and output power of the circuit due to excessive losses in the conversion process.