Development of an ultra wide band (UWB) array antenna

Download

thesis_HAC_final_version_DateCorrected.pdf

Date

2022-4

Author

Ceylan, Hasan Akın

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

310
views

566
downloads

Demand for ultrawideband antenna arrays in telecommunications, space and airborne platforms, RADAR applications and MIMO systems, etc. is rising consistantly. A modern approach to develop an ultrawideband array is to utilize the mutual coupling between array elements. Even though individual elements are of narrowband characteristic in isolated form, they gain ultrawideband performance in array configuration under strong mutual coupling. In this work, an ultrawideband tightly coupled dipole array antenna is designed, fabricated and measured. Overlapping dipole arms is utilized as the tight coupling scheme. Infinite array of proposed TCDA has the bandwidth from 0.9 GHz to 6.8 GHz for VSWR<3.1 condition. For the unit cell of the infinite TCDA, gain varies from -11.1 dBi to 12.8 dBi with respect to frequency. The Klopfenstein tapered line balun and impedance transformer are inserted to feed the infinite array, yielding BW from 1.28 to 6.12 GHz for VSWR<3.1 condition, while having several extremely narrowband common mode VSWR spikes occuring in the band. In order to prove the concept, the TCDA is fabricated with 5×5 configuration, on RO4350b with 0.762 mm thickness with 0.035 mm copper. The ground plane is fabricated with FR4 core material of 1.5 mm thickness. The fabricated TCDA is measured with left-open elements, i.e. active element measurements with unterminated v elements. As the measurement results, the center element of the array has a bandwidth from 2.67 GHz to 6.8 GHz for VSWR<3.1 excluding small peak at VSWR in 3.15 to 3.3 GHz. 5×5 array has a secondary operational BW from 7.73 GHz to 20 GHz for VSWR<3.1. The measured gain of center element varies from -3.75 dBi to 8.36 dBi in 3 to 12 GHz measurement in unechoic chamber. 9 elements of the 25 total are measured, array patterns are synthesized via MATLAB using the 9 measured elements.

Subject Keywords

Dipole array, Ultra wideband, Tightly coupled array, Overlapping dipole

URI

https://hdl.handle.net/11511/97313

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Investigation of tightly coupled arrays for wideband applications Arda, Kaan; Dural Ünver, Mevlüde Gülbin; Department of Electrical and Electronics Engineering (2020-10) This thesis aims to provide in depth research on tightly coupled dipole arrays to be used in ultrawideband apertures applications. First, operation principles of tightly coupled dipole arrays are investigated. Starting from the Wheeler’s current sheet aperture concept, some calculations on bandwidth and impedance concepts are conducted. B.A. Munk’s addition to the concept, use of capacitive elements between adjacent dipoles, are introduced. Array unit cell is modeled using equivalent circuit approach,...
Ultra wideband tightly coupled reflectarray antenna Koldaş, Mutlu; Aydın Çivi, Hatice Özlem; Department of Electrical and Electronics Engineering (2022-2-08) In this thesis, an ultra wideband tightly coupled dipole reflectarray antenna is de signed, fabricated, and measured. This reflectarray consists of a wideband log-periodic dipole array feed antenna and a reflecting surface. The unit element of the reflecting surface is a tightly coupled overlapping bowtie dipole attached with a delay line to approach ultra wideband aim. Infinite array approach and Floquet port excitation ap plied in unit cell simulations to obtain reflection phase curves versus the length o...
DESIGN AND SIMULATION OF CIRCULAR ARRAYS OF TRAPEZOIDAL-TOOTH LOG-PERIODIC ANTENNAS VIA GENETIC OPTIMIZATION Gurel, L.; Ergül, Özgür Salih (2008-01-01) Circular arrays of log-periodic (LP) antennas are designed and their operational properties are investigated in a sophisticated simulation environment that is based on the recent advances in computational electromagnetics. Due to the complicated structures of the trapezoidal-tooth array elements and the overall array configuration, their analytical treatments are prohibitively difficult. Therefore, the simulation results presented in this paper are essential for their analysis and design. We present the des...
Measurement-based replanning of GSM cell capacities considering retrials, redials and hand-offs Onur, Ertan; Ersoy, C; Caglayan, MU (2002-01-01) During the optimization of a Global System for Mobile Communications (GSM) network, the operations and maintenance center (OMC) measurements are of significant importance. Because of false predictions, the capacity planning of a cell may be done inaccurately. If the capacity of the cell is not adequate to handle all of the busy-hour requests, the requests are not granted a channel and users are blocked. Thus, when the blocking ratio is high, the cellular capacity should be replanned. However, the capacity p...
Design of a dual polarized low profile antenna for microwave brain imaging Üçel, Kaan; Alatan, Lale; Department of Electrical and Electronics Engineering (2022-5-9) In this thesis, a low profile, low cost, wide band (0.9-2GHz) dual linearly polarized printed dipole antenna is designed to be used in microwave brain imaging systems. Dual polarization feature offers superior data acquisition through polarization diversity for better image quality. Starting from a simple printed dipole, antenna structure is modified step by step to meet these design requirements. Since a conductive surface in close vicinity of the antenna affects antenna performance, in order to obtain uni...

Citation Formats

H. A. Ceylan, “Development of an ultra wide band (UWB) array antenna,” M.S. - Master of Science, Middle East Technical University, 2022.