Compact High-Isolated MIMO Antenna Module With Chip Capacitive Decoupler for 5G Mobile Terminals

In this letter, a compact high-isolated multiple-input–multiple-output (MIMO) antenna module based on a chip capacitive decoupler is proposed for the fifth-generation (5G) smartphones. The antenna module consists of two feeding ports, radiating metal strips, and a chip capacitive decoupler within a compact size of 16 × 6 mm
²
. In this design, two L-shaped metal strips are used as distributed capacitors to compress the size of the module. Meanwhile, a chip capacitive decoupler is added to improve isolation between the two feeding ports, which is realized with an analysis of common and differential modes. In addition, spiral slots are used to adjust the isolation between the modules. A prototype MIMO antenna with four such dual-port antenna modules was tested in the 3.5 GHz band. The measured –6 dB bandwidths of the two ports are 310 MHz (3.42–3.73 GHz) and 360 MHz (3.33–3.69 GHz), respectively, and the isolation is 24 dB at 3.5 GHz. The measured efficiencies are 60.5% and 52.7% at 3.5 GHz. The compact MIMO antenna module with high-isolation property provides a hopeful solution for the 5G mobile terminals.