Design and analysis of fractal antennas for MIMO wireless communication systems

مقدم أطروحة جامعية

Salim, Ali Jabbar

مشرف أطروحة جامعية

Ahmad, Adil H.
Fyath, Raad S.

الجامعة

الجامعة التكنولوجية

الكلية

-

القسم الأكاديمي

قسم الهندسة الكهربائية

دولة الجامعة

العراق

الدرجة العلمية

دكتوراه

تاريخ الدرجة العلمية

2011

الملخص الإنجليزي

-Modern developments in wireless communications have shown that by using multiple antenna elements at both transmitter and the receiver, it is possible to ultimately increase the capacity in a wireless communication system without increasing the transmission power and bandwidth.

This system with multiple antenna elements at both link-ends is termed the Multiple-Input Multiple-Output (MIMO) system.

This work addresses a design of the small antennas based on fractal geometry for small mobile terminals running MIMO applications.

There are many factors that stand out constructing of MIMO system in a mobile terminal which characterized by its small size.

One of these factors, the use of smallsized antennas as possible.

The present work make use of the unique features of fractals such as selfsimilarity and space -filling properties to realize antennas that are characterized by multiband and compact size.

The application of the geometric partial arrangement property which known as (Koch) with fourth iteration is adopted in this work.

Several tests are conducted to make these antennas operate within the frequency bands (2.4 GHz and 5.8GHz) standards IEEE 802.11 b/g and IEEE 802.11a respectively for the purposes of wireless communication applications.

Modeling and performance evaluation of the proposed antennas are analyzed and optimized using the Computer Simulation Technology (CST) MICROWAVE STUDIOTM software package (ver.2010), which utilizes the Finite Integral Technique (FIT) for electromagnetic computation.

In this work, new four miniaturized antennas with multiband behavior are proposed.

Each one of these antennas based on the basis of a well-known antenna called Planar Inverted F-Antenna (PIFA), commonly used in mobile terminals which are usually single band.

These antennas are Fractal Planar Inverted F-Antenna (FPIFA), Slot-Fractal Planar Inverted F-Antenna (S-FPIFA), Folded- Fractal Planar Inverted F-Antenna (F-FPIFA) and Rotated Folded -Fractal Planar Inverted F-Antenna (RF-FPIFA).

Each antenna is invested in a system consisting of four elements and the simulation results showed that the isolation between the antennas in each one of the four systems is found to be better than 12dB and 20dB in the lower and higher bands respectively.

Due to the small distance between antennas and small ground plane, changes in one element affects the performance of the others.

Proper antenna locations on the ground plane as well as feed location and shorting pin affect the antenna parameters.

The evaluation performance of these systems is done through the calculations of envelope correlation and the Mean Effective Gain (MEG) and the results were compatible with the conditions that must be provided.

The envelope correlation is calculated to be much less than 0.1 and the ratio of the mean effective gain between the antennas is close to unity.

This makes the proposed systems suitable for use in MIMO dual band wireless communication applications.

A MIMO channel model is established based on the simulation using the MATLAB package and this model is used to calculate the channel capacity for each of the four systems.

The results showed that the system of (F-FPIFA) gives a higher capacity in both bands than the rest systems.

التخصصات الرئيسية

هندسة الاتصالات

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-305158