Common antenna device and portable wireless device using the same

摘要

PROBLEM TO BE SOLVED: To use a unified antenna to both satellite communication and terrestrial communication by adding a linear radiation element to the tip of a feeder pin which supplies a high frequency current to a microstrip planar antenna via a capacitive element. SOLUTION: An MSA (microstrip planar antenna) 1 functions as a circular polarized antenna by the 1st frequency when the parameters such as the relative dielectric constant, size, thickness, etc., of a dielectric substrate 1c, the size of a radiation element 1b, and the positions, etc., of a feeder pin 1a are properly designed. A linear radiation element 8 works as a grounded liner polarized antenna by the 2nd frequency via a helical antenna that is placed under a ground conductor 4. A capacitive element 7 is connected to the upper end part of the pin 1a of the MSA 1, and the element 8 of the helical antenna, etc., is connected to the upper part of the element 7. The mutual interference is reduced between the 1st and 2nd frequencies via the element 7 and the radiation pattern of the circular polarized wave is particularly improved.