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

An Overview of Recent Development of the Gap-Waveguide Technology for mmWave and Sub-THz Applications

The millimeter-wave (mmWave) and sub-terahertz (sub-THz) bands have received much attention in recent years for wireless communication and high-resolution imaging radar applications. The objective of this paper is to provide an overview of recent developments in the design and technical implementation of GW-based antenna systems and components. This paper begins by comparing the GW-transmission line to other widely used transmission lines for the mmWave and sub-THz bands. Furthermore, the basic operating principle and possible implementation technique of the GW-technology are briefly discussed. In addition, various antennas and passive components have been developed based on the GW-technology. Despite its advantages in controlling electromagnetic wave propagation, it is also widely used for the packaging of electronic components such as transceivers and power amplifiers. This article also provided an overview of the current manufacturing technologies that are commonly used for the fabrication of GW-components. Finally, the practical applications and industry interest in GW technology developments for mmWave and sub-THz applications have been scrutinized.Funding Agencies|European Union - Marie Sklodowska-Curie [766231WAVECOMBEH2020-MSCA-ITN-2017]</p

30 GHz Broadband Bow-tie Printed Ridge Gap Waveguide Antennas

The development of wireless and satellite communication systems has led to high demand for microwave and millimeter wave application components, which play an essential role in the upcoming 5G communication. The coverage area of such systems is control by transmitted power as well as the antenna gain of the system. Hence, it is essential to design a high gain antenna that can mitigate the losses and extend the system coverage area. Higher frequencies lead to smaller sizes of RF components including antennas. However, the implementation of passive components and guiding structure becomes difficult based on traditional guiding structures such as microstrip lines, and waveguides at millimeter wave bands. Microstrip line suffers from cavity modes, which leads to surface waves and has more losses at higher frequencies. The rectangular waveguide has high power handling capability, low losses, and high Q-factors which makes it very attractive for high-frequency applications. On the other hand, at high frequencies, the wavelengths become challenging to construct with current machining techniques as ensuring good electrical contact become very challenging. In this thesis, planar high gain antennas are designed based on Printed Ridge Gap Waveguide (PRGW). The primary objective of this work is to develop high gain, wideband antennas that can support the future demand for high data transmission. Therefore, a detailed analysis for PRGW has been introduced as well as featured designs of the high gain antenna. This antenna array can perform for future 5G communication purpose, and it fulfills all the requirements of mm-wave bands. In this work, a groove-based wideband bow-tie slot antenna array is designed at 30 GHz based on printed ridge gap waveguide technology (PRGW). A two-section T-shaped ridge is designed to feed a bow tie slot placed on the upper ground of PRGW. The gain of the proposed slot antenna is enhanced by using a horn-like groove. Then, the proposed high gain element is deployed to build up a 1 x 4 bow-tie slot antenna array loaded with three-layer groove antenna. The proposed antenna array is fabricated and measured, where the measured results show a -10 dB impedance bandwidth from 29.5 to 37 GHz (22%). The fabricated prototype achieves a high gain of 15.5 dBi and a radiation efficiency higher than 80% over the operating frequency bandwidth. Besides, to reduce the edge diffraction in the E-plane, an artificial corrugation ring is deployed with a certain depth so that it can improve the overall antenna performance

Review on Millimeter Wave Antennas- Potential Candidate for 5G Enabled Applications

The millimeter wave (mmWave) band is considered as the potential candidate for high speed communication services in 5G networks due to its huge bandwidth. Moreover, mmWave frequencies lead to miniaturization of RF front end including antennas. In this article, we provide an overview of recent research achievements of millimeter-wave antenna design along with the design considerations for compact antennas and antennas in package/on chip, mostly in the 60 GHz band is described along with their inherent benefits and challenges. A comparative analysis of various designs is also presented. The antennas with wide bandwidth, high-gain, compact size and low profile with easiness of integration in-package or on-chip with other components are required for 5G enabled applications.&nbsp

Control Radiation Pattern for Half Width Microstrip Leaky Wave Antenna by Using PIN Diodes

In this paper, a novel design for single-layer half width microstrip leakywave antenna (HW-MLWA) is demonstrated. This model can be digitally control its radiation pattern at operation frequency and uses only two values of the bias voltage, with better impedance matching and insignificant gain variation. The scanning and controlling the radiation pattern of leaky-wave antennas (LWA) in steps at an operation frequency, by using switches PIN diodes, is investigated and a novel HW-MLWA is introduced. A control cell reconfigurable, that can be switched between two states, is the basic element of the antenna. The periodic LWA is molded by identical control cells where as a control radiation pattern is developed by combining numerous reconfigurable control cells. A gap capacitor is independently connected or disconnected in every unit cell by using a PIN diode switch to achieve fixedfrequency control radiation pattern scanning. The profile reactance at the free edge of (HW-MLWA) and thus the main lobe direction is altered by changing the states of the control cell. The antenna presented in this paper, can scan main beam between 18o to 44o at fixed frequency of 4.2 GHz with measured peak gain of 12.29 dBi

