PURPOSE: To use the solar energy and to minimize the power consumption of a reception system by arranging solar cells between antenna elements and comparing the voltage of a power source, to which the electromotive force corresponding to the quantity of received light is supplied, to control switching.

CONSTITUTION: A communication antenna system consists of an outdoor unit part ODU for transmission/reception of a radio wave used for communication and an indoor unit part IDU. Solar cells 10b are arranged between antenna elements 10a, and a power switching control circuit part 11 is provided which compares the voltage of the power source, to which the electromotive force corresponding to the quantity of received light is supplied, with that of the power supplied from a receiver to control switching. The voltage switching control circuit part 11 drives a down converter 10c as the frequency converter by power generation from solar batteries 10b, discharging from a secondary battery 11a, or power supply from the side of the receiver IDU. The power switching control circuit part 11 compares voltages so that one of these three kinds of power supply is automatically selected.