Dielectric Resonator Antenna Elements Research Articles

2 × 2 MIMO dual spiral octagonal prism liquid DRA with snake-shaped DGS for OAM multiplexing.

In this paper, we proposed a 2 × 2 multiple-input multiple-output (MIMO) dual spiral octagonal prism liquid dielectric resonator antenna (DRA) with snake-shaped defective ground structure (DGS) for space multiplexing of orbital angular momentum (OAM). The DRA element adopts an inner and outer nested dual spiral structure filled with 0.035 g/ml of brine outside and a cylinder filled with distilled water inside. The proposed MIMO antenna can generate resonance at 1.78-3.02 GHz and 4.01-7.73 GHz (S11≤-10 dB). The isolation among ports is below -20 dB at 2.6 GHz and below -40 dB at 5.1 GHz, which can effectively isolate the l = ±1 and l = ±3 modes' OAM waves through the snake-shaped DGS. The proposed MIMO antenna improves spectral efficiency by OAM spatial multiplexing with l = ±1 and l = ±3 modes' OAM, which improves the data transmission efficiency. The proposed MIMO antenna provides a novel, to the best of our knowledge, solution for wireless communications to improve spectral efficiency.

Frequency-Reconfigurable Millimeter-Wave Rectangular Dielectric Resonator Antenna.

This paper introduces an innovative and cost-effective approach for developing a millimeter-wave (mmWave) frequency-reconfigurable dielectric resonator antenna (DRA), which has not been reported before. The antenna integrates two rectangular DRA elements, where each DRA is centrally fed via a slot. A strategically positioned PIN diode is employed to exert control over performance by modulating the ON-OFF states of the diode, thereby simplifying the design process and reducing losses. In the OFF state, the first DRA, RDRA-I, exclusively supports the TE311 resonance mode at 24.3 GHz, offering a 2.66% impedance bandwidth and achieving a maximum broadside gain of 9.2 dBi. Conversely, in the ON state, RDRA-I and RDRA-II concurrently operate in the TE513 resonance mode at 29.3 GHz, providing a 2.7% impedance bandwidth and yielding a high gain of up to 11.8 dBi. Experimental results substantiate that the proposed antenna presents an attractive solution for applications necessitating frequency-reconfigurable and high-performance mmWave antennas in 5G and Beyond 5G (B5G) communication systems.

Wideband millimeter-wave hybrid dielectric resonator antenna array with dual-slot feeding

ABSTRACTA hybrid dielectric resonator antenna (DRA) array is proposed for the wideband millimeter-wave communication. The radiator is composed with a pair of stacked dielectric resonators (DRs), which are H-shaped and Hexagon-shaped DRs, respectively. The dual-slots on the substrate integrated waveguide (SIW) cavity are utilized for higher mode generation in the DRA element. The antenna bandwidth is improved by the stacked DRs and dual-slot feeding. The structural characteristics and key parameters of feeding slots are discussed in detail. The DRA array fed with parallel power distribution feeding network is fabricated and measured to verify the reliability of the simulations, and the simulations and measurements have reasonable consistency. The impedance bandwidth is from 23.55 GHz to 27.28 GHz (14.7%), and the measured gain ranges from 13.1 dBi to 15.7 dBi. The radiation patterns are stable in the operation band. The proposed DRA array has a promising application prospect for 5 G communication system.

Novel corrugated rectangular dielectric resonator antenna with wide half power beam width

ABSTRACT In this work, a dielectric resonator antenna element is corrugated in a specific way, which led to increase its half power beam width (HPBW). The HPBW of the antenna is investigated for different values of corrugation depth and it has been concluded that HPBW can be increased by increasing this depth. By embedding periodic grooves in the DRA walls, it is possible to adjust the radiation intensity ratio of the upper wall to the side walls. By increasing this ratio, the HPBW of the antenna can be increased. To confirm the concept of beam widening method, a prototype of the corrugated DRA is fabricated and measured. Measured results show an impedance bandwidth of 23% (3.8–4.8 GHz). The measured E- and H-plane HPBWs at 4.1 GHz are 137° and 123°, respectively. Measured and simulated results are in a good agreement.

