Analysis of Microstrip Structures Using DGS for 5G Applications


Thesis Type: Doctorate

Institution Of The Thesis: Gazi University, Mühendislik Fakültesi, Elektrik - Elektronik Mühendisliği, Turkey

Approval Date: 2021

Thesis Language: Turkish

Student: BURAK DÖKMETAŞ

Principal Supervisor (For Co-Supervisor Theses): Nursel Akçam

Co-Supervisor: Erdem Yazgan

Abstract:

Nowadays, the unprecedented increase in the number of wireless communication network users, has brought problems such insufficient bandwidth and limited channel capacity. For that, the mm-wave fifth-generation (5G) communication technology development is solicited to offer higher data rates and superior channel capacity. In addition to its several features including the less power consumption, the better reliability, and the high transmission rate, the 5G technology is a basic stone for implementing a wide range of today’s emerging technologies such as self-driving cars and smart homes. However, some problems are present at the mm-waves frequency spectrum such as path loss attenuations, atmospheric absorption and signal fading that have to be fixed especially in case single antenna element. Multiple Input Multiple Output (MIMO) antenna has emerged to be a key solution for present and future wireless communication systems, proving the concurrent operation of multi-antennas, increasing channel capacity along with the advantages of high data rates. The design of a 4-element MIMO antenna using Defected Ground Structure (DGS) for milimeter-wave frequency bands is presented in this work. According to the measurement results, a 7 GHz bandwidth between 24-31 GHz frequencies, 8.39 dBi maximum gain at 27 GHz and -40 dB isolation between each antenna elements was obtained. The proposed design is expected to contribute to the literature with its compact structure, high gain value and wide bandwidth. Furthermore a Band Stop Filter (BSF) using DGS is designed and fabricated in this study. The proposed BSF has a very compact structure with a size of 14.28 mm × 4 mm × 0.508 mm and shows a reject characteristic of less than 20 dB in the frequency range of 10.8 -11.8 GHz. In addition to the simulation and measurement results, the equivalent circuit model of the design has been extracted and various parametric studies have been carried out. 

Key Words : MIMO antenna systems, DGS, bandstop filter, 5G