Modes Of Dielectric Resonator Antenna Research Articles

Recent progress in dielectric resonator antenna: Materials, designs, fabrications, and their performance

Dielectric resonator antenna (DRA) has secured an esteemed position in the field of antenna engineering technology due to its versatile features, including compactness, light-weight, low loss, high radiation efficiency, ease of excitation, diverse feeding techniques, multiple excitation modes, ease of integration with passive and active microwave integrated circuit components, a wide variety of available materials, simple fabrication techniques, and high degree of flexibility over wide frequency range. This article presents a comprehensive up-to-date review of research carried out in the field of DRA technology which includes an overview of DRA technology, its history, present status, and prospects. The basic parameters of microwave dielectric ceramic materials and the classification of materials based on utilization and material parameters are briefly discussed. The applications of DRA in different fields of science, engineering, and technology, overview of different reported DRA shapes, and the feeding techniques used to excite different modes of DRA are mentioned. Based on the control of DRA permittivity, shape/geometry, feeding techniques, and structural modifications, performance parameters engineering of DRA and its achievable performance in terms of low profile, compactness, high gain, wide beam, circular polarization, wide bandwidth, DRA decoupling methods for multiple input multiple output arrays, dielectric patch antenna, filtering DRA, and reconfigurable DRA are discussed. Different techniques used to attain and enhance the particular performance of DRA are highlighted. This review article also dilates upon the fabrication processes and characterization methods of DRA microwave dielectric ceramics, which play a very vital role in controlling the performance and properties of DRA.

3-D-Printed Wideband Circularly Polarized Dielectric Resonator Antenna With Two Printing Materials

A new 3-D-printed wideband circularly polarized (CP) dielectric resonator antenna (DRA) with two printing materials is investigated. The DRA has a multilayer comb-shaped structure at its top for generating CP fields. Three dielectric strips are embedded inside the DRA body to support multiple transverse-electric (TE) DRA modes to widen the DRA bandwidth. To slightly improve the axial-ratio (AR) performance, the DRA is twisted in the horizontal plane. For demonstration, a prototype operating in C-band was designed and printed with two different materials. The reflection coefficient, AR, radiation pattern, antenna gain, and efficiency of the antenna are measured, and reasonable agreement between the measured and simulated results is observed. The prototype has a measured 10 dB impedance bandwidth of 69.7% (4.80–9.94 GHz) and 3 dB AR bandwidth of 68.6% (4.52–9.24 GHz), achieving a wide overlapping bandwidth of 63.2% (4.80–9.24 GHz). Both the AR and overlapping bandwidths are record-high for a single-fed CP DRA. The prototype has a measured peak antenna gain of 8.3 dBic inside the overlapped passband.

Design of the Single-/Dual-Port Wideband Differential Dielectric Resonator Antenna Using Higher Order Mode

In this letter, a wideband differential hollow rectangular dielectric resonator antenna (DRA) designed using higher order mode is investigated. The fundamental TE111 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</sup> and higher order TE113 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</sup> modes of the rectangular DRA were employed for the design. To merge these two DRA modes together, the hollow DRA with its air region displaced from the center is employed. Both the single- and dual-port wideband differential DRAs are considered. For the dual-port version, a wide differential impedance bandwidth of ~46% was achieved. For the single-port version, a 180° hybrid coupler was designed to feed the differential DRA compactly. The measured result shows that its impedance bandwidth can be achieved as ~44%. In addition, the proposed differential DRA provides a stable broadside radiation pattern with lower cross-polarized field.

