Patent ID: 7035592

Claim:
A radio apparatus capable of calibration of antenna directivity, comprising: an antenna ( 104 ); a transmission circuit ( 102 ) and a receiving circuit ( 105 ) sharing said antenna when transmitting/receiving signals; a reference signal generator ( 107 ) generating a prescribed reference signal; switching means ( 103 ) selectively connecting an output of said transmission circuit or said reference signal to an input of said receiving circuit in calibration; control means ( 100 ) supplying a transmit signal to said transmission circuit while receiving a receive signal from said receiving circuit for controlling transmission directivity of said transmit signal transmitted through said transmission circuit and said antenna while controlling receiving directivity of said receive signal received through said antenna and said receiving circuit; and arithmetic means ( 100 H) calculating a correction value for correcting difference in quantity of phase rotation and/or quantity of amplitude fluctuation between said transmission circuit and said receiving circuit, wherein said arithmetic means includes: means controlling said switching means to connect the output of said transmission circuit to the input of said receiving circuit in calibration for calculating first information related to the quantity of phase rotation and/or the quantity of amplitude fluctuation caused in a signal passing through said transmission circuit and said receiving circuit, means controlling said switching means to connect said reference signal to the input of said receiving circuit in calibration for calculating second information related to the quantity of phase rotation and/or the quantity of amplitude fluctuation caused in a signal passing through said receiving circuit, means subtracting said second information from said first information thereby calculating third information related to the quantity of phase rotation and/or the quantity of amplitude fluctuation caused in a signal passing through said transmission circuit, and means calculating said correction value on the basis of said second information and said third information.