Crossed-dipole antenna

A crossed-dipole antenna comprising:

• a core of a columnar shape having a top surface, a side surface, and a bottom portion, the core being composed of a dielectric material;
• a reflecting plate arranged at the bottom portion of the core;
• a first element group that resonates at a first resonance frequency f1 and is composed of four first elements that are formed on an outer surface of the core, extend from a central portion of the top surface of the core with a first length L1 and a first width W1, and are arranged to be orthogonal to one another;
• a second element group that resonates at a second resonance frequency f2 and is composed of four second elements that are formed on the outer surface of the core, extend from the central portion of the top surface of the core with a second length L2 and a second width W2, and are arranged to be orthogonal to one another and so as not to overlap with the first elements;
• and
• feeders that transmit electric power to each element in the first and second element groups,
• wherein each of the first elements and the second elements extends along the outer surface of the core and is bent from the top surface to the side surface, the first length L1 is less than a fourth of a first wavelength 21 corresponding to the first resonance frequency f1, and the second length L2 is less than a fourth of a second wavelength 22 corresponding to the second resonance frequency f2.