Conductor Backed CPW-Fed Dual-Mode Excited High Gain Cylindrical Cavity DRA for Unmanned Aircraft Systems (UAS) or Drone Data-Link Applications at C Band

ABSTRACTIn this article, a dual-mode high gain cylindrical cavity dielectric resonator antenna (CCDRA) excited by conductor backed coplanar waveguide (CB-CPW) has been investigated for unmanned aircraft systems (UAS) or drone data-link applications at the C band. A CB-CPW has been used to excite the CCDRA to achieve bore-sight radiation pattern. A wide impedance bandwidth of 1100 MHz (4.3–5.4 GHz) has been achieved due to excitation of HE11δ and HE21δ modes in dielectric resonator antenna (DRA) by inserting a cylindrical shaped air cavity in DRA. The antenna is finally optimized using 3-D electromagnetic simulator to achieve high gain, good impedance bandwidth, and stable radiation pattern. The prototype antenna achieves 22% impedance bandwidth with more than 7.5 dB average peak gain and 95% estimated efficiency throughout the operating band. The experimental results validate the performance of CCDRA. Such antenna can be easily installed on the unmanned aerial vehicle/drone platform for data-link as well as other applications.

Excitation of Higher Order Modes of Cylindrical Dielectric Resonator Antenna using Dual-slot feed

Excitation of the higher order modes (HOM) of a cylindrical dielectric resonator antenna(DRA) of high relative permittivity, using dual feed scheme is investigated. The feed scheme uses a pair of narrow slots and is chosen on the basis of the field distribution of the desired DRA modes. Numerical studies using ANSYS HFSS show that the dual-feed excited a combination of two HOMs, which are identified as HEM21δ and TM01δ. The mixed-up nature is further verified through studying the radiation pattern of the DRA which shows azimuthal asymmetry and low gain. It is suggested that if one of the HOM is suppressed, better antenna performance can be achieved.

Mode excitation in the microstrip slot‐coupled three‐layer hemispherical dielectric resonator antenna

In this study, a microstrip slot-coupled multilayer dielectric resonator antenna (DRA) structure is rigorously analysed from the modal perspective, taking into account all layers. The choice of layer permittivities of the multilayer structure to reduce the Q-factor and obtain optimum bandwidth performance of the antenna is outlined. Next, the mechanism of bandwidth enhancement for the centred and offset slots is examined taking into account the excited modes in the structure. It is found that while the centred slot couples to one DRA mode, an offset slot can couple to multiple DRA modes together with the slot mode. Thereafter, the excitation efficiency of modes in the multilayer DRA structure is highlighted to thoroughly characterise the modal contribution in the coupling behaviour for the centred and offset-slots.

Compact dual-band ring dielectric resonator antenna with moon-shaped defected ground structure for WiMAX/WLAN applications

In this article, compact ring-shaped dielectric resonator antenna (DRA) along with moon-shaped defected ground structure (DGS) was studied. The proposed antenna was fed by microstrip line shifted from center position, which excited TE01δ mode in ring DRA. Moon-shaped DGS was acting as a radiator and also reduced the size of proposed antenna by an amount of 14.87% (lower frequency band) and 48.77% (upper frequency band). The proposed antenna was designed to resonate at two different frequencies namely 2.24 and 5.82 GHz with a fractional bandwidth of 30.17% and 22.14%, respectively. Based on optimized design parameters, archetype of antenna structure has been constructed and measured successfully, which shows good agreement with simulated ones. The proposed antenna design was suitable for WLAN (2.4/5.2/5.8 GHz); WiMAX (2.5/5.5 GHz); AMSAT (5.6/5.8 GHz); and WAVE (5.9 GHz) bands. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:503–511, 2016.

Mode Excitation in the Coaxial Probe Coupled Three-Layer Hemispherical Dielectric Resonator Antenna

In this paper, a coax-probe excited multilayer dielectric resonator antenna (DRA) structure is rigorously analyzed from the modal perspective. The full-wave Green's function approach is presented for the analysis of such multilayer structures with an arbitrary number of layers with greatly reduced computational overhead. Additional reduction in computation time is demonstrated for a centered probe. Also, the modes of the multilayer DRA can be identified from the analysis, which can be used to explain the broadband nature of the coupling. The layer permittivities are optimized for broadband operation of the coax-fed DRA. The bandwidth enhancement for a centered and offset probe is seen to be due to a combination of several DRA modes and the probe resonance. Frequency tuning of the antenna structure is also demonstrated by exciting the antenna at a higher order mode, maintaining the broadband characteristics. The radiation characteristics of the antenna are also investigated.