Polarization reconfigurable antennas for space limited multiple input multiple output system

Wireless communication undergoes rapid changes in recent years. More and more people are using modern communication services, thus increasing the need for higher capacity in transmission. One of the methods that is able to meet the demands is the use of multiple antennas at both link ends known as Multiple Input Multiple Output (MIMO) system. However, for the space limited MIMO system, it is relatively difficult to accomplish good performance by using conventional antennas. Therefore, to further improve the performance offered by MIMO, Polarization Reconfigurable Antennas (PRAs) can be adopted. The diversity in polarization can be exploited to increase channel capacity. Moreover, the use of PRAs can also provide savings in terms of space and cost by arranging orthogonal polarized together instead of two physically space separation antennas. Here, single and dual port PRAs are proposed. Two techniques are deployed to achieve the PRAs are slits perturbation (switches on the radiating patch) and alteration of the feeding network (switches on the ground plane). Switching mechanism (ideal and PIN diode) is introduced to reconfigure the polarization between left-hand circular polarizations, right-hand circular polarizations, or linear polarization, operating at wireless local area network frequency band (2.4 – 2.5 GHz). Furthermore, by exploiting the odd and even mode of the coplanar waveguide structure, dual ports PRAs are realized with the ability to produce orthogonal linear polarization (LP) and circular polarization (CP) modes simultaneously. Good measured port polarization isolations (S21) of -16.3 dB and -19 dB are obtained at the frequency of 2.45 GHz for configuration A1 (orthogonal LP) and A2 (orthogonal CP), respectively. The proposed PRAs are tested in 2 x 2 MIMO indoor environments to validate their performances by using scalar power correlation method when applied as receiver in both line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios. Channel capacity improvement has been achieved for spatial diversity (92.9% for LOS and 185.9% for NLOS) and polarization diversity (40.7% for LOS and 57.9% for NLOS). The proposed antenna is highly potential to be adopted to enhance the performance of the MIMO system, especially in dealing with multipath environment and space limited applications

Energy efficient anti-collision algorithm for the RFID networks

Energy efficiency is crucial for radio frequency identification (RFID) systems as the readers are often battery operated. The main source of the energy wastage is the collision which happens when tags access the communication medium at the same time. Thus, an efficient anti-collision protocol could minimize the energy wastage and prolong the lifetime of the RFID systems. In this regard, EPCGlobal-Class1-Generation2 (EPC-C1G2) protocol is currently being used in the commercial RFID readers to provide fast tag identification through efficient collision arbitration using the Q algorithm. However, this protocol requires a lot of control message overheads for its operation. Thus, a reinforcement learning based anti-collision protocol (RL-DFSA) is proposed to provide better time system efficiency while being energy efficient through the minimization of control message overheads. The proposed RL-DFSA was evaluated through extensive simulations and compared with the variants of EPC-Class 1 Generation 2 algorithms that are currently being used in the commercial readers. The results show conclusively that the proposed RL-DFSA performs identically to the very efficient EPC-C1G2 protocol in terms of time system efficiency but readily outperforms the compared protocol in the number of control message overhead required for the operation

Radiation pattern reconfigurable fm antenna

In this work, a radiation pattern reconfigurable antenna design using compact printed spiral monopoles that operates at 102 MHz is reported. The proposed antenna changes its radiation behaviour that responds towards a desired direction with the use of RF switches. The antenna is printed on a 76.6mm × 50mm PCB layer providing more than 20MHz bandwidth at -10 dB threshold and is easily fabricated with low manufacturing cost. The antenna was also simulated on 500mm × 500mm ground plane that represents the roof top of a vehicl

A Compact Antenna Design for Fifth Generation Wireless Communication System

This paper proposes a compact antenna design for wireless communication system that can operate at dual band frequencies which are 24.25 GHz and 38 GHz. The antenna with an overall size of 6.3 mm X 6.0 mm is printed on RogersRT5880 type of substrate with a thickness of 0.787 mm. The simulated reflection coefficient result is < -10 dB for both frequencies which makes it suitable for 5G applications. The proposed antenna has a stable gain value of 7.23 dBi at 24.25 GHz and 3.69 dBi at 38 GHz. All the simulation result was performed by using CST Microwave Studio Software. The result shows the feasibility of this antenna to be applied for future 5G application. © The Authors, published by EDP Sciences, 2017

An electronically reconfigurable patch antenna design for polarization diversity with fixed resonant frequency

