Millimeter-Wave Components and Antennas for Spatial and Polarization Diversity using PRGW Technology

The evolution of the wireless communication systems to the future generation is accompanied by a huge improvement in the system performance through providing a high data rate with low latency. These systems require access to millimeter wave (mmWave) bands, which offer several advantages such as physically smaller components and much wider bandwidthcomparedtomicrowavefrequencies. However, mmWavecomponentsstillneed a significant improvement to follow the rapid variations in future technologies. Although mmWave frequencies can carry more data, they are limited in terms of their penetration capabilities and their coverage range. Moreover, these frequencies avoid deploying traditional guiding technologies such as microstrip lines due to high radiation and material losses. Hence, utilizing new guiding structure techniques such as Printed Ridge Gap Waveguide (PRGW) is essential in future mmWave systems implementation. ThemainpurposeofthisthesisistodesignmmWavecomponents,antennasubsystems and utilize both in beam switching systems. The major mmWave components addressed in this thesis are hybrid coupler, crossover, and differential power divider where the host guidingstructureisthePRGW.Inaddition,variousdesignsfordifferentialfeedingPRGW antennas and antenna arrays are presented featuring wide bandwidth and high gain in mmWave band. Moreover, the integration of both the proposed components and the featured antennas is introduced. This can be considered as a significant step toward the requirements fulfillment of today's advanced communication systems enabling both space and polarization diversity. The proposed components are designed to meet the future ever-increasing consumer experience and technical requirements such as low loss, compact size, and low-cost fabrication. This directed the presented research to have a contribution into three major parts. The first part highlights the feeding structures, where mmWave PRGW directional couplers and differential feeding power divider are designed and validated. These components are among the most important passive elements of microwave circuits used in antennabeam-switchingnetworks. Different3-dBquadraturehybridcouplersandcrossover prototypes are proposed, featured with a compact size and a wide bandwidth beyond 10 % at 30 GHz. In the second part, a beam switching network implemented using hybrid couplers is presented. The proposed beam switching network is a 4 × 4 PRGW Butler matrix that used to feed a Magneto-electric (ME) dipole antenna array. As a result, a 2-D scanning antenna array with a compact size, wide bandwidth, and high radiation efficiency larger than84%isachieved. Furthergainenhancementof5dBiisachievedthroughdeployinga hybridgainenhancementtechniqueincludingAMCmushroomshapesaroundtheantenna array with a dielectric superstrate located in the broadside direction. The proposed scanning antenna array can be considered as a step toward the desired improvement in the data rate and coverage through enabling the space diversity for the communication link. The final activity is related to the development of high-gain wide-band mmWave antenna arrays for potential use in future mmWave applications. The first proposed configuration is a differential feeding circular polarized aperture antenna array implemented with PRGW technology. Differential feeding antenna designs offer more advantages than single- ended antennas for mmWave communications as they are easy to be integrated with differential mmWave monolithic ICs that have high common-mode rejection ratio providing an immunity of the environmental noise. The proposed differential feeding antenna array is designed and fabricated, which featured with a stable high gain and a high radiation efficiency over a wide bandwidth. Another proposed configuration is a dualpolarized ME-dipole PRGW antenna array for mmWave wireless communication. Dual polarizationisconsideredoneofthemostimportantantennasolutionsthatcansavecosts and space for modern communication systems. In addition, it is an effective strategy for multiple-input and multiple-output systems that can reduce the size of multiple antennas systems by utilizing extra orthogonal polarization. The proposed dual- polarized antenna array is designed to achieve a stable gain of 15 ± 1 dBi with low cross- polarization less than -30 dB over a wide frequency range of 20 % at 30 GHz

