Resonator Antenna Research Articles

A Review of Circularly Polarized Dielectric Resonator Antennas: Recent Developments and Applications.

A comprehensive review on recent developments and applications of circularly polarized (CP) dielectric resonator antennas (DRAs) is proposed in this paper. DRAs have received more considerations in various applications due to their advantages such as wide bandwidth, high gain, high efficiency, low losses, and low profile. A broad justification for circular polarization and DRAs is stated at the beginning of the review. Various techniques such as single feed, dual, or multiple feeds used by different researchers for generating circular polarization in DRAs are briefly studied in this paper. Multiple-input-multiple-output (MIMO) CP DRAs, which can increase channel capacity, link reliability, and data rate, have also been analyzed. Additionally, innovative design solutions for broadening the circular polarization bandwidth and reducing mutual coupling are studied. Several applications of DRA are also discussed comprehensively. This paper finishes with concluding remarks.

Multi-band orbital angular momentum mode-division multiplexing by a compact set of microstrip ring-shaped resonator antenna.

Optical beams carrying orbital angular momentum (OAM) have received much attention due to the prospects of their use in terahertz communications, biomedical engineering, and imaging. Here we propose an antenna design for the generation of multiple beams carrying OAM with different topological states at the same frequency. The proposed OAM generator is based on a compact set of microstrip ring-shaped resonators. An analytical solution for the radiated field of a single circular ring resonator antenna is derived involving the cavity model and the magnetic current approach. To verify our theoretical description, the numerical full-wave simulation is performed for an actual size OAM generator with the use of the ANSYS HFSS electromagnetic solver, and an antenna prototype operating in the microwave band is fabricated and tested. Conditions of the antenna operation in the combined OAM and mode-division multiplexing (OAM-MDM) regimes are discussed. Obtained results prove that the proposed antenna can be used as a compact and low-cost generator of multiple beams with different OAM states.

A Performance Assessment of A Slotted Reconfigured Microstrip Patch Antenna for Multi-Wireless Applications

A Dual Frequency reconfigurable antenna is presented in this paper. Achieving Reconfigurability in the resonant frequency of microstrip patch antenna by introducing slots and structure alteration has been proposed. The proposed designs of rectangular microstrip patch antennas are resonating at 5 and 2.1 GHz(reconfigured) respectively. Modeling of reconfigurable antenna to achieve max size reduction by introducing partial ground concept and patch structure alteration has been used. Modelling of reconfigurable antenna for multiband operation is the one of the major challenges and the solution for this challenge is by introducing the slots over the patch of the antenna. To achieve wider bandwidth for wireless applications changing the structure patch and partial ground plane concept is proposed. Reconfigured antennas are well known for their characteristics like lightweight, low profile, and compact enough to be employed in smart wearable technology as well as portable electronics (such as, watches, smartphones, iPads, PDAs, and laptops), A Finite Element Method (FEM) and numerical Finite Integration Technique (FIT) are used in CST Microwave studio to estimate the antenna scattering and far-field characteristics.

Crosstalk in CMOS Terahertz Detector Array With On-Chip SPR Antenna

Although surface plasmon resonance (SPR) antennas have been integrated into CMOS THz detectors as an alternative to the traditional radio-wave antenna, spatial crosstalk of SPR antenna in detector arrays remains an issue and there is little study in this field. In this paper, a CMOS THz detector array at 0.65 THz with on-chip SPR antennas is designed in standard CMOS technology and the pixel crosstalk related to the SPR antenna parameters are investigated. Simulation results show that the adjacent SPR antenna spacing significantly affect the antenna crosstalk due to the surface wave propagation. To suppress the pixel crosstalk, the adjacent SPR antenna spacing is designed as 1.65 times larger than half of the antenna size. Under the condition, the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S₁₂</i> parameter between the adjacent antennas is reduced to -15 dB. High antenna isolation can be further available by the increase of the isolation layer thickness of the pixel up to 1 μm. Based on the simulation results, a 1×16 THz detector array at 0.65THz was fabricated. The experimental results show that the pixels in the array achieve uniform <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">NEP</i> , with an average value of about 32.6 pW/Hz <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</sup> and a standard deviation coefficient of about 9.6%. The results can be further optimized to meet various crosstalk requirements for CMOS THz detectors.

