2018 年 15 巻 18 号 p. 20180687
In this paper, an antenna element and array for broadband application are proposed. The original antenna element consists of a parallel-double transmission line (PDTL) fed ellipse dipole and a reflecting plate for unidirectional radiation, high-gain, and high efficiency operation. By introducing a circular patch as parasitic radiator, the voltage standing wave ratio (VSWR) ≤ 2 is achieved from 3 GHz to 9 GHz and the element shows a stable radiation pattern during the operating band. In order to reach a high gain performance, a 4 × 8 array is investigated. For the broadband performance of the proposed antenna array, a broadband and low loss tapered PDTL network is used to construct the array. Finally, to verify the feasibility of the proposed antenna, a prototype array is manufactured and measured. Experimental results are found in acceptable agreement with the simulated ones in terms of gain, radiation efficiency, radiation pattern, and VSWR. The result indicates that the proposed antenna has an impedance bandwidth (IBW) for VSWR ≤ 2 of 100% ranging from 3.0 to 9.0 GHz. Meanwhile the radiation efficiency is better than 82.7% and the gain varies from 14.8 to 20.9 dBi within the IBW.
