US Patent 10498037 Antenna circuit

In an antenna circuit including an antenna 1 and an antenna 2 that is connected in series with the antenna 1 and includes inductance, a variable capacitor Cv and a variable resistor Rv connected in parallel with the antenna 2 are provided. This enables controlling of an actual amplitude ratio r and a phase difference θ between currents I1 and I2 flowing through the two antennas 1 and 2 into desired values. Flows of the currents I1 and I2 with the phase difference θ through the antennas 1 and 2 enable forming of a favorable communication area. In addition, setting of the actual amplitude ratio r between the currents I1 and I2 flowing through the antennas 1 and 2 to a value other than 1 enables forming of an asymmetric communication area.