Quadruple band MIMO dielectric resonator antenna for 5G SUB-6 GHz applications

A quadruple band with L-slotted MIMO square dielectric resonator antenna (SDRA) for Fifth Generation (5G) applications at the sub-6 GHz band which can cover 5G New Radio band N77 (3.3 – 4.2) GHz and N79 (4.4 – 5) GHz. The proposed structure consists of a single SDRA which mounted on a substrate excited by an aperture slot underneath Dielectric Resonators (DR)s. The performance of SDRA is improved by introducing L shaped slots on the central part of DRA. Results show that the MIMO SDRA antenna achieves |S&lt;sub&gt;11&lt;/sub&gt;|&amp;lt; -10 dB and S&lt;sub&gt;21&lt;/sub&gt;&amp;lt;= -15 dB for all resonant frequencies at 3.5 GHz, 4 GHz, 4.6 GHz and 5 GHz, indicating a good performance of the antenna at the desired frequencies. The maximum realized gain is 5.61 dB and 5.01 dB at port 1, 4 GHz and port 2, 4.6 GHz, respectively. The radiation efficiencies are acceptable for all resonant frequencies. Moreover, a low (&amp;lt; 0.1) envelop correlation coefficient, and about 10 dB of diversity gain at both desired frequencies. Thus, the antenna can be used for 5G sub-6 GHz applications.&lt;p&gt; &lt;/p&gt;

A Low-Cost Miniaturized Filtering Dielectric Resonator Antenna Based on SISL for 5G Applications

To realize a low-cost, miniaturized, and high selective design, the filtering dielectric resonator antenna (FDRA) for 5G applications is first proposed based on the substrate-integrated suspended line (SISL). The FDRA consists of two same rectangular DRs embedded in air cavities, which are fixed by the hollowed substrate rings. A T-shape feeder, rectangular feeder, and metalized holes are introduced to excite the fundamental <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm {TE}}_{\delta 11}^{x}$ </tex-math></inline-formula> mode of DRA. The substrate rings and DR are regarded as a composite dielectric to miniaturize the antenna and have effects on the radiation nulls. Because of the different loading effects from the different feeders, the resonance frequency 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">${\mathrm {TE}}_{\delta 11}^{x}$ </tex-math></inline-formula> mode excited by the different feeders is slightly different. Therefore, a wide bandwidth can be achieved. In the hybrid feed scheme, three radiation nulls are introduced near the edge of the frequency band without an extra filtering circuit. To improve the suppression level, the effective size of the radiator is increased by increasing the width of the substrate rings without changing the size of the whole structure. Therefore, two prototype antennas with different widths of substrate rings are designed, manufactured, and measured. Good agreement can be observed between simulated and measured results.

Dual-Port Compact MIMO-DRAs: Exploiting Metallic Sheets to Increase Inter-Port Isolation at 28-GHz 5G-Band

This brief proposes a novel decoupling method based on metallic sheets to improve inter-port isolation in dual-port single-element multiple-input-multiple-output (MIMO) dielectric resonator antenna (DRA) systems. Two different structures, including an H-plane and an E-plane decoupled MIMO arrangement, have been investigated. The exploitation of metallic sheets can significantly impact the electromagnetic (EM) field distribution inside the dielectric resonator (DR) and restrict the strongest portion of the EM energy couple to the nearby slot. As a result, inter-port isolation can be improved significantly. As the single DR element is used and metallic sheets are embedded within the element, no additional footprint is required, making the MIMO antenna arrangements compact and simple. The outcomes convey a maximum enhancement in the inter-port isolation of the H-plane decoupled MIMO arrangement is about 23.45 dB, while that of the E-plane decoupled MIMO arrangement is about 17.08 dB across the operating frequency band.

