Study On The Fresnel Lens As An Optical Antenna Of LED-based Indoor Visible Light Communication

White LED is viewed as the revolutionary technology of the solid light in21st century.It has lots of advantages, such as high brightness, low power consumption, long life, highluminous efficiency, safety, reliability and durability, etc. Except the lighting function,white LED has a short response time and high-speed modulation characteristics. UsingLED in visible light communication system has great potential. Integrated with wirelesscommunications, Indoor visible light communication is a green economicalcommunications technology and an effective complement to the radio frequency technology.The signal is modulated onto white LED to transmit the information through light.Comparing to the traditional communication way, this technology has a much fewer cost, awider area covering and a much safer mechanism without radiation.The optical antenna, as a major device of a visible light communication system, playsan important role in the communication quality of the system. For indoor communicationenvironment, an optical receiver antenna should have the characteristics of high receivedpower, high signal to noise ratio,wide field of view, miniaturization and low cost, etc.In this paper, we analysized the current visible light communication system andfocused on the optical receiving technology of indoor visible light wireless communication.Then we completed the design of the equal-pitch plane Fresnel lens and composite Fresnellens respectively. The main contents are as follows:Firstly, analyzed the principle of visible light communication white LED source anddescribed its basic structure and type. Then we studied further on the performance of thewhite LED light, including its optical and electrical properties, radiation property, etc. Afterthe discussion of the channel characteristics, we found our two types of lighting layout ofwhite LEDs.Secondly, The design principles of optical receiving antenna were introduced,including non-imaging optics theory, geometrical optics theory and the edge-ray principle.Then the important parameters of the receiving antenna, such as optical gain, efficiency andgeometric concentrating ratio, were given to evaluate its optical properties. In the end, weproposed the design method of the Fresnel lens as an optical receiving antenna. Thirdly, We studied the pricinple of the Fresnel lens. By calculating the prism structure,the equal-pitch plane Fresnel lens was designed. Then the optical concentration ratio, theoptical efficiency and the spot size of these lenses were analyzed respectively with differentparameters by means of Trace pro. Furthermore, the concentration performance is discussedat different incident angles.Finally, we proposed a composite Fresnel-based concentrator and the opticaltransmission of different prism structures were analyzed. Then we made a simulation of thecomposite Fresnel lens. In order to obtain good irradiance uniformity on the photodetector,the prism structures were optimized by using a simplex algorithm. For the chromaticaberration effect using Fresnel lens, we presented an achromatic Fresnel doublet, analyzedits structure and explained the achromatic principle.