OLED Panel Radiation Pattern and Its Impact on VLC Channel Characteristics

Organic light-emitting diodes (OLEDs) show several attractive features superior to traditional semiconductor LEDs for visible light communication (VLC). This paper experimentally tests and models the radiation pattern of a bent OLED panel for the first time. Different from a Lambertian radiation pattern, we propose an improved analytic mixed Gaussian model to describe the rotational radiation asymmetry, whose parameter values are found by applying an expectation-maximization algorithm for curve fitting with measurements. The OLED radiation pattern is observed to show strong directionality along the bent axes. Its impact on VLC channel characteristics is further studied. Compared with the Lambertian source, the OLED source is more flexible in radiation pattern control and shows advantages in smaller root mean square delay spread and optical path loss.