Cylindrical Dielectric Resonator Research Articles

Dielectric resonator antenna with graphene layer and NMP structure for THz applications

Antennas with high performance and technological materials are relevant for several application on THz band. In this work, we investigate the cylindrical dielectric resonator antenna (CDRA) with non-resonant microstrip patch (NMP) feed combined with a thin layer of graphene on the top of the Dielectric Resonator (DR) designed for 3.30 THz. The NMP structure provides high order HEM12δ mode with great advantages in gain values and radiation efficiency. The graphene layer associated with the NMP structure provided improvements in gain and return loss, as well as, tuning characteristics by changing the chemical potential. The antenna was simulated in Ansys HFSS, and the results obtained with NMP radius of 12.7 μm are S11=−37.98 and 7.9dB gain. Besides, the bandwidth increased 6.6% to 20%. These results corroborate the effectiveness and enhancement of the antenna parameters providing a great alternative for Terahertz band applications.

A comprehensive study on crystal structure, phase compositions of the BiVO4-LaVO4 binary dielectric ceramic system and a typical design of dielectric resonator antenna for C-band applications

Novel multi-component (Bi1-xLax)VO4 (BLVOx) (0.05 ≤ x ≤ 0.9) solid-solution/composite ceramics crystal structures, phase compositions as well as its applications in the C-band dielectric resonator antenna have been designed and investigated. With the increased substitution of La3+, phase transitions among the monoclinic scheelite (mBiVO4), tetragonal zircon (zt(La,Bi)VO4) and monoclinic monazite (mLaVO4), driven by the compositional changes, were detected. La3+ played an essential role in the optimization of the dielectric properties of BLVOx. The measured Q × f values at the microwave band are considerably larger around the range of compositions forming the zircon phase and reached the maximum value (12,800 GHz) at pure zircon phase (x = 0.5), demonstrating that the impact of zircon structure on the intrinsic loss should not be disregarded and is beneficial for low dielectric loss. Meanwhile, the εr and TCF values could be tuned by regulating the concentration ratio of Bi3+/La3+ to obtain composites or solid-solutions with appropriate εr and near-zero TCF values. Additionally, a cylindrical dielectric resonator antenna (CDRA) of BVLO0.5 ceramic was designed with high simulated radiation efficiency (99.8%) and gain (4.58 dBi) at the center frequency (6.73 GHz), indicating its potential application in C-band because of its tunable permittivity and low-loss.

Transparent ionic liquid antenna based on multi-modes using multiple feeding structures

With the rapid development of modern wireless communication technology, there is an increasing demand for the functionality of the communication system carried by a single platform. To improve the utilization of the antenna, a multimode liquid antenna is proposed in this paper. The antenna is fabricated using 3D printing technology and mainly consists of a cylindrical dielectric resonator, a coaxial feeding structure, and a slot-coupling feeding structure. By hollowing out the middle of a resin container and filling it with low-loss ionic liquid with stable dielectric properties, a liquid dielectric resonator antenna (DRA) is formed. The various resonant modes (slot mode, HEM11δ, TM11δ, TM21δ, and TM31δ modes) can be excited by introducing different feeding structures. The operating frequencies and radiation patterns can be modulated by mode switching. Simulated and measured results show that the antenna operates in the frequency bands of 2.25–2.76 GHz (20.4 %) and 4.82–5.73 GHz (17.3 %), and the maximum gain can be up to 10.3 dBi. The proposed antenna structure avoids the complex RF control circuit design, which has various applications including 5G/6G communications, transparent electronic devices, and Internet of Things.

