A filtering antenna based on a dumbbell-shaped resonator is proposed, fabricated and measured. A Γ-shaped antenna and the proposed dumbbell-shaped resonator are used and integrated to be a filtering antenna. The Γ-shaped antenna which acts as a radiator is excited by a coupled line. Measured results show that the filtering antenna achieves an impedance bandwidth of 6.7% at a reflection coefficient |S11| < -10dB and has a gain of 1.35 dBi. Moreover, a radiation zero occurs at 3.1GHz. Compared with the characteristics of fundamental Γ-shaped antenna, the design of the dumbbell resonator has little impact on antenna's radiation patterns. In addition, to explain the mechanism of filtering antenna, the analysis of surface current distribution on patch is given. The size of filtering antenna is 0.33λ0×0.17λ0 (λ0 is the free-space wavelength at 2.45 GHz). Compared to other recent works, a simpler structure and more compact size are the key features. Owing to the operating bandwidth and the characteristic of filtering, the proposed antenna can be used in modern wireless communications systems.
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