A novel Multi-permittivity Cylindrical Dielectric Resonator Antenna for Wideband Applications

In this paper, a novel multi-permittivity cylindrical dielectric resonator antenna for wideband application is presented. The multi-permittivity cylinder is formed by combining two different permittivity material sectors in such a way that each sector (with constant permittivity) is 90 degree apart. A direct microstrip line coupling terminated with T-stub at the open end is used to excite the multi-permittivity cylindrical dielectric resonator. The angular position of the multi sector dielectric resonator with respect to the longitudinal axis of the microstrip line and length of the additional strip at the open end of the feeding circuit is key parameters for wideband operation of the antenna. By optimizing all parameters of the proposed antenna, wideband impedance bandwidth of 56% (12.1 GHz - 21.65 GHz) is achieved. The average gain of the antenna throughout the bandwidth is 5.9 dB with good radiation properties in both E-plane and H-plane. A well matched simulation and experimental results show that the antenna is suitable for wideband applications

Study Of Inhomogeneous Dielectric Resonators For Linearly Circularly Polarized Microwave Antenna Applications

In the last three decades a huge amount research has been dedicated to homogeneous (single permittivity) dielectric resonators (DRs) with cylindrical, rectangular/square and hemispherical shapes being the center of attention. These DRs have been investigated theoretically, numerically, and experimentally therefore, all the major performance controlling parameters are known for the homogeneous DRs. It well known that a homogenous DR can serve only one purpose at a time i.e. strong coupling to the source and hence narrow impedance bandwidth and vice versa. To overcome these drawbacks of homogenous DRs, in this work inhomogeneous DRs are designed in such a way that the basic geometry of the resonator is maintained so that the available theoretical, numerical and experimental analysis tools can be effectively applied to the proposed inhomogeneous DRs. The inhomogeneities in the resonators are introduced systematically in the azimuth (ϕ) direction so that the electromagnetic field distribution in the resonators remains the same with different range of energy confinement. To validate these ideas three different resonators based on cylindrical dielectric resonator (CDR) and rectangular/square shape resonators are investigated. For inhomogeneous CDR two 90ᴼ pie shape sectors of relatively high permittivity were introduced in the ϕ-direction in a way that sectors with same permittivity are placed in the opposite quadrant. Similarly, another inhomogeneous DR (split-oval shape) was designed by inserting high permittivity rectangular strip in the middle of two half cylindrical DR in the ϕ direction. Lastly, the third design of this research is based on a square shape DR in which the permittivity is lowered by introducing air-gap within the resonator which appears like a nested square DR. The proposed inhomogeneous DRs are tested for linearly polarized (LP) wideband antenna applications with a common excitation technique i.e. microstrip line. While, for circularly polarized (CP) designs, it is important to excite two orthogonal modes with the same amplitude hence different feeding techniques are used. Theoretical, numerical and experimental analysis of the inhomogeneous dielectric resonator antennas (DRA) showed that by properly designing inhomogeneous resonators, impedance bandwidth response, axial ratio (AR) bandwidth, gain and efficiency of the DRA‘s can be improved. For all three inhomogeneous LP DRA‘s approximately 56% impedance bandwidth was achieved which shows 80.5% enhancement of bandwidth over homogeneous DRAs with stable radiation characteristics throughout the operating band. The AR bandwidth response of the CP inhomogeneous DRA‘s was recorded to be 200% more than that of homogeneous counterparts. For the first two inhomogeneous DRAs gain was improved up to 6.5 dBi while for the nested square DR gain remained almost the same as that of the homogeneous square DR. With reference to these findings it was found that performance of the DRA can be noticeably improved with systematic introduction of inhomogeneity in the DR

Antenna Design for 5G and Beyond

With the rapid evolution of the wireless communications, fifth-generation (5G) communication has received much attention from both academia and industry, with many reported efforts and research outputs and significant improvements in different aspects, such as data rate speed and resolution, mobility, latency, etc. In some countries, the commercialization of 5G communication has already started as well as initial research of beyond technologies such as 6G.MIMO technology with multiple antennas is a promising technology to obtain the requirements of 5G/6G communications. It can significantly enhance the system capacity and resist multipath fading, and has become a hot spot in the field of wireless communications. This technology is a key component and probably the most established to truly reach the promised transfer data rates of future communication systems. In MIMO systems, multiple antennas are deployed at both the transmitter and receiver sides. The greater number of antennas can make the system more resistant to intentional jamming and interference. Massive MIMO with an especially high number of antennas can reduce energy consumption by targeting signals to individual users utilizing beamforming.Apart from sub-6 GHz frequency bands, 5G/6G devices are also expected to cover millimeter-wave (mmWave) and terahertz (THz) spectra. However, moving to higher bands will bring new challenges and will certainly require careful consideration of the antenna design for smart devices. Compact antennas arranged as conformal, planar, and linear arrays can be employed at different portions of base stations and user equipment to form phased arrays with high gain and directional radiation beams. The objective of this Special Issue is to cover all aspects of antenna designs used in existing or future wireless communication systems. The aim is to highlight recent advances, current trends, and possible future developments of 5G/6G antennas

