A. R. Othman

2.45 GHz RFID reader array antenna with hexagonal geometry arrangement

In this paper, 2.45 GHz Radio Frequency Identification (RFID) reader antenna with hexagonal geometry is proposed to obtain a high gain directional pattern. The mittering technique is used at each junction of the transmission line to reduce the power loss. The parametric study is conducted to get the best dimension and position of all six elements of truncated patch antenna to operate at 2.45 GHz. The simulation and measurement readings of the antenna are compared. In conclusion, the performance of the designed antenna improves the referenced antenna in terms of gain and size. The measured gain is 9.0 dBi and the size of the designed antenna is about 37% smaller than the referenced antenna.

A review on compact slot antenna for wireless MIMO communication system

This paper present the review on the wireless system specifically with Multiple Input Multiple Output (MIMO) technique. This is due to the advantage of MIMO system that able to enhanced the overall wireless channel capacity. Besides system performances, the size and mobility of the communication devices are also contributed the successfulness of proposed wireless communication system. The compact antenna design has been discussed by many researchers for various application. However, the needs of compact antenna with capability of multiple application is very significant in wireless communication today. Therefore, this paper will review the compact antenna design for wireless MIMO application based on slot design methods.

High gain, low noise Cascode LNA using T-matching network for wireless applications

This paper presents a high gain, low noise Cascoded LNA using T-matching network applicable for wireless applications. The amplifier use FHX76LP Low Noise SuperHEMT FET. The LNA designed used T-matching network consisting of lump reactive element at the input and the output terminal. The cascode low noise amplifier (LNA) produced gain of 18.5 dB and noise figure (NF) of 1.30 dB. The input reflection (S11) and output return loss (S22) are -11.5 dB and -12.3 dB respectively. The bandwidth of the amplifier recorded is 1.4 GHz. The input sensitivity is compliant with the IEEE 802.16 standards.

Miniaturized Implantable Ultra-Wideband Antenna with Bio-Compatible Substrate Material

Ultra-wideband (UWB) technology was nowadays increased in interest for various applications due to its distinctive characteristics where it able to carry signals passes through obstacles unlikely narrow-band frequency that tends to reflect the signal. Through this paper, a design of miniaturized implantable UWB antenna utilizing various bio-compatible materials is studied. These materials are to be compared and determined the best material to be used for the design in terms of its return loss, center frequency, bandwidth, antenna gain and total efficiency. The antenna is designed in a structure of circular-ring with slit patch antenna using CPW profile with dimension of 10×10 mm2. As for the materials used in this study are Silicon, PDMS and Teflon PTFE. Each of this substrate has a thickness of 0.5 mm, 2.5 mm, and 1.5 mm correspondingly. After comparing these three materials, the one that gives the best result is Teflon PTFE with return loss at 11.91 GHz and 5.58 GHz bandwidth that covers from 9.16 GHz to 17.74 GHz frequency range. The antenna gives out total gain and efficiency of 2.54 dB and 86.5% respectively.

Design of Linear Polarization Antenna for Wireless MIMO Application

This paper present the design of the linear polarized antenna for wireless MIMO communication system. It is impossible to fulfil the demand of the wireless communication system due to limitations in channel capacity on single input single output (SISO) systems. Multiple input multiple output (MIMO) system has become a famous research field for the next generation wireless communication system in order to overcome this problem. Since polarization diversity is effective to avoid the fading loss caused by multipath effects, therefore, polarization diversity becomes one of the most important techniques that can be used to enhance MIMO system performances. It can be utilized to improve the communications channel capacity and utilize the frequency spectrum with frequency reuse technique. Therefore, the development of linear polarized antenna is significant in order to improve the wireless MIMO system performance based on polarization diversity technique. Polarization diversity can be utilized to double the frequency spectrum to realize frequency reuse and improve the communications capacity. This project is to design an antenna that can provide linear polarization to reduce the signal losses.

