Wideband Conformal Transmitarrays for E-Band Multi-Beam Applications

Wideband conformal transmitarrays at E-band are developed for multibeam applications in this article. A triple-layer element with double split rings is presented for wideband transmissions, achieving a 360° continuous phase variation range at 74 GHz with less than 2.3 dB transmission loss. A comprehensive design methodology of multibeam conformal transmitarrays is demonstrated for various platforms with different curvatures. To validate the theoretical analysis, conformal transmitarrays with two different curvatures are designed, fabricated, and measured. Multiple radiation beams are realized between ± 30° and ± 45° for the two prototypes, respectively. Good agreement is obtained between simulation and measurement. The 3 dB gain bandwidths are 30% from 66.5 to 90 GHz, and 27.8% from 68 to 90 GHz for the two designs, respectively, covering the entire E-band.