Resonator Antenna Research Articles

A compact dielectric resonator antenna with wideband circular polarization characteristics for C and X‐band applications

AbstractA wideband circularly polarized (CP) stacked rectangular dielectric resonator antenna (RDRA) is proposed in this article. The 3 dB axial ratio (AR) and 10 dB impedance bandwidth overlap of more than 66% is obtained. For increased bandwidth, the antenna comprises two dielectric resonators separated by an air gap. The upper dielectric layer is rotated at relative to the lower layer to obtain orthogonal modes for CP Both layers have dielectric constant . The rotation aids excitation of orthogonal modes , and in RDRA. The higher‐order modes generate left‐hand circular polarization at frequencies 6.75, 7.8, and 10.7 GHz, respectively. The upper layer consists of three holes giving a 10 dB impedance bandwidth of 66.7% from 6.52 to 11.02 GHz. The CP gain of 8.7, 6.8, and 6.4 dBi for 6.75, 7.8, and 10.7 GHz, respectively, is measured. The conformal orthogonal feeds enable a 72 3 dB AR bandwidth across the entire frequency band. The radiation efficiency is observed above 89 in the entire band (6.5–11 GHz). This work demonstrates a 66.7 overlap of 10 dB impedance and 3 dB AR bandwidth along with high gain in a single design which is suitable for 5G applications in C‐band as well as other X‐band applications.

Metasurface loaded dual port circularly polarized dielectric resonator antenna with reduced RADAR cross section and mutual coupling features

The design of dual port radiator with a polarization diversity technique and reduced radar cross section (RCS) is described in this study. Cross slot is used to stimulate cylindrical ceramic for generating circular polarization features. Mirror orientation of aperture between port-1 and port-2 improves the isolation level by 25 dB. To suppress the antenna’s monostatic RCS, split ring resonator (SRR) based frequency selective surface is positioned between and around the dual ports. Experimental outcomes confirm the designed radiator operates from 4.11–5.24 GHz along with 3-dB axial ratio in between 4.15–4.92 GHz. The value of monostatic RCS is reduced by 15 dBsm in between the operating band. Broadsided radiation characteristics and good value of diversity parameter makes the designed radiator applicable for C-band Radar applications.

RESEARCH TREND ON IMPROVEMENT OF DIELECTRIC RESONATOR ANTENNA: A BIBLIOMETRIC ANALYSIS

Dielectric Resonator Antennas (DRAs) have components in modern wireless communication systems due to their compact size, high radiation efficiency, and frequency versatility. With escalating demands for higher data rates and spectrum efficiency, the enhancement of DRAs has garnered significant attention in antenna research. Despite the promising characteristics of DRAs, there exists a gap in providing a consolidated overview of the state-of-the-art advancements and emerging themes in DRA research. This study aims to bridge this gap by conducting a meticulous bibliometric analysis to delineate the research trends, highlight gaps, and guide future investigations. Our methodology involves a systematic search and analysis of scholarly publications related to the improvement of DRAs. We use bibliometric tools, citation analysis, and co-authorship networks to explore publication trends, influential authors, and collaborative networks within the DRA research community. By identifying emerging themes, key contributors, and collaborative networks, this study is poised to inform researchers, practitioners, and policymakers about the prevailing trends in the field. The insights gained are expected to guide future research directions, foster interdisciplinary collaboration, and contribute to the continued evolution of DRAs. In conclusion, this bibliometric analysis aims to provide a roadmap for navigating the intricate research landscape on the improvement of DRAs. The anticipated outcomes hold the potential to drive innovation, inspire collaborative initiatives, and contribute to the ongoing advancement of DRAs in the rapidly evolving realm of wireless communication systems.

