Broadband Phased Array Antenna by Combining Array Traveling Wave Mode and Unit Resonance Mode

Abstract

A new multi-mode combination method that combines traveling wave mode in an array with resonance mode in an antenna unit, is proposed to realize expand the bandwidth of the array. The proposed concept is demonstrated by integrating a resonant element structure (a folded split slit loop formed by combined slots) into a connected parallel slot tightly coupled array (TCA). The array unit in an infinite array with the operation frequency band of 1.08–3.41 GHz is designed based on the master-slave boundary method for a group of periodic structures. The E-field distributions at several typical frequency points indicate that the array operates with traveling wave mode at f = 1.40/3.00 GHz and resonant mode at f = 3.35 GHz, respectively. A finite array with 7 × 7 units is designed and manufactured, the array can operate at 1.0–3.63 GHz with an active VSWR less than 3. To better illustrate the radiation performance of the antenna, the obtained gain diagram of the 16 × 16 array is given. The designed array has the following characteristics: (1) the design guideline is simple, (2) both traveling wave mode and resonant mode have the same polarized radiation, (3) the designed 16 × 16 array can scan its main beam angle up to 70° in E- and H-planes over the whole operation band.