3-D SISL Feeding Network for 2-D Cavity-Backed Endfire Dipole Array at 24 GHz

This letter presents a 4 x 4 cavity-backed endfire dipole array with a novel feeding structure named as 3-D substrate integrated suspended line (SISL) feeding network (TSISLFN). Based on the SISL's structural superiority, air-filled substrate integrate waveguide can be vertically integrated with planar SISL in a self-packaged manner to form the TSISLFN. TSISLFN can be easily integrated with 2-D cavity-backed dipole array and the overall architecture can be realized through printed circuit board technology. Then, the cost and weight of the whole structure are significantly reduced compared to the metal-waveguide counterpart. TSISLFN possess merits of self-packaging, low cost, and low loss. Both 2 x 2 and 4 x 4 cavity-backed endfire dipole arrays fed by TSISLFN are fabricated and measured. At 24.5 GHz, high efficiency of better than 91% and 79%, gain of 15.2 and 20.6 dBi are all obtained for the proposed 2 x 2 and 4 x 4 array, respectively. Similar narrow beam widths in both E and H planes are also obtained.