Design of Multi-band Antenna for Wireless MIMO Communication Systems

This paper present the design of band antenna for wireless Multiple Input Multiple Output (MIMO) communication system. The advantage of MIMO system is able to enhanced the overall wireless channel capacity. Besides system performances, the size and mobility of the communication devices are also contributed the successfulness of proposed wireless communication system. The multi-band antenna design has been discussed by many researchers for various application. This paper present the design of multiband antenna by using slot techniques. The design was simulated by using microwave CST studio. The results show that, the proposed antenna can operate at 2.4, 3.5 and 5.2 GHz frequency band.

Channel Capacity of Indoor MIMO Systems in the Presence of Spatial Diversity

The capacity of Multiple Input Multiple Output (MIMO) systems has received much attention in recent years. This paper analyze the capacities of MIMO channel model for indoor propagation with increasing the distance between transmit and receive antenna through simulation and measurement. A spatial diversity method is employed during measurement and simulation process. The investigation on the channel capacity for various distance and spacing of both transmitter and receiver antenna have been done. The investigations of channel capacity are included with difference distance between transmitter and receiver sides and different in element antenna spacing. For the simulation, the path loss for the free space and physical effect are been considered. The 2 × 2 rectangular microstrip patch array antenna is used in order to characterize channel parameter at 2.4 GHz operating frequency. The system measurement was been conducted in UTeM Microwave Laboratory, according to the real situation in indoor environment.

A review on circular polarization antenna for wireless MIMO application

This paper will review the development of wireless MIMO communication system and the circular polarization antenna. It is impossible to fulfil the demand of the wireless communication system due to limitations in channel capacity on single input single output (SISO) systems. Multiple input multiple output (MIMO) system has become a famous research field for the next generation wireless communication system in order to overcome this problem. Since polarization diversity is effective to avoid the fading loss caused by multipath effects, therefore, polarization diversity becomes one of the most important techniques that can be used to enhance MIMO system performances. It can be utilized to improve the communications channel capacity and utilize the frequency spectrum with frequency reuse technique. Therefore, the development of polarized antenna is significant in order to improve the wireless MIMO system performance based on polarization diversity technique.

Design of broadband tri-polarized antenna for wireless MIMO systems

This paper present about the development of broadband tri-polarized antenna design that operates at frequencies of 2.4GHz for wireless MIMO communication system. Polarization diversity is one of the handy techniques to improve performance between base station and the user because it can reduce spatial correlation that can decrease system performance. The design process can be divided into three design steps. First, the linear broadband antenna is designed by using a fork like tuning stub method. Then, the dual circular polarization antenna is designed by using a stub method on a two ports circular microstrip antenna. Finally, two selected designs from step one and step two are combined. This combination antenna will obtain broadband tri-polarized antenna that operates at 2.4GHz. The design is simulated by using CST Design Microwave software. The antenna was designed to generate linear polarization, RHCP (right hand circular polarization) and LHCP (left hand circular polarization) on port 1, port 2 and port 3 respectively. The simulation design is then fabricated on FR4 board and measured. Then, the simulation and measurement result are compared and analyzed.

Design and fabrication of radio frequency amplifier with 3 dB π-network attenuator isolation

This paper presents the design and fabrication of radio frequency amplifier (RFA), which operates at 5.8 GHz unlicensed frequency for WiMAX application. The RFA designed used T-matching network consisting of lump reactive elements, 3 dB attenuator and microstrip line at the input and output impedance. The RFA developed in this project contribute a gain of 15.6 dB with overall noise figure of 2.4 dB. The overall measured bandwidth is 1.240 GHz with S parameters S11, S12 and S22 measured are -12.4 dB, -25.5 dB and -12.3 dB respectively. The isolation result shows that there is a significant contribution using 3 dB π-network. The RFA used FET transistor EPA018A from Excelics Semiconductor Inc.