Theoretical investigation and design of wideband dielectric resonator antennas

Download
2015
Yüksel, Yılmaz Çağrı
The aim of this thesis is to utilize Dielectric Resonator Antennas (DRA) as array elements due to their advantages over other conventional antenna elements such as dipoles and microstrip patches. Depending on both the excitation mechanisms and the antenna shape, a Dielectric Resonator Antenna (DRA) provides its designer multiple independent degrees of freedom. In this thesis three antenna shapes, namely hemispherical, cylindrical and rectangular DRAs, are investigated. The cylindrical and the rectangular shaped DRAs are used in designs. A design software that calculates the initial dimensions of the DRAs is developed and these dimensions are optimized through the full-wave analysis performed by using a Finite Element Method (FEM) based electromagnetic field solver. The concept of a compact DRA with wideband operation in 2.9-3.3 GHz frequency band is presented. The return losses, impedance characteristics, internal field distributions and radiation patterns of DRA elements are discussed. The effect of dimensional parameters of both antenna element and feed network are investigated. The rectangular and stack-cylindrical shaped DRAs are manufactured and excited via microstrip slots. For rectangular DRA a -10dB impedance bandwidth of 20.3% and a gain of 5.28dB are obtained. An enhancement is achieved both in the -10dB impedance bandwidth (44.7%) and the gain of the antenna (9.35dB) with stacked-cylindrical DRA configuration. A Taylor amplitude tapered linear array is designed to achieve 10 degree half power beam width (HPBW) with 30dB side lobe level (SLL). An 8-arm modified Wilkinson unequal power divider is designed to implement a linear array with high ratios between excitation amplitudes. Array characteristics are measured in the near field antenna measurement chamber. The prototype and the test results for the antenna element and the array structure are discussed. For rectangular DRA array, 10.1dB gain, -26dB SLL and 9.60 HPBW are obtained. For stacked-cylindrical DRA configuration, 14.3dB gain, -26.9dB SLL and 9.50 HPBW are achieved.

Suggestions

Wideband omnidirectional and sector coverage antenna arrays for base stations
Alatan, Lale (2018-01-01)
By using parallel strip line fed printed dipole antennas as array elements, an omnidirectional antenna array and a wide angle sector coverage array operating in octave band are designed. A maximum deviation of ±1.25 dB from the omnidirectional pattern is achieved for the omnidirectional array, and the average gain of the antenna was measured as being 5 dB in the 1.35–2.7GHz band. For the sector coverage array, a special reflector design is utilized to maintain a half power beam width of around 115◦ with a s...
Analysis of spherical-rectangular printed antennas and antenna arrays using cavity model
Demir, Oğuz; Dural Ünver, Mevlüde Gülbin; Department of Electrical and Electronics Engineering (2017)
Printed antennas are commonly used since these antennas are preferred in many applications due to their advantageous properties. In order to employ these antennas in such applications, a thorough investigation and analysis are generally required. Although this can be implemented with fully numerical methods for the sake of high accuracy, the complex calculations required in the process lead to heavy computational load, hence generally demands high quality simulation software. In this thesis, the spherical-r...
Design of magneto-electric dipole antenna for wideband communication systems
Alparslan, Semih; Alatan, Lale; Department of Electrical and Electronics Engineering (2018)
This thesis includes the design, simulation, production and measurement of a differential fed magneto-electric dipole antenna with cavity operating at ultrawideband (3.3 GHz – 10 GHz). This antenna consists of a differential feeding structure, an electric dipole, a magnetic dipole and a cavity. The ultra-wideband operation is achieved through the use of differential feeding structure and cavity. A step-by-step procedure is followed during the design process of the differential fed magneto-electric dipole an...
Efficient numerical analysis and design of reflectarray antennas
Erçil, Erdinç; Aydın Çivi, Hatice Özlem; Alatan, Lale; Department of Electrical and Electronics Engineering (2015)
The accurate numerical analysis of electrically large reflectarray antennas has been a challenging task since their advent because it becomes impractical to employ the generalized numerical electromagnetic tools for their numerical analysis. Therefore the classical approach is to resort to approximate methods. However, approximate methods trade off accuracy against memory and speed. In this thesis study; an approximate analysis technique is established such that it is more accurate than the present approxim...
Reconfigurable Reflectarrays: Design, Analysis and Fabrication
Aydın Çivi, Hatice Özlem (2015-05-17)
Reflectarray antennas combine the advantages of both reflector and phased array antennas. Therefore, they offer low-loss, low-cost solutions for the high gain, beam steering and beam shaping applications. First the current progress and future perspectives regarding the design and analysis of reflectarrays are discussed. Then, recent technological developments and techniques that are used to realize reconfigurability in reflectarrays are presented.
Citation Formats
Y. Ç. Yüksel, “Theoretical investigation and design of wideband dielectric resonator antennas,” M.S. - Master of Science, Middle East Technical University, 2015.