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.

Co-Design of Dielectric Resonator Antenna and T-Shaped Microstrip Feeding Network for Back-Radiation Suppression

In practice, the broadband feeding network on the back side of an antenna can have a nonnegligible effect on the antenna's back radiation due to the feeding network's radiation contribution. Thus, a back-radiation cancellation scheme is proposed by co-designing the antenna and its feeding network to solve this problem. The antenna and its feeding network can be viewed as a two-element array. Their radiation toward the antenna's backward direction can cancel each other when both have equal amplitude and opposite phases along the back direction. A differential fed dielectric resonator antenna (DRA) through a rat-race coupler ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${180}^\circ $</tex-math></inline-formula> hybrid coupler) and a T-shaped broadband differential feeding network are compared and analyzed to verify the proposed scheme. In addition, 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> DRA array with a T-shaped broadband differential feeding network in a previous work (where the feeding network's radiation effect on the back side was overlooked) is used for experimental validation of the proposed scheme. Simulations and measurements demonstrate significant back-radiation suppression than the ideal differential feeding network.

Stable High-Gain Linearly and Circularly Polarized Dielectric Resonator Antennas Based on Multiple High-Order Modes

Dielectric resonator antennas (DRAs) under high-order multiple-modes resonator (MMR) for stable high gain are proposed in this communication. The approach is to implement slot cuts on the surface of DR for reconstructing the electric field distribution of high-order resonance modes. In this way, the sidelobes are reduced and two high-order modes are reallocated to construct a continuous wide band. Various MMR configurations were proposed in this work. First, a DRA operating 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">$^{\mathrm {x}}_{031}$ </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">$^{\mathrm {x}}_{051}$ </tex-math></inline-formula> modes is proposed with a pair of loaded slots to realize a fractional bandwidth (FBW) of 26% and a stable gain as high as 8.3 dBi within the desired passband. Second, a DRA with TE <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\mathrm {x}}_{051}$ </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">$^{\mathrm {x}}_{071}$ </tex-math></inline-formula> modes is developed by introducing two pairs of slots, and an impedance FBW of 12.8% and a stable gain as high as 11 dBi are achieved. Third, three pairs of slots are introduced to the DRA with TE <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\mathrm {x}}_{091}$ </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">$^{\mathrm {x}}_{0,11,1}$ </tex-math></inline-formula> modes, and an impedance FBW of 6.4% and a stable antenna gain as high as 12.3 dBi are obtained. At last, a circularly polarized (CP) DRA array with four proposed linearly polarized (LP) DRA elements is designed with an impedance bandwidth of 51.8%, a 3 dB axial-ratio (AR) FBW of 32%, a peak gain of 13.89 dBic, and a 1 dB gain bandwidth of 19.9%.

A 3D-Printed DRA Shared-Aperture Array for Low Cost Millimeter-Wave Applications

In this article, a K-/Ka-band shared-aperture array with high isolation is proposed using 3D-printed dielectric resonator antennas (DRAs). The design procedure with DRAs enables flexibility while implementing shared-aperture arrays. Furthermore, DRAs as nonmetallic radiators are attractive for millimeter-wave (mm-wave) applications due to the absence of ohmic loss. In addition, 3D-printing technology facilitates the design of complex shapes with high-dimensional accuracy. The K- and Ka-bands DRAs are orthogonally oriented to provide improved isolation and cross-polarization level. Meanwhile, the corresponding feeding networks are implemented using the substrate integrated coaxial line (SICL) and the substrate integrated waveguide (SIW). Thus, further isolation improvement is provided by using two different feeding mechanisms for the K- and Ka-bands radiators. Moreover, the SICL network is shared with the SIW wall to efficiently utilize the feeding aperture. As a proof-of-concept, the 3D-printed shared DRAs are designed and fabricated. The standard printed circuit board (PCB) technology is used for the fabrication of the antenna boards. The measurement data agree with the simulations, realizing high isolation and cross-polarization level. The proposed array features low profile, ease of integration, and wideband operation, which makes it viable candidate for mm-wave applications.

