Wideband Back-Cover Antenna Design Using Dual Characteristic Modes With High Isolation for 5G MIMO Smartphone

© 2022 IEEE - All rights reserved. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1109/TAP.2022.3145456A novel method of designing a wideband high isolated dual-antenna pair using dual characteristic modes (CMs)is presented for fifth-generation (5G) multiple-input multiple output (MIMO) smartphone applications. A set of orthogonal CMs resonating from the square-loop slot is first introduced and works for the lower band. Then, another set of orthogonal CMs resonating from the edge branches is introduced with a shared compact radiator and works for the higher band. In combination with two sets of degenerated CMs and a capacitive coupling feeding structure, the proposed dual-antenna pair achieves abroad impedance bandwidth and high isolation without the need for any external decoupling structures. Based on this dual-antenna pair, an 8×8 MIMO array is developed and integrated into the back cover of a smartphone, which realizes zero ground clearance on the system circuit board. To verify the design concept, prototypes of the antenna pair and MIMO array were fabricated and measured. It shows that experimental results agree well with the simulation results. More importantly, the presented 8×8 MIMO array has high isolation of more than 20 dBis achieved across the operating band of 3.3-3.8 GHz.Peer reviewedFinal Accepted Versio

Parasitic Element Based Frequency Reconfigurable Antenna with Dual Wideband Characteristics for Wireless Applications

A Microstrip Frequency Reconfigurable circular patch slot antenna for switchable Bluetooth, WiMAX, WLAN, and satellite communication applications is analyzed and presented in this work. The optimized overall size of 47 mm x40 mmx1.6 mm is utilized in the design, and which can cover wide range of frequencies below 10 GHz. In the initial phase, different monopole antennas are designed with various shapes of same size and later parasitic patch elements has been added to those monopole antennas. The circular monopole driven element and parasitic element are connected with a PIN diode, and which reinforced in achieving frequency reconfigurability. The proposed antenna is resonating at various frequencies of 2.4 GHz, 4 GHz, and 8.4 GHz when the diode in ON condition and resonating at 3 GHz, 5.4 GHz, and 8.4 GHz when the diode is in OFF condition. The performance of the designed antenna prototype is scaled and differentiated with the results of simulation and found good matching with respect to performance characteristics

Slot Antennas - A Comprehensive Survey

Wireless Communication has found a rapid growth over the past decades starting from handheld devices to spacecraft applications. The efficient operation of all such wireless devices depends on the design and proper working of the transmitting and receiving antennas. Microstrip antennas are most commonly preferred for major wireless applications, because of their miniaturized structure, ease of fabrication, low power consumption, flexibility with printed circuit board, low profile, light weight, effective return loss and better radiation properties. This paper provides a comprehensive survey on microstrip antennas whose performance is improved to meet the increasing demand, by introducing slots of different shapes and sizes. These slots of various kinds helps in obtaining wider bandwidth over the C and Ultrawideban

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

A Review on Different Techniques of Mutual Coupling Reduction Between Elements of Any MIMO Antenna. Part 1: DGSs and Parasitic Structures

This two-part article presents a review of different techniques of mutual coupling (MC) reduction. MC is a major issue when an array of antennas is densely packed. When the separation between the antennas i

Multiple Slot Fractal Structured Antenna for Wi-Fi and Radio Altimeter for uncertain Applications

A multiple slot fractal antenna design has been determined communication efficiency and its multi-function activities.  High-speed small communication devices have been required for future smart chip applications, so that researchers have been employed new and creative antenna design. Antennas are key part in communication systems, those are used to improve communication parameters like gain, efficiency, and bandwidth. Consistently, modern antennas design with high bandwidth and gain balancing is very difficult, therefore an adaptive antenna array chip design is required. In this research work a coaxial fed antenna with fractal geometry design has been implemented for Wi-Fi and Radio altimeter application. The fractal geometry has been taken with multiple numbers of slots in the radiating structure for uncertain applications. The coaxial feeding location has been selected based on the good impedance matching condition (50 Ohms). The overall dimension mentioned for antenna are approximately 50X50X1.6 mm on FR4 substrate and performance characteristic analysis is performed with change in substrate material presented in this work. Dual-band resonant frequency is being emitted by the antenna with resonance at 3.1 and 4.3 GHz for FR4 substrate material and change in the resonant bands is obtained with change in substrate. The proposed Antenna is prototyped on Anritsu VNA tool and presented the comparative analysis like VSWR 12%, reflection coefficient 9.4%,3D-Gain 6.2% and surface current 9.3% had been improved