Investigating a Cylindrical Dielectric Resonator Antenna Fabricated with Li3MgNbO5 Microwave Dielectric Ceramic

This work aims to fabricate a single-feed line Cylindrical Dielectric Resonator Antenna (CDRA) using low-temperature sintered Li3MgNbO5 microwave dielectric ceramic as a resonator, excited in HEM11δ mode. The ceramic synthesized using the conventional solid-state route resulted in a single-phase material exhibiting a cubic structure with an Fm-3m space group. The densely packed cylindrical disk of the ceramic was subsequently characterized for its microwave dielectric behaviour in TE01δ mode using the Hakki-Coleman method. The dielectric permittivity (ε r) measures 14.4, with a loss factor (tan δ) nearly equal to 4.01 × 10−4 and a temperature coefficient (τf) of −50.9 ppm °C−1. The antenna design was executed using the high-frequency structure simulator design software, utilizing the dielectric ceramic as the resonator, Cu strip as the feedline, and FR4 as the substrate. The maximum energy was coupled to the antenna when the resonator was placed at 11.75 mm on the substrate. The fabricated CDRA, using appropriate simulated parameters, resonated at 7.67 GHz, offering a return loss (S11) of −32.64 dB and an impedance bandwidth of 10.73%. Furthermore, the CDRA displayed a voltage standing wave ratio of 1.04, ensuring a nearby ideal impedance match and a bandwidth of 810 MHz to support high-speed data transmission.

Dielectric Behavior Characterization of RE/BaTiO3 Using Time Domain Spectroscopy: Application on High-Performance Dielectric Resonator Antennas

We are working to design dielectric resonator antennas based on binary composites made of epoxy resin (RE) and barium titanate (BaTiO3 or BT). The composite samples are prepared at room temperature and under atmospheric pressure. The dielectric properties of these composites were assessed using time domain spectroscopy (TDS). The antennas structure are designed, simulated, and optimized using electromagnetic software Ansys, HFSS. Two types of antennas are studied. The first type consists of a cylindrical dielectric resonator that gives three antenna models in terms of bandwidths, the antennas having a single frequency band, the antennas having dual-band, and the antenna covering three frequency bands, with peak gains varying between 3.68 and 8.15 dB achieved. The second type consists of dielectric resonators composed of two adjacent identical shapes each consisting of a rectangular joined with a cylindrical with the same height. The proposed antenna achieves ultra-wideband with a relative bandwidth of 97% covering the range of 6 to 17.32 GHz, and dual-band circularly polarized ( AR<3dB ), the range of the lower band is 9.62 to 10.14 GHz and the range of the upper band is 16.74 to 16.94 GHz. The focus of this research is on creating novel antennas for applications in wireless communications systems.

Wideband Millimeter-Wave Perforated Cylindrical Dielectric Resonator Antenna Configuration

This article delves into the capabilities of 3D-printed millimeter-wave (mmWave) layered cylindrical dielectric resonator antennas (CDRAs). The proposed design yielded promising results, boasting a remarkable 53% impedance bandwidth spanning the frequency spectrum from 18 to 34 GHz. Furthermore, the axial ratio (AR) bandwidth achieved an impressive 17%, coupled with a maximum gain of 13.3 dBic. These notable results underscore the efficacy of the proposed design, positioning it as a viable solution for applications in Beyond 5G (B5G). A novel assembly technique was also investigated, employing additive manufacturing to seamlessly merge two layers with distinct dielectric constants into a singular layer. This innovative approach systematically eliminates the potential for air gaps between layers, enhancing the antenna’s overall performance. This approach exhibited potential, particularly in the performance of a millimeter-wave circularly polarized (CP) cylindrical DRA featuring a perforated coating layer. The synergy between measurements and simulations demonstrates a remarkable alignment, providing robust validation of the effectiveness of the proposed design.

Dual‐mode dielectric resonator antenna design with stub‐loaded feeding slot

AbstractA dual‐mode dielectric resonator antenna based on a microstrip line‐slot coupling feed, operating in both the GMS‐900 and GMS‐1800 frequency bands, is presented. The antenna structure consists of a rectangular dielectric substrate and a cylindrical dielectric resonator, which is fed by a microstrip line‐slot coupling. The cylindrical resonant cavity and the dual‐stub coupling slot are designed so that the HEM111 and HEM311 modes are excited simultaneously, resulting in resonance at the two desired frequency points. The gain of the antenna is 3.74 and 7.63 dBi at 0.9 and 1.8 GHz respectively, and the efficiency of the antenna is greater than 70% in both operating bands.

