Ground Radiation Antenna for Mobile Devices Using Controlled Endless Metal Rim Mode

Abstract

In this paper, we introduce a ground radiation antenna that uses controlled endless metal rim modes. In the proposed technique, the metal rim mode is tuned and excited as a one-wavelength radiator by asmall ground radiation antenna. The proposed antenna occupies a clearance of 1mmx4mm in a 30mmx20mm ground plane. A metal rim with dimensions of 34mmx24mm surrounds the ground plane, and the metal rim is separated from the ground plane by a gap of 2mm. In addition, a lumped capacitor is inserted between the metal rim and the ground plane to control the characteristic mode of the metal rim such that the resonance of the metal rim is tuned to be equal to the operating frequency. By performing simulations and measurements, we compare the performance of the proposed antenna with that of a reference antenna that does not have an inserted capacitor between the metal rim and the ground plane. The results show that a significant improvement of the radiation performance is obtained by employing the proposed technique.