Novel modulated antennas and probes for millimeter wave imaging applications

Microwave and millimeter wave (300 MHz - 300 GHz) imaging techniques have shown great potential for a wide range of industrial and medical applications. These techniques are fundamentally based on measuring relative and coherent electromagnetic fields distributions, e.g., electric fields, around the object to be imaged. Various imaging systems can be devised for measuring relative electric field distributions; each with it own advantages and limitations. This dissertation is focused on addressing critical challenges related to the practical implementation of various microwave and millimeter wave imaging systems. Specifically, this research is meant to achieve three main objectives related to designing efficient modulated imaging methods/array elements, reducing the sensitivity to standoff distance variations in near-field imaging, and designing a simple and accurate vector network analyzer (VNA) for in-situ imaging applications. The concept of modulating millimeter wave antenna and scatterer structures, directly to increase the overall system sensitivity and reduce the image acquisition time, is central to the development presented herein. To improve upon the conventional modulated scatterer technique (MST) based on dipole scatterers; a new multiple loaded scatterer (MLS) method and novel loaded elliptical slot are introduced and analyzed. A unique near-field differential probe based on dual-loaded modulated single waveguide aperture is developed to compensate for and reduce the effect of standoff distance variations in near-field imaging. Finally, a novel vector network analyzer (VNA) design is introduced to meet the rising need for in-situ vector measuring devices. To realize a robust handheld millimeter wave VNA, a custom-designed waveguide phase shifter based on sub-resonant loaded slots is introduced. The proposed MLS method, modulated elliptical slot, dual-loaded modulated aperture probe, and VNA are thoroughly investigated and their efficacy for microwave and millimeter wave imaging is demonstrated --Abstract, page iii

Design of millimeter-wave bandpass filters with broad bandwidth in Si-based technology

In this paper, a novel design approach is proposed for on-chip bandpass filter (BPF) design with improved passband flatness and stopband suppression. The proposed approach simply uses a combination of meander-line structures with metal-insulator-metal (MIM) capacitors. To demonstrate the insight of this approach, a simplified equivalent LC-circuit model is used for theoretical analysis. Using the analyzed results as a guideline along with a full-wave electromagnetic (EM) simulator, two BPFs are designed and implemented in a standard 0.13-μm (Bi)-CMOS technology. The measured results show that good agreements between EM simulated and measured results are achieved. For the first BPF, the return loss is better than 10 dB from 13.5 to 32 GHz, which indicates a fractional bandwidth (FBW) of more than 78%. In addition, the minimum insertion loss of 2.3 dB is achieved within the frequency range from 17 to 27 GHz and the in-band magnitude ripple is less than 0.1 dB. The chip size of this design, excluding the pads, is 0.148 mm 2 . To demonstrate a miniaturized design, a second design example is given. The return loss is better than 10 dB from 17.3 to 35.9 GHz, which indicates an FBW of more than 70%. In addition, the minimum insertion loss of 2.6 dB is achieved within the frequency range from 21.4 to 27.7 GHz and the in-band magnitude ripple is less than 0.1 dB. The chip size of the second design, excluding the pads, is only 0.066 mm 2 .Peer reviewe

Dual-band (28,38) GHz coupled quarter-mode substrate-integrated waveguide antenna array for next-generation wireless systems

A novel dual-band substrate-integrated waveguide (SIW) antenna array topology is proposed for operation in the 28 and 38 GHz frequency bands. Four miniaturized quarter-mode SIW cavities are tightly coupled, causing mode bifurcation, and yielding an antenna topology with four distinct resonance frequencies. A pair of resonances is assigned to both the 28 and 38 GHz band, achieving wideband operation in both frequency ranges. Moreover, owing to the exploited miniaturization technique, an extremely compact array topology is obtained, facilitating easy and straightforward integration. The computer-aided design process yields a four-element antenna array that entirely covers the 28 GHz band (27.5-29.5 GHz) and 38 GHz band (37.0-38.6 GHz) with a measured impedance bandwidth of 3.65 and 2.19 GHz, respectively. A measured broadside gain of 10.1 dBi, a radiation efficiency of 75.75% and a 3 dB beamwidth of 25 degrees are achieved in the 28 GHz band. Moreover, in the 38 GHz band, the measured broadside gain amounts to 10.2 dBi, a radiation efficiency of 70.65% is achieved, and the 3 dB beamwidth is 20 degrees

Two dimensional switched beam antenna at 28 GHz for fifth generation wireless system

