Patent attributes
A slot antenna is provided with at least two conductive plates arranged to face each other. A slot is arranged on one of or both of the facing conductive plates and has a long and narrow opening shape. A power feeding unit is arranged between the facing conductive plates and is electrically and physically connected with the facing conductive plates, respectively. When power is fed to the power feeding unit, the power is fed between the facing conductive plates by the power feeding unit. Thus, excitation with a frequency dependent on the electrical length of the slot is induced at the slot, and a current excited at the slot is distributed entirely over one conductive plate, the current becomes a radiation source, and an electromagnetic wave is radiated from the one conductive plate. At this time, the other conductive plate operates as the reflecting plate of the electromagnetic wave.