In this paper, an electronically polarization re-configurable circular patch antenna, with fixed resonantfrequency and operating at Wireless Local Area Network(WLAN) frequency band (2.4–2.48 GHz,) is presented. Thestructure of the proposed design consists of a circularpatch as a radiating element fed by a coaxial probe, coop-erated with four equal-length slits etched on the edge alongthe x-axis and y-axis. A total of four switches were usedand embedded across the slits at specific locations, thuscontrolling the length of the slits. By activating and deacti-vating the switches (ON and OFF) across the slits, the cur-rent on the patch is changed, thus modifying the electricfield and polarization of the antenna. Consequently, thepolarization excited by the proposed antenna can beswitched into three types; linear polarization, left-handcircular polarization or right-hand circular polarization.This paper proposes a simple approach that enablesswitching the polarizations and excites at the same oper-ating frequency. Simulated and measured results of theideal case (using copper strip switches) and the real case(using PIN diode switches) are compared and presented todemonstrate the performance of the antenna

Performance verification on UWB antennas for breast cancer detection

Breast cancer is a common disease among women and death figure is continuing to increase. Early breast cancer detection is very important. Ultra wide-band (UWB) is the promising candidate for short communication applications. This paper presents the performance of different types of UWB antennas for breast cancer detection. Two types of antennas are used i.e: UWB pyramidal antenna and UWB horn antenna. These antennas are used to transmit and receive the UWB signal. The collected signals are fed into developed neural network module to measure the performance efficiency of each antenna. The average detection efficiency is 88.46% and 87.55% for UWB pyramidal antenna and UWB horn antenna respectively. These antennas can be used to detect breast cancer in the early stage and save precious lives

Energy efficient routing protocols for wireless sensor networks: comparison and future directions

Wireless sensor network consists of nodes with limited resources. Hence, it is important to design protocols or algorithms which increases energy efficiency in order to improve the network lifetime. In this paper, techniques used in the network layer (routing) of the internet protocol stack to achieve energy efficiency are reviewed. Usually, the routing protocols are classified into four main schemes: (1) Network Structure, (2) Communication Model, (3) Topology Based, and (4) Reliable Routing. In this work, only network structure based routing protocols are reviewed due to the page constraint. Besides, this type of protocols are much popular among the researchers since they are fairly simple to implement and produce good results as presented in this paper. Also, the pros and cons of each protocols are presented. Finally, the paper concludes with possible further research directions

Energy efficient routing protocols for wireless sensor networks: comparison and future directions

Wireless sensor network consists of nodes with limited resources. Hence, it is important to design protocols or algorithms which increases energy efficiency in order to improve the network lifetime. In this paper, techniques used in the network layer (routing) of the internet protocol stack to achieve energy efficiency are reviewed. Usually, the routing protocols are classified into four main schemes: (1) Network Structure, (2) Communication Model, (3) Topology Based, and (4) Reliable Routing. In this work, only network structure based routing protocols are reviewed due to the page constraint. Besides, this type of protocols are much popular among the researchers since they are fairly simple to implement and produce good results as presented in this paper. Also, the pros and cons of each protocols are presented. Finally, the paper concludes with possible further research directions

Higher-Order-Mode Triple Band Circularly Polarized Rectangular Dielectric Resonator Antenna

The paper presents a triband circular polarized rectangular dielectric resonator antenna. A single coaxial cable feeds the DRA to a double stub strip on the DRA side. A patch strip coupled to the feed assists in widening the bandwidth of the proposed DRA. The degenerate mode pair TE∂11x and higher-TE∂23x has been excited to achieve CP and enhance the antenna gain. The higher-order mode has been excited using a low-cost simple excitation mechanism without compromising on the size and shape of the DRA. An impedance bandwidth of 48% with a gain ~6–9 dBic was achieved in all resonance frequencies. Additionally, the AR bandwidth of 5.5%, 4.2%, and 2.76% was obtained at three different frequencies. Note that the proposed DRA exhibits a wide beamwidth of 112o, which is good for better signal reception. A comparison between the measured with simulated results shows that the measured results are matched by the simulated result trends

Key success factors for team integration practice in Malaysian industrialised building system (IBS) construction industry

Industrialised Building System (IBS) has been recognized as synonymous with industrialisation of the construction industry .In Malaysia, the domination of traditional method in IBS project has gained much attention not only from researchers but also construction industry practitioners as the implementation of IBS through traditional approach almoat always led to the rise of construction problems such as increasing project time and cost, redesigning, ineffective supply chain, and others.Fragmentation process in traditional method is not a line with the concept of IBS which is required a high communication and collaboration among the project stakeholders. This study took closer look at current practice of IBS projects in Malaysia, at the need for an integration approach, and at the availability of integrated approaches in IBS projects with the objective of identifying critical success factors for integrated teams in IBS construction projects. The findings from the Focus Group Discussion (FGD) among construction industry stakeholders revealed the main barriers to the IBS adoption in Malaysia’s construction industry to be poor integration among project stakeholders during the planning and design phase.This was due to the domination of the fragmentation concept of the traditional method