Design considerations of MIMO antennas for mobile phones

YesThe paper presents a new modeling and design concept of antennas using polar- ization diversity of 2 £ 2 and 3 £ 3 Multiple Input Multiple Outputs (MIMO) system that is proposed for future mobile handsets. The channel capacity is investigated and discussed over Raleigh fading channel and compared to a linear/planner antenna array MIMO channel. The capacity is also discussed over three types of power azimuth spectrums. The results are compared to the constraints capacity limits in which the maximum capacity observed

PSO-CCO_MIMO-SA: A particle swarm optimization based channel capacity optimzation for MIMO system incorporated with smart antenna

With the radio channels physical limits, achieving higher data rate in the multi-channel systems is been a biggest concern. Hence, various spatial domain techniques have been introduced by incorporating array of antenna elements (i.e., smart antenna) in recent past for the channel limit expansion in mobile communication antennas. These smart antennas help to yield the improved array gain or bearm forming gain and hence by power efficiency enhanmaent in the channel and antenna range expansion. The use of smart antenna leads to spatial diversity and minimizes the fading effect and improves link reliability. However, in the process of antenna design, the proper channel modelling is is biggest concern which affect the wireless system performance. The recent works of MIMO design systems have discussed the issues in number of antenna selection which suggests that optimization of MIMO channel capacity is required. Hence, a Particle Swarm Optimization based channel capacity optimzation for MIMO system incorporated with smart antenna is introduced in this paper. From the outcomes it is been found that the proposed PSO based MIMO system achieves better convergenece speed which results in better channel capacity

Mutual Coupling Reduction between Closely Spaced U-slot Patch Antennas by Optimizing Array Configuration and its Applications in MIMO

Multiple-input, multiple-output (MIMO) systems have received considerable attention over the last decade. There are some limitations when obtaining the most from MIMO,such as mutual coupling between antenna elements in an array. Mutual coupling and therefore inter-element spacing have important effects on the channel capacity of a MIMO communication system, its error rate, and ambiguity ofMIMO radar system. There is a huge amount of research that focuses on reducing the mutual coupling in an antenna array to improve MIMO performance. In this research, we focus on the antenna section of the system.Antenna design affects the performance of Multiple-Input-Multiple-output (MIMO) systems. Two aspects of an antenna‟s role in MIMO performance have been investigated in this thesis. Employing suitable an antenna or antenna array can have a significant impact on the performance of a MIMO system. In addition to antenna design, another antenna related issue that helps to optimize the system performance is to reduce mutual coupling between antenna elements in an array. Much research has focused on the reduction of mutual coupling. In this research, the effect of the antenna configuration in array on mutual coupling has been studied and the main purpose is to find the array configuration that providesthe minimum mutual coupling between elements. The U-slot patch antenna is versatile antennas that because of its features like wide bandwidth,multi-band resonance and the ease of achieving different polarizations. This research first investigated the u-slot patch antenna, its features and capabilities. Seconda CAD optimization to design a low profile, dual band U-slot patch antenna is provided. Designed antenna is a dual band antenna that is intended to work at 3.5 and 5 GHz and have sufficient gain of at least 3dB. The effect of mutual coupling on MIMO systems is studied and then different array configurations were considered for two closely spaced U-slot patch antennas. Different configurations show different mutual coupling behavior. After modeling and simulation, the array was designed, implemented and finally tested in an anechoic chamber. These results are compared to both simulation and theoretical results and the configuration with minimum amount of mutual coupling was found. Some radar experiments also have been done to prove the effect of mutual coupling on radar performanc