MIMO-DRA with triple-band CP & low EM coupling: a methodical design approach

This article presents a methodical approach for designing a circularly polarized multiple-input-multiple-output (MIMO) dielectric resonator antenna (DRA) with triple frequency bands and low mutual electromagnetic (EM) coupling. The MIMO configuration is composed of two identical circularly polarized DRA elements in an orthogonal arrangement. To achieve circular polarization (CP) radiation, each rectangular DR element is modified and rotated with respect to the feeding-aperture. Meanwhile, the low mutual coupling is obtained by arranging the DRA elements orthogonally, and also by etching a Y-shaped slot on the ground plane. The Y-shaped slot facilitates the increase of the coupling current path, which decreases the inter-port coupling. The simulated outcomes are validated through an experimental test of the fabricated prototype. The proposed concept provides triple impedance bands as well as triple CP bands with low EM coupling ( < −25 dB). This article fills a research gap by developing a circularly polarized triple-band MIMO-DRA that can be used for a variety of wireless applications, including WiMAX, Wi-Fi, WLAN, and satellite communication.

Wideband Low-Profile Connected Rectangular Ring Dielectric Resonator Antenna Array for Millimeter-Wave Applications

A wideband low-profile connected rectangular ring dielectric resonator (DR) antenna (DRA) array is presented for millimeter-wave (mmWave) applications. It consists of four rectangular ring DRA elements. The DRA elements are excited by microstrip feedlines through four slots on the ground plane. A slot mode, the DRA <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm {TE}}^{\text {y}}_{1\delta 1}$ </tex-math></inline-formula> mode, and the perturbed <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm {TE}}^{\text {y}}_{3\delta 1}$ </tex-math></inline-formula> mode are simultaneously excited, giving a wideband design. To avoid the alignment problem, the DRAs are connected to their adjacent elements through dielectric arms. It is found that the position of the dielectric arms has significant effects on the antenna performance. To demonstrate the idea, a prototype with a dielectric constant of 20.8 was designed, fabricated, and tested for licensed mmWave bands (24.25–29.5 GHz). A reasonable agreement between the measured and simulated results is observed. The measured 10 dB impedance bandwidth ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\vert \text{S}_{11}\vert \le - 10$ </tex-math></inline-formula> dB) is 31.6% (22.52–30.97 GHz), with a measured boresight realized gain being higher than 8 dBi from 22.5 to 30 GHz. The measured mutual couplings between the DRA elements of the array are lower than −20 dB in the operating frequency range. Furthermore, our prototype has a low profile of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.074~\lambda _{0}$ </tex-math></inline-formula> , where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{0}$ </tex-math></inline-formula> is the wavelength in air at the center frequency.

5G MILLIMETER WAVE MIMO DIELECTRIC RESONATOR ANTENNA

A four-element rectangular dielectric resonator antenna (DRA) array for fifth generation (5G) multiple-input-multiple-output (MIMO) application at 28 GHz is presented. Each DRA element of the array has a very small dimension of 3 &amp;times; 0.03 &amp;times; 6 mm and oriented at an angle of 90 deg to each other. Total dimension of the proposed antenna system is 20 &amp;times; 20 &amp;times; 7 mm. Each antenna of the system has high radiation efficiency (&amp;#60; -0.004 dB). Defected ground structure is used to obtain very good isolation (&amp;#62; 27 dB) between any two DRA elements of the array. Moderate directivity (&amp;#62; 4.1 dBi) of the MIMO antenna can be increased up to 7.8 dBi using thin metal walls to separate each DRA element of the system. This MIMO antenna system is capable of giving 4 GHz impedance band width extending from 25.78 to 29.78 GHz. Computer simulation technology is used to design and investigate the performance parameters of this MIMO antenna system. Performance parameters of the proposed antenna are compared with similar types of antennas found in recent literature.

Design of Self-Decoupling Dielectric Resonator Antenna With Shared Radiator

The method of mode cancellation to design a two-port dielectric resonator antenna (DRA) for an in-band full-duplex (IBFD) application is investigated in this communication. The whole antenna structure is straightforward, only composed of a single DRA element, a pair of feeding lines, and a pair of metallic probes. Attributing to the features of different modes used in this design, mutual coupling between the exciting port and the passive port can be suppressed to an extremely low level without using an extra decoupling structure. A prototype is fabricated and measured for verification. The measured results demonstrate that the proposed antenna has broad bandwidth and high isolation level can be achieved throughout the whole working band.

