Design and performance study of pattern reconfigurable MIMO antennas for mobile smartphones

This paper presents compact pattern reconfigurable antennas for mobile handsets in MIMO configuration. Each antenna of the MIMO configuration being coupled fed monopole in meandered form is capable of covering several cellular frequency bands in the range of 1.75–2.67 GHz including 4G‐LTE, 2G‐GSM, 3G‐UMTS, and WLAN. The MIMO antennas are printed diagonally at the left and right no‐ground portions on the top layer of the substrate to enhance the isolation performance. The substrate used is FR‐4 with relative permittivity of 4.35 and loss tangent of 0.02. The volume of the substrate is 120 × 65 × 1.6 mm3 with each antenna occupying an area of 26.5 × 14.5 mm2. The pattern reconfigurability is achieved by connecting and disconnecting a 4.5 × 2 mm2 metallic strip using the p‐i‐n diode switch. The antennas are pattern reconfigurable in the frequency range of 1.9–2.1 GHz. The isolation achieved is better than 16 dB over all the frequency bands covered by each antenna. A prototype has been fabricated and tested. The simulated and measured results show a good performance of the MIMO antennas. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:148–156, 201

Investigations of MIMO Antenna for Smart Mobile Handsets and Their User Proximity

In this chapter, a monopole antenna with compact size, simple structure, easy to fabricate is reported which covers LTE700 (band13/14) (746–798 MHz), GSM1800 (1710–1885 MHz), PCS1900 (1850–1990 MHz), and LTE2600 (2500–2690 MHz) band based on 6-dB return loss. The proposed MIMO antenna consists of two radiating elements. The main radiating element is a composition of driven element, which is directly fed with microstrip line, and one parasitic element. The parasitic element provides the resonance at higher frequency band and the combination of driven elements and parasitic elements provide above-said frequency bands. The current distribution, far-field radiation patterns, and diversity parameters are checked out for the MIMO antenna in free space. Further performances are studied in the presence of user proximity

Recent developments of reconfigurable antennas for 4G and 5G wireless communications: A survey

YesReconfigurable antennas play important roles in smart and adaptive systems and are the subject of many research studies. They offer several advantages such as multifunctional capabilities, minimized volume requirements, low front-end processing efforts with no need for a filtering element, good isolation, and sufficient out-ofband rejection; these make them well suited for use in wireless applications such as fourth generation (4G) and fifth generation (5G) mobile terminals. With the use of active materials such as microelectromechanical systems (MEMS), varactor or p-i-n (PIN) diodes, an antenna’s characteristics can be changed through altering the current flow on the antenna structure. If an antenna is to be reconfigurable into many different states, it needs to have an adequate number of active elements. However, a large number of high-quality active elements increases cost, and necessitates complex biasing networks and control circuitry. We review some recently proposed reconfigurable antenna designs suitable for use in wireless communications such as cognitiveratio (CR), multiple-input multiple-output (MIMO), ultra-wideband (UWB), and 4G/5G mobile terminals. Several examples of antennas with different reconfigurability functions are analyzed and their performances are compared. Characteristics and fundamental properties of reconfigurable antennas with single and multiple reconfigurability modes are investigated.European Union’s Horizon 2020 research and innovation programme under grant agreement H2020-MSCA-ITN-2016 SECRET-722424

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

MIMO ANTENNAS FOR MOBILE HANDSET AND TABLET APPLICATIONS.

PhDThe fast development of wireless communication technologies is pressing the antenna engineers to investigate and design compact multiband antennas for the multiple-input multiple-output (MIMO) systems, which is the key technology for the next generation of mobile communications. The growing increase in the demand for transmitting and exchanging large volume data, such as multimedia and interactive materials is constantly fueling the need for higher data rates. MIMO systems have demonstrated the capability to increase channel capacity, with a simultaneous increase in range and reliability, without taking any additional bandwidth thus resulting in improved data throughput. However, the performance of a MIMO system is highly dependent on the nature of its propagation environment and the placement of antennas on device platform. The true benefits of MIMO can be exploited through a smart design that can adapt with changing system requirements or environmental conditions. This research project has investigated the methods to make multiband MIMO and multiband reconfigurable antennas on small mobile terminals with high communication performance. This involves the methods for avoiding coupling between multiple antennas and possible tuning of the antennas for next generation mobile handsets. The aim of this work is to develop MIMO and reconfigurable antennas for wireless terminals such as mobile handsets and tablets. The project is divided in two phases with the first phase involving the development of multiband MIMO antennas for handheld terminals and the second phase involves the design of reconfigurable antenna for mobile handsets. Several prototypes of handset antennas, capable of covering various cellular frequency bands, have been developed. The research involves a substantial work on theoretical analysis, computer simulation and experimental verification