The Investigation of Polarization Diversity in MIMO System at 2.4 GHz

This paper describes the concept of multiple input multiple output (MIMO) system using polarization diversity that can enhance the channel capacity and increased the data output performance of the system. The microstrip antenna array is designed, fabricated and measured at the desired operating frequency for this measurement. Computer Simulation Technology (CST) software is used to design and simulate the microstrip antenna array. The simulation and measurement data results are compared and discussed. The fabricated microstrip antenna is used to develop the Radio Frequency (RF) MIMO test bed system. The system measurement has been conducted in Microwave Laboratory at Faculty of Electronic and Computer Engineering, University Technical Malaysia Melaka at the operating frequency of 2.4 GHz. The spatial diversity and polarization diversity are applied in measurement campaign to investigate the performance of the wireless MIMO channel. The data obtained from the measurement is processed using MATLAB software in order to calculate the MIMO channel capacity. The analysis has been focused on the effect of the MIMO channel capacity due to the proposed measurement setup configurations. The channel capacity is increased from 0.03 b/s/Hz to 0.09 b/s/Hz when polarization diversity is applied at both transmitter and receive

A Study on Mutual Coupling Suppression for MIMO Antenna Array

Wireless communication is rapidly becoming the most popular solution to deliver voice and data services due to flexibility and mobility that can be offered at moderate infrastructure costs. Unfortunately, current wireless systems are unable to support some services offered by wire line systems due to the limited data rates achievable over wireless links. At the same time, there is a growing demand from the operators for better coverage to reduce infrastructure costs and enhance the wireless experience of the customers. One of the most promising solutions to overcome these issues is multiple-input multiple-output (MIMO) technology. A Multiple-input multiple-output (MIMO) Antenna system is a well-known technique to enhance the performance of wireless communication systems. The channel capacity that a MIMO antenna system provides is much larger than that provided by the conventional wireless system. The MIMO wireless technology uses multiple antennas at the transmitter and receiver to produce significant capacity gains over single-input single-output (SISO) systems using the same bandwidth and transmit power. It has been shown that the capacity of a MIMO system increases linearly with the number of antennas in the presence of a scattering-rich environment. In spite of this advantage, the MIMO antenna system has many practical problems because the signal processing techniques do not consider the degradation of the correlation coefficients due to the coupling between antenna elements. Many researchers try to resolve the problem system-wise, or by using baseband algorithms and signal processing techniques. Therefore, to solve this problem and to operate the MIMO antenna system with properly, the characteristics of the MIMO antenna in real environment must be considered when developing processing algorithms. To implement a MIMO antenna system in real MIMO environment, we must consider the mutual coupling between MIMO antenna elements. Suppressing the coupling between antenna elements is an important problem in MIMO or multiple antenna systems because the coupling between the antenna elements influences the correlation coefficient in free space significantly. This thesis describes several design techniques for MIMO antenna system having low mutual coupling between each antenna element. Two examples of the proposed models employed parasitic elements for mutual coupling suppressionthey show strong possibility of mutual coupling suppression between patch antenna elements to realize an independent channel for MIMO antenna system. It is proposed a compact 2-channel WiBro-MIMO antenna for the practical handy terminal. It is employed the projected (凸) ground structure for isolation between two antenna elements and it suppressed both of the mutual coupling and the radiation coupling. In addition, for the MIMO application, a ultra small and ultra wideband antenna having a novel antenna input impedance matching structure is proposed in this thesis. The MIMO antenna design techniques proposed in this thesis are shown very low mutual coupling and very good antenna characteristics such as radiation pattern, antenna gain, resonable antenna size, etc.. Due to the these merits of the proposed design techniques, it is expected the proposed design techniques could be applied in the wireless communication system which is employed in MIMO system.Chapter 1. Introduction = 1 Chapter 2. Planar array of mutual coupling suppression = 4 2.1 4-CH antenna for narrow band = 4 2.1.1 Single element structure = 4 2.1.2 4-channel antenna array = 7 2.1.3 Mutual coupling suppression using parasitic elements = 9 2.2 2-CH antenna for broad band = 18 2.2.1 Mutual coupling suppression using reversed 'U' structure = 18 2.3 Summary = 29 Chapter 3. 2-CH MIMO antenna for WiBro handy terminal = 32 3.1 WiBro system = 32 3.2 Design configuration of 2-channel MIMO antenna = 33 3.2.1 Antenna configuration and evaluation of the and the factors = 33 3.2.2 Experimental results of the fabricated antenna = 38 3.3 Summary = 46 Chapter 4. A monopole antenna with a novel impedance matching structure = 48 4.1 Characteristics of small antennas = 48 4.2 Antenna design procedure = 50 4.2.1 1/8 λ Folded monopole antenna characteristic = 50 4.2.2 A novel design for impedance matching = 51 4.2.3 Experimental results and discussion = 58 4.3 Summary = 60 Chapter 5. Conclusion = 61 References = 63 Publications and Conference = 66 Acknowledgment = 6

