Antenna apparatus and communication system

摘要

Conventional antennas devices provide in sufficient performance in terms of directivity, efficiency, or the like. An antenna device includes a radiating element 11 which is provided with a feed terminal 16 to draw power and has a spiral shape; a passive element 12 which is installed side by side with the radiating element 11 and has a spiral shape; an earth ground 15 disposed in opposing relation to the radiating element 11 and the passive element 12; a first connecting electrode 13 for connecting one end of the radiating element 11 to the earth ground 15; and a second connecting electrode 14 for connecting one end of the passive element 12 to the earth ground 15, and the first and second connecting electrodes 13 and 14 are displaced with respect to each other in a plane which includes the spiral shape.