30 GHz Printed Ridge Gap Components and Antennas for Imaging Systems

Working at millimeter waves (MMW) has gained massive attention for wireless communications and imaging systems. For imaging systems, MMW can be used for security to provide good resolution images and detect concealed weapons as it can penetrate common clothes and reflect from the human body and metal objects. Moreover, MMW is safe for human health, contrary to conventional X-ray imaging, which uses an ionized wave. Thus, it has a harmful effect on human health. This research is focusing on building an active wide-view angle millimeter-wave imaging system with a small area of mechanical movement to reduce the data collection time. The imaging system is composed of three main parts: 1) the millimeter-wave components and antennas, 2) the mechanical part for moving the antennas and performing the scan of the imaging area, and 3) the imaging reconstruction algorithm. In order to have an efficient imaging system, the printed ridge gap technology (PRGW) is used to build the imaging system components and antennas. High efficiency coaxial to PRGW transition with a fractional bandwidth of 59.22% at 32.25 GHz is designed to feed the system components. For the transmitting part of the imaging system, a moderate gain PRGW differential feeding planar aperture antenna and a wideband rat-race coupler are designed. The antenna, the rat-race, and the coaxial transition are combined to form the transmitting part, then fabricated and measured. The resulted bandwidth is from 25.62 to 34.34 GHz with a return loss better than 10 dB, a maximum gain of 12.28 dBi, and 3-dB gain bandwidth from 25.62 to 33.77 GHz. For the receiving antenna, a PRGW Butler matrix and its components (directional couplers, 45◦ phase shifters, and crossovers) are designed. A semi-log periodic antenna fed by the PRGW is designed as the radiating element. The PRGW components, the coaxial transition, and the antennas are combined to form the receiving part of the imaging system, which is fabricated and measured. The resulting beam directions are at ±13◦ and ±36◦, at the center frequency (30 GHz). The return loss and the isolations are better than 10 dB over the frequency range from 26.1 to 33.5 GHz. For the imaging reconstruction algorithm, a synthetic aperture radar algorithm is used. Two tests are carried out, one uses CST simulation results, and the other uses measured data from the Concordia antenna chamber lab. The results show an output resolution of 0.6 λ. Finally, the whole imaging system is built with the designed differential feeding antenna as the transmitter, the designed Butler matrix as the receiver, and the synthetic aperture algorithm as the image reconstruction algorithm. The performance network analyzer (PNA) is used to collect the data (s-parameters) required to reconstruct the image, and the antenna range controller system (NSI 5913) is used to mechanically scan the imaging area. The imaging system is used to scan a mannequin carrying an object shaped like a pistol and a knife. The results show that the two objects are detected

Impedance Transformers

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Reconfigurable Leaky Wave Antenna based on Metamaterial Substrate Integrated Waveguide for 5G oriented beamsteering application

This work presents the study and the development of a Leaky Wave Antenna, based on a Composite Right-Left Handed transmission line and a Substrate Integrated Waveguide. The antenna system is designed to work in the frequency band of 26 GHz - 30 GHz, demonstrates beamsteering functionalities and a high gain. The conducted study is envisioned in the background of the fifth generation mobile networks (5G), in order to fulfil the requirements for the realization of a small cell antenna

New feeding networks and planar antenna designs for leaky-wave systems and communication applications

The fast development in modern communication systems such as radars, medical imaging, sensors or satellites demands efficient and compact antenna designs that can satisfy the high data throughput and beam scanning requirements. This is commonly achieved by different means including electromechanical or mechanical steering, which sometimes are not the best option as additional cost, size or losses may be introduced. However, low-cost and compact structures can be obtained by using planar leaky-wave antennas, whose inherent high directivity and electrical beam steering capabilities have been realised to be a solution for the issues encoun tered by these systems. Nevertheless, there are several limitations that these antennas still need to overcome. One clear example is the lack of efficient and simple feeding networks for certain types of leaky-wave antennas that can reduce their performance and compactness. In turn, there are modern indoor applications, such as WiFi or radio frequency identification (RFID), where selective distributed communications are required but current leaky-wave antennas cannot efficiently provide or their use implies cost and weight constraints. In this thesis, planar configurations are presented to provide efficient and low profile solutions for leaky-wave antennas using concepts such as partial reflective surfaces or simple technologies as parallel-plate waveguides. It is also demonstrated that novel systems for two-dimensional (2D) or wideband beam scanning can also be obtained by the use of simple feeders including vertical electric dipoles. In addition, a broad-beam alternative to a non-selective and expensive beam scanning performance inside airplanes for RFID systems is introduced easing weight restrictions. These configurations represent an advancement for the state-of-the-art and are interesting alternatives to their non-planar counterparts. To support these designs, theoretical analysis, full-wave simulations and measurements are provided

