Design and implementation of a technology planar 4x4 butler matrix for networks application

In this paper, switched beam smart antenna systems are investigated to improve the performance of wireless networks. The microstrip technology of antenna arrays with Butler matrix topology as a beam-former is used to implement the switched beam smart antenna system. The optimum design of a 4x4 planar Butler matrix array, operating at 5.6 GHz for WLAN applications. System’s design and optimization was based on computer simulations

A multi-group study of green supplier selection, green supplier development and organizational performance in Chinese manufacturing

China is one of the world’s most polluted countries due to its growing manufacturing hub which has created environmental problems. This scenario has changed environmental expectations of government, customers and competitors by forcing companies with different enterprise size, ownership and industry to implement green initiatives in order to increase their economic performance in terms of their environmental impact. Green supplier selection and development are important parts of the green supply chain management concept to overcome negative impacts of the Chinese industrial processes. This study investigated the effects of green supplier selection and green supplier development on organizational performance among Chinese manufacturers in different multi-groups based on enterprise size, ownership and industry. Besides, pressures from government, customers and competitors were investigated as moderators on the relationship between green supplier selection, green supplier development and organizational performance. Research framework and hypotheses were developed based on resource-based view and stakeholder theory. Quantitative analysis was conducted using data collected from 608 manufacturing enterprises in China. Structural equation modeling was used for data analysis. Three major findings were found in the study. Firstly, both green supplier development and green supplier selection had significant and positive effects on organizational performance in terms of operational, environmental and financial performances. Secondly, there were significant differences in both green supplier selection and green supplier development among different enterprise ownership groups and industry groups, but not in different firm size groups. Finally, green supplier selection and green supplier development had stronger effects on organizational performance in cases of greater government involvement and customer participation. Furthermore, the moderating effect of competitive pressure was proven for the relationship between green supplier selection and organizational performance but not for green supplier development. Overall, the findings are useful for Chinese manufacturers to select appropriate green suppliers and develop the desired level of green performance for each supplier

Design of a butler matrix beamforming circuit at 28 GHZ for 5G mobile communication

Mobile communication has become prevalent nowadays. The demand for high speed data and information exchange urge on a better communication services. Furthermore, existing services may not able to satisfy the increasing data volume with increasing number of users. The current technology may suffer from congestion and spectrum shortage issue. Thus, 5G is introduced with new spectrum particularly at higher frequencies. However, at high frequencies, a higher propagation loss is expected. The solution is to have a high gain array antenna with particular beamforming features to compensate the high loss. Thus, this work proposes a Butler Matrix beamforming circuit to feed an array at particular 28 GHz for 5G mobile communication. However, the antenna part will not be in the scope of this work. The beamforming circuit will be design, simulate and optimize using CST software. The components namely the coupler, crossover and phase shifter are designed and analyzed separately before integrated to be one Butler Matrix network circuit. Conventional hybrid coupler is designed to operate at desired 28GHz with 90 degrees phase different and equal power divided between the output ports before it is improved with tee junction structure, which reduce the overall dimension without much sacrificing the performances. The coupler then combined to form a crossover with 0 degrees phase different and good isolation. A delay line which give 45 degrees phase shift is designed and connect the structure to form a Butler Matrix beamforming circuit

Dual-series 2 x 4 switched-beam nolen matrix for fifth generation wireless communication system

A new evolvement towards 5G technology requires a super high frequency to provide large channel capacity, low power consumption and low interference. Up to the present, the passive microwave devices with the super high frequency range are becoming necessity to be deployed due to the great features that are capable in representing significant advances in wireless communications. However, high interference occurs due to multiple signals coexisting in the super high frequency. Integration of switched-beam antenna that employs scanning of multi-beams with a proposed Nolen Matrix can be a solution to overcome this issue. The coupler with loaded T-shaped stubs, loaded stubs and Schiffman phase shifters as well as edge chamfered inset feeding microstrip patch array antenna are designed as the key components for the dual-series 2 x 4 switched-beam Nolen matrix. The loaded Tshaped stubs are introduced at each side of the microstrip lines nearby the square patch of the couplers to achieve various coupling values. All simulation results are obtained using Computer Simulation Technology software. The S-parameter measurement of the proposed couplers and dual-series 2 x 4 switched-beam Nolen matrix are performed using vector network analyzer, while its radiation pattern measurement is executed in an anechoic chamber. The amplitude and phase imbalances are ± 1 dB and 5° between 24.75 GHz and 27.25 GHz for the proposed couplers as well as between 25.75 GHz and 26.25 GHz for the phase shifters, respectively. Whereas, the respective amplitude and phase imbalances of 2 x 4 switched beam Nolen matrix are ± 3.5 dB and 10° across the designated frequency range of 25.75 GHz to 26.25 GHz. Meanwhile, at the center frequency of 26 GHz, the simulated and measured main beam directions are 10° and 12°, respectively when signal is fed at port 1, whereas -31° and -31.5°, respectively at port 2, with the highest measured gain of 10.19 dB and percentage of radiation efficiency of 59.98 %

