Gain enhancement of square patch microstrip antenna loaded by square ring at X-Band : design and fabrication

Other Title(s)

تحسين تحصيل الهوائي الشريطي المربع المحمل بحلقة مربعة ضمن حزمة X : تصميم و تصنيع

Dissertant

al-Abd al-Latif, Yusuf Aqib Isa

Thesis advisor

al-Mulla, Samir Y.
Ahmad, Zaki A.

Comitee Members

Hannun, Amin H.
Abbud, Ahmad H.
Gadaymi, Wail A.
Amin, Sabah M. Muhammad

University

University of Basrah

Faculty

Science College

Department

Department of Physics

University Country

Iraq

Degree

Ph.D.

Degree Date

2013

English Abstract

Micristrip Antennas play an integral role in wireless communications systems, where it is distinguished from other antennas by lightweight and small size and possessing of different geometric shapes, allowing them to use in different areas.

But on the other hand has some weaknesses such as low gain and narrow bandwidth, so researchers focused effort to find a way to increase gain or increase the bandwidth, or both.

This research deals with the design and study of a new type of microstrip antennas for the purpose of increasing the gain of the antenna operates at high frequencies within the x-band.

This study has included several axes: First: Design two microstrip antennas with square patch radiator built on a dielectric material substrate of a dielectric constant ( ) and have a thickness ( ), operates at a dominant mode with a resonant frequency (10.74 GHz) and (11.26 GHz) respectively.

A coaxial transmission line technique has been used to feed the two antennas, also adopted equations derived in the transmission line model (TL Model) for find irradiated dimensions (length and width) and the location of the feeding point at both frequencies above.

Second: The two antenna designs have been simulated using a more sophisticated program after testing its accuracy called (Sonnet Software), operates at high frequency and based mainly on the method of moments (MoM) in its analysis.

By this software we were able to finding optimum values for the dimensions of the square radiator, as well as, finding the correct location to the feeding point at which the input impedance of the patch equal to 50 Ω to get a good matching between the feed line and antenna.

An important antenna parameters have been obtained by this software, like directivity, gain, standing wave ratio (VSWR) and the value of the bandwidth in the -10 dB has been obtained, where the bandwidth of the antenna which operates at the frequency 10.74 GHz is equal to BW%=6.6%, directivity D = 10.5 dB, and gain G = 5.214 dB .Also it was calculated and sketch radiation fields pattern emitted from the antenna in the far field region.

Third: Design a new microstrip antenna by adding a square ring of a width surrounding the square patch of the conventional antenna mention above, and the inner edge of the ring is away from the edge of the square patch in all direction.

This loaded ring is added in order to improve gain or bandwidth or both.

In this research focused our attention on improving the gain; so the proposed antenna was simulated using (Sonnet Software) to find the optimum values for and at which the directivity and gain becomes as high as possible.

It was found that gain increases by 4.59 dB and directivity increases by 2.9 dB when and of the antenna which operates at a resonant frequency 10.74 GHz, and the gain increases by 5.18 dB and directivity increases by 4.6 dB when and of the antenna which operates in the resonant frequency of 11.26 GHz, while bandwidth is remaining unchanged in both cases.

Fourth: Been strengthened theoretical results in practice where it was manufactured proposed antennas in laboratory, the radiation pattern has been calculated in the principle planes (E-Plane) and (H-Plane) and compared with the theoretical results.

The gain of the two proposed antennas has been calculated in practice, we found it almost identical with the theoretical results.

Finally, empirical relationship have been developed between and values in terms of the .

Main Subjects

Physics

No. of Pages

148

Table of Contents

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-744455