Fixed and reconfigurable multiband antennas

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel UniversityWith the current scenario of development of antennas in the wireless communication field, the need of compact multiband, multifunctional and cost effective antenna is on the rise. The objective of this thesis is to present fixed and reconfigurable techniques and methods for small and slim multiband antennas, which are applicable to serve modern small and slime wireless, mobile and cognitive radio applications. In the fixed designs, independent control of the operating frequencies is investigated to enhance the antennas capabilities and to give the designer an additional level of freedom to design the antenna for other bands easily without altering the shape or the size of the antenna. In addition, for mobile phone antenna, the effect of user’s hand and mobile phone housing are studied to be with minimum effect. Although fixed multiband antennas can widely be used in many different systems or devices, they lack flexibility to accommodate new services compared with reconfigurable antennas. A reconfigurable antenna can be considered as one of the key advances for future wireless communication transceivers. The advantage of using a reconfigurable antenna is to operate in multiband where the total antenna volume can be reused and therefore the overall size can be reduced. Moreover, the future of cell phones and other personal mobile devices require compact multiband antennas and smart antennas with reconfigurable features. Two different types of frequency reconfigurability are investigated in this thesis: switchable and tunable. In the switchable reconfigurability, PIN diodes have been used so the antenna’s operating frequencies can hop between different services whereas varactor diode with variable capacitance allow the antenna’s operating frequencies to be fine-tuned over the operating bands. With this in mind, firstly, a switchable compact and slim antenna with two patch elements is presented for cognitive radio applications where the antenna is capable of operating in wideband and narrow bands depending on the states of the switches. In addition to this, a switchable design is proposed to switch between single, dual and tri bands applications (using a single varactor diode to act as a switch at lower capacitance values) with some fine tuning capabilities for the first and third bands when the capacitance of the diode is further increased. Secondly, the earlier designed fixed antennas are modified to be reconfigurable with fine-tuning so that they can be used for more applications in both wireless and mobile applications with the ability to control the bands simultaneously or independently over a wide range. Both analytical and numerical methods are used to implement a realistic and functional design. Parametric analyses using simulation tools are performed to study critical parameters that may affect the designs. Finally, the simulated designs are fabricated, and measured results are presented that validate the design approaches

Statistical Review Evaluation of 5G Antenna Design Models from a Pragmatic Perspective under Multi-Domain Application Scenarios

Antenna design for the 5G spectrum requires analysis of contextual frequency bands, design of miniaturization techniques, gain improvement models, polarization techniques, standard radiation pattern designs, metamaterial integration, and substrate selection. Most of these models also vary in terms of qualitative & and quantitative parameters, which include forward gain levels, reverse gain, frequency response, substrate types, antenna shape, feeding levels, etc. Due to such a wide variety in performance, it is ambiguous for researchers to identify the optimum models for their application-specific use cases. This ambiguity results in validating these models on multiple simulation tools, which increases design delays and the cost of deployments. To reduce this ambiguity, a survey of recently proposed antenna design models is discussed in this text. This discussion recommended that polarization optimization and gain maximization are the major impact factors that must be considered while designing antennas. It is also recommended that collocated microstrip slot antennas, fully planar dual-polarized broadband antennas, and real-time deployments of combined slot antenna pairs with wide-band decoupling are very advantageous. Based on this discussion, researchers will be able to identify optimal performance-specific models for different applications. This discussion also compares underlying models in terms of their quantitative parameters, which include forward gain levels, bandwidth, complexity of deployment, scalability, and cost metrics. Upon referring to this comparison, researchers will be able to identify the optimum models for their performance-specific use cases. This review also formulates a novel Antenna Design Rank Metric (ADRM) that combines the evaluated parameters, thereby allowing readers to identify antenna design models that are optimized for multiple parameters and can be used for large-scale 5G communication scenarios

Low correlation multiple antenna system for mobile phone applications using novel decoupling slots in ground plane

A compact low profile multiple antenna system for multiple-input-multiple- output (MIMO) applications is proposed. The antenna system combines two monopole type printed antennas with a slotted ground plane for low correlation and high isolation characteristics. The main antenna covers the twelve wireless communication bands required for LTE, GSM, UMTS2110, Bluetooth, WiMAX and WLAN. The auxiliary antenna has a very small volume compared to the main one and covers the ultra-wideband (UWB) frequency range (3.74-12 GHz). The antennas are positioned at opposite ends of the system's ground in order to reduce the mutual coupling between them. The isolation maintained is better than 20 dB over the desired frequency bands, resulting in an envelope correlation coefficient of less than 0.08. The simulation results show good S-parameters, high gain and radiation efficiency, and relatively stable radiation patterns. Due to the compact size and the ultrawide bandwidth, the proposed multiple antenna system is suitable for communication handsets that have size limitations. Results are presented and discussed. © 2013 IEEE