M. I. Jais

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.

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

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.

1.575 GHz dual-polarization textile antenna (DPTA) for GPS application

This paper presents a novel dual-polarization textile antenna (DPTA) for Global Positioning System (GPS) applications. In this design, four sector radiating elements are centrally-fed by a coaxial probe. A novel antenna structure is successfully achieved by integrating electronic components into a wearable textile antenna. Silver loaded epoxy adhesive is used in embedding four PIN diode switches on ShieldIt super textile of the proposed antenna. The activation of certain PIN diode switches configuration determines the polarization of DPTA. Dimension-wise this antenna is compact and small where it consists of 40mm radius. The proposed DPTA design successfully generated dual polarization omni-directional radiation pattern with maximum gain 1.81 dBi at angle of 0°/3600, 90°, 180° and 270°. Its small size, flexible and wearable features enables this DPTA to be easily integrated onto safety jacket and rain coat for tracking, search and rescue applications.

A fabrication of intelligent spiral reconfigurable beam forming antenna for 2.35-2.39 Ghz applications and path loss measurements

A reconflgurable beam forming antenna prototype using a spiral feed line is proposed in this paper. The presented antenna is integrated with PIN diode switches at a speciflc location of spiral feed line. It is discovered that the beam steering ability is greatly in∞uenced by the spiral arm feed network. Four PIN diode switches have been incorporated at four difierent arms of spiral feed line to realize a beam forming ability. The intelligence behaviour of this antenna is conferred when the switches are connected to programmable intelligent computer (PIC) microcontroller. Certain conflgurations of PIC allow the antennas radiation patterns to be adaptively changed within 0.01ms. Therefore, the proposed antenna is capable of electronically forming the beam up to four difierent angles of +176 - , +10 - , i1 - and i12 - . This antenna is small in size with 100mm by 100mm of substrate dimension. In this research, the site fleld antenna performance relying on the received signal strength (RSS) testing is tested intensively in Universiti Malaysia Perlis with varied distant points of line-of- sight (LOS) and non-line-of-sight (NLOS) propagation. With good simulation and measurement results, this antenna could be a promising candidate to be installed in applications such as a smart antenna system, cognitive radio, WiMAX and long term evolution (LTE).

Design Analysis of 2.45 GHz Meander Line Antenna (MLA)

A Meander Line Antenna (MLA) for 2.45 GHz is proposed. This research focuses on the optimum value of gain and reflection coefficient. Therefore, the MLAs parametric studies is discussed which involved the number of turn, width of feed (W1), length of feed (LI) and vertical length partial ground (L3). As a result, the studies have significantly achieved MLAs gain and reflection coefficient of 3.248dB and -45dB respectively. The MLA also resembles the monopole antenna behavior of Omni-directional radiation pattern. Measured and simulated results are presented. The proposed antenna has big potential to be implemented for WLAN device such as optical mouse application.

Review of angle of arrival (AOA) estimations through received signal strength indication (RSSI) for wireless sensors network (WSN)

Awareness of the physical location of each node is required by the many wireless sensor network (WSN) applications. There are various tracking schemes available such as time-of-flight, time difference of arrival and angle of arrival. This review paper focuses and describes previous related work regarding of the angle of arrival (AOA) estimations in particular through received signal strength indication (RSSI). AOA estimation is useful in tracking the desired signal and also improving the signal reception for movable users. With the AOA detection, the beam pattern of the antenna system can be reconfigured either mechanically or electrically to improve the signal reception. The AOA estimation with RSSI offers less complexity since the phase information of the signal will not be used to calculate the angle as usually practiced in the traditional phased array antenna systems. Hence this review focuses on identifying the advantages and disadvantages in AOA estimation through RSSI. The potential future direction of this research will be proposed at the end of this review.

Adaptive zero-interference of compact reconfigurable antenna for GPS application

A novel design of reconfigurable antenna for GPS application is presented in this research. This project proposed a circular disc-shape antenna with beam steering radiation pattern. The antenna is designed by a coaxial probe technique which allow current flow to the center of the antenna. Then, the incident distributed to the surrounding fan ring parasitic via bridges. Three PIN diode switches have been implemented to the proposed antenna design. It is discovered that the switching element is capable to control the beam pattern to achieve a different main lobe angle at the specified location. The proposed antenna achieved to generate beam steering angle of 26°, 176° and 348° with a maximum directivity of 1.948 dB and a gain of 1.456 dB. The reconfigurable antenna which attaches to the Rogers RT5880 with dielectric constant of (2.2) has a 63 mm square dimension. Which all the compensations, the proposed antenna is suitable to be implemented in GPS application.

2.45 GHz beam-steering textile antenna for WBAN application

A beam-streering textile antenna for wireless body area network (WBAN) applications is proposed and investigated in this work. This proposed antenna is centrally-fed by a coaxial probe before currents are distributed to the four circular radiating elements. This novel structure successfully integrated the reconfigurable feature into a wearable textile antenna using electronic components. Four RF switches are integrated at an ideal location of each arm without any external circuit. With certain specific RF switch configurations, the proposed antenna generated beam steering angles at 0°, 90°, 180° and 270° with a maximum directivity of 6.8 dBi at 0°/360°. Its small size of 88 mm2 square, flexible and wearable features enables this antenna to be easily integrated onto safety jacket and rain coat for tracking, search and rescue based communication purposes.

Gain enhancement of circular patch antenna using parasitic ring

This paper investigates the performance of a circular patch antenna deployed with a parasitic ring and compares the performances with a conventional circular patch antenna in terms of gain, return loss, and radiation pattern. The antenna is fed by a coaxial probe and provided with a full ground plane. Compared with previous gain enhancement methods, the proposed metal ring resonator offers reduced design complexity. With a simple parametric study, the optimum width of the parasitic ring could be identified. Adopting this method, the proposed antenna has increased gain approximately 20% while maintaining the return loss at an operating frequency of 5.8 GHz.