Optimizing the geometry of a cylindrical dielectric resonator antenna (CDRA) in combination with the design of a microstrip patch antenna to improve antenna efficiency.

Optimizing the geometry of a cylindrical dielectric resonator antenna (CDRA) in combination with the design of a microstrip patch antenna to improve antenna efficiency.

High gain circularly polarized graphene inspired dielectric resonator antenna for 6G IOT THz optical communication and optical refractive index bio sensing applications

In this article a high gain (≈13dBi) circularly polarized dielectric resonator antenna (DRA) has been designed with silicon and graphene based nano materials for 6G terahertz (THz) nano communication and bio sensing applications. This antenna having 2.2 % (4.32 to 4.42THz) 3 dB axial ratio and 3.72 % (4.32 to 4.5 THz) impedance bandwidth. Circular Polarization (CP) is achieved by the combination of Silicon/11.9 and Graphene based cylindrical dielectric resonator with 450 inclined rectangular silicon dielectric slab having height 8.4 µm. Patch top cylindrical dielectric resonator filled with Silicon/11.9 material along with graphene material having chemical potential 0.1 eV and relaxation time 0.1 ps at 3000 K temperature. Proposed DRA having 55 % radiation efficiency with 13dBi gain to utilize its directive property as a bio sensor application. Proposed DRA also use as high frequency optical beam to utilize this DRA works as bio sensor to detect the hemoglobin in bio molecules having average sensitivity 2750 GHz/RIU, FOM-11.38 and Q factor 71.0. So that above properties proposed DRA is good candidate for 6G optical /nano communication and bio sensing applications.

A Simple Cylindrical Dielectric Resonator Antenna Based on High-Order Mode with Stable High Gain

A Simple Cylindrical Dielectric Resonator Antenna Based on High-Order Mode with Stable High Gain

Mutual Coupling Reduction Between Two Tightly Packed Half-Split Cylindrical Dielectric Resonator Antennas

Mutual Coupling Reduction Between Two Tightly Packed Half-Split Cylindrical Dielectric Resonator Antennas

Direct Optical Modulation of RF Radiation Patterns in a Loaded Dielectric Resonator

Here we demonstrate the direct optical modulation of RF radiation patterns in a high permittivity (ϵ ∼ 80) cylindrical dielectric resonator antenna (DRA) loaded with a silicon superstrate. A hybrid mode (HEM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11δ</sub> ) is excited via microstrip. The far-field radiation pattern is characterized with an angle-dependent RF radiation measurement setup, and the near-field is measured using an optically induced conductance technique. We show that when light is incident upon the superstrate, the optically generated electron-hole-pairs (EHPs) in the silicon superstrate modulate and inhibit the far-field RF radiation. We compare our experimental results with finite element method simulations and show excellent agreement. Finally, we perform a proof of principle experiment to mix optically modulated signals with the baseband RF far-field radiation, paving the pathway for future free space optical/RF hybrid communications setups and modulation schemes as well as phase circuitry-free RF beam shaping and steering.

A low profile perturbed CDRA with convex conformal ground plane excited by differential feed

A low profile, Convex Conformal Cylindrical Dielectric Resonator Antenna (CCCDRA) with perturbation excited by dual coaxial probes in Differential Feed Arrangement (DFA) with TM11δ and TM21δ modes being observed at 7.7 GHz, and 8.7 GHz respectively, is presented and examined in this paper. The radiation performance of the bent Cylindrical Dielectric Resonator Antenna (CDRA) is investigated and it can be observed that at the bent angle of φ1 = 24°, high broadside gain is obtained therefore it is chosen for the proposed design. Investigation on the DFA is carried out and it is observed that the differentially driven CDRA offers a low cross polarization as well as directional broadside radiation pattern. Wide impedance bandwidth is achieved by perturbing the CDRA in such a way so as to maximize the Surface Area to Volume (S/V) ratio, resulting in lowering the Q-factor. A high-gain of 9.6 dBi at 8 GHz for wideband wireless applications, featuring 30.5 % fractional bandwidth is achieved. Additionally, the proposed CDRA has a height of 0.16 λ0 with a low profile. The simulation results are found to be in good agreement with the experimental measurements performed on a fabricated prototype.