Passive Components for Ultra-Wide Band (UWB) Applications

UWB technology brings the convenience and mobility of wireless communications to very high-speed interconnects in the home and office due to the precision capabilities combined with the low power. This makes it ideal for certain radio frequency sensitive environments such as hospitals and healthcare as well as radars. UWB intrusion-detection radar is used for detecting through the wall and also used for security with fuse avoidance radar, precision locating and tracking (using distance measurements between radios), and precision time-of-arrival-based localization approaches. The FCC issued a ruling in 2002 that allowed intentional UWB emissions in the frequency range between 3.1 and 10.6 GHz, subject to certain restrictions for the emission power spectrum. Other definitions for ultra-wideband range of frequency are also used such as any device that has 500 MHz bandwidth or fractional bandwidth greater than 25% is considered an UWB enable high data rate to be transferred with a very low power that does not exceed −41.3 dBm

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

UWB Technology

Ultra Wide Band (UWB) technology has attracted increasing interest and there is a growing demand for UWB for several applications and scenarios. The unlicensed use of the UWB spectrum has been regulated by the Federal Communications Commission (FCC) since the early 2000s. The main concern in designing UWB circuits is to consider the assigned bandwidth and the low power permitted for transmission. This makes UWB circuit design a challenging mission in today's community. Various circuit designs and system implementations are published in this book to give the reader a glimpse of the state-of-the-art examples in this field. The book starts at the circuit level design of major UWB elements such as filters, antennas, and amplifiers; and ends with the complete system implementation using such modules

Wideband low-profile circularly polarized antenna array

Tato bakalářská práce se zaměřuje na studii nového typu širokopásmové nízkoprofilové kruhově polarizované anténní řady s vysokým ziskem. Cílem práce je navrhnout, optimalizovat a zrealizovat navrženou anténu pro pracovní kmitočtové pásmo 5,5 - 7 GHz. Práce se zabývá teoretickými základy za účelem následné prezentace konceptu antény. Dále popisuje jednotlivé fáze návrhu a implementace. Anténa byla navržena pomocí plně vlnového simulačního programu CST Microwave Studio a vyrobena na dielektrickém substrátu. Výsledky simulovaných i měřených vlastností jsou vyhodnoceny v závěru.This bachelor’s thesis is focused on the study of a novel type of wideband low-profile circular array antenna with circular polarization and high gain. The aim of this thesis is to design, optimize and implement the proposed antenna for a 5.5 - 7 GHz frequency band. The thesis deals with theoretical fundamentals in order to subsequently present the concept of the antenna. Furthermore, it describes its design and implementation stages. The antenna was designed in the full-wave program CST Microwave Studio and fabricated on dielectric substrate. Both simulated and measured property results are evaluated in the conclusion.

Design and Analysis of Singly Fed Dielectric Resonator Antenna with A Wideband Circular Polarization

The proliferation of mobile communications technology increases the demands for faster and more robust services, in addition to the ever decreasing sizes of antennas. These demands can be satisfied using circularly polarized (CP) dielectric resonator antennas (DRAs) exhibiting wide operational bandwidth capability. By utilizing such antennas, the probability of linking the transmitted and received signals is higher, and the system is more reliable since the CP wave is transmitted in all planes and less susceptible to unwanted reflections and absorptions. As CP system is insensitive to the transmitter and receiver orientation, the time consuming practice of continuously aligning the antennas can be avoided. Furthermore, the antennas profile can be reduced simply by using dielectric material with higher permittivity. The thesis focuses on the design and analysis of singly-fed regular-shaped DRAs with a wideband circular polarization. Two new single-point excitation schemes that can be easily used to excite an arbitrarily shaped DRA are introduced, where a square spiral and a rectangular open half-loop are used for DRA excitation. These proposed feeding methods are based on employing conformal conducting metal strips that are placed on the DRA surface. Additionally, two different approaches are employed onto the DRA design to enhance the CP bandwidth. The first approach is based on using a multilayer dielectric, and the second introduces a parasitic half-loop inside the feeding element. The generated broad CP bands have been achieved in conjunction with sufficient impedance matching bandwidths. The studied geometries have been modeled using a comprehensive self developed MoM code that employs the volume surface integral equation (VSIE). The computed results have been validated against those obtained from measurements as well as CST microwave studio simulations. Theoretical and experimental results demonstrate a several folds enhancement in the CP bandwidths compared to those reported in the literature for identical DRA geometries

1-D broadside-radiating leaky-wave antenna based on a numerically synthesized impedance surface

A newly-developed deterministic numerical technique for the automated design of metasurface antennas is applied here for the first time to the design of a 1-D printed Leaky-Wave Antenna (LWA) for broadside radiation. The surface impedance synthesis process does not require any a priori knowledge on the impedance pattern, and starts from a mask constraint on the desired far-field and practical bounds on the unit cell impedance values. The designed reactance surface for broadside radiation exhibits a non conventional patterning; this highlights the merit of using an automated design process for a design well known to be challenging for analytical methods. The antenna is physically implemented with an array of metal strips with varying gap widths and simulation results show very good agreement with the predicted performance