RING ANTENNA

PROBLEM TO BE SOLVED: To attain good electric characteristics even when a ring antenna is located close to a conductor.SOLUTION: A C shaped loop element 22a is formed on an upper surface of a ring shaped body part 1a having a substantially rectangle cross section shape and made of a dielectric substance. A cut part 23a is formed at a part of the C shaped loop element 22a formed into a loop shape. Further, an arc shaped driven element 21a is formed on an inner peripheral surface of the body part 1a maintaining a substantially concentric relationship with the C shaped loop element 22a and forming a predetermined gap between itself and the C shaped loop element 22a. The C shaped loop element 22a is excited by the driven element 21a. A power supply part, connected with one end of the driven element 21a formed on a lower surface of the body part 1a, is connected with a tip of a power supply conductor 16 thereby supplying power to the driven element 21a. Even if this ring antenna 1 is housed in a metal housing exterior package, good electric characteristics are attained.