Mutual Coupling Reduction in Antenna Using EBG on Double Substrate

In this paper, a mutual coupling studies is conducted between two-element array antenna on dual substrate. A single patch antenna is firstly designed on dual substrate layer to testify appropriate performance at 2.45 GHz. Subsequently, an array of two element patches on dual substrate are constructed with one of them is incorporated with three EBG unit cell on the bottom substrate. The radiating patch is on the top substrate, while the EBG unit cells is on the bottom substrate. With EBGs in separate layers from the antenna array, the antenna elements are closely separated by a distance of 22 mm with a significant reduced mutual coupling of -26.61 dB. This correspond to a distance reduction of 34.68%. The proposed structure implemented only three EBG unit cells. Apart from that, the study of overlapped case of EBG with the antenna is also presented

High capacity and miniaturized flexible chipless RFID tag using modified complementary split ring resonator

This paper aims to produce a high data capacity and miniaturized flexible chipless RFID tag based on the frequency signature using the Modified Complementary Split Ring Resonator (MCSRR). The proposed 19 bits chipless RFID tag using the frequency shifting technique consists of five slotted overlaying MCSRR with Different Width (MCSRR with DW) structures and the dimension of 48 mm x 48 mm. The structure is designed by using a flexible (Polyethylene Terephthalate ) PET substrate with permittivity of 0.2. The operating frequency is between 0.9 GHz and 2.7 GHz. The advancement of slotted overlaying MCSRR with DW structures has successfully miniaturized the chipless RFID tag structure to about 107 mm2/ bit, 0.02/2 mid =bit and 0.09 GHz/bit by maximizing the number of resonators in a limited space and minimizing the frequency separation between the resonators. The omnidirectional tag antenna is incorporated with the proposed MCSRR structure using the retransmission measurement method. The log-periodic antenna with a gain of 5-7 dBi is used for this measurement to improve the range distance between tag and reader system. Based on the retransmission measurement involving the antenna tag, the 19 bits chipless RFID tag which consists of five MCSRR with DW structures can be detected with a maximum range distance of 30 cm and a power transmitted level of 30 dBm

Dual Band to Wideband Pentagon-shaped Patch Antenna with Frequency Reconfigurability using EBGs

A dual band to wideband reconfigurable pentagon-shaped antenna with EBG unit cell is proposed. A minimal number of two EBG unit cell is deployed to realize frequency reconfigurable mechanism.  By varying the state of the EBG the antenna is capable to change its dual band operation to wideband alternately. There are three cases that have been analysed, first case is the EBG incorporated antenna with ideal and second is with the active EBG. Subsequently, the third cases is the fabricated ideal EBG incorporated antenna. The dual band operation is at 1.8 GHz and 5.2 GHz while the wide band from 1.6 GHz to 2.37 GHz (770 MHz). The proposed reconfigurable antenna is suitable to be implemented for LTE (1.6 GHz), Wi-Fi (5.2 GHz), WiMAX (2.3 GHz) and cognitive radio application

Reconfigurable radiation pattern of planar antenna using metamaterial for 5G applications

In this research, a reconfigurable metamaterial (MM) structure was designed using a millimeter-wave (MMW) band with two configurations that exhibit di erent refractive indices. These two MM configurations are used to guide the antenna’s main beam in the desired direction in the 5th generation (5G) band of 28 GHz. The di erent refractive indices of the two MM configurations created phase change for the electromagnetic (EM) wave of the antenna, which deflected the main beam. A contiguous squares resonator (CSR) is proposed as an MM structure to operate at MMW band. The CSR is reconfigured using three switches to achieve two MM configurations with di erent refractive indices. The simulation results of the proposed antenna loaded by MM unit cells demonstrate that the radiation beam is deflected by angles of +30 an

Reconfigurable metamaterial structure for 5G beam tilting antenna applications

In this paper, we propose a metamaterial (MTM) structure with a reconfigurable property designed to operate at the millimetre-wave (mm-wave) spectrum. Four switches are used to achieve the reconfigurable property of the MTM with two configurations. These two configurations exhibit different refractive indices, which used to guide the radiation beam of the antenna to the desired direction. The proposed planar dipole antenna operates at the 5th generation (5G) band of 28 GHz. The electromagnetic (EM) rays of the proposed antenna pass through different MTM configurations with different phases, subsequently results in the tilting of the radiation beam toward MTM configuration of high refractive index. Simulated and measured results of the proposed antenna loaded by MTM demonstrate that the radiation beam is tilted by angles of +34° and −31° in the E-plane depending on the arrangement of two MTM configurations onto the antenna substrate. Furthermore, the gain is improved by 1.7 and 1.5 dB for positive and negative tilting angles, respectively. The reflection coefficients of the antenna with MTM are kept below −10 dB at 28 GHz

Dual band to wideband pentagon-shaped patch antenna with frequency reconfigurability using EBGs