Bandwidth-Constrained Capacity Bounds and Degrees of Freedom for MIMO Antennas

The optimal spectral efficiency and number of independent channels for MIMO antennas in isotropic multipath channels are investigated when bandwidth requirements are placed on the antenna. By posing the problem as a convex optimization problem restricted by the port Q-factor a semi-analytical expression is formed for its solution. The antennas are simulated by method of moments and the solution is formulated both for structures fed by discrete ports, as well as for design regions characterized by an equivalent current. It is shown that the solution is solely dependent on the eigenvalues of the so-called energy modes of the antenna. The magnitude of these eigenvalues is analyzed for a linear dipole array as well as a plate with embedded antenna regions. The energy modes are also compared to the characteristic modes to validate characteristic modes as a design strategy for MIMO antennas. The antenna performance is illustrated through spectral efficiency over the Q-factor, a quantity that is connected to the capacity. It is proposed that the number of energy modes below a given Q-factor can be used to estimate the degrees of freedom for that Q-factor.Comment: 13 pages, 17 figure

Design of a Practical and Compact mm-Wave MIMO System with Optimized Capacity and Phased Arrays

In this paper we evaluate the feasibility of short range outdoor mm-wave MIMO links in the 70 GHz portion of the E-band (71–76 GHz). We use phased arrays in order to strongly reduce the impact of the multipath components, thus making the channel mainly line-of-sight (LOS). We design the array using a simple patch as a single element and simulate the performances for a 200 m link and a MIMO system with equal element spacing at the transmitter and the receiver. Each node of the MIMO system consists of a uniform rectangular array (URA) where the single element is a patch antenna, in order to achieve higher gains and narrow beams. Such configuration is much more compact compared to the antennas currently employed for the same bandwidth. We optimize the interelement distances at the transmitter and the receiver and evaluate the capacity achievable with different array sizes. The results show that, for the proposed link budget, capacity up to 29 bit/s/Hz is achievable at a range of 200 m, with practical dimensions. We also show that the beamforming capabilities make the design much more flexible than the single reflector antenna systems. In the last part of the paper, we verify that our antenna can also operate in rainy conditions and longer ranges

Dual-Band Ten-Element MIMO Array Based on Dual-Mode IFAs for 5G Terminal Applications

A dual-band ten-element MIMO array based on dual-mode inverted-F antennas (IFAs) for 5G terminal applications is presented in this paper. The proposed dual-mode IFA is composed of two radiators, which are etched on the outer and inner surfaces of the side-edge frame. The outer part of the antenna generates the low-order mode at 3.5 GHz, while the inner part radiates another one-quarter-wavelength mode at 4.9 GHz. In this way, the IFA can achieve dual-band operation within a compact size of 10.6 × 5.3 × 0.8 mm 3 . Based on the proposed antenna, a dual-band ten-element multiple-input and multiple-output (MIMO) array is developed for 5G terminal applications. By combining neutralization line structures with decoupling branches, the isolations between the elements are improved. To validate the design concept, a prototype of the ten-element MIMO array is designed, fabricated, and measured. The experimental results show that the proposed antenna can cover the 3.3-3.6 GHz and 4.8-5.0 GHz bands with good isolation and high efficiency. Furthermore, the envelope correlation coefficient (ECC), and channel capacity are also calculated to verify the MIMO performances for 5G sub-6GHz applications