Norbahiah Misran

Compact Tapered-Shape Slot Antenna for UWB Applications

A compact microstrip line-fed ultrawideband (UWB) tapered-shape slot antenna is presented. The proposed antenna comprises a tapered-shape slot and rectangular tuning stub. The antenna is fabricated onto an inexpensive FR4 substrate with an overall dimension of 22 × 24 mm2. The experiment shows that the proposed antenna achieves good impedance matching constant gain, stable radiation patterns over an operating bandwidth of 3-11.2 GHz (115.5%) that covers the entire UWB. The nearly stable radiation pattern with a maximum gain of 5.4 dBi makes the proposed antenna suitable for being used in UWB communication applications.

BROADBAND E-H SHAPED MICROSTRIP PATCH ANTENNA FOR WIRELESS SYSTEMS

A broadband inverted E-H shaped microstrip patch antenna is proposed and experimentally investigated. The antenna employs novel E-H shaped patch with L-probe feed technique. Prototype of the proposed antenna has been fabricated and measured for electromagnetic analysis including the impedance bandwidth, radiation pattern, and antenna gain. The designed antenna has a dimension of 80mm by 50mm, leading to broad bandwidths covering 1.76GHz to 2.38GHz. Stable radiation patterns across the operating bandwidth are observed. In addition, a parametric study is conducted to facilitate the design and optimization process.

CIRCULAR MICROSTRIP SLOT ANTENNA FOR DUAL- FREQUENCY RFID APPLICATION

A compact wideband dual-frequency microstrip antenna is proposed in this paper. By employing an ofiset microstrip-fed line and a strip close to the radiating edges in the circular slot patch, an antenna operating at dual frequency with the impedance bandwidth of 26.2% and 22.2% respectively is presented. By attaching a strip to the radiating edges opposite to the microstrip-fed line, this alters the current distribution and radiation on the antenna at the second resonant frequency. The second frequency is also tunable by varying the lengths of the microstrip-fed line. It is demonstrated that the proposed antenna covers the widebands of UHF and microwave for RFID application. A good agreement is obtained between the simulated and experimental results.

DESIGN ANALYSIS OF HIGH GAIN WIDEBAND L-PROBE FED MICROSTRIP PATCH ANTENNA

A new high gain wideband L-probe fed inverted EE-H shaped slotted (LEE-H) microstrip patch antenna is presented in this paper. The design adopts contemporary techniques; L-probe feeding, inverted patch structure with air-fllled dielectric, and EE-H shaped patch. The integration of these techniques leads to a new patch antenna with a low proflle as well as useful operational features, as the broadband and high gain. The measured result showed satisfactory performance with achievable impedance bandwidth of 21.15% at 10dB return loss (VSWR • 2) and a maximum gain of 9.5dBi. The antenna exhibits stable radiation pattern in the entire operating band.

A Novel High-Gain Dual-Band Antenna for RFID Reader Applications

A novel high-gain dual-band antenna for radio frequency identification (RFID) reader applications covering free ISM bands of 2.45 and 5.8 GHz is presented in this letter. The antenna is composed of a U-shaped copper strip with unequal arm, a printed rectangular ring, and the ground plane. A good impedance bandwidth of 120 MHz has been achieved from 2.37 to 2.49 GHz for the lower band, while the upper band covers 420 MHz (from 5.55 to 5.97 GHz). The U-shaped feeding strip excites the rectangular ring effectively by providing a good impedance matching with over 85% of total antenna efficiency in both the frequency bands and also 9.56 and 10.17 dBi gain in the lower and higher frequency band, respectively.

DESIGN ANALYSIS OF FERRITE SHEET ATTACHMENT FOR SAR REDUCTION IN HUMAN HEAD

In this paper, reducing Speciflc Absorption Rate (SAR) with ferrite sheet attachment is investigated. The flnite-difierence time-domain method with Lossy-Drude model is adopted in this study. The methodology of SAR reduction is addressed and then the efiects of attaching location, distance, size and material properties of ferrite sheet on the SAR reduction are investigated. Computational results show that the SAR averaging over 10gm was better than that for 1gm and SAR reduction of 57.75% is achieved for SAR 10gm. These results show the way to choose a ferrite sheet with the maximum SAR reducing efiect for phone model.

Multi-slotted microstrip patch antenna for wireless communication

A new design technique of microstrip patch antenna is presented in this paper. The proposed antenna design consists of inverted patch structure with air-fllled dielectric, direct coaxial probe feed technique and the novel slotted shaped patch. The composite efiect of integrating these techniques and by introducing the new multi- slotted patch, ofier a low proflle, high gain, broadband, and compact antenna element. A wide impedance bandwidth of 27.62% at i10dB return loss is achieved. The maximum achievable gain is 9.41dBi. The achievable experimental 3-dB beamwidth (HPBW) in the azimuth and elevation are 60.88 - and 39 - respectively at centre frequency.

DESIGN ANALYSIS OF NEW METAMATERIAL FOR EM ABSORPTION REDUCTION

A new triangular metamaterials (TMMs) is designed for electromagnetic (EM) absorption reduction at microwave frequencies in this paper. The reduction of EM absorption with a new TMMs attachment is investigated in this research. The flnite-difierence time-domain method with lossy-Drude model is adopted in this investigation. The method of EM reduction is presented and the efiects of position, distance, and size of metamaterials are analyzed. TMMs have achieved a 1.0923W/kg for SAR 1gm which is 45.44% reduction of the initial SAR value for the case of 1gm SAR.

A Novel Compact Split Ring Slotted Electromagnetic Bandgap Structure for Microstrip Patch Antenna Performance Enhancement

A novel design of an electromagnetic bandgap (EBG) structure based on the uniplanar compact EBG (UCEBG) concept is proposed in this paper. The structure is realized by inserting split- ring slots inside two reversely connected rectangular patches, which is known as a split-ring slotted electromagnetic bandgap (SRS-EBG) structure. The bandgap properties of the EBG structure are examined by the suspended microstrip line and flnite element methods (FEM). The achieved bandgaps have widths of 4.3 (59.31%) and 5.16GHz (38.88%), which are centered at 7 and 13GHz, respectively. The SRS-EBG is applied to enhance the performance of a single-element microstrip patch antenna (at 7GHz) and a two-element array (at 13GHz) conflguration. A wider bandwidth is obtained with a better re∞ection coe-cient level for the single element antenna; a reduction in mutual coupling of more than 20.57dB is obtained for the array design. In both cases, the gain and radiation characteristics are improved. The results are verifled by measuring the fabricated lab prototype, and a comparison with the computed results showed good agreement.

Analysis of Electromagnetic Absorption in Mobile Phones Using Metamaterials

Abstract The reducing specific absorption rate with metamaterials attachment is investigated in this article. The finite-difference time-domain method with a lossy-Drude model is adopted in this analysis. The technique of specific absorption rate reduction is discussed, and the effects of attaching location, distance, and size of metamaterials, perfect electric conductor, and materials on the specific absorption rate reduction are investigated. Metamaterials have achieved a 42.12% reduction of the initial specific absorption rate value for the case of 1 gm specific absorption rate and 53.94% reduction for the cases of 10 gm specific absorption rate. These results suggest a guideline to choose various types of metamaterials with the maximum specific absorption rate reducing effect for a phone model.