Theoretical investigation and design of wideband dielectric resonator antennas

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.


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...
Phased array antenna calibration and experimental validation
Yalım, Alper; Demir, Şimşek; Department of Electrical and Electronics Engineering (2013)
In this thesis, nine different methods aiming calibration of Phased Array Antenna (PAA) and Multifunctional Radars which employ PAA are presented. Those calibration methods are described, procedures of the methods are explained in detail, and information about constraints and measurement restrictions of those methods is given. As one step further, comprehensive work is focused on Multi-Element Phase Toggling (MEP) method and Rotating Element Vector (REV) method. Results of simulations are shown, theoretical...
Analysis and design of slotted substrate integrated waveguide antenna on cylindrical surface
Bayraktar, Ömer; Aydın Çivi, Hatice Özlem; Department of Electrical and Electronics Engineering (2014)
This thesis presents novel traveling wave conformal shunt slot arrays on cylindrical substrate integrated waveguide (CSIW) placed on a cylindrical surface in the circumferential direction at K-band. Mutual couplings of longitudinal slots on broad wall of CSIW are formulated and active admittance formulas of the slots are derived which are used in Elliott’s design procedure to design slotted CSIW arrays. The designs are carried out at 25 GHz using non-uniform and uniform slot separations. The non uniform slo...
Design of asymmetric coplanar strip folded dipole antennas /
Karaciğer, Kamil; Alatan, Lale; Department of Electrical and Electronics Engineering (2014)
This thesis includes the design, simulation, production and measurement of an asymmetric coplanar strip folded dipole antenna suitable to be used as an element in a linear array operating at S-band (2.7 GHz - 3.3 GHz). In this same manner, its usefulness as an array antenna is also explored in this thesis. This antenna element consists of a microstrip line feed, microstrip to coplanar stripline transition (BALUN) and asymmetric coplanar strip (ACPS) folded dipole. The planar folded dipole can be constructed...
Modified neural multiple source tracking algorithm in the presence of mutual coupling
Caylar, Selcuk; Leblebicioğlu, Mehmet Kemal; Dural, Guelbin (2007-06-15)
In smart antenna systems, mutual coupling between elements can significantly degrade the processing algorithms [1]. In this paper mutual coupling effects on Modified Neural Multiple Source Tracking Algorithm (MN-MUST) has been studied. MN-MUST algorithm applied to the Uniform Circular Array (UCA) geometry for the first time. The validity of MN-MUST algorithm in the presence of mutual coupling has been proved for both Uniform Linear Array (ULA) and UCA. Simulation results of MN-MUST algorithm are provided fo...
Citation Formats
Y. Ç. Yüksel, “Theoretical investigation and design of wideband dielectric resonator antennas,” M.S. - Master of Science, Middle East Technical University, 2015.