Noorsaliza Abdullah

Microstrip Sierpinski carpet antenna design

Low cost of fabrication and low profile features of microstrip antennas, attract many researchers to investigate the performance of this antenna in various ways. Today, fractal antenna becomes popular among the researcher because they have a peculiar properties that make them suitable for multiband applications. Fractal technologies allowed us to design miniature antennas and integrate multiple telecommunication services such as cellular (GSM 900 and GSM 1800), wireless LAN, GPS and HiperLAN into a single device. Microstrip Sierpinski carpet antenna is proposed for a multiband operation. The fractal antenna offer solutions for the integration of all this application.

Wideband Sierpinski carpet monopole antenna

This paper described the design and fabrication of the fractal Sierpenksi carpet monopole antenna. The properties of antennas such as bandwidth and radiation pattern have been investigated. Wide bandwidth with input return loss of -10 dB has been achieved from 1 GHz to 10 GHz using this fractal antenna. The radiation patterns have been investigated at 2.73 GHz and 4.29 GHz. The cross polar isolation is in the range of -20 dB for both frequencies. The radiation pattern is in the direction of the main lobe.

Size Reduction and Multiband Characteristic Using Koch Fractal Dipole

The Koch fractal dipole antenna is designed, simulated and fabricated for operating at 900MHz frequency band. By using Koch fractal antenna mathematic equation and some consideration, the desired resonant frequencies can be achieved. The designed antenna is started with developing microstrip dipole antenna for the same frequency operation. The size of Koch fractal dipole is reduced around 40% compactness compared to microstrip dipole. A multiband characteristic is investigated until third iteration with identication angle, thetas = 60deg trace width, W = 1mm and fabricate onto FR-4 substrate using SMA connector

VHF Adaptive Antenna Using a Rear Defogger

An array antenna for the VHF band, which has several ports on a defogger, is proposed. In addition, the concept of a reactively steered adaptive array is introduced to form an adaptive beam pattern. The resistivity of a heating wire does not degrade the receiving performance significantly. The cost of the adaptive array consisting of a single receiver is low, and this array does not impact the industrial design. Its performance is evaluated by numerical simulation and experiments over a bandwidth of FM radio.

A shared aperture VHF smart antenna using the rear defogger

In the land mobile propagation, there is no line of sight between transmitter and receiver. In addition, the delayed signal caused by huge buildings and heave may generate. In this situation, the transmission quality is significantly degraded. An adaptive antenna is an effective means to overcome such fading phenomena. However, an adaptive antenna is consisted of several antennas and receivers. Since a lot of antennas compromise the vehicular industrial design, it is preferable for industrial design not to use additional antenna elements. In Japan, various data communication service using VHF band for the analogue TV broadcast are planned. High speed digital data transmission will be used for the service. It will be necessary for the application to apply the diversity or the adaptive antennas.

Design Sierpinski Gasket Antenna for WLAN Application

This project mainly discussed on designing and fabricating the antenna using fractal concept to obtain the dual band resonant frequency at 2.4 GHz and 5.8 GHz for wireless local area network (WLAN) application. The application of fractal geometry can be used to miniaturize the antenna due to their self-similarity and this project focusing on designing the Sierpinski gasket antenna for first iteration. The antenna had been simulated using CST microwave studio, while the fabricated antenna had been tested using network analyzer. The results of both antenna simulation and measurement are in good agreement with the design expectation. The antenna was fabricated on printed circuit board (PCB) using epoxy/ glass (FR- 4) substrate with 30cm by 30cm metallic copper ground plane.

STEERABLE ANTENNA USING ALGORITHM BASED ON DOWNHILL SIMPLEX METHOD

Electronically steerable passive array radiator(ESPAR) antennas are expected to gain prominence in the fleld of wireless communication, because they can be steered toward a desired signal and they can eliminate interference; in addition, they have a very simple architecture that has signiflcantly low power consumption and are inexpensive to manufacture. In this paper, we proposed an ESPAR antenna that has fastest convergence time. The downhill simplex method is used to maximize the correlation coe-cient between the received signal and the reference signal. The simulation results indicate that this antenna can be steered toward the desired signal if one signal is used; in addition, it can eliminate interference if two signals, namely, the desired signal and the interference are used by automatically varying the reactance values.

A study of ESPAR antenna

Recently, ESPAR antenna has gained much attention because of its capability to eliminate interference automatically. Many studies had been carried out using different optimization method. This paper introduced downhill simplex method as an optimization. From the simulation, it shows that this method is the fastest and efficient method compared to other methods.

Design, Simulation, Fabrication and Measurement of a 900MHZ Koch Fractal Dipole Antenna

This paper present the design and fabrication of the Koch fractal dipole antenna. A multi-band element has been designed based on the Koch fractal which operates over two frequency band. The property of antennas such as return loss, S11 has been investigated at frequency of 900 MHz for GSM band. Wide bandwidth with input return loss of -10 dB has been achieved from 0 to 8 GHz using this fractal antenna. The size of fabricated antenna is reduced around 64% compare to conventional dipole antenna at these frequencies.

Design of rectenna for wireless energy harvesting

the design of rectenna for wireless energy harvesting is presented in this paper. The rectenna design consists of a microstrip patch antenna and a rectifier circuit, in which both of them resonate at 2.45 GHz. CST software was used as the simulation tool of the proposed microstrip patch antenna. Then, the designed antenna was fabricated and assembled together, and tested using network Analyzer. The rectifier consists of two tapered microstrip lines, a Schottky diode, a λ/4 microstrip line, a matching microstrip line, and an output low pass filter. The circuit is printed on the substrate of FR4 (εr = 4.3 and h = 1.6 mm). The circuit was designed and optimized using Advance Design System (ADS), then fabricated using micro-strip lines with an FR4 substrate. According to the received wireless power, the values of output DC voltage and power have been measured and the best value of load resistance to harvest maximum output DC power has been selected through simulation.