Ultra wideband butler matrix for beam-forming network

The need of having passive microwave devices that can operate in Ultra Wideband (UWB) frequency range has been arising these days due to their features that capable in bringing significant advances in wireless communications such as low power consumption, minimal interference and large channel capacity. However, the low power consumption has led to short range communication. Butler Matrix Beam Forming System is one of the solutions to solve such issue. Multilayer UWB couplers and multilayer UWB phase shifter are possible devices to develop a compact system design of Butler Matrix for UWB as the crossover function has been eliminated by this technique. New designs of multilayer UWB couplers and multilayer UWB phase shifters, which are used to construct the UWB Butler Matrix are introduced. These two main components are designed to function in the UWB frequency range to permit construction of the UWB Butler Matrix. In this research, the proposed UWB Butler Matrix achieves an improvement of 18.6% wider bandwidth compared to available UWB Butler Matrix and 31.1% size reduction compared to planar configurations of Butler Matrix. Simulation results are obtained by using Computer Simulation Technology Microwave Studio 2012. All measurements of S-parameters and phase differences performances are performed using a Vector Network Analyzer. Meanwhile, the measurements on beam directions of the UWB Butler Matrix are steered towards a particular direction by switching the input port accordingly. The switched beam antenna array system shows that four orthogonal beams are produced at four different directions. All measurements result show a very good agreement with the simulation result

High Gain Broadband mm-Wave Antenna Arrays for Short-range Wireless Communication Systems

Recently, the ever-increasing demand for fifth-generation (5G) wireless applications has turned millimeter-wave (mm-wave) multi-beam array antenna into quite a promising research direction. Besides offering a remarkable bandwidth for high-speed wireless connectivity, the short wavelengths (1 to 10 mm) of mm-wave signals makes the size of the antenna array with beamforming network (BFN) compatible with a transceiver front-end. The high losses associated with mm-wave wireless links and systems considered the foremost challenge and may restrict the wireless communication range. Therefore, a wideband substrate integrated waveguide (SIW)-based antenna with high gain and beam scanning capabilities would be a solution for these challenges, as it can increase the coverage area of mm-wave wireless systems and mitigate the multipath interference to achieve a high signal to noise (S/N) ratio, and thereby fulfill the link budget requirements. This thesis focuses on the analysis and design of single- and multi-beam mm-wave antenna arrays based on SIW technology to fulfill the growing demand for wideband high-gain planar antenna arrays with beam steering capability at V-band. A tapered slot antenna (TSA) and cavity-backed patch antenna are used as the main radiators in these systems to achieve high-gain and high efficiency over a wide range of operating frequencies. Accordingly, numerous design challenges and BFN-related issues have been addressed in this work. Firstly, an antipodal Fermi tapered slot antenna (AFTSA) with sine-shaped corrugations is proposed at V-band. The antenna provides a flat measured gain of 20 dB with a return loss better than 22 dB. In addition, A broadband double-layer SIW-to-slotline transition is proposed to feed a planar linearly tapered slot antenna (PLTSA) covering the band 46-72 GHz. This new feeding technique, which addresses the bandwidth limits of regular microstrip-to-slotline transitions and avoids the bond wires and air bridges, is utilized to feed a 1x4 SIW-based PLTSA array. Secondly, a new cavity-backed aperture-coupled patch antenna with overlapped 1-dB gain and impedance bandwidth of 43.4 % (56-87 GHz) for |S11| < -10 dB and an average gain of 8.2 dBi is designed. A detailed operating principle is presented. Based on the proposed element, an SIW based 1x8 array is constructed, whose beam-shape is synthesized by amplitude tapering according to Taylor distribution to reduce the sidelobe level. Moreover, a four-layered 4x4 cavity-backed antenna array with a low-loss full-corporate SIW feed network is implemented for gain and aperture efficiency enhancement. The measured results exhibited a bandwidth of 38.4 % (55.2-81.4 GHz) for |S11| < -10 dB and a gain of 20.5 dBi. A single-layer right-angle transition between SIW and air-filled WR15 waveguide along with an equivalent circuit model is introduced and used to measure the performance of both proposed linear and planar arrays. Thirdly, two 1-D scanning multi-beam array designs based on SIW technology, at 60 GHz, have been presented. The first design is a compact multi-beam scanning 4x4 slot antenna array with broadside radiation. The BFN is implemented using a dual-layer 4x4 Butler matrix, where the 450 and 00 phase shifters are designed on a separate layer with different permittivity, resulting in a significant size reduction compared to a conventional single layer. A detailed theoretical analysis, principle of operation and the circuit-model of the proposed phase shifter have been discussed, showing less desperation characteristics compared to ordinary phase shifters. The measured results show an azimuthal coverage of 1210. The second design is a wideband high gain multi-beam tapered slot antenna array with end-fire radiation. An SIW Butler matrix with a modified hybrid crossover is used as a BFN. The fabricated prototype exhibits a field of view of 970 in the azimuthal plane, with measured gain ranges from 12.7 to 15.6 dBi. Lastly, a novel three-layered SIW-fed cavity-backed linearly polarized (LP) patch antenna element is presented, covering a bandwidth of 36.2 % (53-76.4 GHz) with a flat gain ranging from 7.6 to 8.2 dBi. A compact two-layered beam forming network is designed with a size reduction of 28 % compared to a standard one-layered BFN without affecting its s-parameters. The results show that the impedance bandwidth is 31.1 % (51.5-70.5 GHz) for |S11|<-16 dB with an average insertion loss of 1.3 dB. The proposed antenna element and BFN are employed to form a compact 2x2 multibeam array at 60 GHz for 2-D scanning applications. The array shows a bandwidth better than 27 % with a radiation gain of up to 12.4 dBi and radiation efficiency of 80%. The multi-beam array features four tilted beams at 330 from a boresight direction with 450, 1350, 2250 and 3150 in azimuth directions, i.e., on e beam in each quadrant

