Antenna apparatus and wireless apparatus and radio relaying apparatus using the same

An antenna apparatus comprising:

• a plurality of antennas formed in a diamond shape in such a manner that each of two 1-wavelength antenna elements is bent at a center thereof and the bent 1-wavelength antenna elements are located opposite to each other;
• a transfer path;
• and
• a reflection plate;
• wherein:
• said plurality of antennas are arranged in such a manner that said plural antennas are separated from each other by keeping an interval defined by multiplying a half wavelength by an integer along a vertical direction with respect to a plane of said diamond shape, and major polarized wave directions thereof are made identical to each other;
• said plurality of antennas are connected to each other by the transfer path;
• a tip portion of an antenna system for connecting said plurality of antennas is opened and a power supply unit is provided at the other end thereof;
• and
• said reflection plate is arranged to be separated by a predetermined interval along the vertical direction with respect to the diamond-shaped plane of said plural antennas.