Raimi Dewan

The improvement of array antenna performance with the implementation of an artificial magnetic conductor (amc) ground plane and in-phase superstrate

This paper discusses performance improvement with the integration of an artiflcial magnetic conductor (AMC) into array antennas. An AMC with defected ground structure (DGS) was designed to construct the AMC ground plane and in-phase superstrate. The two distinguishable structures were integrated into an array antenna, which serves as a reference antenna at 5.8GHz. The impedance bandwidth (BW) of the reference antenna signiflcantly improved to 287% when integrated with an AMC ground plane and with 37% reduced size. On the other hand, the integration of in- phase superstrate efiectively enhances the gain and BW of the reference antenna by 1dBi and 44%, respectively. The efiects of air gaps on the reference antenna with both the AMC ground plane and in- phase superstrate are discussed. The antenna performance factors, such as return loss and radiation pattern, are also discussed for the reference antenna, the reference antenna with the AMC ground plane, and the reference antenna with in-phase superstrate, respectively. There is satisfactorily good agreement between the simulation and measurement results. The proposed antenna is useful in WLAN (5.15{5.35GHz and 5.725{5.825GHz) and WiMAX (5.725{5.825GHz) applications.

X-Polarization array antenna with parallel feeding for WiMAX 3.55 GHz application

An X-Polarization array microstrip patch antenna for WiMAX application is introduced in this paper. The array antenna operates at WiMAX frequency of 3.55 GHz. The substrate used is FR-4 with the thickness of 1.6 mm, relative permittivity of 4.5 and loss tangent of 0.019. The antenna use parallel feeding network to feed all the eight elements with coaxial port. The array has gain of 6 dBi, and directivity 8.754 dBi. The array antenna only requires single input port unlike conventional X-Polarization array antenna that uses multiple input port application. Parametric study of cross angle to antenna performance is studied which have not been discussed in the past research and coupling between the elements in the array is presented.

Design of dual-band B-shaped monopole antenna for MIMO application

A dual-band B-shaped monopole antenna for MIMO application is presented. The proposed antenna consists of B-shaped element which operates at dual band frequencies of 2.45GHz and 5.8GHz. The prototype has been fabricated and when tested, the impedance bandwidths are 29.9% and 33.8% for 2.45GHz and 5.8GHz, respectively. Good agreement between the measurement and simulation results in term of return loss and radiation pattern have been obtained.

Reconfigurable wideband and narrowband tapered slot Vivaldi antenna with ring slot pairs

A tapered slot Vivaldi antenna with reconfigurable capability is proposed in this paper. The tapered slot length was implemented on ring slot pairs to generate narrowband multiples at 1.5, 3.24, 3.44, and 4.12 GHz. Studies on the assignment of tapered slot length to ring slot pairs on Vivaldi antennas are presented and discussed. The combination of a tapered slot Vivaldi antenna, tapered slot length, and ring slots pairs successfully produces a tunable tapered slot Vivaldi antenna that is able to operate in wideband and narrowband, allowing for wireless communication. The wideband of the proposed antenna is from 1.5 to 5 GHZ. The study is also extended to the filtering effect tapered slot length on the ring slot pair. The proposed antenna performs well in terms of radiation pattern, return loss, and gain. The measurement results of the antenna’s performance satisfactorily agree with the simulation ones.

Triple band circular ring-shaped metamaterial absorber for x-band applications

This paper presents the design, fabrication, and measurement of triple band metamaterial absorber at 8GHz, 10GHz and 12GHz which are in the X-band frequency range. The unit cell of the metamaterial consists of three concentric copper rings at difierent radii, printed on 0.8mm thick FR4 substrate in order to obtain triple resonant frequencies. The highly symmetrical ring structure in nature makes this absorber insensitive to any polarization state of incident electromagnetic (EM) waves for normal incident waves. The proposed structure is capable to operate at wide variations angle of incident wave. The simulated result shows that the triple-band metamaterial absorber achieves high absorbance for normal incident electromagnetic waves of 97.33%, 91.84% and 90.08% at 8GHz, 10GHz and 12GHz, respectively, when subjected to normal incident electromagnetic. With metamaterial absorber maintaining 50% of absorbance value, the corresponding full width half maximum (FWHM) are 5.61%, 2.90% and 2.33%. The operating angles in which the metamaterial structure can maintain 50% absorbance at TE mode and TM mode are 67 - and 64 - , respectively. The experimental result verifles that the absorber is well performed at three difierent resonant frequencies with absorbance greater than 80%.

Design of triple band Artificial Magnetic Conductor

This paper presents a design of Artificial Magnetic Conductor (AMC). The AMC operates in three operating frequencies which are 2.3 GHz, 5.8 GHz and 8.36 GHz with the bandwidth of 5.64 %, 1.73% and 3.58 % respectively. The size of AMC unit cells is relatively smaller compare to previous researches that have been done. Parametric results for the reflection phase diagram are also presented.

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.

Chipless RFID tag based on meandered line resonator

A meandered microstrip transmission line resonator is proposed for the design of chip-less RFID tag. The 6 bit resonator is operates from 3 to 5 GHz. The tag consists of a micro strip open stub resonators and two Ultra-wide Band (UWB) monopole antennas. The 30 mm × 35 mm chip-less RFID tag is designed on Taconic substrate with permittivity of 2.75. The modification technique from the straight line of micro strip open stub toward meandered line is introduced.

Reduced-size witricity charger design and its parametric study

Wireless electricity (Witricity) application is recently gaining interest owing to its effectiveness and reliability in mid-range wireless power transfer (WPT). This paper presents a parametric study on Witricity design in order to achieve a good coupling efficiency in term of S21 at the targeted frequency. The dimension of the design is 80 mm × 80 mm, which offer 75% size reduction compared to previous design of 161 mm × 161 mm. The results show that it is possible to compute the resonance frequency by varying the thickness of the substrate, dimension of the capacitors and the number of turns at transmitter and receiver side.

Improved design of tapering and through element series antenna

In this paper, an array of series fed antenna based on tapering patch width and through element is presented. The antenna has wide impedance bandwidth of 16.18% covering from 5.34 GHz to 6.28 GHz with a gain of 6.53 dBi. The use of through element technique reduces the overall length of array structure by 25.47%. It also has lower side lobe level, and wider impedance bandwidth compared to the past research.