Fifth generation (5G) wireless system is expected to enable new device-to-device (D2D) and machine-to-machine (M2M) applications that will impact both consumers and industry. Moreover, for efficient M2M communication, both one dimensional (1-D) and two dimensional (2-D) beam switching is highly needed for high data-rate wireless radio links. A planar array with 2-D beam switching capabilities is highly desirable in 5G system. This thesis proposes a new technique of achieving simple and cost effective 2-D beam switching array antenna at 28 GHz for 5G wireless system. The technique involves lateral cascading of Butler matrix (BM) beamforming network (BFN). However, designing a planar BM at 28 GHz that will allow K-connector is not a trivial issue because the distances between the ports are X/4 electrical length apart. Nevertheless, two branch line coupler (BLC) with unequal ports separation at 28 GHz on a single substrate are designed and applied to design 1-D switched beam antennas based on BLC and 4 * 4 BM. Then two of these antennas are laterally cascaded to achieve 2-D beam switching antenna. This novel concept is the basis for choosing BM BFN in the design. The proposed 1-D array antennas on BLC and BM have wide measured impedance bandwidth of 18.9% (5.3 GHz) and 21.7% (6.1 GHz) and highest gain of 14.6 dBi and 15.9 dBi, respectively. The 2-D switched beam antenna on cascaded BLC has highest realized gain of 14.9 dB, radiation efficiency of 86%, 86.8%, 85.5%, and 83.4% at ports 1 to 4, respectively. The switching range of from -25o to +18° in the x-z plane and from -18o to 24o in the y-z plane, while the 2-D switched beam antenna based on cascaded 4 * 4 BM has switching range of -41o to 43o in the x-z plane and -43o to 42o in the y-z plane with highest realized gain of 14.4 dBi. The proposed antennas have great potentials for 5G wireless communication system applications

mmWave polarization diversity wideband multiple-input/multiple-output antenna system with symmetrical geometry for future compact devices

The fifth generation (5G) of mobile networks is a significant technological advancement in telecommunications that provides faster data speeds, lower latency, and greater network capacity. One of the key technologies that enables 5G is multiple-input/multiple-output (MIMO) antenna systems, which allow for the transmission and reception of multiple data streams simultaneously, improving network performance and efficiency. MIMO is essential to meeting the demand for higher data rates and improved network performance in 5G networks. This work presents a four-element MIMO antenna system dedicated to the upper 5G millimeter-wave (mmWave) spectrum. The suggested antenna system is designed using an ultra-thin RO5880 substrate having total dimensions of 20 x 20 x 0.254 mm(3) with symmetrical geometry. The proposed antenna covers a fractional bandwidth of 46.875% (25-38 GHz), covering potential 5G bands of 26, 28, and 32 GHz, and offers isolation of >18 dB. The proposed MIMO system is fabricated and tested in-house. The antenna showed efficiency >88% at the potential band of interest and a peak gain of 3.5 dBi. The orthogonal arrangement of the resonating elements provides polarization diversity. Also, the MIMO parameters obtained, such as mean effective gain (MEG), envelope correlation coefficient (ECC), diversity gain (DG), channel capacity loss (CCL), and total active reflection coefficient (TARC), are found to have good performance. The measured results obtained are found to be in good agreement with simulations, hence making the proposed MIMO antenna suitable for handheld mmWave 5G devices.Prince Sultan University, Riyadh, Saudi Arabi

A New Calibration Kit for VNA Measurements of General Microstrip Line Devices Using Gap Waveguide Technology

A new calibration kit for VNA Measurements of general microstrip line devices is presented. The proposed calibration kit and test fixture is based on a gap waveguide to microstrip transition which can provide an interface for measurements on microstrip line devices with low influence on the DUT performance due to its compact size

An Innovative Lens Type FinLine to Microstrip Transition

Due to the disadvantages of vacuum tubes in terms of warm-up time, size, and highvoltage needs, solid-state power amplifiers (SSPAs) with gallium nitride (GaN) monolithic microwave integrated circuits (MMICs) are the key solution for power levels up to some kilowatts in continuous wave. An SSPA is the most convenient solution for these RF power levels due to its low weight, small size, negligible warm-up time, low-voltage operation, and high reliability. Spatial power amplifiers (SPAs) combining techniques are the best candidates for SSPAs due to the intrinsic low attenuation in dividing and combining functions. SPAs mainly use two types of probes: transverse and longitudinal, such as FinLines. This paper describes a broadband FinLine to microstrip (FLuS) transition based on dielectric lens theory. Comparative simulations with traditional FinLine transitions show a significant improvement in matching performances and a very significant increase in mechanical resistance of the transition. The proposed innovative FLuS uses a substrate shaping designed according to dielectric lens theory. Frequency simulations of a FLuS inside the WR22 waveguide are shown. These evidence the better performances of this transition than the classic FLuS transition using quarter-wave transformer (QWT) matching. A Q band spatial power combiner with dielectric lens FLuS was made and measured, showing the excellent performances of this innovative FLuS transition

