M. F. Jamlos

A MIMO ANTENNA DESIGN CHALLENGES FOR UWB APPLICATION

This paper proposes a compact printed ultra-wideband (UWB) multiple-input-multiple-output (MIMO) antenna with a dimension of 38 £ 91mm 2 . The presented UWB-MIMO antenna comprises two identical patch elements with D separation distance on the same substrate. The basic single antenna structure has a novel design comprising seven circles surrounding a center circle with partial ground plane implementation. Furthermore, the experimental antenna has peak gain of 5.3dBi between an operating frequency of 2.8GHz and 8.0GHz under a minimum re∞ection coe-cient of less than i10dB (S11 < i10dB). Moreover, the antenna successfully achieved mutual coupling minimization of < i17dB, eventually resulting in enhancement of radiation e-ciency. Besides, the UWB- MIMOs correlation coe-cient was efiectively reduced to less than i22dB, which re∞ected an improvement in the antennas diversity. In this paper, the proposed antenna is examined both numerically and experimentally.

Reconfigurable Four-Parasitic-Elements Patch Antenna for High-Gain Beam Switching Application

A reconfigurable beamforming of a four-parasitic-elements patch antenna (FPPA) for WiMAX application is presented. The proposed FPPA is successfully capable to steer the radiation pattern in azimuth planes (0 ^°, 45 ^°, 135 ^°, 225 ^°, and 315 ^° angles) and in elevation plane (0 ^°, 13 ^°, 15 ^°, 10 ^°, and 12 ^°). This is realized in the unique form of four parasitic elements encircling the center main radiator. The activation of the parasitic required a shorting pin to the ground that indicates on state condition, and vice versa. It is discovered in CST simulation software that the specified location of the pins are really significant to ensure the parasitic performs either as a reflector or director. Moreover, each of the shorting pins is linked to the RF p-i-n diode BAR5002v switch. Also, the FPPA is fabricated on a 130-mm square Taconic substrate. The proposed antenna design has a maximum gain of 8.2 dBi at all desired angles with a half-power beamwidth of 58 ^°.

A novel 2.45 Ghz switchable beam textile antenna (SBTA) for outdoor wireless body area network (WBAN) applications

A novel switchable beam textile antenna (SBTA) for wireless body area network (WBAN) applications is proposed. The SBTA is centrally-fed by a coaxial probe and the power distributed over four circular radiating elements. Four RF switches are integrated through which the SBTA is able to generate beam steering in four directions: 0 - , 90 - , 180 - , and 270 - , with a maximum directivity of 6.8dBi at 0 - . Its small size (88mm £ 88mm) and ∞exibility enables the structure to be easily integrated into safety jackets, rain coats, etc., for tracking, and search and rescue communication purposes. The structure successfully integrates reconflgurability into a wearable textile antenna.

A Novel Compact Tree-Design Antenna (NCTA) with High Gain Enhancement for UWB Application

In this paper, a novel compact tree-design antenna (NCTA) for ultra-wideband (UWB) application with high gain and impedance matching improvement is analyzed and presented. The novel antenna is composed of a single centered circle connected to seven outer circles via three bridges with partial ground plane execution. Instead of functioning as filters, these seven circles play a major role in producing UWBs frequency resonant of 3.3 to 10.8 GHz with a minimum reflection coefficient of −10 dB (|S 11| < −10 dB). Furthermore, this compact antenna structure (38 mm × 38 mm) which is fed by the microstrip line generates a high gain of up to 5.5 dBi. Moreover, the proposed tree-design antenna possesses a linear polarization with a proficient omni-directional radiation pattern at 3.5 and 5 GHz and a divisive radiation pattern at 7.5 and 10 GHz. The parametric study performed for the purpose of antenna compaction is emphasized in the details of this research. The numerical and measurement results exhibit the success of the antennas performance. The attainable NCTA is sufficiently competent to be an initial structure consideration for the future Multi-Input Multi-Output (MIMO) development.

MINIATURIZED SIZE BRANCH LINE COUPLER USING OPEN STUBS WITH HIGH-LOW IMPEDANCES

In this paper, a miniaturized branch-line coupler is proposed. The topology of the circuit is designed using novel design of T-model approach with open stubs with high-low impedances, which provides necessary bandwidth for WLAN band at 2.45 GHz. The miniaturized branch-line coupler is designed and fabricated with a low-cost FR4 substrate as a platform in producing significantly reduction by more than 64.21% compared to the conventional coupler on inexpensive board. Furthermore, the coupler can equally divide the input signal with 90° phase of difference while maintaining the initial power from the source.

