Wideband and UWB antennas for wireless applications. A comprehensive review

A comprehensive review concerning the geometry, the manufacturing technologies, the materials, and the numerical techniques, adopted for the analysis and design of wideband and ultrawideband (UWB) antennas for wireless applications, is presented. Planar, printed, dielectric, and wearable antennas, achievable on laminate (rigid and flexible), and textile dielectric substrates are taken into account. The performances of small, low-profile, and dielectric resonator antennas are illustrated paying particular attention to the application areas concerning portable devices (mobile phones, tablets, glasses, laptops, wearable computers, etc.) and radio base stations. This information provides a guidance to the selection of the different antenna geometries in terms of bandwidth, gain, field polarization, time-domain response, dimensions, and materials useful for their realization and integration in modern communication systems

High Gain Compact Strip and Slot UWB Sinuous Antennas

Three ground-backed compact strip-and slot-sinuous antennas are analyzed. Proposed configuration allows for a single lobe, polarization-versatile, high efficiency, and ultrawide band antenna not needing a cumbersome lossy back cavity typical of conventional single-lobe sinuous antennas. Simulations show attained performances as well as tuning possibilities

Design and Analysis of Substrate-Integrated Cavity-Backed Antenna Arrays for Ku-Band Applications

Mobile communication has become an essential part of our daily life. We love the flexibility of wireless cell phones and even accept their lower quality of service when compared to wired links. Similarly, we are looking forward to the day that we can continue watching our favorite TV programs while travelling anywhere and everywhere. Mobility, flexibility, and portability are the themes of the next generation communication. Motivated and fascinated by such technology breakthroughs, this effort is geared towards enhancing the quality of wireless services and bringing mobile satellite reception one step closer to the market. Meanwhile, phased array antennas are vital components for RADAR applications where the antenna is required to have certain scan capabilities. One of the main concerns in that perspective is how to avoid the potential of scan blindness in the required scan range. Targeting to achieve wide-band wide-scan angle phased arrays free from any scan blindness our efforts is also geared. Conventionally, the key to lower the profile of the antenna is to use planar structures. In that perspective microstrip patch antennas have drawn the attention of antenna engineers since the 1970s due to their attractive features of being low profile, compact size, light weight, and amenable to low-cost PCB fabrication processes. However, patch elements are basically resonating at a single frequency, typically have \u3c2% bandwidth, which is a major deficit that impedes their usage in relatively wide-band applications. There are various approaches to enhance the patch antennas bandwidth including suspended substrates, multi-stack patches, and metalized cavities backing these patches. Metalized cavity-backed patch structures have been demonstrated to give the best performance, however, they are very expensive to manufacture. In this dissertation, we develop an alternative low-cost bandwidth enhancement topology. The proposed topology is based on substrate-integrated waveguides. The great potential of the proposed structure lies in being amenable to the conventional PCB fabrication. Moreover, substrate-integrated cavity-backed structures facilitate the design of sophisticated arrays that are very expensive to develop using the conventional metalized cavity-backed topology, which includes the common broadside arrays used in fixed-beam applications and the scanned phased arrays used in RADAR applications

A Review: Substrate Integrated Waveguide Antennas and Arrays

This study aims to provide an overview and deployment of Substrate-Integrated Waveguide (SIW) based antenna and arrays, with different configurations, feeding mechanisms, and performances. Their performance improvement methods, including bandwidth enhancement, size reduction, and gain improvement are also discussed based on available literature. SIW technology, which acts as a bridge between planar and non-planar technology, is a very favorable candidate for the development of components operating at microwave and millimeter wave band. Due to this, SIW antennas and array take the advantages of both classical metallic waveguide, which includes high gain, high power capacity, low cross polarization, and high selectivity, and that of planar antennas which comprises low profile, light weight, low fabrication cost, conformability to planar or bent surfaces, and easy integration with planar circuits

Antenna Bandwidth and Radiation Control by Topology and use of Non-Conductive Materials.

