Differentially Fed Dual-Band Base Station Antenna with Multimode Resonance and High Selectivity for 5G Applications

A dual-polarized antenna with multimode resonance and high selectivity is proposed in this paper to cover the 5G sub-6 GHz bands. The proposed antenna achieves dual wide impedance bandwidth characteristics by incorporating a dual mode coupled patch and four planar coupled strips around the driven patch. Through the four resonant modes of these structures, the antenna effectively covers the two desired frequency bands. Moreover, the electric/magnetic coupling between the driven patch, dual mode coupled patch, and planar coupled strips enables the creation of three radiation nulls that suppress unwanted radiation. To further improve the out-of-band rejection level and half power beamwidth, four shorted strips are introduced around the radiator. The introduction of these strips results in a 4th radiation null at higher out-of-band frequencies and expands the antenna's half power beamwidth from 52° to 62°. To demonstrate the feasibility of the design, both the proposed antenna and its array were manufactured and tested. Measured results show that the filtering element was able to operate within frequency bands of 3.24-3.83 GHz (16.7%) and 4.74-5.30 GHz (11.2%) with a reference of |Sdd11| < -14 dB. The input ports exhibited a high level of isolation, measuring 40 dB. Furthermore, the four radiation nulls proved effective in suppressing out-of-band radiation

Single Layered Periodic Structure Loaded Textile Patch Antennas

This thesis provides an investigation of a Single Layered Periodic Structure Loaded Textile Patch Antenna with probe feed excitation. Specifically, this thesis is concentrated on the application of wearable antenna arrays with space suit, since this thesis has collaboration with the University of North Dakota (UND) Space Suit Laboratory in the Space Studies Department. Topics include; platform interaction and placement of the antenna system. The goal is to increase antenna gain by loading the antenna with periodic cells. First, an introduction to items contained within this thesis will be given. The second chapter introduces microstrip patch antennas, their basic characteristics, and their feeding excitation methods. Continuing with microstip patch antennas, and how they are viewed with their fringing field effects. Then the theoretical designs of the physical dimensions of a patch antenna relative to its electrical length are included. This part then ends with a basic introduction to periodic structures, namely Electromagnetic Band Gap (EBG) structures. The third chapter covers wearable antennas, with and without periodic structures, and their applications. A review of surface waves and wave modes is given. This review produces a picture of how this once un-utilized energy (i.e. surface waves) can be recycled and reused to benefit positively increased gain. This can be accomplished by use of periodic structures loaded with the antenna. The fourth chapter covers the material, manufacturing, assembling, and measuring processes of textile antennas. This range of processes is journeyed as a joint collaboration between UNDs Electrical Engineering Department\u27s Applied Electromagnetics Laboratory, and the Technology Department\u27s Machine Shop. Lastly, simulation and design of a periodic loaded patch antenna are analyzed. This begins by first designing and simulating a free standing periodic cell coined C-mirror . The simulation results for reflection and dispersion characteristics are given. A 1 GHz antenna with specifications of textile material was designed. Once this antenna was realized, it was then loaded uni-planar with periodic cells with no vias. Experiments included varying the orientation, number of rows, and the placement of the cells with respect to the antenna. It was found that the Up-Down (UD) orientation with 2 rows and λo/12 placement demonstrated the greatest increase in gain. Furthermore, surface currents were seen to interact with the periodic cells. It could be seen that the arrangement of the cells adapted a network internally with the current flowing through the cells obtaining an inductive behavior and the capacitive behavior occurred between the cells stubs as well as between the cells defined by the Periodic Boundary Conditions (PBC). This surface current behavior, with the orientation of the periodic array with no vias became known as a Uni-Planar Parasitic Loaded Patch Antenna

Passive Planar Microwave Devices

The aim of this book is to highlight some recent advances in microwave planar devices. The development of planar technologies still generates great interest because of their many applications in fields as diverse as wireless communications, medical instrumentation, remote sensing, etc. In this book, particular interest has been focused on an electronically controllable phase shifter, wireless sensing, a multiband textile antenna, a MIMO antenna in microstrip technology, a miniaturized spoof plasmonic antipodal Vivaldi antenna, a dual-band balanced bandpass filter, glide-symmetric structures, a transparent multiband antenna for vehicle communications, a multilayer bandpass filter with high selectivity, microwave planar cutoff probes, and a wideband transition from microstrip to ridge empty substrate integrated waveguide