Study and miniaturisation of antennas for ultra wideband communication systems

PhDWireless communications have been growing with an astonishing rate over the past few years and wireless terminals for future applications are required to provide diverse services. This rising demand prompts the needs for antennas able to cover multiple bandwidths or an ultrawide bandwidth for various systems. Since the release by the Federal Communications Commission (FCC) of a bandwidth of 7.5 GHz (from 3.1 GHz to 10.6 GHz) for ultra wideband (UWB) wireless communications, UWB has been rapidly evolving as a potential wireless technology and UWB antennas have consequently drawn more and more attention from both academia and industries worldwide. Unlike traditional narrow band antennas, design and analysis of UWB antennas are facing more challenges and difficulties. A competent UWB antenna should be capable of operating over an ultra wide bandwidth as assigned by the FCC. At the same time, a small and compact antenna size is highly desired, due to the integration requirement of entire UWB systems. Another key requirement of UWB antennas is the good time domain behaviour, i.e. a good impulse response with minimal distortion. This thesis focuses on UWB antenna miniaturisation and analysis. Studies have been undertaken to cover the aspects of UWB fundamentals and antenna theory. Extensive investigations are also conducted on three different types of miniaturised UWB antennas. 5 The first type of miniaturised UWB antenna studied in this thesis is the loaded orthogonal half disc monopole antenna. An inductive load is introduced to broaden the impedance bandwidth as well as the pattern bandwidth, in other words, an equivalent size reduction is realised. The second type of miniaturised UWB antenna is the printed half disc monopole antenna. By simply halving the original antenna and tuning the width of the coplanar ground plane, a significant more than 50% size reduction is achieved. The third type of miniaturised UWB antenna is the printed quasi-self-complementary antenna. By exploiting a quasi-self-complementary structure and a built-in matching section, a small and compact antenna dimension is achieved. The performances and characteristics of the three types of miniaturised UWB antennas are studied both numerically and experimentally and the design parameters for achieving optimal operation of the antennas are also analysed extensively in order to understand the antenna operations. Also, time domain performance of the Coplanar Waveguide (CPW)-fed disc monopole antenna is examined in this thesis to demonstrate the importance of time domain study on UWB antennas. Over the past few years of my PhD study, I feel honoured and lucky to work with some of the most prestigious researchers in the Department of Electronic Engineering, Queen Mary, University of London. I would like to show my most cordial gratitude to those who have been helping me during the past few years. There would be no any progress without their generous and sincere support. First of all, I would like to thank my supervisors Professor Clive Parini and Professor Xiaodong Chen, for their kind supervision and encouragement. I am impressed by their notable academic background and profound understanding of the subjects, which have proved to be immense benefits to me. It has been my great pleasure and honour to be under their supervision and work with them. Second of all, I would like to thank Mr John Dupuy for his help in the fabrication and measurement of antennas I have designed during my PhD study. Also, a special acknowledgement goes to all of the staff for all the assistance throughout my graduate program

A novel compact fractal UWB antenna with triple reconfigurable notch reject bands applications

A compact, circular UWB fractal antenna with triple reconfigurable notch rejection bands is proposed. It rejects the crowded frequency bands WiMAX, WLAN and X band interferences produced in UWB communication systems. The proposed fractal structure consists of a basic circular patch with circular fractal iterations. By employing this new structure of fractals, the overall size of antenna is reduced 53% to 21 × 25 mm, in comparison with traditional circular monopole antenna. The implemented antenna operates at 3.1–10 GHz. Re-configurability is realized by designing slots and split ring resonators in desired frequencies with the attached PIN diodes. WLAN band rejection was realized by creating a pair of optimized L-shaped slots in the ground plane. By etching a split ring resonator and a U-shaped slot, X and WiMAX bands were also rejected. Furthermore, by attaching diodes to aforementioned slots and designating the diodes on/off, different bands can be included or rejected. In time domain, the antenna properties are evaluated by a figure of merit called fidelity factor. Finally, the antenna properties are measured in anechoic chamber and the results agrees with simulation findings

Electromagnetic Absorbers Based on Frequency Selective Surfaces

Frequency Selective Surfaces (FSSs) are bidimensional arrays of particles arranged in a periodic manner. These surfaces can be lossless or lossy, depending on the manufacturing process. They can be fabricated by using metallic or controlled-resistance surface deposition. Lossy surfaces can be also obtained through the integration of lumped components on a metallic surface. The use of FSSs has fostered new research lines in the design of electromagnetic absorbing surfaces, bringing improvements both in terms of bandwidth/thickness ratio maximization and in terms of customizability of the absorbing bandwidth (narrowband, multi-band, wideband, ultra-wideband) for specific applications. Artificial impedance surfaces (or HighImpedance Surfaces, - HIS) are thin resonant cavities synthesized by printing a periodic frequency selective surface on the top of a grounded dielectric slab. By proper tailoring of the geometrical and electrical properties of the FSS as well as the substrate, several electrically-thin absorbing designs can be obtained. Ultranarrowband absorbers with extremely stable angular behavior, often addressed as metamaterial absorbers, can be realized by exploiting only dielectric losses of commercial substrates. Narrowband, wideband and ultra-wideband configurations are instead implemented by also resorting to ohmic losses in a non-conductive FSS. A thorough review of the available absorbers will be presented together with multi-band and tunable design techniques. Manufacturing processes and practical examples will be also addressed, and the most interesting fields of application of the presented structures will be described