Y. Konishi et al., AN OPTICALLY CONTROLLED ARRAY ANTENNA WITH A BEAM-FORMING NETWORK (BFN) USING 2 LASER SOURCES, Electronics & communications in Japan. Part 1, Communications, 78(3), 1995, pp. 65-73
With respect to the optically controlled array antenna in which the op
tical Fourier transform and the O/E conversion are used for generation
and control of the microwave excitation distribution in the optical r
egion, the excitation amplitude and phase distribution and the radiati
on characteristics are studied theoretically and experimentally for a
two-laser system in which two laser sources with their oscillation fre
quency difference set at the desired microwave frequency are used. Fir
st, the excitation distribution and the radiation pattern are expresse
d theoretically in the case where a circular aperture image mask is us
ed and the relationship between the image mask aperture diameter and t
he element antenna spacing is derived. Next, a two-laser experimental
system is shown which uses LD pumped Nd:YAG lasers as the laser source
s. An excitation distribution experiment was carried out at 1.54 GHz.
From the experimental results, it is found that a stable excitation di
stribution corresponding to the theoretical value can be obtained in t
he experimental system in the two-laser system as in the one-laser sys
tem. Further, by using the measured excitation distribution, the array
radiation pattern is computed. In this way, it is confirmed that the
radiation pattern in a beam shape corresponding to the image mask aper
ture diameter can be obtained.