Literature Review Of Vast Rectenna - 1028 Words

7 CHAPTER 2 AMBIENT RF ENERGY HARVESTING COMPONENTS AND LITERATURE REVIEW 2.1 RECTENNA ITS COMPONENT A rectenna is a rectifying antenna, a sort of antenna that is used to convert microwave energy or radio frequency energy into direct current signal that can power low sensor devices. They are modelled as a part of wireless power transmission systems that transmit power through radio waves or electromagnetic waves. A basic rectenna, comprises of a microstrip patch antenna with a RF diode. It is nonlinear rectifying element (for example Schottky diode, Zener diode, IMPATT diode.... etc.). The diode rectifies the alternating current or bidirectional current induced in the patch antenna by the RF waves, to generate DC or unidirectional†¦show more content†¦2.1.2 RECTIFIER A rectifier is an electrical device that converts bi-directional current or alternating current (AC), to unidirectional current or direct current (DC). This process is called rectification. Rectifiers have many uses including high-voltage direct current power transmission systems, in DC power supplies and in detection of radio signals. There are two types of rectifier, the half wave rectifier and the full wave rectifier. In our case, given the need of matching as the less number of components, half wave rectifier has been used. 2.1.2.1 Half Wave Rectifier The half wave rectifier rectifies only half cycle of the AC input waveform. The half wave rectifier consists of a step down transformer, a diode connected to the transformer and a load resistance connected to the cathode side of the diode. 2.1.2.2 Full Wave Rectifier The circuit of full wave rectifier uses two rectifier elements and the transformer with secondary center tapped. One for the positive half cycle and other for the negative half cycle. The output DC in full wave rectifier is twice that of half wave rectifier and the frequency is twice that of the supply frequency. 2.1.3 IMPEDANCE MATCHING Impedance matching is one of the most eminent part of the RF circuits. It is utilized for the purpose of transferring maximum