To reduce the transmission loss by using a low-loss optical transmission line as a signal transmission line transmitting a microwave signal between a transmitter-receiver and an antenna element.
An electrooptical converter 8a is connected to a transmitter and the microwave signal supplied from the transmitter is converted by the electrooptical converter 8a into a light subcarrier signal through the direct current modulation of a laser diode and divided equally into two by an optical multiplexer/demultiplexer 7. One subcarrier signal is led to an antenna element 1a through a variable optical attenuator 6a, a nano-liquid crystal phase modulator 5a, an optical fiber 4a, an optic/electric converter 3a, and a power amplifier 2a. The other subcarrier signal is led to an antenna element 1b through a variable optical attenuator 6b, a nano-liquid crystal phase modulator 5b, an optical fiber 4b, an optic/electric converter 3b, and a power amplifier 2b. Thus, the subcarrier signals are transmitted by the optical fibers 4a and 4b to reduce the transmission loss on the signal transmission line.
SUGIYAMA YASUYUKI
MATSUMOTO SHIRO
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