This thesis is about the researching for 5th generation (5G) communication system, which focus on the improvement of 3D beamforming technology in the antenna array using in the Full Dimension Multiple-Input Multiple-Output (FD-MIMO) system and Millimeter-wave (mm-wave) system. When the 3D beamforming technology has been used in 5G communication system, the beam needs a weighting matrix to direct the beam to cover the UEs, but some compromises should be considered. If the narrow beams are used to transmit signals, then more energy is focused in the desired direction, but this has a restricted coverage area to a single or few User Equipments (UEs). If the BS covers multiple UEs, then multiple beams need to be steered towards more groups of UEs, but there is more interference between these beams from their side lobes when they are transmitted at same time. These challenges are waiting to be solved, which are about interference between each beam when the 3D beamforming technology is used. Therefore, there needs to be one method to decrease the generated interference between each beam through directing the side lobe beams and nulls to minimize interference in the 3D beamforming system. Simultaneously, energy needs to be directed towards the desired direction. If it has been decided that one beam should covera cluster of UEs, then there will be a range of received Signal to Interference plus Noise Ratio (SINR) depending on the location of the UEs relative to the direction of the main beam. If the beam is directed towards a group of UEs then there needs be a clustering method to cluster the UEs. In order to cover multiple UEs, an improved K-means clustering algorithm is used to cluster the multiple UEs into different groups, which is based on the cosine distance. Itcan decrease the number of beams when multiple UEs need be covered by multiple beams at same time. Moreover, a new method has been developed to calculate the weighting matrix for beamforming. It can adjust the values of weighting matrix according to the UEs' location and direct the main beam in a desired direction whilst minimizing its side lobes in other undesired directions. Then the minimum side lobe beamforming system only needs to know the UEs' location and can be used to estimate the Channel State Information (CSI) of UEs. Therefore, the scheme also shows lower complexity when compared to the beamforming methods with pre-coding. In order to test the improved K-means clustering algorithm and the new weighting method that can enhance the performance for 3D beamforming system, the two simulation systems are simulated to show the results such as 3D beamforming LTE system and mm-wave system.

abstract: The commercial semiconductor industry is gearing up for 5G communications in the 28GHz and higher band. In order to maintain the same relative receiver sensitivity, a larger number of antenna elements are required; the larger number of antenna elements is, in turn, driving semiconductor development. The purpose of this paper is to introduce a new method of dividing wireless communication protocols (such as the 802.11a/b/g/n and cellular UMTS MAC protocols) across multiple unreliable communication links using a new link layer communication model in concert with a smart antenna aperture design referred to as Vector Antenna. A vector antenna is a ‘smart’ antenna system and as any smart antenna aperture, the design inherently requires unique microwave component performance as well as Digital Signal Processing (DSP) capabilities. This performance and these capabilities are further enhanced with a patented wireless protocol stack capability. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2019

Traditional antennas have a lot of limitations as their performance is usually fixed by their initial geometry. On the other hand, modern communication systems are getting way to complicated compared to their earlier counterparts. This necessitates some special types of smart or reconfigurable antennas, which can dynamically adapt to the requirements of the communication systems more effectively. Using conventional single functional antennas is therefore not an efficient approach in these sort of communication systems. Considering all these factors, in this thesis, a beam steerable reconfigurable antenna system is presented that can yield the radiation patterns of multiple antennas with a single structure, necessary for 5G communication. This antenna system occupies comparatively much smaller space and can provide highly directive gain at different directions. It is expected that- in near future, further improvements of this type of antenna system can be performed to pave the way for some additional necessary functions required in modern communication systems.

Due to the increasing demand and a more complicated environment for signal transmitting, the traditional antenna can hardly satisfy the current technology needs. For a telecommunication service provider, a dual-band integrated antenna array is a good way to reduce cost and increase the capacity since it can operate at different bands. The active part can also achieve beam-forming to adapt to multiple environments. Since two arrays are integrated together, the interface and coupling will be a problem. The performance of the active array is also important since it is supposed to be operated at a complex environment. This thesis will focus on how to achieve better performance of active array and reduce the impact of passive array such as mutual coupling and the change of field distribution of active array. In this thesis project, the limiting factor for the performance of active array is the narrow bandwidth. To solve that, we use another layer of parasitic patch to generate multiple resonances near the fundamental mode. For the passive antenna array, we use crossed-dipole such that the thin wires will block less signal. The return loss result and radiation pattern comparison can show that the bandwidth is broadened with parasitic patches, and the passive array has little influence on the active array. It is a proper way to design a dual-band antenna product with a low budget. / På grund av den ökande efterfrågan och en mer komplicerad miljö för signalsändning kan den traditionella antennen knappast tillfredsställa den nya teknologins behov. För leverantören av telekommunikationstjänster är en integrerad dubbelbandsantennuppsättning ett bra sätt att minska kostnaderna och öka kapaciteten eftersom den kan fungera på olika band. Den aktiva delen kan också uppnå strålformning för att anpassa sig till flera miljöer. Eftersom två arrayer är integrerade tillsammans blir gränssnittet och kopplingen ett problem. Prestandan för en aktiv array är också viktig eftersom den är tänkt att användas i en komplex miljö. Detta examensarbete kommer att fokusera på hur man uppnår bättre prestanda för en aktiv array och minskar effekten av den passiva arrayen. För det här examensarbetet är den främsta faktorn som begränsar prestandan för aktiv array den smala bandbredden. För att lösa detta använder vi ett annat lager av parasitisk patch för att generera flera resonanser nära det grundläggande läget. För passiv antennuppsättning använder vi korsade dipoler så att de tunna ledningarna blockerar mindre av signalen. Jämförelsen av returförlustresultatet och strålningsmönster kan visa att bandbredden breddas med parasitiska patch, och den passiva arrayen har liten inverkan på den aktiva arrayen. Det är ett riktigt sätt att designa en dual-band antennprodukt med en låg budget.