Cylindrical Dielectric Resonator Antenna 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.

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.

A droplet-shape inspired wideband bow-tie dielectric resonator antenna for sub-6 GHz and IoT applications

In this article, an approach to realizing a dielectric resonator based bow-tie shaped antenna for the sub-6 GHz, 5G and IoT applications is discussed that utilizes droplet-shaped radiators for its two arms. The droplet-shaped radiating element is systematically derived to obtain a wider bandwidth response by truncating the sides of an aperture-coupled cylindrical DRA operating at HE11δ mode. The proposed bow-tie dielectric resonator antenna (DRA) is a modified dipole structure that uses a balanced line to differentially feed the two radiating segments to attain an overall wideband characteristics. A wideband matching balun circuit facilitates the antenna feeding which produces equal amplitude signals with 180° phase difference at its two output ports throughout the band of interest. The measurement of the proposed antenna confirms that it can serve several 5G bands like n77 (3300–4200 MHz), n78 (3300–3800 MHz), n48 (3550–3700 MHz) and n79 (4400–5000 MHz) with an overall wide bandwidth of 42.7% in the sub-6 GHz range. This planar configuration has a realized gain value ≥7.5 dBi within 3.37–3.91 GHz and it remains higher than 6 dBi almost throughout the working bandwidth of 3.18–4.91 GHz with considerably wide beamwidth. This broadband DRA has a consistent broadsided radiation pattern with cross-polarization discrimination (XPD)> 20 dB and its radiation efficiency varies between 60%–70% within 3.2–4.8 GHz. The antenna occupies a volume 1.2λ×1.2λ×0.1λ corresponding to its lower frequency of operation and it can support many more significant applications including WiMAX (3.3–3.8 GHz), Citizens Broadband Radio Service (CBRS) (3.55–3.7 GHz) and LTE (3.41–3.5 GHz uplink/3.51–3.6 GHz downlink). All these characteristics make this antenna a suitable candidate for use in transceiver modules for indoor communication, base stations, and vehicular communication.

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.

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.

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

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.

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

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.

Design and Fabrication of Wideband Dielectric Resonator Antenna Using Low Loss Ultra‐Low Sintering Temperature Li6B4O9 Microwave Dielectric Ceramic for Wireless Communication Applications

AbstractLow dielectric constant (ɛr), high quality‐factor (Q × f), and temperature stable microwave dielectric ceramics with ultra‐low sintering temperature are the preferred choice of researchers for the development of low‐cost and high‐performance dielectric resonator antenna (DRA), which have wide application prospects for wireless communication technology. In this work, wideband DRAs fabricated using ultra‐low sintering temperature, low‐loss, and high‐quality Li6B4O9 microwave dielectric ceramics are reported. Li6B4O9 ceramic synthesized via solid‐state reaction at sintering temperature of 620 °C demonstrates excellent microwave properties with optimum ɛr = 5.95, high Q × f = 38,700@12.4 GHz, and thermal coefficient of the resonant frequency (TCF ≈ −68.6ppm/○C). For the first time, performance comparison of two Li6B4O9‐based cylindrical DRAs with different ceramic aspect (radius to height) ratios excited by slot coupled microstrip line is realized. In the first DRA with ceramic aspect ratio of 0.864, DRA HE11δ mode is excited and bandwidth of 20.01% , 95% radiation efficiency, and 6.3 dBi maximum gain is attained. In the second DRA with ceramic aspect ratio of 2.367, slot and dielectric resonator resonances are merged to attain wide bandwidth of 38.15% over which antenna broadside radiation performance is preserved. The proposed DRAs can be utilized for high‐capacity, high‐speed wireless communication applications.

A Multiband Millimeter-Wave Rectangular Dielectric Resonator Antenna with Omnidirectional Radiation Using a Planar Feed.

In this study, a millimeter-wave (mmWave) dielectric resonator antenna (DRA) with an omnidirectional pattern is presented for the first time. A key feature of the proposed design is the utilization of a planar feed network to achieve omnidirectional radiation from a rectangular DRA, which has not been reported previously in the open literature. In addition, the proposed antenna offers multiband operation with different types of radiation patterns. The degenerate TE121/TE211 modes were excited at 28.5 GHz with an overall internal electromagnetic field distribution that was similar to that of the HEM21δ mode of a cylindrical DRA. The achieved omnidirectional bandwidth and gain were 1.9% and 4.3 dBi, respectively. Moreover, broadside radiation was achieved by exciting the TE111 fundamental mode at 17.5 GHz together with the resonance of the feeding ring-slot at 23 GHz. The triple-band operation offers a highly versatile antenna that can be utilized in on-body and off-body communications. Furthermore, the proposed design was validated through measurements, demonstrating good agreement with simulations.

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.

English

An ultra-wideband (UWB) antenna is designed, which is fed by a coplanar waveguide along with Dielectric ResonatorAntenna (DRA) is discussed. The patch of ultra-high-frequency antenna structure comprises many full circles and half circles, rearranging the two focal point orientation and dimension of radius such that the antenna works in ultra-wideband frequency range and a rectangular slot in the middle of the antenna patch to change the orientation of current distribution. The antenna is resonating at 8.9GHz with a reflection coefficient (S11) of -15.39dB, Gain is negative at resonating frequency, and Polarization at resonating frequency is linear. The proposed antenna is designed by mounting Cylindrical Dielectric Resonating Antenna (CDRA) on the rectangular slot made on the patch. By mounting a cylindrical DRA structure on the patch, the antenna is resonating at 3.6 GHz with a reflection coefficient (S11) value - 22.54dB, achieving a Gain of 3.44dB at resonating frequency. The Polarization achieved by placing cylindrical DRA is circular Polarization which is more useful in Ground Penetrating Radar (GPR) applications. The proposed antenna is practically designed, and performance characteristics are measured and verified with simulation results.

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.

Design and Performance prediction of Liquid based Tunable Cylindrical Dielectric Resonator Antenna

In this paper, we report a liquid-based tunable Cylindrical Dielectric Resonator Antenna (CDRA), whose resonance is varied by loading the cavity installed in the CDRA with different volumes of liquid. The tunability of the CDRA is investigated by loading the cavity with two different types of liquids, one with lower permittivity (i.e.) oil and the other with higher permittivity (i.e.) water. CDRA loaded with oil is found to be tunable over a small frequency range of 32MHz (5.76GHz to 5.728GHz), whereas the change in water volume in the cavity provides a wide tuning range of 452MHz (5.76GHz to 5.308GHz). Further, the antenna gain is found to be almost constant, around 5.1 dB, for oil-based CDRA. In a water-filled cavity, the gain is observed to reduce by 1dB as the volume is increased from 0 to 100%.

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.