Radiation Pattern Measurement in the Planar Coordinate

Chen Yang,Jun Wen,Yi Wang,Yi-Hao Wang,Zhao Ding,Li-Feng Bian

doi:10.1109/jphot.2019.2949147

Abstract

A planar measurement approach is presented to obtain the radiation pattern, by which rotation operations can be removed or reduced for a source with narrow and divergent viewing angle, respectively. The Etendue conservation is applied to derive the intensity distribution relationship between planar and spherical surfaces, which is further used for the radiation feature measurement on planar systems. As an indirect approach, sampling position distribution and measurement sensitivity is then discussed. Four application scenarios of the method are proposed and experimentally studied, including: 1D, 3D wireframe, pattern reconstruction for Monte Carlo ray-tracing planar data and 3D pattern estimation for luminaires. 1D radiation pattern obtained by classical goniophotometer method is employed as an evaluation standard, and experiments indicate that the results agree well between the two approaches. Therefore, the planar measurement can be applied as an alternative or supplementary method of the goniophotometer to test angle-dependent attributes of sources.

Highlights

Radiation pattern is a significant tool to describe angular dependent strength for sources, such as light from luminaires or radio waves from antennas
Four application scenarios of the method are proposed and experimentally studied, including: 1D, 3D wireframe, pattern reconstruction for Monte Carlo ray-tracing planar data and 3D pattern estimation for luminaires. 1D radiation pattern obtained by classical goniophotometer method is employed as an evaluation standard, and experiments indicate that the results agree well between the two approaches
The cos−3 θ term representing the intensity relationship between planar to spherical surfaces is derived according to the Etendue conservation, which is further recommended for measuring radiation patterns in the planar coordinate

Summary

Introduction

Radiation pattern is a significant tool to describe angular dependent strength for sources, such as light from luminaires or radio waves from antennas. A lot of efforts have been made to optimize the radiation pattern measurement methods Due to advantages such as flexibility and processing time-efficiency, Charge-Coupled Device (CCD) cameras are employed to construct video-goniophotometers in applications such as bidirectional scattering distribution function measurement [14], [15]. An approach is proposed to measure the radiation pattern in planar coordinate system, which can remove or reduce the rotation operation, especially for sources with narrow viewing angles. To achieve this target, the Etendue conservation is applied to derive intensity distribution mapping relationship between the planar and spherical system. Experiments are carried out about four proposed application scenarios of the method, including: 1D measurement, 2D wireframe pattern measurement, radiation pattern reconstruction based on planar data generated by MC ray-tracing, and 3D pattern estimation for luminaires

Relationship by Etendue Conservation

Sampling Position Arrangement

Measurement Sensitivity

Experiment and Results

Pattern Reconstruction for Monte Carlo Ray Tracing Data

Conclusion