Wide‐beam bent cross‐shaped DRA antenna for wide‐angle beam‐scanning phased array

AbstractIn the paper, a bent cross‐shaped dielectric resonator antenna element with wide half‐power beamwidth of 224.9° is proposed and applied for designing a 1 × 8 wide‐angle beam‐scanning linear phased array. To obtain small gain drop and reduce the mutual coupling of the scanning array, the dielectric wall loaded rectangular truncated slots are inserted. For validation, a prototype operating at 5.8 GHz is designed. Measurement results indicate that the main beam of the designed phased array can scan from −70° to +70° GHz with a gain drop of less than 1.75 dB and a sidelobe level of less than −5.08 dB.

Design of Dielectric Resonator Antenna Array With Wide-Angle Scanning Based on Dual Magnetic Currents

A wide-beam dielectric resonator antenna (DRA) and its related phased array with wide-angle scanning are presented in this article. To improve the scanning coverage and cross polarization discrimination (XPD) simultaneously, the wide-beam method utilizes dual magnetic currents (MCs) in the same direction. The operating principle is theoretically analyzed using suspended MC theory. Two wide-beam DRAs working in TE <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{y}_{1\delta 1}$ </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">$^{y}_{1\delta 3}$ </tex-math></inline-formula> modes with parasitic loops are studied to verify the presented beam-broadening method. The simulated 3 dB beamwidths of the two DRAs are higher than 205° and 140° in the E- and H-planes, respectively. Two wide-beam DRAs operating at 5.5 GHz were fabricated and measured. Based on the wide-beam DRA element, the passive eight-element array antenna and three feeding networks corresponding to scanning angles of 0°, 40°, and 80° were machined. The total array system is verified to have an enhanced beam scanning angle of ±85° with a gain fluctuation of 2.5 dB. The co-polarization is stable and the XPD is greater than 20 dB for any scanning angle.

A Shaped-Beam Antenna for Wide-Angle Scanning Phased Array

A phased array usually suffers from severe gain drop when its beam steers in a wide range. In this article, an alleviating technique based on a gain-compensating approach is proposed. Isolated element pattern (IEP) and array factor are jointly considered. When calculating the array factor, mutual couplings between antennas in an array are also included. The IEP is optimized in such a way that the element gain is nearly inversely proportional to the peak gain of the array factor. As a result, the peak gain of the overall array beam can be kept almost the same in a wide scanning range. As an example, a cylindrical dielectric resonator antenna (DRA) array is investigated. In such a design, a dip is introduced to the top of the element pattern so that the top peak in the array factor envelope can be compensated. This idea is demonstrated by using an X-band cylindrical DRA, with its beam shaped by using a loading peripheral metal ring and two top dielectric slabs. This shaped-beam DRA element is used to construct a nine-element H-plane linear phased array. The element and array prototypes were fabricated and measured, and reasonable agreement between the measured and simulated results is observed. The measured 3-dB beamwidths of the DRA element are 172° and 149° in the E- and H-planes, respectively. It is found that the H-plane main beam of the DRA array can scan from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$- \mathrm{72}^{\circ }$ </tex-math></inline-formula> to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$+ \mathrm{72}^{\circ }$ </tex-math></inline-formula> with a small gain fluctuation of less than 0.9 dB.

Wideband Polarization Agile Dielectric Resonator Antenna With Reconfigurable Broadside and Conical Beams

A new broadside and conical beam reconfigurable dielectric resonator antenna (DRA) with three orthogonal linear polarizations (LPs) and two orthogonal circular polarizations (CPs) agility is presented. It consists of a quad-strip-fed DRA element and a reconfigurable feeding network. First, the DRA element is designed to make unidirectional <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm{HEM}}_{11 \delta }$ </tex-math></inline-formula> mode and omnidirectional <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm{TM}}_{01 \delta }$ </tex-math></inline-formula> mode operate in the same wide band by tactfully removing a concentric annular column from its interior. Furthermore, a center-loaded metal post helps to improve the impedance matching of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm{TM}}_{01 \delta }$ </tex-math></inline-formula> resonance significantly. Afterward, the switchable feed network is designed to implement diverse phase distributions of four output ports, i.e., providing the quad-port in-phase excitation, dual-port differential excitations, and quad-port sequentially rotated phase excitation strategies for a vertical LP, ±45° slant horizontal LPs, and two CPs, respectively. Finally, a fully functional prototype is designed, fabricated, and measured to validate the design. The measured results show that the overlapping impedance bandwidth of 36.8% for all the states and the axial-ratio bandwidth of 33.8% for the CPs are obtained.