A dual band to wideband reconfigurable pentagon-shaped antenna with EBG unit cell is proposed. A minimal number of two EBG unit cell is deployed to realize frequency reconfigurable mechanism. By varying the state of the EBG the antenna is capable to change its dual band operation to wideband alternately. There are three cases that have been analysed, first case is the EBG incorporated antenna with ideal and second is with the active EBG. Subsequently, the third cases is the fabricated ideal EBG incorporated antenna. The dual band operation is at 1.8 GHz and 5.2 GHz while the wide band from 1.6 GHz to 2.37 GHz (770 MHz). The proposed reconfigurable antenna is suitable to be implemented for LTE (1.6 GHz), Wi-Fi (5.2 GHz), WiMAX (2.3 GHz) and cognitive radio application

Wideband antenna with reconfigurable band notched using EBG structure

A wideband antenna with band notch function using electromagnetic bandgap (EBG) structure is proposed. The antenna is capable of reconfiguring up to three band notch operation. Three EBGs are aligned underneath the feed line of the wideband antenna. The transmission lines over EBGs unit cells perform as a band stop filter. A switch is placed on each of the EBG structure, which enables the reconfigurable band stop operation. The simulated and measured reflection coefficients, together with the radiation patterns, are shown to demonstrate the performance of the antenna

Integrated antenna array with artificial magnetic conductor for IEEE802.11A application

Microstrip antenna is a preferable choice for antenna due to low profile, low weight, ease of fabrication, inexpensive to manufacture, and adaptable to design at non planar and planar surfaces. However, the drawbacks of designing antenna using microstrip technology are low gain, narrow bandwidth, low efficiency and low power. Many research works were carried out to improve the performance of microstrip antenna. One of the techniques that increasingly attractive nowadays is the integration of metamaterial to microstrip antenna. Metamaterial is a material that not existed in nature and designed artificially. But, due to some useful characteristics of the material, metamaterial is designed as to mimic the non-naturally occurring material to improve performance of devices such as microstrip antenna. Metamaterial that is used in this research is Artificial Magnetic Conductor (AMC). AMC is designed to mimic the unique behaviour of Perfect Magnetic Conductor (PMC). PMC provides phase reflection properties in a limited frequency band. AMC acts as a modified ground plane and in-phase superstrate when positioned at the bottom substrate and top substrate of the antenna respectively. A technique of Defected Ground Structure is implemented in the AMC unit cell, enhancing its bandwidth up to 94%. An array of antenna is developed as the reference antenna at 5.8 GHz operating frequency. The array antenna is integrated with AMC ground plane and in-phase superstrate. An analysis was carried out on the performance improvement to array antenna made by the two distinguishable structures. The developed array antenna with AMC ground plane achieves bandwidth enhancement of 287% while improves efficiency up to 12%. On the other hand, the developed array antenna with in-phase superstrate successfully improves the bandwidth and efficiency of the antenna by 44% and 6%. Additionally, the integration of in-phase superstrate improves the directivity of the array antenna. It is discovered that the existence of air gap limits the gain of the array antenna with AMC ground plane. Furthermore, the air gap improves the gain of the array antenna with in-phase superstrat

Compact wide-band branch-line coupler with meander line, cross, and two-step stubs

Despite being widely used, branch-line couplers (BLC) still suffer from large size. This makes it difficult to incorporate BLC into miniature microwave devices. The work presented here is the design and implementation of a 3-dB reduced-size wide-band 3-branch-line coupler (3-BLC). By combining meander line, cross, and two-step stubs techniques, size reduction and bandwidth improvement is successfully achieved on 3-BLC design. The 3-BLC length was reduced along the horizontal branches using two-step reduction technique while the center vertical branch was reduced using cross stubs. A simple two-turn meander line is utilized at the two ends vertical branches of the coupler to obtain balanced length with the middle vertical branch. Hence, its width was optimized to maximize the coupler bandwidth. The 3-BLC was designed to operate at 2.45 GHz wireless local area network frequency band (IEEE 802.11 b/g) and fabricated on a 1.6 mm thick FR-4 board. The simulated and measured results are in very good agreement and show a fractional bandwidth of 50% and a sized reduction of 61.64% at the center of the frequency band. The proposed coupler design provides BLC that occupies less space, simple to implement, and wide-band BLC architecture with generic 3-BLC wide-band characteristics retained

The investigation of substrate's dielectric properties for improving the performance of witricity devices

In designing a better Witricy device, there are several parameters that contribute to the improvement of efficiency. In this article, the substrate characteristics, which gaining less attention despite their potential for the improvement of Witricity performance are thoroughly studied. The characteristics such permittivity and loss tangent that very common in microwave design are investigated. The investigation has proven that RO 3010 substrate composed of ceramic-filled Polytetrafluoroethylene (PTFE) composites is the best material for the optimal Witricity performance, independent of the spiral coil's number of turns. This is due to its high-energy storage capacity obtained from the real permittivity, and roughly low loss factor and tangent loss. Hence, the Rogers RO 3010 substrate is proposed in this study as it performs reliable 50% to 74% coupling efficiency with the varied number of spiral coil turns