Antenna device having two resonance frequencies

摘要

An antenna device having two resonance frequencies wherein two radiating patches are respectively provided on one surface and on the other surface of a dielectric plate which is disposed above a ground plate with a space interposed therebetween. A coupling control capacitor element is connected between these two radiating patches and resonance control capacitor elements are connected between the radiating patches and the ground plate, respectively. Capacitance of the coupling control capacitor element is selected such that a current coupled from one of the two radiating patches to the other and a current supplied from the said one of the radiating patches to the other via the coupling control capacitor element are in opposite phase at the other one of the radiating patches.