Dual‐band pattern diversity liquid antenna with passive beam‐steering of the broadside modes

AbstractA dual‐band liquid cylindrical dielectric resonator antenna with pattern diversity at two different frequency bands is proposed using the lower order and higher order modes of the HEM and TM modes namely HEM11δ, HEM12δ+1, HEM31δ+1, HEM13δ, TM01δ, and TM02δ. The proposed antenna is designed to cover the GPS L2 band and the lower Wi‐Fi band at 1.227 and 2.4 GHz frequencies, respectively. The HEM modes which constitute the primary radiating modes achieved around 20.84% and 19.35% impedance bandwidth at lower and higher bands, respectively. In the later stage, beam‐steering is performed, whereby the realised broadside HEM modes at both lower and higher bands were passively steered with simple physical re‐orientation of the antenna structure. For this, the liquid's natural fluidic property of adhering to gravity is taken as an advantage which makes the proposed antenna adaptively steer its radiation pattern always towards the sky, irrespective of the tilt angle of the antenna. This concept of passively steering two modes at two different frequency bands without the use of any mechanical, electrical, or other associated components is presented for the first time.

Lossy dielectric resonator array absorber made of multiwalled carbon nanotubes/epoxy composite

A cylindrical lossy dielectric resonator array absorber is designed and verified by experiments. The designed cylindrical resonator array is made of a lightweight carbon multiwalled nanotube/epoxy composite material, and the gaps filled with polypropylene are used to fix the cylindrical array. Studies have shown that the lossy dielectric resonator array structure has dual-mode resonance characteristics, and the hybrid array composed of cylinders with different diameters can further generate multi-resonant coupling effects, thereby significantly improving the absorptivity. The total thickness of the designed absorber is 4 mm, and the normal incidence absorptivity is greater than 97% in the frequency range of 8–12 GHz. The measured results are consistent with the simulation, which verifies the reliability of the design concept and preparation method.

Slots-Fed Polarization- and Pattern-Diversity Cylindrical Dielectric Resonator Antenna With High-Gain Characteristic

This paper proposes a high-gain polarization- and pattern-diversity dielectric resonator antenna (DRA). It makes use of the high-order HEM <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_{31δ}$</tex-math></inline-formula> and TE <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_{02δ+1}$</tex-math></inline-formula> modes of the cylindrical DRA. To facilitate this diversity design, the dielectric waveguide model (DWM) is applied to seek the solution for these two DRA modes. In the design, two sets of slot pairs completely underneath the DRA are employed to excite the HEM <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_{31δ}$</tex-math></inline-formula> x and HEM <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_{31δ}$</tex-math></inline-formula> y modes separately, which produces the polarization-diversity performance. When these two slot pairs (totally four slots) have equal-amplitude and in-phase inputs, the omnidirectional TE <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_{02δ+1}$</tex-math></inline-formula> mode of the cylindrical DRA is excited, which combines with the previous broadside HEM <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_{31δ}$</tex-math></inline-formula> modes to obtain the pattern-diversity performance. For demonstrating the idea, a slots-fed polarization- and pattern-diversity cylindrical DRA made of K9 glass is designed for WLAN-5.8 GHz application. Measured result show the proposed DRA provides a peak gain of 6.02 dBi, which is a new high by compared with other reported polarization- and pattern-diversity DRAs. Besides, the proposed DRA is more appropriate for the microwave integrated circuit since only the planar slot-feeding is required.

A Four-Port MIMO Cylindrical DRA with High Isolation in Ultra-Compact Size for WLAN Applications.