Study of the dielectric properties of Y3TaO7 electroceramic

In this work, the Y3TaO7 weberite-type structure was synthesized by solid state reaction at 1773 K for 6 h, and its crystalline phase was characterized using X-ray diffraction (XRD). Morphological analysis was performed using scanning electron microscopy (SEM). Electrical characterization of the electroceramics was investigated with temperature variation employing complex impedance spectroscopy (CIS). The Nyquist diagram was fitted employing one resistor (R) – constant phase element (CPE) associations correlating to grain boundary. Activation energy (Ea) values for the relaxation processes were determined as 1.07, 1.06 and 1.15 eV for imaginary impedance (Z″), imaginary electrical modulus (M”) and conductivity (σ′), respectively, indicating a consistent thermo-activated conduction process. The temperature coefficient of the resonant frequency (τf) was found to be 31.24 ppm.K−1, suggesting for the development of new dielectric materials with τf ∼ 0. The performance of the dielectric resonator antenna (DRA) was assessed through numerical simulation, demonstrating a strong correlation in impedance and operating frequency at 5.01 GHz. This study aims to facilitate the design of Y3TaO7-based materials, offering significant potential for applications in microelectronic devices in the radiofrequency (RF) and microwave (MW) range.

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.

A four-port self-multiplexing tunable graphene based dielectric resonator antenna with defective ground structure for high isolation and MIMO capabilities

Objectives and designA novel self-multiplexing terahertz antenna with four tunable ports is proposed in this work. The configuration comprises four rectangular dielectric resonators (DRs) affixed to a substrate, which are excited through L-shaped microstrip-fed slots positioned beneath them. To guarantee efficient isolation among the tunable antenna components, periodic unit cells are introduced into the ground plane, forming a defective ground structure (DGS). Each L-shaped slot element is equipped with a graphene strip to regulate the tunability of each DR element. Results and applicationsThis antenna can operate in various modes with resonant frequencies at 4.01, 4.23, 4.37, and 4.57 THz. It holds potential for future terahertz wireless applications that require the utilization of adjacent channels with distinct communication frequencies. Furthermore, a four-port antenna design is implemented, offering tunable MIMO capabilities with self-quadruplexing ability. The MIMO parameters, specifically the envelope correlation coefficient (ECC) and diversity gain (DG), have been assessed and found to fall within acceptable limits across the operating frequency bands. Additionally, an equivalent circuit model (ECM) is analysed to shed light on the antenna's working principle and verify the obtained results.

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.

A cutting-edge broadband Camembert-inspired dielectric resonator antenna

This article introduces an innovative approach to significantly broaden the bandwidth of Cylindrical Dielectric Resonators. A four-element Camembert-Shaped Cylindrical Dielectric Resonator Antenna (CDRA) is presented, using an air gap separating the resonators to enhance the antenna bandwidth. The radiators, i.e., the DRA blocks, are made of high relative-permittivity ceramic material (εr = 25 & 30) and are excited by microstrip-line feed. The proposed methodology involves the strategic design of these resonators, incorporating dielectric materials to finely optimize the frequency response. Experimental validation demonstrates a remarkable improvement in bandwidth when compared to conventional methodologies. This novel technique holds immense promise for applications requiring wideband antennas. The demonstrated effectiveness of this approach not only addresses contemporary challenges but also opens up new avenues in antenna design, catering to the escalating demands of modern communication systems. In addition to the compact dimensions of the elementary radiating element, the separation distance between them, set at λ/4, enhances the array antenna overall size, and its gain is nearly 10 dBi. The proposed antenna covers cellular network applications such as UMTS mobile phone band around 2.1 GHz, as well as wireless DECT phone bands around 1.9 GHz, facilitating data transmission over short distances and beyond, with an impedance bandwidth of 20%.