The demand for ultra-wideband (UWB) antennas have been on the rise in the last decade. There are many different systems and devices such as ground penetrating radars (GPRs) and wireless communications where such antennas find very unique applications. Many topologies and configurations have been studied and reported in designing UWB antennas. These topologies are corresponding to radiation pattern, polarization, and band of operation. In addition, in low frequencies, the size of the antenna becomes a major factor that must be taken into consideration. A portion of this thesis focuses on the design of novel UWB antennas. A new approach in design of a cavity-backed coupled sectorial loop antenna (CB-CSLA) with directional radiation pattern is presented. This antenna is backed by a short cylindrical cavity with a special modal suppressing septum to accomplish a unidirectional radiation pattern while maintaining a very wide bandwidth. Another approach, more applicable to ground penetrating radars, based on dielectric loaded multi-resonant slot antenna is also presented. Unidirectional radiation is achieved by a symmetrically loading the slot radiators. Since the slot length is reduced, radiation is preferentially aimed towards the dielectric superstrate. By gradually changing the index of refraction, the radiation from the dielectric back to the surrounding medium is facilitated. A prototype with dimension of 0.28λ by 0.2λ by 0.07λ is fabricated and shown to have a bandwidth of 35.5% and a front to back ratio of 12dB. For the new 700MHz band considered for wireless communication applications, a novel planar wideband slot antenna is designed. The slot antenna size is reduced from the traditional λ/2 slot to λ/4. Then parasitic coupling, using a number of λ/4 slot elements appropriately positioned around the driving element, and direct feeding are used to increase the bandwidth. For communication applications, a novel miniaturized impedance matched antenna with an omnidirectional horizontally polarized radiation pattern is presented. The antenna structure resembles a circular loop formed by a circular array of shunt miniaturized n-fold resonant dipole antennas which is referred to as a miniature composite wire-loop antenna (MCWLA). This antenna has a diameter of λ/9 and a height of less than λ/500.PhDElectrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/120697/1/hbukhari_1.pd

Coupled Oscillator Phased Antenna Array Element for Phase Shifter-less Beam Steering

La rápida expansión de las comunicaciones inalámbricas y la creciente demanda de ancho de banda están acelerando el desarrollo de tecnologías que operan a altas frecuencias. Para dar solución al canal de propagación hostil que estas bandas de frequencia sufren, los arrays de antenas suscitan un creciente interés, pues son capaces de producir un haz dirigible con alta directividad. Los esquemas de conformado de haz convencionales utilizan componentes costosos y voluminosos, y los arrays basados en phase-shifters, que representan la técnica más extendida actualmente, están perdiendo popularidad de cara a futuras aplicaciones, en las cuales la rentabilidad y eficiencia están siendo altamente impulsadas. Este trabajo de final de máster describe el diseño de un elemento de un array, que forma el elemento básico de un array de conformado de haz que no utiliza phase shifters. Operando a 2.45 GHz, la arquitectura de beam-forming propuesta en este documento utiliza una técnica de acoplo entre osciladores operando bajo el fenómeno de injection locking para controlar la distribución de fase en el array.The ubiquity of modern wireless communications and the huge and ever-growing demand of data bandwidth are accelerating the development of technologies operating at higher frequencies. To overcome the hostile propagation channel that these frequencies face, a lot of attention has been put on antenna arrays, which produce high directivity with steerable beam direction. Conventional beam-forming schemes rely on bulky and costly components, and traditional phase shifter-based arrays, which account for the currently most widespread beam-forming technique, are losing popularity for future applications, where system cost-effectiveness is strongly embraced. This master¿s dissertation covers the design of an array element, that forms the basic antenna element of a phase-shifterless beamsteering antenna array operating at 2.45 GHz. The beam-forming architecture proposed in this document presents a nearest-neighbor coupling technique between oscillators operating under the injection locking phenomenom to control the phase distribution in the array.Montero Bayo, L. (2018). Coupled Oscillator Phased Antenna Array Element for Phase Shifter-less Beam Steering. http://hdl.handle.net/10251/109364TFG

Development of micromachined millimeter-wave modules for next-generation wireless transceiver front-ends

This thesis discusses the design, fabrication, integration and characterization of millimeter wave passive components using polymer-core-conductor surface micromachining technologies. Several antennas, including a W-band broadband micromachined monopole antenna on a lossy glass substrate, and a Ka-band elevated patch antenna, and a V-band micromachined horn antenna, are presented. All antennas have advantages such as a broad operation band and high efficiency. A low-loss broadband coupler and a high-Q cavity for millimeter-wave applications, using surface micromachining technologies is reported using the same technology. Several low-loss all-pole band-pass filters and transmission-zero filters are developed, respectively. Superior simulation and measurement results show that polymer-core-conductor surface micromachining is a powerful technology for the integration of high-performance cavity, coupler and filters. Integration of high performance millimeter-wave transceiver front-end is also presented for the first time. By elevating a cavity-filter-based duplexer and a horn antenna on top of the substrate and using air as the filler, the dielectric loss can be eliminated. A full-duplex transceiver front-end integrated with amplifiers are designed, fabricated, and comprehensively characterized to demonstrate advantages brought by this surface micromachining technology. It is a low loss and substrate-independent solution for millimeter-wave transceiver integration.Ph.D.Committee Chair: John Papapolymerou; Committee Chair: Manos Tentzeris; Committee Member: Gordon Stuber; Committee Member: John Cressler; Committee Member: John Z. Zhang; Committee Member: Joy Laska

Recent advances in materials and technologies for body-centric and IoT antenna systems

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