A novel ultra-compact four-port multiple-input-multiple-output (MIMO) cylindrical dielectric resonator antenna (DRA) with improved isolation is proposed for WLAN applications in this paper. The antenna is originally radiated with the assistance of two different excitation mechanisms to generate decoupled orthogonal modes. To further diminish the coupling field and improve the isolation, a suitable U-shaped slot is created on the common ground plane. Two additional rectangular slits are also etched to adjust the impedance matching of other ports. To better reveal the operating mechanism of the decoupling scheme, the common mode (CM) and differential mode (DM) impedance analysis methods between DRA ports are presented. The etched U-shaped slot can tune the impedance of CM and DM to be consistent to realize the decoupling. The antenna is simulated, fabricated, and tested to verify the decoupling mechanism. The results demonstrate that the isolation between ports 1 and 2 is enhanced from 5 dB to 23 dB, and other ports exhibit low coupling of better than 12 dB. Moreover, the antenna with the full size of 30 × 30 × 8.1 mm3 can be used either as a four-port DRA with a bandwidth of 300 MHz or as a two-port DRA with a bandwidth of 700 MHz, at a center frequency of 5.6 GHz.

Circular polarized 3D-printed cylindrical DRA using parasitic dielectric helix

This article presents a 3D-printed cylindrical dielectric resonator antenna operating at 5.8 GHz that achieves circular polarization by integrating a fully dielectric parasitic helix with a higher permittivity than the cylindrical resonator. The antenna polarization can be right-handed or left-handed depending on the turning sense of the helix. An extensive parametric study was done for the helix design to evaluate the effects of the dimensions and dielectric constant of the helix over the matching and axial ratio of the antenna. The manufacturing is made using low-loss dielectric filaments and a low-cost 3D printer. Simulation and measurement results show that both antennas are well-matched and operate with the corresponding circular polarization, with an axial ratio bandwidth compatible with UAV applications.

A Pattern-Reconfigurable Cylindrical Dielectric Resonator Antenna With Three Switchable Radiation Patterns

A pattern-reconfigurable antenna with three switchable radiation patterns is investigated. It consists of a three-layer cylindrical dielectric resonator antenna (DRA) and a parasitic monopole antenna. Its feed network comprises a Y-shaped feedline, a square ring slot, and seven diodes. For the first time, by controlling the operation states of the diodes, the radiation pattern of the antenna can be switched between the omnidirectional, broadside, and unilateral modes. The omnidirectional pattern is obtained by virtue of the parasitic monopole, whereas the broadside pattern can be obtained when the DRA and radiation mode of the feeding ring slot are excited. If the parasitic monopole, DRA, and radiation mode of the slot are all excited, their radiation fields can be superimposed to give a unilateral radiation pattern. The radiated <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> -field is vertically polarized for all of the three radiation modes. A prototype working in 2.4-GHz ISM band was fabricated and tested to verify the idea, and reasonable agreement between the measured and simulated results is observed.

Bandwidth Improvement of a Cone-Inverted Cylindrical and Cross Hybrids Dielectric Resonator Antennas

This work employs the coaxial probe method to stack and excite two cone-inverted cylindrical and cross-hybrid dielectric resonator antennas at a standard operating resonant frequency of 5.438 GHz. A drawback of these standard Dielectric Resonator Antennas (DRAs) is their narrow bandwidth. For good antenna performance, a stacked DR geometry and a thick dielectric substrate with a low dielectric constant are desired since this provides large bandwidth, better radiation power, reduces conductor loss and reduces the nonappearance of surface waves. Many approaches, such as changing the shape of the dielectric resonator, have been used to enhance bandwidth. Using DRA, which has the lowest dielectric constant, increases the bandwidth and the electromagnetic energy. In the current work, bandwidth improvement was significantly achieved by the proposed geometry by varying the antenna size. A novel hybrid DRA configuration is used to increase the bandwidth of the antenna to 89.27% and 149.23% due to cone-inverted cylindrical and cross-hybrid dielectric resonator antennas, respectively. The DRA is designed numerically via the Finite Difference Time Domain (FDTD) method. Several parameters like return loss, input impedance (verified at ) and radiation pattern are calculated. Furthermore, the stacked-hybrid technique is used to enhance the antenna's performance, which is useful for broadband communication and the demand for wireless.