Dual‐port circularly polarized wideband dielectric resonator antenna for S‐band application

SummaryThis article explains the design and implementation of a multiple input multiple output (two‐port) antenna, based on dielectric resonators. The antenna design not only demonstrates high isolation between its ports but also showcases robust diversity performance. The initial step introduces an asymmetrical ground plane radiating stub microstrip feed for circular polarization generation in a single‐port cylindrical dielectric resonator antenna (CDRA). This approach utilizes an asymmetrical ground plane and incorporates three radiating stubs connected to a microstrip feed line to generate HEM11δ modes in a cylindrical DRA. The proposed dual‐port CDRA offers high impedance bandwidth of 29.73% (2.95–3.98 GHz) and the axial ratio falls below 3 dB specifically from 3.01–3.35 GHz. The antenna demonstrates left‐handed circularly polarized fields with an average gain of 4.95 dBi and a radiation efficiency of 90.56%. All of these characteristics make the developed radiator appropriate for WiMAX (3.3–3.5 GHz) applications.

Flat-Knit, Flexible, Textile Metasurfaces.

Lightweight, low-cost metasurfaces and reflectarrays that are easy to stow and deploy are desirable for many terrestrial and space-based communications and sensing applications. This work demonstrates a lightweight, flexible metasurface platform based on flat-knit textiles operating in the cm-wave spectral range. By using a colorwork knitting approach called float-jacquard knitting to directly integrate an array of resonant metallic antennas into a textile, two textile reflectarray devices, a metasurface lens (metalens), and a vortex-beam generator are realized. Operating as a receiving antenna, the metalens focuses a collimated normal-incidence beam to a diffraction-limited, off-broadside focal spot. Operating as a transmitting antenna, the metalens converts the divergent emission from a horn antenna into a collimated beam with peak measured directivity, gain, and efficiency of 21.30, 15.30, and -6.00 dB (25.12%), respectively. The vortex-beam generating metasurface produces a focused vortex beam with a topological charge of m=1 over a wide frequency range of 4.1-5.8GHz. Strong specular reflection is observed for the textile reflectarrays, caused by wavy yarn floats on the backside of the float-jacquard textiles. This work demonstrates a novel approach for the scalable production of flexible metasurfaces by leveraging commercially available yarns and well-established knitting machinery and techniques.

Decoupling analysis for different exciting modes in MIMO DRA using absorbing surface walls

SummaryIn this paper, a decoupling mechanism is discussed for different mode excitations in the cylindrical dielectric resonator antenna (cDRA) by utilizing absorbing surface wall. In the cDRA, the fundamental radiating mode is HE11δ. Another higher order mode for radiation purpose in cDRA is HE12δ. Both HE11δ and HE12δ create broadside radiation. To analyze multiple‐input multiple‐output (MIMO) performance, two different dual‐port DRAs are proposed. Each antenna structure consists of two DRA with dual similar ports supporting the same mode. Therefore, two different antenna structures are proposed for two different modes. For each antenna, two 2 × 3 absorber array walls are designed, and they are placed in between the DRA to reduce the mutual coupling. When the absorber array walls are placed in between the antenna elements, they blocked the free‐space electromagnetic (EM) field interaction in between the DRA. Due to the reduction of free‐space radiation interaction, the mutual coupling between the ports is improved tremendously. For both HE11δ and HE12δ modes, the mutual coupling is reduced by more than 10 dB. To analyze efficacy of the proposed method, the antenna structure featuring the HE11δ mode is fabricated and experimentally tested.

Recent development in reconfigurable dielectric resonator antenna and microwave filter: design and application

SummaryDeveloping wireless communication systems depends on reconfigurable microwave filters (MF) and dielectric resonator antenna (DRA) because the functionality of the various filters and antennas available for a wireless communication system is limited, and reconfigurable DRA and MF are utilized to overcome these limitations. The throughput of a multiantenna system can be achieved with reconfigurable DRA and filter. Various switching strategies and classifications of reconfigurable DRA and MF are presented. The electrical reconfiguration technique is most suitable for developing a reconfigurable DRA and filter among all the switching techniques. In this approach, reconfigurability may be accomplished by utilizing a PIN diode, a varactor diode, and a radio‐frequency microelectromechanical switch (RF‐MEMS). These switches are more reliable, highly efficient, and easily integrated with the microwave circuit. Reconfigurable DRA with machine learning is demonstrated. The application of reconfigurable DRA and filters in cognitive radio (CR) is also demonstrated. Also, the review article focused on the performance parameters, design, and challenges of reconfigurable antenna and MF.