Practical investigation of Butler matrix application for beamforming with circular antenna arrays

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Étude et réalisation de matrices à commutation de faisceaux en technologie guide d'ondes intégré au substrat

RÉSUMÉ Les applications radar pour les voitures demandent des composants de hautes performances mais avec faible coût de revient. Cette thèse présente la conception des réseaux d’alimentation d’antennes en ondes millimétriques utilisant la technologie du guide d’ondes intégré aux substrats (GIS), pour satisfaire les exigences du coût et du faible encombrement dans ces applications de radar. Dans un système radar, l’antenne défini la largeur du secteur couvert, la portée, la discrimination angulaire et le filtrage du bruit généré par d’autre sources. Généralement les antennes intelligentes remplissent ce cahier des charges. La direction dans laquelle le réseau ayant la réponse maximale serait la direction du pointage de faisceau. Pour un choix de faisceau dans une direction désirée, un ajustement de phase doit être accompli. Les matrices à commutation donnent des distributions de phase aux sorties différentes pour chaque port d’entrée. Le guide d’ondes intégré aux substrats (GIS) offre une technologie intéressante pour les réseaux d’alimentation d’antennes en termes de faible pertes par radiation, ce qui assure un très faible niveau d’interférences et d’effets parasitiques entre les circuits de GIS. Nous proposons dans ce travail plusieurs matrices de formation de faisceaux basées sur la technologie GIS. La thèse est présentée sous forme d’articles. Ce travail montre les étapes entreprises afin de mener à terme la conception, la fabrication, les mesures et l’évaluation de plusieurs topologies de la matrice de Butler. Nous verrons donc dans un premier temps les composants nécessaires au bon fonctionnement d’un tel système soit: les coupleurs 3 dB, les déphaseurs et les croisements. Le choix de la configuration sera justifié pour chacun de ces éléments. L’usage de simulateur (Ansoft HFSS) basé sur la méthode des éléments finis (une méthode à ondes complètes) sera nécessaire dans ce travail. Ce logiciel donne des résultats assez proches des essais expérimentaux. Trois matrices de Butler sont développées, la première à 77 GHz sans croisement, une deuxième est une structure à deux couches à 24 GHz et la troisième est une matrice complètement planaire avec un coupler 0 dB à 12.5 GHz.---------- ABSTRACT Automotive radar applications require components with high performance but low cost. This thesis presents the design of millimeter wave antennas feeding networks using the substrate integrated waveguide (SIW) technology, to satisfy the requirement of low cost and compactness in these radar applications.In a radar system the antenna define the width of covered area, the range, the angular discrimination and the filter noise generated by other sources. Generally smart antennas must be used to satisfy the specifications. The beam pointing can be achieved only by adjusting the phase of signals from different elements. For a choice of beam in a desired direction, a phase adjustment must be done. Switching matrices are used to provide phase distribution at output ports that is different for each input port. The substrates integrated waveguide (SIW) is a promising technology for the antenna feed networks in terms of low radiation and transmission losses with reduced interferences among SIW circuit elements. We propose in this work several beamforming matrices based on SIW technology. This thesis is presented in paper form. First of all, this work shows the steps taken to finalize the design, fabricate, measurement and evaluation of several Butler matrix topologies. We will see at first that the building components necessary for the proper functioning of such a network: the 3 dB couplers, phase shifters and crossovers. The choice of a configuration will be justified for each of these elements. An electromagnetic simulator (Ansoft HFSS) based on the finite element method (full-wave method) is used in this work. This software package would be able to yield results close to experimental counterparts. Three Butler matrices are developed, the first at 77GHz without crossover, the second is related to a two layer structure at 24 GHz and the third is completely made planar with a cross-over at 12.5 GHz. The Nolen matrix compared to Butler matrix has the advantages of being free from crossovers in the structure. The loads placed on unused ports in the Blass matrix do not appear in the Nolen matrix which increases efficiency. We propose two architectures, the first one is related to perpendicular configuration in Ku band while the second platform presents a parallel topology which shows a good performance over a broad band around 77 GHz