Patent ID: 6396442
Filing Date: 2002-05-28
Classification: H01Q

Abstract:
A circularly polarized antenna device comprising:a circularly polarized antenna unit including a radiation electrode on a top surface of a substantially circular cylindrical dielectric base, the radiation electrode being used for transmitting and receiving a circularly polarized electric wave, the circularly polarized antenna unit being mounted to a top surface of a feeder circuit board with a bottom surface of the dielectric base serving as a mounting surface; wherein a recess is formed in the bottom surface of the dielectric base of the circularly polarized antenna unit; wherein a feeder circuit for supplying electrical power to the radiation electrode is formed on an area of the top surface of the feeder circuit board covered by the recess of the dielectric base; wherein a shield for the feeder circuit is provided inside the recess of the dielectric base; wherein a feeder electrode which connects to the feeder circuit so as to be in electrical connection therewith is formed on an outer peripheral side surface of the dielectric base so as to be separated from the radiation electrode; and wherein electrical power output from the feeder circuit is supplied to the radiation electrode through the feeder electrode by capacitive coupling.