Broadband Dual-Polarized Cup Dielectric Resonator Antenna With Stable Omnidirectional Radiation Patterns

Broadband Dual-Polarized Cup Dielectric Resonator Antenna With Stable Omnidirectional Radiation Patterns

Structure property correlation of (1-x)MgTiO3 - xSrTiO3 microwave dielectric ceramics for dielectric resonator antenna applications

The current paper reports on the crystal structure, microwave dielectric properties as well as the antenna parameters of (1-x)MgTiO3 - xSrTiO3 (abbreviated as (1-x)MT-xST) for x = 0.025, 0.05, 0.075, 0.1 ceramic based dielectric resonator antennas (DRAs). The (1-x) MT - xST samples have been prepared with the help of a solid-state reaction route. The SrTiO3 was introduced to MgTiO3 as a τf compensator for developing a tunable τf material. Rietveld refinement results of X-ray diffraction data suggest that all the samples exhibit a combination of two crystallographic phases i.e., rhombohedral (R-3) + cubic (Pm-3m). The SEM micrographs show clear and well-defined grains for (1-x)MT - xST (for x = 0.025–0.1) ceramics. The modes of vibration of the crystal structures of the materials have been identified by the Raman spectroscopy method. The bond strength, bond valency, bond energy, and tolerance factor have been determined for (1-x)MT - xST (for x = 0.025–0.1) materials. The microwave dielectric performances of ceramics have been analyzed over a frequency band of 1–10 GHz. It has been found that the dielectric constant is almost constant along the microwave frequency range. The behavioral change of tuned temperature coefficient of resonant frequency (τf) along with quality factor have been reported. Besides, DRAs have been formed using all ceramic compositions, and simulations were performed to determine the various antenna properties, such as efficiency, input impedance, radiation properties, gain, and reflection coefficient. This study supports the use of microwave dielectric ceramics in antenna fields and highlights the enormous potential of (1-x)MT - xST for (x = 0.05) materials in communication systems.

Metasurface loaded ceramic based MIMO antenna with improved gain and circular polarization characteristics

In this communication, the conceptualization involves the design of a multiple input multiple output (MIMO) (dual-port) ring dielectric resonator antenna and the integration of a meta-surface onto this configuration. It introduces three distinctive attributes, which characterize the novelty of the proposed design: (a) facilitates the conversion of linearly polarized waves into circularly polarized counterparts; (b) contributes to a substantial enhancement in gain in between the working band; and (c) there is notable improvement in the isolation between the antenna ports to more than 25 dB. The experimental measurements validate the simulated results of proposed design and confirms its applicability in between 2.45–3.0 GHz. Notably, a 3-dB axial ratio is created in the frequency span of 2.56–2.99 GHz, along with an impressive gain of approximately 8.3 dBi. Its consistent radiation pattern and excellent diversity performance make it suitable for WiMAX (2.6 GHz) use.

Design of dual-port MIMO dielectric resonator antennas with high isolation for terahertz communication

A simple decoupling technique by using conformal metal strips is investigated for isolation enhancement of terahertz (THz) multi-input–multi-output (MIMO) dielectric resonator (DR) antennas (DRAs) in this paper. Metal strips with proper dimensions are symmetrically printed on both sides of the upper surface of DRs. The introduction of metal strips can cause disturbance to the electromagnetic (EM) fields inside the DRs by introducing the induced fields, thereby suppressing the diffusion of EM fields and rearranging the EM fields, ultimately reducing the level of coupling and enhancing the isolation between ports. Two kinds of MIMO antennas, i.e., using two DRs and sharing one DR, are used as implementation examples to verify the effectiveness of the proposed technique. Corresponding results show that by optimizing the dimensions of the metal strips reasonably, the isolation for antenna containing two DRs increased from 14.7 to 59.2 dB at 2.98 THz, while the isolation for another sharing one DR increased from 7.1 to 40 dB at 3.64 THz. Excellent improvement of isolation has been achieved through the proposed technique and the proposed MIMO antennas are expected to be applied in future THz communication.

