High-Isolation Dual-Band Compact Duplex Array Based on Radiator-Shared System

A dual-band, dual-polarized, duplex compact antenna array based on a radiator-shared system is proposed, operating at lower band (LB): 2.4–2.8 GHz and higher band (HB): 4.6–4.9 GHz. The proposed array consists of LB and HB elements alternately placed with a compact spacing of less than 0.5λ. The LB unit operates in both LB and HB bands. A hybrid independent dual-band decoupling method is proposed to regulate the in-band and cross-band couplings. All the in-band couplings are decreased to below −20 dB. Independent decoupling regulation of each band is realized by the electromagnetic transparency property of the dual-band hybrid decoupling surface. The introduction of duplex balun divides the reused port of LB unit into two independent feeding ports, achieving cross-band coupling below −20 dB. Additionally, it enables independent regulation of the array's radiation performance, incorporating electrical downtilt of 6° in the LB and 10° in the HB, along with stable beam scanning with a range of ±45° in both bands. The measured results of the 6 × 8 prototype arrays have verified the correctness of the simulation ones.