Design and Analysis of C Band Bracelet Shaped Wearable DRA with Low SAR

A Bracelet shaped wearable Dielectric Resonator Antenna (DRA) is designed and analyzed in this paper. The proposed DRA is made of Bakelite and is capable of operating efficiently in the vicinity of four different frequencies (5.9 GHz, 6.5 GHz 7.1 GHz, 7.6 GHz) in C Band. A performance characteristic of the Bracelet DRA is investigated with the help of a model of human wrist wearing the Bracelet DRA. The DRA worn on human wrist model gives directivity ranging from 7.4dBi to 8.3dBi at different operating frequencies. Radiation efficiency up to 82.1% at 5.9 GHz is obtained. Maximum Specific Absorption Rate (SAR) obtained is 1.15 W/Kg which is within the safe level of 1.6 W/kg set by the Federal Communications Commission (FCC), United States. Simulation of the designed DRA is done using CST Microwave Studio Software. Comparable or better performance characteristics of the proposed DRA is obtained than those of several C band wearable antenna structures reported in recent literature.

A review on Di-electrical resonant antenna based on the performance of gain and bandwidth

A review on Di-electrical resonant antenna based on the performance of gain and bandwidth

Design of high-gain wideband substrate integrated waveguide dielectric resonator antenna for D-band applications

The emerging mobile broadband applications and services demand high-performance networks operating at high frequencies. There is need for high gain and wideband antennas for mobile equipment to support high-speed communications in the millimeter (mm) wave and terahertz (THz) frequencies. In this paper, we propose a wideband substrate integrated waveguide (SIW) fed dielectric resonator antenna (DRA) for D-band applications. A rectangular dielectric resonator element is designed to operate in higher order modes. Wideband operation is achieved by merging adjacent resonances of the different modes. We present a systematic and sequential application of impedance matching techniques to merge the passbands of a multi-mode dual-band DRA, to achieve a wideband response. The proposed design operates between 123.97 GHz and 152.13 GHz. This represents a -10 dB bandwidth of 20.39% at the center frequency of 138.05 GHz. The proposed antenna design has stable broadside radiation patterns, exhibiting a high gain of 11.67 dBi, directivity of 13.36 dBi and maximum total efficiency of 79% . The proposed design is suitable for future generation wireless communication in the terahertz band.

A novel probe‐fed directional dielectric resonator antenna for mobile communication

AbstractA directional dielectric resonator antenna (DDRA) for 5G mobile communication system is proposed. The antenna is side‐fed with the metal probe to make it work in quasi‐TEδ11 mode, so as to realize the characteristics of directional radiation. The stacked structure is adopted, and the two side walls of the rectangular dielectric resonator parallel to the microstrip line are grooved to improve the frequency bandwidth of the antenna. Furtherly, the Koch snowflake fractal is used for the second iteration of the top cylindrical dielectric resonator, and the parasitic metal columns inside the DRA are also helpful for the enhancement of bandwidth. The prototype was fabricated and tested to verify the design, and the measured results show −10 dB impedance bandwidth of about 23% and an average gain of 5.2 dBi within the operation band.

Analysis of Induced Current on Power Transmission Lines for the Reradiation Interference in Medium Wave Based on Characteristic Modes