A slotted frustum-shaped 4 × 4 MIMO dielectric resonator antenna with enhanced isolation for 5G Wi-Fi applications

In this paper, a slotted frustum-shaped 4 × 4 multiple-input multiple-output (MIMO) dielectric resonator antenna (DRA) is designed and developed for portable 5G Wi-Fi ( 5.15 − 5.85 GHz ) applications. The DRA is excited by HE M 11 δ and HE M 21 δ modes. A slotted right-angle frustum-shaped (SRFS) structure of alumina material as a dielectric resonator (DR) is positioned on the ground plane of the FR4 substrate to design a DRA. Based on the designed DRA, a compact ( 2.57 λ g × 2.57 λ g , where λ g is guided wavelength and calculated at a lower cut-off frequency, 5.0 GHz , for ϵ f of 4.4 ) 4 × 4 MIMO antenna with high isolation of greater than 27.13 dB (from 5.0 to 6.1 GHz ) and 24.3 dB (from 6.1 to 6.25 GHz ) is proposed. The developed MIMO antenna's measured working frequency ranges from 5.0 to 6.25 GHz , with an impedance bandwidth, B W i of 22.22 % , peak gain, G P of 5.85 dBi and an average peak gain, G av of 5.25 dBi . The calculated MIMO antenna's diversity performance parameters, channel capacity loss ( C CL ij ) , diversity gain ( D G ij ) , envelop correlation coefficient ( E CC ij ) , mean effective gain ( M EG i ) , total active reflection coefficient ( T ARC ) , and channel capacity ( C C ) are obtained as < 0.17 bits / sec / Hz , > 9.99 dB , < 0.0301 , < − 6.06 dB , < − 12.5 dB , and < 21.6 bits / sec / Hz , respectively. The agreement between the simulation and measurement results is found to be remarkably consistent.

Experimental investigation of water-based beam reconfigurable dielectric resonator antenna

In the present article, a novel dielectric resonator antenna (DRA) for the control of radiated beams is presented. The proposed DRA is capable of not only reconfiguring the beam width and gain, but also generating single, double, and multiple beams without changing the shape of the antenna. The DRA consists of a cuboid-shaped dielectric resonator having two chambers for storing the water. By varying the water levels in the chambers the beam width can be varied from 56° to 116° and gain 9.8 dBi to 5.86 dBi at the operating frequency of 9.2 GHz. In addition, multiple beams can also be produced by reducing the water level in one chamber. The prototype of the proposed DRA is fabricated and measured for different water levels. The simulated and measured results are in close agreement. The proposed DRA can find its potential application in microwave, space, and wireless communication systems.

Circularly polarized dielectric resonator based MIMO antenna for sub-6 GHz 5G cognitive radio applications

A 2-port wideband circular polarized (CP) multiple input multiple output (MIMO) dielectric resonator antenna (DRA) integrated with cognitive radio (CR) application is designed and investigated. This is a novel concept of integrating wideband CP-MIMO antenna based on dielectric resonator (DR), with CR concept. The multi-functional reconfigurable filter is designed within the feedline of the antenna making it applicable for both the operations of CR, namely, underlay and interweave. Rogers RT Duroid 5880 is used as the substrate for the designed CP-MIMO antenna. The antenna shows wide Axial Ratio (AR) bandwidth of 48.14% (2.2–3.50 GHz) and an overlapping bandwidth of 41.85% (2.37–3.50 GHz). The DR based MIMO antenna shows sensing range of 2.37–3.66 GHz. For the interweave operation, the designed CP-MIMO antenna shows narrowband frequency reconfigurability from 2.45–2.83 GHz. For the underlay case, the designed antenna shows band notch tunability between 3.23–3.62 GHz. The proposed antenna can be used effectively in sub-6 GHz band of the 5G communication systems.

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.