Reconfigurable Antennas

In this new book, we present a collection of the advanced developments in reconfigurable antennas and metasurfaces. It begins with a review of reconfigurability technologies, and proceeds to the presentation of a series of reconfigurable antennas, UWB MIMO antennas and reconfigurable arrays. Then, reconfigurable metasurfaces are introduced and the latest advances are presented and discussed

Optically Transparent Antennas and Filters for Smart City Communication

Incremental usage of mobile devices demand a new generation of wireless networks (5G) to provide faster data rates, more reliable coverage, monitor city infrastructure usage, and increase network capacity. The frequencies proposed for the upcoming 5G network would result in shorter broadcast distances and network dead zones, countered by incorporating transparent antennas into glass high rises. Transparent antennas possess, however a major challenge: low gain. This lower gain can be countered by means of employing antennas in an antenna array, boosting the gain and even giving the array the ability to beam form for the upcoming 5G network. The 5G dead zones can be countered with strategically placed transparent reflectors embedded into the glass surfaces of city high-rises. This dissertation shows there are significant effects due to the transparent antennas’ carrier concentration and film thickness. Changes in film conductivity and thicknesses results in shifts for filter and antenna resonances. A 4x1 GZO antenna array was constructed to operate at 5.8 GHz, and the results show approximately 10dBi of lower aperture gain between a copper version of the array and the GZO version of the array. However, the 4x1 GZO array shows an approximate 12dBi increase in gain over a single GZO antenna element. The technology developed in this dissertation has a broader impact other than for smart cities and the upcoming 5G network. Transparent antenna arrays offer sight insensitive military communication systems and eye-worn medical and commercial devices to monitor eye health and other various health signs

Metamaterial-Inspired Frequency-Selective Surfaces.

This dissertation presents a new approach to designing frequency-selective surfaces having extensive applications in communications and radar systems. Unlike conventional surfaces composed of resonance-length elements, the new structures use sub-wavelength elements, and therefore, operate in TEM mode. Consequently, their frequency response is harmonic-free up to a frequency where their elements' dimensions become comparable with the wavelength. Hence, their behavior is described through quasi-static circuit models. These surfaces, which will be referred to as miniaturized-element surfaces, are easily synthesized since filter theory and circuit simulators are utilized in their design process. The small dimensions of the elements of the surface and its TEM mode of operation decrease the surface sensitivity to the incidence angle of the excitation (plane-wave). This allows the application of such surfaces in conjunction with phased-arrays and their placement in close proximity to an antenna. These surfaces can also operate properly with smaller panel dimensions. The theory of the new surfaces is introduced in Chapter 3 where a surface consisting of an array of wavelength/12-long elements is presented. The transmission response of this surface includes a passband and a transmission zero. For this design, the first harmonic is located at a frequency six times higher than the operation frequency. Using varactors, frequency tuning of nearly an octave is shown. Chapter 4 presents multipole spatial filters. Through an accurate circuit model, dual-bandpass and maximally flat filters that are wavelength/240 thick are demonstrated. Chapter 5 introduces a reconfigurable surface that produces a frequency response with two operation modes: bandstop and bandpass. Moreover, using varactors, the center frequency and the bandwidth are tuned independently. The discussion on tunability is continued in Chapter 6 which introduces another varactor-tuned structure that operates, similar to the previous designs, without additional biasing circuitry for the varactors. However, this structure is immune to single point failure as it uses a parallel biasing method. Finally, Chapter 7 demonstrates a wavelength/10-thick, coupled filter-antenna array to achieve a high-order filtering for beamforming arrays. This design eliminates the need for integrating bulky filters required in the receive chain of array elements.Ph.D.Electrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/64588/1/farhadbp_1.pd

Metamaterial

In-depth analysis of the theory, properties and description of the most potential technological applications of metamaterials for the realization of novel devices such as subwavelength lenses, invisibility cloaks, dipole and reflector antennas, high frequency telecommunications, new designs of bandpass filters, absorbers and concentrators of EM waves etc. In order to create a new devices it is necessary to know the main electrodynamical characteristics of metamaterial structures on the basis of which the device is supposed to be created. The electromagnetic wave scattering surfaces built with metamaterials are primarily based on the ability of metamaterials to control the surrounded electromagnetic fields by varying their permeability and permittivity characteristics. The book covers some solutions for microwave wavelength scales as well as exploitation of nanoscale EM wavelength such as visible specter using recent advances of nanotechnology, for instance in the field of nanowires, nanopolymers, carbon nanotubes and graphene. Metamaterial is suitable for scholars from extremely large scientific domain and therefore given to engineers, scientists, graduates and other interested professionals from photonics to nanoscience and from material science to antenna engineering as a comprehensive reference on this artificial materials of tomorrow