Innovative Traveling-Wave Optoelectronic Devices for Radio over Fiber and Terahertz Applications

RÉSUMÉ La structure des composants conventionnels pour les applications optoélectroniques à haute fréquence ainsi que son intégration avec d'autres composants peuvent être modifiées en utilisant les guides d’ondes à faible perte. Par ailleurs le concept des circuits intégrés au substrat (Substrate Integrated Circuits: SICs), largement utilisé dans les structures des applications micro-ondes, peut être employé pour l’intégration de ces composantes dans les applications à ondes millimétriques (millimetre Wave: mmW) et sous-millimétriques. Dans les systèmes de communication optique et systèmes optoélectroniques, photodétecteurs et modulateurs sont les éléments clés pour la conception des récepteurs et des émetteurs. Les photodétecteurs à ondes progressives (Traveling-Wave: TW) et les modulateurs conventionnels, dans leurs structures, utilisent les lignes microrubans (Microstrip: MS) et les guides coplanaires (Coplanar Waveguide: CPW). Les substrats majoritairement utilisés pour la fabrication des composantes optoélectroniques et électro-optiques, citées ci-dessus, sont en arséniure de gallium (GaAs) et niobate de lithium (LiNbO3). Il faut bien noter que les pertes de micro-ondes/mmW dans les lignes microrubans et les guides coplanaires augmentent avec la fréquence. Ces pertes incluent les pertes ohmique, diélectrique et de rayonnement. Le guide d'ondes rectangulaire ayant une faible perte après la fréquence de coupure sans grand changement, est un guide d'ondes de remplacement pour les composants mmW. Son inconvénient est qu’il n’est pas planaire et difficilement intégrable. Le guide d'ondes intégré au substrat (Substrate Integrated Waveguide: SIW) est une forme planaire du guide d’ondes rectangulaire. Dans ces guides d’ondes les trous métallisés remplacent les parois métalliques du guide rectangulaire. De nouveaux composants optoélectroniques peuvent être proposées avec l’intégration de la structure SIW pour les fréquences mmW. Les photodétecteurs et les modulateurs sont les candidats potentiels pour les nouveaux composants optoélectroniques.----------------ABSTRACT The structure of conventional optoelectronic devices for new high frequency applications as well as the integration with other devices may be modified by using low-loss microwave waveguides. Also the concept of substrate integrated circuits (SICs), which has widely been used in the microwave domain, can be utilized for the integration of optoelectronic devices at millimetre wave (mmW) and sub-mmW frequency ranges. Photodetectors and modulators, as optoelectronic devices, are two key components of receivers and transmitters in optical communication systems. Conventional traveling-wave (TW) photodetectors and modulators make use of microstrip (MS) and coplanar waveguide (CPW) in their structures as transmission line electrodes. These electrode structures with high losses cannot be utilized in mmW devices. Microwave/mmW losses of MS and CPW, including ohmic, dielectric and radiative losses, in optoelectronic and electro-optical materials such as gallium arsenide (GaAs) and lithium niobate (LiNbO3) are increased with frequency. Rectangular waveguide (RWG) with constant low loss in specific frequency range after its cut-off frequency is an alternative waveguide for mmW devices, although it is non planar and non integrable. Substrate integrated waveguide (SIW) derived from the general SICs concept is a planar form of RWG with some metalized via holes instead of metallic side walls of RWG. New optoelectronic devices and in particular TW photodetector and modulator can be proposed based on SIW structure for mmW frequency, terahertz (THz) photonics and electro-optical applications. In the design of waveguide photodetectors, the microwave/mmW loss as an important factor for bandwidth limitation is related to two sections, namely, active MS multilayer detection and non-active MS single layer transmission. It is expected that the long section of lossy microstrip line after the detection would significantly limit the bandwidth of the photodetector and may be replaced by low-loss SIW structure. A transition of MS in the photodetector to the multilayer SIW, to separate the photodetector DC bias and SIW metallic plates, is designed and realised in this work