High‐gain end‐fire bow‐tie antenna using artificial dielectric layers

This study presents a high‐gain bow‐tie antenna for applications in next generation base‐stations operating from 2.5 to 3.9 GHz. The proposed structure consists of three circular sector patches that are attached laterally to the microstrip feed‐line, which is etched on both sides of the common dielectric substrate to create symmetrical bow‐tie antenna. By loading the antenna with a 2 × 5 array of enhanced end‐coupled split‐ring (EECSR) unit‐cells results in significant enhancement in the antenna gain performance. This is because the EECSR unit‐cells behave as parasitic radiators, which is analogous to Yagi–Uda antennas. The EECSR unit‐cells provide a medium of high effective permittivity that effectively reduces the spacing between parasitic directors. As a consequence, a compact and miniature structure is achieved compared with conventional quasi‐Yagi–Uda planar designs. The dimension of EECSR unit‐cell is 33 × 36 mm 2 with inter‐element spacing of 0.075 λ 0 at 3.5 GHz. A prototype of the antenna was fabricated and its performance was measured to validate the simulation results. The measured peak gain of the antenna with 4 × 5 array of EECSR is 12.65 dBi at 3.73 GHz, constituting a peak gain enhancement of 7.45 dBi in the Worldwide Interoperability for Microwave Access band compared with an equivalent conventional bow‐tie antenna.