Research On Measurement Device And Methodology Of RF Energy Distribution

The performance of Rechargeable Wireless Sensor Network(WRSN) with the RF power tech-nology is limited by the RF energy supply. The current work is based on omnidirectional chargers rather than directional chargers in the actual deployment and does not consider the impact of indoor multi-path effect on the RF energy distribution. For the deficiencies of the prior studies, this paper accomplished the following key work:(1) Design of portable RF energy distribution measurement device, named Phonemeter. The device is adaptive to the widely used smart phone and is low-cost, ease-to-use and easy-to-carry. Photometer consists of the hardware and software. Furthermore, in this paper, a series of perfor-mance tests are designed and conducted to obtain the parameters of Phonemeter; and based on the experimental results, some optimization designed are completed. Finally, based on Phonemeter, this paper comes up with a distributed RF energy measurement system.(2) Study the indoor seven path RF power distribution fitting model based on the directional charger. The existing seven path model is required to fit the directional antenna pattern and some environment-related or devices-related factors. Firstly this paper uses the antenna pattern experi-mental data to fit the directional charging theoretical model. Then based on this model, this paper fits the indoor seven path model with the data measured by Phonemeter, and gives the evaluation results.(3) Research on the optimization problems of WRSN with the directional charger. This paper researches how to optimized the rotation angles of chargers with the limited number to guarantee the sufficient energy level of each sensor nodes, based on the fitted indoor seven path model. This paper completes the problem formulation and transformation, and then gives greed and random rounding approximate method, and accomplishes algorithm performance evaluation by numerical simulation.