Conception et réalisation d'un récepteur composé de réseau d'antennes YAGI multicouches verticales et de composants en ondes millimétriques

RÉSUMÉ Les applications en ondes millimétriques telles que les réseaux sans-fils haute vitesse demandent des composants de hautes performances, faibles coûts de revient, modulaires et compacts. Ce mémoire présente la conception d’une chaine de démodulation en ondes millimétriques utilisant le concept du multicouche. Tout d’abord, une antenne Yagi multicouche est proposée et démontrée à 5.8 GHz. La structure utilise pour la première fois les éléments parasites des antennes Yagi dans une structure de substrats empilés verticalement. Cela permet d’atteindre un gain de 12 dBi. Deux configuration sont présentées : une première basée sur un dipôle et une deuxième basée sur un patch circulaire afin d’avoir une double polarisation. Les résultats mesurés montrent un très bon accord avec les simulations. Basé sur les principes démontrés précédemment, l’antenne est adaptée à 60 GHz, puis un réseau d’antennes Yagi verticales en ondes millimétriques est introduit pour la première fois exploitant les technologies multicouches. Une analyse est faite pour définir les limites du design. L’antenne élément mesurée atteint un gain de 11 dBi. Le réseau 4x4 a une taille 50x50x60 mm3, et atteint un gain mesuré de 18 dBi sur 7% de bande passante. Une autre configuration du réseau utilisant des antennes Yagi inclinées permet d’avoir une réduction des lobes secondaires tout en ayant un impact minimum sur le gain. Les antennes proposées sont d’excellents candidats pour des systèmes intégrés, faibles coûts, demandant une petite empreinte en ondes millimétriques. Finalement, un nouveau six-port double couche utilisant des Guides Intégrés au Substrats (GIS) est présenté et démontré. Celui-ci permet de faire la démodulation QPSK. Son architecture utilise des coupleurs multicouches, fournissant une grande surface de couplage à travers deux fentes ; un déphaseur inédit, large bande composé de deux stubs plan-H et une ligne de référence ; ainsi que de deux diviseurs de puissance. Les simulations et mesures montrent que le circuit fonctionne correctement sur toute la bande V. La démodulation QPSK complète est testée sous le logiciel de simulation ADS et montre les excellentes performances du système.----------ABSTRACT Millimeter wave applications such as high-speed wireless connections require modular, compact-size, low-cost and high-performance systems. In order to realize a complete receiver satisfying those requirements, compact stacked multilayered designs are presented in this thesis. First, high-gain compact stacked multilayered Yagi designs are proposed and demonstrated at 5.8 GHz. The structure makes use for the first time of vertically stacked Yagi-like parasitic director elements that allow easily obtaining a simulated gain of 12 dBi. Two different antenna configurations are presented, one based on dipole geometry for single polarization, and the other on a circular patch to achieve dual polarization. Measured results of the fabricated antenna prototypes are in good agreement with simulated results. Second, based on the above-demonstrated principle, the antenna is redesigned and adapted for 60 GHz applications, and a novel design showing for the first time an array of Yagi elements in millimeter wave stacked structure is presented. An analysis is performed to define the structure limits. The measured element attains 11 dBi of gain. The proposed 4x4 array has a size of 50x50x60 mm3, and reaches a measured gain of 18 dBi over 7% of bandwidth. An alternative configuration of the array using angled Yagi antenna elements allows for a significant improvement of the side lobe level without a visible impact on the gain. The proposed antennas present excellent candidates for integrated low-cost millimeter-wave systems that require small footprint. Third, a novel dual layered six-port front-end circuit using the Substrate Integrated Waveguide (SIW) technology is presented and demonstrated. The six-port architecture makes use of multilayer couplers, providing a wide coupling area through two slots; a new broadband SIW phase shifter composed of two H-plane stub lines and one reference line; and two SIW power dividers. Simulation and measurement results show that the proposed six-port circuit can easily operate at 60 GHz for V-band system applications. The complete QPSK demodulation is tested through the ADS simulation platform to prove the good performances of the designed circuits