Design Of Compact Tri-Polarized Antenna For Multiple Input Multiple Output (MIMO) System

In recent years, wireless communication system such as radar, navigation system, video conferencing, medical application and others has been widely developed. In order to meet the miniaturization requirements of portable communication equipment, an antenna with compact size has received much attention. Regardless of the application, most of the modern wireless communication systems require high data rate and channel capacity. With these provocations, Multiple Input Multiple Output (MIMO) system was introduced to provide efficient performance and combat multipath effect. The objective of this project was to design, simulate, and fabricate a compact tri-polarized antenna for MIMO system with operating frequency of 2.4GHz. In this project, antennas were designed by using inverted suspended method where the FR4 substrate and copper ground plane were separated with an air gap layer. Modified L-probe fed was used for all antenna designs where the strip line was printed on the upper side of the FR4 substrate and connected to the coaxial probe for ease of fabrication. The rectangular patch was printed at the lower side of the FR4 substrate. First of all, single polarizations for linear polarized (Design A) and circular polarized antennas (Design B) were designed. Then, dual-polarized antennas (Design C) were designed. Lastly, a compact tri-polarized antenna (Design D) was designed with a combination of three different polarizations; including linear polarization(LP), left-handed circular polarization (LHCP) and right-handed circular polarization(RHCP). All the antenna designs were simulated by using Computer Simulation Technology (CST) software. Single-polarized antenna, dual-polarized antenna and tripolarized antenna were successfully designed and achieved design specifications. Based on the simulation and measurement results, the designed antennas covered frequency of 2.4GHz with reflection coefficient below -10dB. The simulated bandwidths of the designed antenna were more than 200MHz for the broadband specification. The simulated axial ratio result was used to determine the performance of polarizations, in which the axial ratio for linear polarized was above 3dB and the axial ratio for circular polarized was below 3dB. Overall, the reflection coefficient, total efficiency, directivity, gain, axial ratio, and bandwidth of compact tri-polarized antenna showed good responses. The measurement results were almost similar to the simulation results. Therefore, this compact broadband tripolarized antenna that is capable of performing in three different polarizations is suitable to be applied in MIMO system that requires polarization diversity

The Effect of Quarter-Wave Transformer Matching Network to the X-Circular Polarized Antenna

This technical paper presents the 2 design of xcircular polarized with slanted rectangular slot microstrip patch antenna by using single port in X-form is at 45 0 , 135 0 , 225 0 and 315 0 . The combination of 4 circular patches of Design 1 and the additional of quarter wave impedance matching technique for Design 2 have been used to design the X-circular polarized with slanted rectangular slot microstrip patch antenna. The designs are simulated using Computer Simulation Technology (CST) with dielectric constant, εr =4.3 and tan δ=0.019 and thickness of substrate, t=1.6mm. The simulation results such as return loss, bandwidth, gain, directivity and polarization have been compare

Reconfigurable Monopole Antennas With Circular Polarization

This thesis presents research on printed circularly-polarized monopole antennas and their application in reconfigurable monopole antennas. The proposed circularly-polarised monopole antennas benefit from advantages such as small size, low-cost, low-profile and simple designs. The first part of this thesis introduces three printed circularly-polarized monopole antennas for global navigation satellite systems and Wi-Fi applications. The primary focus is on the ground plane which is used as a radiating component in realizing circular-polarization. It is shown that by employing the ground plane as a radiator results in a wide axial ratio bandwidth. The radiation patterns of the antennas and their relationship with antenna ground plane sizes is investigated. Then, a frequency-reconfigurable monopole antenna with circular-polarization for wireless local area networks and global navigation satellite systems is presented. The ground plane current distribution, rearranged by a switch, enables the right-hand circularly-polarized band to move in frequency from the GPS band to Wi-Fi frequency bands. Finally, a simple polarization reconfigurable printed monopole antenna for wireless applications is described. Once again, with the help of the ground plane and by changing its current distribution, linear-polarization, right-hand or left-hand circular-polarization is realized. The polarization agility is controlled by two PIN diodes, which alter the ground plane surface currents. The antenna is one of the few polarization-reconfigurable monopole antennas reported in the literature. For all the presented antennas, parametric studies of key geometric parameters are given for clear understanding of the circular-polarization radiation mechanism

