基于室内可见光通信技术的新型两级光学接收天线设计与分析

Design and analysis of novel two-stage optical receiving antenna for indoor visible light communication technology

针对室内可见光通信系统的应用需求,设计了一种新型两级光学接收天线.根据复合抛物面聚光器光学增益随视场增大而减小的聚光特性,将复合抛物面聚光器截面基准曲线旋转设计得到具有一定旋转角与厚度的透镜壁复合抛物面聚光器.进一步结合透镜壁复合抛物面聚光器和半球透镜的优势设计了一种新型两级光学接收天线,在增益保持的情况下视场角增大了近20~?.在一个5 m×5 m×3 m的空旷房间,通过Trace Pro建立光学天线的分析模型,Matlab软件对室内可见光通信系统进行信道建模.计算结果表明,采用这种新型两级光学接收天线,与直接接收的情况相比,平均接收功率增幅为757.2%,是复合抛物面聚光器的5.62倍;信噪比平均值增幅为28.07%,是复合抛物面聚光器的1.67倍;光学增益为11.49,是复合抛物面聚光器的2.81倍.且光斑半径仅为2.5 mm,较复合抛物面聚光器减小了近37.5%,使得能量集中均匀分布,进一步证实该新型两级光学接收天线适用于室内可见光通信系统.

White light emitting diode has become the next generation of light source because of its high illuminance efficiency, low power consumption, and long life, and it has also been adopted in the application of indoor visible light communication （VLC） system. The VLC has great development potentials, however, there is a lack of research on optical receiving antenna which is a key component of VLC. Therefore, in this paper we design a novel two-stage optical receiving antenna for indoor VLC system. In the designed antenna, the lens wall of a compound parabolic concentrator with a certain rotation angle and thickness is obtained through rotating the parabolic reflector cross-section reference curve. Furthermore, a novel two-stage optical receiving antenna is designed by taking advantage of lens-wall compound parabolic concentrators and hemispherical lenses. This significantly increases the view angle by nearly 20° in the case of gain retention. The analytical model of the optical antenna in a 5 m × 5 m × 3 m open room is established by using a software of TraceProTM. The indoor VLC system is also modelled and implemented by using a software of MatlabTM. The results show that the growth rate of average received power is 757.2%, which is 5.62 times that of the compound parabolic concentrator, and the signal-noise-ratio is increased by 28.07%, on average, which is 1.67 times that of the compound parabolic concentrator. The optical gain of the two-stage optical receiving antenna is 11.49, which is 2.81 times that of the compound parabolic concentrator. The spot radius is only 2.5 ram, which is reduced by nearly 37.5% compared with the spot radius of the compound parabolic concentrator, and the energy concentration is evenly distributed at the same time. This further confirms that the designed two-stage optical receiving antenna is suitable for indoor VLC system. Finally, the performance analysis and experimental verification of the new two-stage optical receiver antenna are also given.