Transmission circuit and communication device incorporating the same

A transmission circuit that is configured to amplify and transmit high-frequency signals to a planar radiating element having a first feed point, a second feed point, a third feed point, and a fourth feed point, the transmission circuit comprising:

• a first amplification circuit, a second amplification circuit, a third amplification circuit, and a fourth amplification circuit that are configured to supply high-frequency signals to the first feed point, the second feed point, the third feed point, and the fourth feed point, respectively;
• a first phase-shift line connected between the second amplification circuit and the second feed point;
• a second phase-shift line connected between the third amplification circuit and the third feed point;
• and
• a third phase-shift line connected between the fourth amplification circuit and the fourth feed point,
• wherein the first feed point and the third feed point are arranged at positions that are offset from a center of the radiating element in opposite directions from each other along a first direction,
• wherein the second feed point and the fourth feed point are arranged at positions that are offset from the center of the radiating element in opposite directions from each other along a second direction that intersects the first direction,
• wherein the first phase-shift line has a line length of λ/8, the second phase-shift line has a line length of λ/4, and the third phase-shift line has a line length of (3/8)λ, where λ is a wavelength of the high-frequency signals supplied to the radiating element.