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

Analysis of Dual-Element Antenna Configurations

Dual-dipole antennas have been extensively researched previously for their bandwidth enhancing effect on Yagi type antennas. In this thesis, dual-dipole antennas are fabricated and measured. These experimental measurement results are verified with simulated values. First, a standard dual-dipole antenna is investigated and found that the high magnitude, opposite current directions on the dipole arms are the reasoning behind the creation of a high gain mode. This pattern is similar to a Yagi antenna. Next, a dual-band implementation of the dual-dipole antenna is shown, with two distinct resonances in a lower band and an upper band. Both bandwidths exhibit a dipole like mode, as well as a high gain mode. Finally, a dual-element cross-dipole antenna application is investigated. The antenna exhibits multiple dipole like modes within the bandwidth, high gain points, and CP generation at the center frequency

Wideband Circularly Polarized Reflectarray Antenna Using Rotational Symmetrical Crossed Dipoles

© 2023 IEEE. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1109/TAP.2023.3247943A wideband circularly polarized (CP) reflectarray (RA) antenna using rotational symmetrical crossed dipoles is presented. This is the first time investigating coupled crossed dipoles as the unit cell for wideband reflection bandwidth in the CP RA design. Equivalent circuit analysis shows that when a CP wave impinges on the designed unit cell, two series resonances, and two parallel resonances are simultaneously excited on the crossed dipoles. Owing to these four different resonances, the CP reflection bandwidth is greatly improved and elaborately adjusted by controlling the coupling between the crossed dipoles. The CP reflection bandwidth ratio of the unit cell is enhanced up to 2:1 for $S_{x} < -15$ dB with a thin thickness of $0.12 \lambda {0}$. Based on this unit cell, a wideband -20° collimated CP RA antenna with a circular aperture of 316 unit cells was designed, fabricated, and measured for final performance verification. The measured results show that a wide CP bandwidth of 7.6-15.9 GHz is achieved with the axial ratio (AR) < 3 dB. In addition, the measured 3 dB gain bandwidth is better than 43.7% with a peak realized gain of 26.3 dBic and maximum aperture efficiency (AE) of 58.3%.Peer reviewe

A comprehensive survey on 'circular polarized antennas' for existing and emerging wireless communication technologies

Circular polarized (CP) antennas are well suited for long-distance transmission attainment. In order to be adaptable for beyond 5G communication, a detailed and systematic investigation of their important conventional features is required for expected enhancements. The existing designs employing millimeter wave, microwave, and ultra-wideband (UWB) frequencies form the elementary platform for future studies. The 3.4-3.8 GHz frequency band has been identified as a worthy candidate for 5G communications because of spectrum availability. This band comes under UWB frequencies (3.1-10.6 GHz). In this survey, a review of CP antennas in the selected areas to improve the understanding of early-stage researchers specially experienced antenna designers has presented for the first time as best of our knowledge. Design implementations involving size, axial ratio, efficiency, and gain improvements are covered in detail. Besides that, various design approaches to realize CP antennas including (a) printed CP antennas based on parasitic or slotted elements, (b) dielectric resonator CP antennas, (c) reconfigurable CP antennas, (d) substrate integrated waveguide CP antennas, (e) fractal CP antennas, (f) hybrid techniques CP antennas, and (g) 3D printing CP antennas with single and multiple feeding structures have investigated and analyzed. The aim of this work is to provide necessary guidance for the selection of CP antenna geometries in terms of the required dimensions, available bandwidth, gain, and useful materials for the integration and realization in future communication systems

Microstrip-fed Wideband Circularly Polarized Printed Antenna

A wideband circularly-polarized printed antenna is proposed, which employs an asymmetrical dipole and a slit in the ground plane which are fed by an L-shaped microstrip feedline using a via. The proposed antenna geometry is arranged so that the orthogonal surface currents, which are generated in the dipole, feedline and ground plane, have the appropriate phase to provide circular polarization. A parametric study of the key parameters is made and the mechanism for circular polarization is described. The measured results show that the impedance bandwidth is approximately 1.34 GHz (2.45 GHz to 3.79 GHz) and the 3 dB axial ratio bandwidth is approximately 770 MHz (2.88 GHz to 3.65 GHz) which represent fractional bandwidths of approximately 41% and 23%, respectively, with respect to a centre frequency of 3.3 GHz

Compact Circularly Polarized Monopole Antenna Using Characteristic Mode Analysis

This study aims to design a circularly polarized compact antenna using characteristic mode analysis (CMA). The proposed antenna consists of a substrate with a slotted annular ring-shaped patch and partial ground. The excitation position of the antenna and its optimal dimensions are determined through the analysis of different operation modes with CMA. After that, an optimized antenna is designed, and an antenna prototype is fabricated for validation. The experimental results show that the reflection coefficient achieves a -10dB impedance bandwidth of 6.85 GHz, a 3dB-axial ratio bandwidth of 0.7 GHz, and a peak gain of 3.2 dBi. These characteristics agree with simulations and make the circularly polarized compact antenna suit for C-band and sub-6 GHz 5G wireless applications

Analysis of Miniaturized, Circularly Polarized Antennas for Bidirectional Propagation

Size reduction is necessary to fit the recent demand for small sized communication systems in consumer electronics. Wireless communication systems rely on antennas for long range transmission of signals, so size reduced antennas have been sought after in recent years. Also, not many antennas are designed for use in bidirectional scenarios like subways, tunnels, bridges, etc. Three sized reduced antennas with circular polarization are presented for use in bidirectional communication systems. An electrically small pattern reconfigurable array, an electrically small two-sided printed cross dipole, and a size reduced printed wideband antenna are introduced within this thesis. All antennas’ results are obtained from simulation, with two of the antenna designs being measured to verify their results