A Cylindrically Conformal Array With Enhanced Axial Radiation

A cylindrically conformal four-element slot array with enhanced axial radiation is proposed in this letter. To realize the axial radiation, first the element adopts conformal dual U-shaped slots with two low-profile cavities to obtain the tilted radiation. Second, four conformal elements integrated uniformly at the circumference of the metallic cylindrical shell are fed by a 1-to-4 microstrip feed network with a 90° sequential phase difference to obtain the axial radiation. Both simulated and measured results are presented and confirm that the 10-dB impedance bandwidth is larger than 400 MHz, covering the frequency range from 3 to 3.4 GHz, and the maximum axial radiation gain is 5.12 dBic. The proposed conformal array has a low profile with only about
$0.03{\lambda _0}$
, which can be mounted on the surface of any carrier conveniently.