# Optically Transparent Honeycomb Mesh Antenna Integrated into OLED Light Source
## 5 Antenna Integration into OLED
### Antenna Effects on the OLED Colorimetric Parameters  
After the study of the effects of the OLED on the radio-electrical parameters of the antenna, it is very important to investigate the influence of this integration on the color appearance of the OLED. Therefore, the optical and photometric characterizations of the OLED were carried out before and after the antenna integration. Figure 17 shows a photograph of the optical and photonic measurements of the OLED. These measurements were carried out on an optical bench at room temperature with the MINOLTA CS-1000 spectroradiometer. This measuring device was placed 1 m from the OLED, allowing the measurement of the optical and colorimetric parameters in the visible field (380-780 nm) in steps [44]. The measurements were carried out in both with and without the antenna and were repeated 21 times to ensure the accuracy of the measured values.  
Then, the colorimetric parameters were calculated using the IES TM-30-18 color-rendering method [45]. Using this method is more appropriate for LED and OLED light sources, because it generates better colorimetric analysis than the CIE fidelity index method. This involves calculating the mean fidelity index (Rf) by the light source rendering test  
Figure 16: Radiation patterns of the transparent antenna with and without OLED; (**a**) in the XZ-plane, (**b**) in the YZ-plane, and (**c**) with OLED in 3D view.  
Figure 17: Measuring bench for the optical characterizations.  
from 99 Color Evaluation Samples (CES) compared to the International Commission on Illumination (CIE) standard [46], which only considers 8 Test Color Samples (TCS) to calculate Ra (Ra: color rendering index calculated according to the CIE 1995 CRI method). Colorimetric parameters such as the Spectral Power Distribution (SPD), Correlated Color Temperature (CCT), chromaticity coordinates (x,y) and (u\({}^{\prime}\),v\({}^{\prime}\)), the Duv value (the distance between the chromaticity coordinates (u\({}^{\prime}\),v\({}^{\prime}\)) of the OLED and the Planckian locus on the CIE 1976 color space), Rf (fidelity index), and Rg (Gamut index) were calculated to understand the change in the color appearance of the OLED after the integration of the antenna.  
Figure 18 illustrates a comparison between the SPD of a warm white OLED (CCT = 3000 K) and the SPD of the OLED measured with the integrated antenna. It was noticed that the SPD changed after the integration of the antenna. A variation in the SPD generally results in changes in the colorimetric parameters.  
The average CCT, chromaticity coordinates (x,y) and (u\({}^{\prime}\),v\({}^{\prime}\)), Duv value, Rf, and Rg are shown in Table 2 for both the cases with and without the antenna. According to the MacAdam ellipse, the slight differences observed in these parameters are not detectable by users. The measurements, therefore, showed no significant difference between these parameters with and without the antenna. However, the luminance value decreased by 25% after the antenna was integrated, so this alteration will cause the lamp brightness to be non-uniform.