Circularly polarized wave antenna and communication device using the same

摘要

A radiation electrode (3) is formed on the upper face (2a) of the substantially columnar dielectric substrate (2). Feed electrodes for a fundamental mode (4A, 4B) and for a higher mode (5A, 5B) are formed on the side peripheral face (2c) of the dielectric substrate. Power is supplied through the respective feed electrodes to the radiation electrode via capacitive coupling. The radiation electrode has both of the functions in the fundamental and higher modes. Thus, the circular polarized wave antenna can be reduced in size. Furthermore, since a capacitive feeding system is employed as described above, the respective resonance frequencies in the fundamental and higher modes can be easily adjusted and set at predetermined frequencies. Also, the circularly polarized wave characteristics in the fundamental and higher modes can be easily enhanced, respectively. <IMAGE> <IMAGE>