Design of Filtering Dielectric Resonator Antenna Arrays Using Simple Feeding Networks

A 1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 3 filtering dielectric resonator antenna (DRA) array is investigated in this communication. The central DRA is excited by a microstrip-coupled slot, while the two side DRA elements are, respectively, excited by the central DRA via a low-profile patch-loaded dielectric bridge laid between them. In order to integrate the filtering function, the open stub of the microstrip feed line is elaborately designed to generate a radiation null at the upper band edge, while two vertical metallic strips are added onto the sidewalls of the central DRA to provide another radiation null at the lower band edge. On the other hand, in order to achieve an enhanced gain in the operating passband, the higher order TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">113</sub> mode of the DRA elements is excited. It is found that due to the loading effects of metallic patches and conformal strips, three stepping resonances of the TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">113</sub> mode are generated in the passband, leading to a wide impedance bandwidth of 13.7% and a stable gain of 11.4 dBi. As a result, both good radiation and filtering performance are achieved without requiring complex filtering circuits. To demonstrate the extensibility of the array, a larger 3 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 3 filtering DRA array with a high peak gain of 14.7 dBi is further designed by just using a three-way power dividing network.

Broadband Dielectric Resonator Antenna Array With Enhancement of Isolation and Front-to-Back Ratio for MIMO Application

Dielectric resonator antenna (DRA) arrays with enhanced isolation and front-to-back ratio (FBR) are proposed in this letter. Specifically, each DRA element is mounted on a small and separated ground plane; all the DRA elements (with small ground planes) share a large common ground plane. Each DRA element is excited by two differential probes at its edges. The DRA element in its <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\boldsymbol{TE}}_{{\boldsymbol{\delta }}11}^{\boldsymbol{x}}$</tex-math></inline-formula> mode is equivalent to a magnetic dipole. Meanwhile, the differential probes also excite electric current on the small grounds that can be viewed as an electric dipole. The equivalent magnetic and electric dipoles are orthogonal, behaving like a magnetoelectric dipole (ME-dipole). By properly adjusting the small ground planes’ size and their height above a sizeable common ground plane, a broadside unidirectional radiation pattern with low backward radiation is realized; moreover, the small ground structures can provide neutralization paths to counteract the original coupling waves. A <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$1 \times 4$</tex-math></inline-formula> single-polarized DRA array is designed, fabricated, and measured. Measurements align well with the simulations, demonstrating significant isolation and FBR improvements compared with the conventional DRA array. The proposed array has about 20% relative bandwidth.

Wide‐angle scanning phased array using wide‐beamwidth dielectric resonator antenna with miniaturised radiator

A wide-beamwidth dielectric resonator antenna with small radiator is used to design a wide-angle scanning phased array. The proposed dielectric resonator antenna element uses concave structure for wide-beamwidth, and the metal patches on the top of the dielectric resonator are used to reduce the size of radiator. The simulated half-power beamwidth of dielectric resonator antenna is 157.8° and 140.9° in the E- and H-planes, respectively, while the size of the radiator of the dielectric resonator antenna is only 9.7 × 9.7 × 10 mm3 (0.162λ0 × 0.162λ0 × 0.167λ0). One 1 × 8 linear phased array is designed based on the dielectric resonator antenna element. Due to the small size of dielectric resonator radiator, the mutual coupling between the array elements is very small and each element in the array has the similar radiation pattern with wide-beamwidth. Because of these critical features, the phased array can scan from −67° to +67° with a gain fluctuation less than 1 dB and a maximum side lobe level less than −10 dB. Measurement results agree well with simulation.

Implementation of Parasitic DRA Elements for Improvement of Circular Polarization

In this letter, for the first time, the sequential rotation technique is implemented by applying four parasitic dielectric resonator elements to achieve a noticeable improvement of circular polarization (CP) purity. Specifically, the parasitic elements cancel the cross-pol E-field component, and then, the improvement of CP performance is achieved. In the proposed structure, the main element is only excited, and parasitic elements have no aperture coupling and feed network system. Therefore, it leads to reduced feed complexity and ohmic loss in millimeter-wave (MMW) frequency. The measured low axial ratio bandwidth ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$&lt; $</tex-math></inline-formula> 1.5 dB) is 12.42%. Furthermore, to design the single-element antenna, a toothed dielectric resonator antenna (DRA) configuration is presented, which not only provides more orthogonal modes but also enhances the CP gain at each resonant frequency. The measured maximum CP gain is 8.33 dBic for a single-element DRA.

