Antenna pattern reconstruction of optical leaky waveguide antenna by phase-less measurement

This paper presents the antenna pattern reconstruction of optical leaky waveguides antenna by phase-less measurement. In recent years, there has been tremendous increased in data traffic due to the widespread of mobile terminals, and high data transmission system for next generation is expected. Optical communication is considered as one of those systems. We have studied grating (GWG) and waffle waveguides (WWG) which are a type of optical leaky waveguide antennas (OLWA). These antennas can tilt a beam by sweeping incident wavelength. Each waveguide measurement is evaluated at near field because the antenna structure is very large with respect to the wavelength. To evaluate the antenna pattern from near field of the beam scanning antenna, amplitude and phase are essential. In the experimental system of optical device, measuring intensity of the light is easy. The measurement of phase is difficult. In this study, directivity of each waveguide is estimated by the aperture distribution method using approximate aperture distribution. The proposed method shows that estimate gain and radiation angle are in good agreement with calculated result.