Development and Analysis of Multi Band MIMO Antennas for 4G or 5G and Beyond for Mobile Base Station Applications

Abstract

In recent years, significant advancements in cellular wireless technologies have newlinebeen witnessed, particularly in mobile base station applications. Key innovations such newlineas MIMO, massive MIMO, and mm-wave antennas have played crucial roles in newlineshaping these developments. However, contemporary base station antennas have faced newlinechallenges such as high cross-polarization, inadequate isolation, poor gain, and bulky newlinestructures. These challenges were addressed in this thesis by developing natureinspired newlineantennas with enhanced characteristics, including improved isolation, low newlinecross-polarization, high gain, and compact structures, aligning with the demands of newlinemodern wireless communication systems and the future deployment requirements of newlinetechnologies like 5G, 6G, and beyond. newlineThe contributions of this thesis included the development of a compact tapered newlinedipole antenna structure that covered a broad frequency band encompassing both 4G newlineand sub-6 GHz frequencies of 5G. High isolation and low cross-polarization were newlineachieved, which are essential for mitigating interference and cross-talk between newlineantenna elements in base station applications. A slot-coupled cross-dipole antenna newlinedesign was developed, incorporating radio network planning and wave propagation newlineanalysis for both Time Division Duplex (TDD) and Frequency Division Duplex (FDD) newlinemodes across 4G and 5G frequency bands. Various modulation techniques were newlineconsidered to optimize performance. Additionally, a miniaturized massive MIMO newlineantenna element was introduced, employing a novel approach capable of providing newlinedual-band bandpass filter characteristics for both 4G and sub-6 GHz 5G bands. A guard newlineband was incorporated to effectively manage interference between these frequency newlinebands in base station environments. newlineFurthermore, a MIMO antenna configuration utilizing metamaterial absorbers newlinewas proposed. This design employed resistively loaded metamaterial absorbers to newlinereduce mutual coupling between MIMO antenna elements, thereby enhancing the newlineperformance and reliability of mobile.