A compact size antenna with high gain enhancement for IEEE 802.15.3

This paper proposed a new antenna design for IEEE 802.15.3 applications. The presented antenna has a compact size of 40mm × 40mm where it can cover ultra-wideband (UWB) operating frequency, 3.1GHz to 10.6GHz. It consists of novel design radiating element and a partial ground plane. An extensive study has been made on the effect of the ground size towards the scattering parameter. Besides, a technique of gain enhancement is also been discussed. This design can be suitable for wideband cognitive radio spectrum sensing and UWB RADAR (Radio Define Ranging). The obtainable antenna performances illuminate the prospective of the presented antenna.

Electronically reconfigurable beam steering antenna using embedded RF PIN based parasitic arrays (ERPPA)

In this paper, an electronically reconflgurable beam steering antenna using embedded RF PIN switches based parasitic array (ERPPA) is proposed for modern wireless communication systems that operate at 5.8GHz frequency. In the proposed antenna, a single driven element is fed by a coaxial probe, while each of the two parasitic elements is integrated with an RF PIN switches that embedded inside the substrate. In the conventional reconflgurable antennas, the RF PIN switches are mounted on narrow slots created on the top or bottom layer of the radiator/parasitic elements, which could lead to the dimensional changes of the antenna and degrade the performance in terms of beam steering and return loss. However, this research proposes an exclusive solution where the RF PIN diodes at parasitic elements are embedded inside the substrate thus no additional slots have to be created to mount the SMCs on the antenna. In this regard, the proposed antenna is highly competent to eliminate the intermodulation efiect generated by the RF PIN diodes and the other passive elements associated with the PIN diodes. In this research, extensive investigations revealed that the parasitic element dimension and the selection of RF PIN switches signiflcantly in∞uence

TRANSPARENT ANTENNA DESIGN FOR WiMAX APPLICATION

A transparent monopole antenna operating at 2.30GHz is presented in this paper. The radiating element and ground plane are both designed using AgHT-4, while the substrate is made of glass. The simulated and measured impedance bandwidths (BWs) are 41.89% (2.00{3.06GHz) and 90.91% (1.5{4.00GHz), respectively. These results were obtained by using a suitable arc-shape slot on the ground plane; and the BWs cover the IEEE 802.16e standard for WiMAX application in the 2.30GHz band. The gain of proposed antenna is 3.16dBi, and there is close agreement between measurement and simulation results, in terms of return loss and radiation patterns.

Conductive E-textile analysis of 1.575 GHz rectangular antenna with H-slot for GPS application

Conductive E-textile analysis of a rectangular antenna with H-slot is proposed. This research focuses on the optimal value of gain and return loss (S11) with 3 types of E-textile as radiating elements. The H-slot functions are tuning and capable to suppress the back lobe direction. The proposed antenna design used 3 type of E-textile (Zelt, Pure Copper Taffeta Fabric and Shieldit Super). All of the antennas have similar full ground plane made from copper foil tape with thickness of 0.035 mm. As a result, the studies have significantly achieved optimum gain and return loss (S11) of 7.7 dB and -17.6 dB respectively. The proposed antenna has big potential to be implemented on smart clothes for GPS application.

A novel compact reconfigurable multi-band antenna

A novel compact antenna with the ability of reconfigurable multi-band applications is proposed. This achieved by integrate the compact 38mm × 38mm antenna with three RF switches. The activation of particular RF switches arrangement would then determine the frequency flexibility. The presented antenna competents to execute up to five multi-bands. The operating frequencies are band 1 (2.72 – 11.8GHz), band 2 (2.4 – 4GHz, 5.3 – 11.6GHz), band 3 (2.7 – 6.5GHz, 7.1 – 11.6GHz), band 4 (2.7 – 4.4GHz, 5.2 – 6.5GHz, 7.1 – 11.7GHz) and band 5 (2.6 – 3.5GHz, 4.8 – 7.0GHz, 7.4GHz – 11.5GHz). The presented antenna generates a proficient divisive radiation pattern at frequencies of 3 GHz, 6 GHz and 9 GHz. The developed antenna has great potential for military and cognitive radio applications.