PURPOSE: To reduce the thickness, size and weight of the plane antenna and to make it possible to receive both horizontal and vertical polarized waves by forming a switching device for polarized waves and plural amplifiers on a substrate and connecting them to a large number of transmitting/receiving probes formed on the base.

CONSTITUTION: A receiving pattern formed on the plane antenna is constituted of connecting respective amplifiers 6 to many probes 3a, 3b,... properly arranged on the substrate so that horizontal and vertical polarizedwaves are amplified by the amplifiers 6 and switched by the polarized wave switching device 7 and a required polarized wave is inputted to a converter. The amplifiers 6 and the device 7 are formed on the substrate constituted of a semiconductor, the amplifiers 6 consists of transistors (TRs), FETs, etc., and the device 7 consists of a diode, a TR, an FTE, or the like. Consequently a converter can be compacted, a thin and compact plane antenna can be obtained, the deterioration of the polarized wave in a transmission line can be reduced and the wave can be efficiently received.