The reradiation interference from power transmission lines (PTL) on the adjacent wireless stations is directly caused by the induced current on metal parts, which means the interference could be suppressed by reducing the induced current. In order to effectively analyze the induced current of PTL, a method for analyzing induced current on PTL based on characteristic modes is proposed combining MoM with intrinsic modes. This method breaks through the traditional antenna resonance theory proposed by IEEE and could effectively avoid model equivalent defects and frequency limitations of traditional methods. Firstly, a generalized characteristic equation about the characteristic mode currents of PTL is constructed, and the numerical solutions of the characteristic mode currents are obtained by the idea of a discrete solution. Then, through the weighted orthogonal relationship between different characteristic mode currents, the expansion coefficients of the characteristic mode currents are obtained; finally, combined with the Poynting theorem, the physical meaning of the expansion coefficients and their related quantities are explained from the perspective of energy and the analysis of the induced current is realized from the physical level. The results of the example analysis show that the error between the peak frequencies of the induced current calculated by the method in this paper and the peak frequencies calculated by MoM does not exceed 2.46% and the method in this paper can well explain the disappearance of the “double wavelength loop resonance frequency” under the excitation of a vertically polarized plane wave.

High-Gain Low-Profile EBG Resonator Antenna Based on Quasi-Icosahedral Shapes

High-Gain Low-Profile EBG Resonator Antenna Based on Quasi-Icosahedral Shapes

Bandwidth Enhancement and Generation of CP of Yagi-Uda-Shape Feed on a Rectangular DRA for 5G Applications.

A wideband circularly polarized rectangular dielectric resonator antenna (DRA) fed by a single feeding mechanism has been studied theoretically and experimentally. The purpose of the study is to determine how adding a parasitic strip next to the flat surface metallic feed would affect various far- and near-field antenna characteristics. Initially, the basic antenna design, i.e., the T-shape feed known as antenna A, produced a 4.81% impedance matching bandwidth (|S11| -10 dB). Due to the narrow and undesirable results of the initial antenna design, antenna-A was updated to the antenna-B design, i.e., Yagi-Uda. The antenna-B produced a decent result (7.89% S11) as compared to antenna-A but still needed the bandwidth widened, for this, a parasitic patch was introduced next to the Yagi-Uda antenna on the rectangular DRA at an optimized location to further improve the results. This arrangement produced circular polarization (CP) waves spanning a broad bandwidth of 28.21% (3.59-3.44 GHz) and a broad impedance |S11| bandwidth of around 29.74% (3.71-3.62 GHz). These findings show that, in addition to producing CP, parasite patches also cause the return loss to rise by a factor of almost three times when compared to results obtained with the Yagi-Uda-shape feed alone. Computer simulation technology was used for the simulation (CST-2017). The planned antenna geometry prototype was fabricated and measured. Performance indicators show that the suggested antenna is a good fit for 5G applications. The simulated outcomes and measurements match up reasonably.

Mutual coupling and RCS reduction of MIMO dielectric resonator antenna for S-band applications

This paper designs and analyses a two-port dielectric resonator-based multiple-input, multiple-output (MIMO) antenna. A tilted L-shaped aperture is used to excite the cylindrical-shaped ceramic. This type of feeding structure produces the circularly polarized (CP) waves and HEM11δ mode inside the ceramic. The proposed antenna shows two main features: (i) the polarization diversity concept reduces the isolation level by 15 dB; (ii) integration of frequency-selective surface (FSS) reduces the radar cross-section (RCS) value by an amount of 7.5 dBsm within the operating band. The fabricated structure confirms the working band of the proposed antenna from 2.8 to 3.2 GHz. 3-dB axial ratios is achieved between 2.8 and 3.05 GHz. The proposed antenna's good diversity parameter value and stable radiation characteristics make it applicable for S-band wireless applications

Enhancing the Directivity of Antennas Using Plasma Rings

A method for improving the radiation directivity of a dipole antenna is introduced based on placing plasma rings in the close proximity of the antenna. The method is applicable to different types of antennas; however, in this work, extensive investigation is focused on its applicability to dipole antennas. Simulation results show that the plasma rings lead to an appreciable enhancement in the gain of a resonant dipole antenna. The dependency of the enhancement in the gain on the plasma parameters has been analyzed. It is also found that the proposed method does not affect the characteristic impedance of the antenna and, therefore, its impedance matching characteristics. The method is experimentally validated using an inexpensive commercial fluorescent lamp. The proposed method can be used for other types of antennas and for antenna arrays.