A Review: Circuit Theory of Microstrip Antennas for Dual-, Multi-, and Ultra-Widebands

In this chapter, a review has been presented on dual-band, multiband, and ultra-wideband (UWB). This review has been classified according to antenna feeding and loading of antennas using slots and notch and coplanar structure. Thereafter a comparison of dual-band, multiband, and ultra-wideband antenna has been presented. The basic geometry of patch antenna has been present along with its equivalent circuit diagram. It has been observed that patch antenna geometry for ultra-wideband is difficult to achieve with normal structure. Ultra-wideband antennas are achieved with two or more techniques; mostly UWB antennas are achieved from coplaner structures

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 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

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

Review on the Design of the Isolation Techniques for UWB-MIMO Antennas

Ultra wide band - Multiple Input Multiple Output antenna technology provides higher data rates and the combination of the ultra wide band (UWB) and the multiple input multiple output (MIMO) technologies provides a solution for the demand of still higher data rates i.e. in excess of 3 Gb/sec in the future.  As the antenna technologies are improving, the size of the MIMO antenna is growing smaller and smaller. Placing the antenna elements in such close proximity increases the coupling between them. Various isolation techniques have to be introduced between the antenna elements to decrease the coupling and to improve the isolation. A study of the various isolation enhancement techniques have been made in this review. It analyses the various isolation enhancement methods such as using orthogonal polarization, parasitic elements, varied decoupling structures, defected ground structures (DGS), neutralization line (NL) and finally by using metamaterials. Metamaterials is a technology to perk up the isolation between the antenna elements. Split ring resonator (SRR) behaves as a metamaterial and it is used as an isolation mechanism in this study. The antennas are simulated and the results are compared. The method using parasitic elements gives the highest isolation of 35 dB and it is 5 dB better than the methods using orthogonal polarization and using the decoupling structure. The performance of all the antennas satisfies the conditions for minimum isolation. The envelope correlation coefficient is nearly zero in all the antennas and it implies good diversity performance. The diversity gain is also calculated for the various antennas and it satisfies good diversity performance. The bandwidth of the antennas is in the UWB frequency range and they have a fractional bandwidth above the required value of 1.09. The capacity loss for all the antennas is very low and the antennas using defected ground structure and the decoupling structure gives very low capacity loss

Investigations on some compact wideband fractal antennas

Today’s small handheld and other portable devices challenge antenna designers for ultrathin, and high performances that have the ability to meet multi standards. In the context, fractal geometries have significant role for antenna applications with varying degree of success in improving antenna characteristics. In this thesis, we have investigated several wideband fractal monopole antennas. This work starts with design and implementation of Koch fractal, hybrid fractal, sectoral fractal, semi-circle fractal monopole antennas with discussion, covering their operations, electrical behavior and performances. The performances of these designs have been studied using standard simulation tools used in industry/academia and are experimentally verified. Frequency reconfigurable Koch snowflake fractal monopole antenna is also introduced. The present antenna can be used as an array element and has a wideband frequency of operation. A square Sierpinski monopole antenna has been designed, which is suitable for use in indoor UWB radio system and outdoor base station communication systems. Technique for obtaining a band stop function in the 5-6 GHz frequency band is numerically and experimentally presented. In addition to examining the performance of UWB system, the transfer function and waveform distortion are discussed. Finally, fractal antenna for array with MIMO environment is developed for mobile communication devices. Aim of this work is to achieve the acceptable performances in terms of isolation, envelope correlation coefficient, capacity loss, radiation patterns and efficiency. Furthermore, a wideband feed network prototype based on a modified Wilkinson power divider is designed. The designed feed network has been used in constructing 2-element and 4-element linear antenna arrays for high gain. This research work has addressed the effectiveness of fractal geometries in antenna and to bring-out the true advantages of their in antenna engineering

A novel SWB antenna with triple band-notches based on elliptical slot and rectangular split ring resonators

In this paper, a wideband antenna was designed for super-wideband (SWB) applications. The proposed antenna was fed with a rectangular tapered microstrip feed line, which operated over a SWB frequency range (1.42 GHz to 50 GHz). The antenna was implemented at a compact size with electrical dimensions of 0.16 ¿ × 0.27 ¿ × 0.0047 ¿ mm3, where ¿ was with respect to the lowest resonance frequency. The proposed antenna prototype was fabricated on a F4B substrate, which had a permittivity of 2.65 and 1 mm thickness. The SWB antenna exhibited an impedance bandwidth of 189% and a bandwidth ratio of 35.2:1. Additionally, the proposed antenna design exhibited three band notch characteristics that were necessary to eradicate interference from WLAN, WiMAX, and X bands in the SWB range. One notch was achieved by etching an elliptical split ring resonator (ESRR) in the radiator and the other two notches were achieved by placing rectangular split ring resonators close to the signal line. The first notch was tuned by incorporating a varactor diode into the ESRR. The prototype was experimentally validated with, with notch and without notch characteristics for SWB applications. The experimental results showed good agreement with simulated results.Postprint (published version