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This paper describes the development of a Fractal printed Yagi-Uda antenna for wireless local area network (WLAN) applications operating at 2.4 GHz frequency. In miniaturizing the dimensions of an antenna, fractal method is applied where the first iteration and second iteration is implemented. The Computer Simulation Technology (CST) software is used as the platform to design and simulate the antenna. The substrate material used is the FR-4 board which has a dielectric constant of 5.4, the thickness of 1.6 mm and tangent loss of 0.019. The antenna performance interm of the reflection coefficient, radiation pattern and gain are compared and analyzed. For the first iteration, 22.81% of reduction size has been achieved and 30.81% reduction of the antenna size for second iteration has been achieved. [ABSTRACT FROM AUTHOR]

A single layered metamaterial structure with capabilities of switching from a wideband metamaterial absorber to an AMC reflector and vice versa is presented in this paper. A flame retardant 4 substrate with physical thickness of 1.60mm was used. The absorption rate, reflection rate, reflection phase and surface current distribution were studied and discussed. The operational incidental wave angles were varied from 0° to 65°. A peak reflection of about 90% was achieved at 11.20 GHz with a usable bandwidth (-90 to +90) of 3.01 GHz by the AMC reflector. The metamaterial absorber demonstrated a wideband performance (from 8.10 GHz to 14.30 GHz). It achieved 100% absorption at 11.20 GHz and not less than 65% absorption across the entire X-band frequencies except for incidental wave angles above 55°. [ABSTRACT FROM AUTHOR]

This paper proposes a flexible compact bowtie antenna for medical application that operates at 2.45 GHz. The proposed antennas are miniaturized using meander technique. Both substrates and conducting material of the antenna are made of flexible material semi-transparent film as the substrate and shieldit fabric as the conducting material which suitable for wearable and on body application. The results show that the total length of the antenna is significantly reduced by up to 38%. However, the gain of the antenna is slightly decreased when the size of the antenna become smaller. The results of this research could provide guidance and has significant implication for future development of wearable electronics especially in medical monitoring application. [ABSTRACT FROM AUTHOR]

A robust and low-profile electromagnetic band-gap (EBG) based on flexible wearable antenna covering 2.4 GHz frequency band is presented. The incorporated EBG with antenna reduces the radiation into the human body around 17 dB and decreases the impacts of frequency detuning. The overall dimension of the antenna integrated with EBG is 56 x 56 x 4 mm3 with relative impedance bandwidth of 8.3% is achieved. The proposed design has improved the gain up to 7 dBi. Specific absorption rate (SAR) assessment is also studied to certify the performance of the antenna when it is located proximity to human tissue. The flexible antenna with aforementioned performances could be chosen as a good candidate for integration into a range of wearable devices for medical application. [ABSTRACT FROM AUTHOR]

In this paper, a mutual coupling study 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 cell 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 corresponds 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. [ABSTRACT FROM AUTHOR]