Millimeter-Wave and Sub-6-GHz Aperture-Shared Antenna and Array for Mobile Terminals Accessing 5G/6G-Enabled IoT Scenarios

In the era of 5G and beyond, the strategic utilization of both sub-6-GHz and millimeter-wave (mmWave) spectrums supports diverse communication services. Through smartphones, consumers can conveniently access a wide range of 5G/6G-enabled Internet of Things (IoT) scenarios anytime and anywhere. In this article, mmWave and sub-6-GHz aperture-shared antenna and array are proposed for mobile terminals. For the mmWave antenna design, a slot radiating array is integrated into the metallic frame of a smartphone. This design incorporates a differential square-ring feeder and utilizes hybrid mode operation, enabling dual-polarized radiation capability across a wide operating frequency band. Importantly, this configuration requires only two metal layers with a 1.0-mm profile. Sharing the same frame, an inverted-F antenna (IFA) and a hybrid mode antenna with loop antenna and IFA operation are designed to work in sub-6-GHz bands. With the design principle of equal clearance, the sub-6-GHz antennas can perform well with the co-existence of the mmWave array. This approach is particularly applicable for sub-6-GHz antennas of different modes and frequencies. The proposed
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mmWave phased array prototype demonstrates a −10-dB bandwidth of 23.3–30.8 GHz (covering the 5G n257/258 bands), a beam scanning range of ±40°, and an in-band realized gain above 10.3 dBi. The sub-6-GHz antennas effectively cover 5G bands n1/2/3/7/18/28. By utilizing impedance tuning technique, the lower band can be further tuned to cover the bands n8/5.