A Dual Slant-Polarized Cylindrical Array of Tightly Coupled Dipole Antennas

This study proposes a design of a low-profile ultra wide-band cylindrical antenna array with plus/minus 45-degree dual polarization. The proposed compact cylindrical antenna array produces an omnidirectional radiation pattern in the azimuth plane to cover all directions. It consists of 20×4 dual-polarized elements within a diameter of 131 mm and a height of 116 mm. The array elements are tightly coupled slant-polarized wideband dipole antennas, and hence, rotational symmetry of radiation patterns in the horizontal plane is achieved for the two orthogonal polarizations. Furthermore, a metasurface structure has been designed and placed over the interconnected array elements to achieve ultrawideband capabilities. The proposed array provides less than −10 dB reflection coefficient over a frequency band between 1.7 GHz and 5.9 GHz. The cross-polarization discrimination (XPD) is 15 dB at boresight in the azimuth plane. The electromagnetic characteristics of the cylindrical array and its corresponding planar array before bending have been evaluated and compared via simulations, and verified by measurements. The compact size, lightweight, and printable design of the proposed antenna array enable low-cost manufacturing and ease of installation. The proposed array design overcomes many challenges encountered in wide-band MIMO systems by covering the entire sub-6 GHz band while providing wide 360-degree coverage in the azimuth plane, hence, supporting multibeam applications

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

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

Genetic algorithm optimization applied to planar and wire antennas

Antenna design has grown more stringent and difficult over the years as the world becomes strictly a wireless environment. The inherent tradeoffs that exist between gain, radiation pattern, bandwidth, and physical size and the multiple parameters that must be considered make antenna design a lengthy and tedious process. Methods have been devised which automate this complex process of antenna optimization through the use of genetic algorithms, particle swarm optimization, and simulated annealing. Genetic algorithms are capable of handling a large number of design parameters and work for optimization problems that have discontinuous or non-differentiable multi-dimensional solution spaces, making them ideal for antenna optimization. In the present work, a genetic algorithm has been used for size reduction in microstrip patch antennas and design tradeoff optimization between beamwidth and gain in helical antennas. A method for reducing the size of microstrip patch antennas by up to 75% by removing rectangular and circular slots from the metal of the microstrip patch is presented. A solid patch antenna that resonates at 10 GHz is forced to resonant at 6 GHz through the removal of the different shaped slots. Given the number and shape of the slots, the genetic algorithm is used to optimize the size and location of the slot on the patch. The designs are obtained by interfacing the genetic algorithm and Ansoft High Frequency System Simulator (HFSS) and validated through design, construction, and testing. High gain, with broad half-power beamwidths (HPBW) is traditionally extremely difficult to achieve due to the inherent tradeoff between the two. A genetic algorithm has been applied to design a helical antenna with a gain of 10 dB and HPBWs of 60 degrees. In order to achieve this, three physical parameters of the helix have been changed, namely the pitch, helix radius, and the ground plane geometry. The second objective is to create an antenna that displays different HPBWs in the two radiation planes. This could be extremely useful in many communication environments and there is yet no existing method to achieve this. The genetic algorithm produced a helical antenna that shows a 19 degrees difference in HPBW between the two radiation planes, while still displaying a 7 dB gain and low side lobes. Numerical Electromagnetic Code 4 (NEC4) is used, and a method of communication between MATLAB and NEC4 has been developed to make the genetic algorithm optimization possible

A new compact printed antenna structure for multiple wideband applications

This paper presents the design of a new compact antenna structure for multiple incorporating operation service. The proposed antenna is suitable to operate at three different frequency bands, (1.77GHz-2.67GHz), (3.1GHz- 4.58GHz), and (5.5GHz-6.5GHz) with a return loss less than -10dB. The antenna structure includes a CPW fed line, the technique used to enlarge the frequency bands is the slots technique and in the same time we have developed a new antenna structure which operates in various wireless communication applications. The antenna parameters have been investigated and optimized by using CST Microwave Studio. To validate the CST Microwave Studio results before the antenna achievement, we have conducted another study by using ADS. The final circuit was achieved, measured and validated. Experimental results show that the proposed antenna with compact size of 42*32.7 mm2 has good radiation characteristics and operating in specific microwave applications ISM band, WLAN, WIFI, WIMAX and RFID