An Arrangement for Four-Element MIMO DRA With Complementary CP Diversity

An integrated four-element dielectric resonator-based multiple-input-multiple-output (MIMO) polarization diversity antenna is proposed in this letter. The MIMO antenna comprises two microstrip-slot fed dielectric resonator antenna (DRA) elements and two conformal open-loop fed DRA elements. These two different types of antenna elements are intended to radiate in two opposite directions to reduce the field components' interference. This aspect can offer a reliable wireless connection. Also, circular polarization diversity is implemented between the diagonally placed antenna elements to improve the isolation and diversity performance. The measured overlapping impedance bandwidth (S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ii</sub> <; -10 dB) of 500 MHz (3.22-3.72 GHz) is attained for the proposed MIMO antenna with interport isolations of more than 15 dB throughout the usable frequency band. The proposed MIMO antenna acquires a measured overlapping axial ratio (AR) bandwidth (AR <; 3 dB) of 200 MHz (3.34-3.54 GHz), which covers the 3.4 GHz carrier frequency for the vehicle-to-vehicle and vehicle-to-infrastructure applications.

Low-Dispersion Leapfrog WCS-FDTD With Artificial Anisotropy Parameters and Simulation of Hollow Dielectric Resonator Antenna Array

An optimized three-dimensional one-step leapfrog finite-difference time-domain (FDTD) method has been investigated, which is with a weakly conditional stability (WCS) to reduce numerical dispersion further. By introducing the artificial anisotropy parameters in a cross-correspondence manner, the phase velocity error is effectively limited without additional computational time and memory cost. An auxiliary field variable is adopted to simplify the iterative formulae with few additional processes, and the same stability has been validated between methods of conventional leapfrog WCS-FDTD and ourselves. Moreover, much lower numerical dispersion is shown to withstand larger Courant-Friedrich-Levy number under the same error condition. To verify our method efficiently, a newly designed hollow dielectric resonator antenna (DRA), instead of a solid one, is conducted effective calculation. Furthermore, two forms of four-element arrays have been developed with the DRA element above, and a T-shaped power divider is designed as a fed network and subjected to calculations and experimental analyses. Reflection coefficients and radiation patterns are shown the effectiveness of both DRA and arrays. The most noteworthy aspect is that our low-dispersion WCS-FDTD scheme can be effectively simulated the hollow DRA and arrays, and with excellent performance in terms of memory occupation, calculation accuracy, and efficiency.

Dual‐band orthogonal polarised shared aperture array with shared‐elements

In this paper, an orthogonal polarised dielectric resonator antenna (DRA) which can operate at S- and C-band, has been designed as “shared-element” for forming a dual-band shared aperture array. Furthermore, in this shared aperture array, the S-band array contains four shared-elements, and the C-band array contains four shared-elements and twelve C-band DRA elements. Moreover, a phase compensation power divider is employed to help offset the radiation performance differences between the two types of antenna elements when forming the C-band array. A prototype array was fabricated and measured, showing that the antenna can cover the band of 2.4–2.63 GHz and 6.9–7.1 GHz, respectively. The isolation between bands is higher than 30 dB. The cross-polarisation levels are less than -30 dB in both bands.

Wideband circularly polarized aperture coupled DRA array with sequential-phase feed at X-band

A novel 2 × 2 wideband dielectric resonator antenna (DRA) array with circular polarization and fed with a sequential-phase feeding network at the X-band is presented in this paper. The proposed DRA array is fed by an aperture coupled feeding network. Each DRA element is constructed by joining two identical pieces of half-cylindrical shape; those are shifted with respect to each other to produce two orthogonal modes, in order to achieve a broadband circular polarization and wideband impedance matching simultaneously. The rigorous analysis and optimization processes throughout this paper are carried out numerically. The proposed array demonstrates a maximum realized gain of 10.3 dB. The measured matching bandwidth ranges from 8 to 12 GHz (40%), with about 37% 3-dB axial ratio bandwidth within the matching bandwidth. The quadruple DRA elements array is fabricated, and its scattering parameters and far-fields performance are measured to validate the numerical results. Acceptable agreement between the simulated and measured results is accomplished. It is demonstrated that the proposed antenna is a potential candidate for radar and satellite applications at X-band.