Radiative Deep-Subwavelength Frequency-Selective Surface-Based Cross-Band Decoupling Method for Base Station Antenna

To address the bandwidth limitations encounteredby existing decoupling methods during the global integrationprocess of base station antennas, a radiative deep-subwavelengthfrequency-selective surface (RFSS)-based cross-band decou-pling method is proposed. The RFSS is formed by adeep-subwavelength FSS whose external profile is defined bya well-optimized narrow frame. It is implemented to not onlybe transparent for high-band (HB) electromagnetic waves butalso effectively radiates low-band (LB) ones. To validate thisconcept, a dual-band base station antenna, which comprises anRFSS-based LB antenna and a 2x2 HB subarray, is proposed.Furthermore, we undertake a detailed analysis of the operationalmechanism underlying the proposed RFSS-based LB antenna.In addition, a prototype for proof of concept is fabricated andmeasured. The results demonstrate that the LB antenna operateswithin a relatively wideband of 1.4-2.7 GHz (63.4%), featuringa low profile of 0.25 lambda l c(at the center frequency of LB), and theHB antenna operates at 3.3-4.2 GHz (24%).