(A) study of conductor effects in ground antennas

다국어 초록 (Multilingual Abstract)

A ground plane plays an important role in mobile antenna designs. The performance of mobile antennas may significantly be affected as the ground condition is changed. This work analyzes an effect of a conductor connected near a ground antenna. In order to demonstrate the change on the resonant frequency and the radiation efficiency, the surface current distribution of the antenna was investigated as the conductor length and position are changed. In this thesis, the antenna is designed to operate at Wi-Fi application (2.4 GHz - 2.5 GHz) with required fractional impedance bandwidth of 6.5% for S11<-10 dB. It is verified via simulated and measured that the antenna efficiency is decreased as much as 10% in comparison with original ground antenna, when the conductor is λ/4 in length. To solve this problem, a lumped inductor is utilized to decouple between the antenna and the conductor, and the improvement in the performance of the antenna could be confirmed.

목차 (Table of Contents)

• ABSTRACT I
• TABLE OF CONTENTS II
• LIST OF FIGURES III
• GLOSSARY OF ACRONYMS AND ABBREVIATIONS V
• 1. INTRODUCTION 1
• 2. BACKGROUND 3
• 2.1. THE CONCEPT OF GROUND ANTENNA 3
• 2.1.1. Direct feeding for J0 Characteristic Mode excitation 3
• 2.1.2. The Loop feed for Magnetic Coupling 5
• 2.2. THE CHANGE IN THE PERFORMANCE OF GROUND ANTENNA BY CONDUCTOR 7
• 3. ANALYSIS OF CONDUCTOR EFFECTS IN GROUND ANTENNA 12
• 3.1. THE EFFECT OF CONDUCTOR LENGTH AND POSITION 12
• 3.2. DECOUPLING METHOD USING INDUCTOR 20
• 4. EXPERIMENTAL RESULTS AND DISCUSSION 22
• 5. CONCLUSIONS 26
• BIBLIOGRAPHY 27