Quadruplex Slot Antenna for Dual-Standard Operation With Small Frequency Ratio

In this communication, a novel four-port slot antenna designed for both 5G New Radio (NR) and WiFi operations is introduced. Wideband NR antennas are achieved using a hybrid mode concept. Then, two NR slot antennas are co-designed as a radiative bandstop structure. By moving the resonance frequencies of the hybrid modes close to the band-reject points of this bandstop filter (BSF), a wideband decoupled dual-antenna structure is achieved. To enhance functionality, two additional ports are incorporated into the dummy slot area between these two NR ports, resulting in a quadruplex antenna. In this final configuration, two of the antennas are optimized for 5G NR applications, covering the 5G N77, N78, and N79 bands (3.3–5.0 GHz), while the remaining two antennas serve the WiFi band (5.15–5.8 GHz). Compared to other presented works, the simulation and experimental results demonstrate that this work not only, for the first time, achieves simultaneously wideband in-band and small frequency ratio (1.05) out-of-band duplex (OBD) in one single module, but also has the advantages of high isolation, compact size, and low cost.