Compact closed‐slot eight‐antenna system for 5G laptops with a metal back cover

Abstract

SummaryThis paper presents the design of a compact closed‐slot sub‐6‐GHz dual‐band eight‐antenna system on a 5G laptop with a metal back cover. The antenna system is installed in a 277 × 2 mm2 clearance area that is 3 mm below the upper edge of the metal back cover of the laptop. Each single closed‐slot antenna element measures 32 × 2 mm2 and features an inverted‐C feeding section and a crossover path consisting of a meandered section and a series chip capacitor. The crossover path can help generate a resonance mode at high frequencies while adjusting the frequency location of the low‐frequency mode, allowing the closed‐slot antenna to support the 3300‐ to 3600‐ and 4800‐ to 5000‐MHz dual‐band operation required for sub‐6‐GHz 5G. The eight closed‐slot antenna elements are oriented in the same direction and aligned in the same axis with a 3‐mm separation between any two adjacent antenna elements. Without the help of any isolation elements, the resultant eight‐element multi‐input multi‐output (MIMO) antenna system possesses measured isolations of larger than 10 dB. The envelope correlation coefficients (ECCs) calculated from the measured complex radiation patterns are all less than 0.105, and the measured antenna efficiencies are over 40%. These results indicate that the proposed MIMO antenna system is ideal for use in laptop devices with a metal back cover and a large screen‐to‐body ratio.