Abstract: A typical high end smart phone is supposed to have enough battery life to get through a full day. But over a time a lot of people find their phones with lack of battery. Perhaps, battery life actually seems to be getting worse with successive generations which leads to dead phone in emergencies. This paper purposes the study of cell phone which aims to overcome the shortcomings of existing phone due to lack of battery. In companies that require employees to be stationed at areas which are prone to power cutoffs and loss of connectivity, usage of RF waves for harvesting energy to the mobile device is a convenient solution. By working on this project for ONGC the aim is to eliminate the aforesaid problem. Battery free cell phone includes interfacing of antenna for transmission and reception of signals. RF harvester for gathering the RF signals from atmosphere and photodiode harvester for gathering the ambient light from the atmosphere and converting it into power. The key challenge in achieving this is that a cellphone is required to perform multiple basic operations: sensing speech at the device, transmitting it to the base station, receiving speech information from the base station and finally actuating the speaker/earphones. Designing a battery-free cell phone system requires us to perform all these functions, in real time, using only a few micro-watts of power. Existing ADC and DAC based approaches to transmitting and receiving speech consume too much power to be applicable for real-time battery-free applications.

Keywords: Battery free cellphone, RF harvester, photodiode, DC-DC Booster, RF- DC Conversion