Search

This paper presents the design of a two-port dual-band dual-circularly-polarized dielectric resonator antenna (DRA). The proposed DRA is formed by stacking two dielectric resonators (DRs) of different shapes, including a hexagonal DR on top and a cross-shaped DR on the bottom. It is designed to resonate at two near-degenerate orthogonal modes of TE111 and TE113, and an aperture-coupled feeding through a cross-like slot is used to achieve dual-band impedance matching simultaneously for right- and left-handed circular polarizations. Tests were conducted on a prototype working in C-band to verify the design concept. The experiment results demonstrate that the proposed DRA has exceptional performance with measured −10 dB reflection bandwidths of 24.4% and 17.4%, 3 dB axial ratio bandwidths of 21.2% and 16.3%, and maximum gains of 5.64 and 8.13 dBic for the lower and upper bands, respectively. Moreover, the measured channel isolation is more than 15.8 dB. The results obtained from the experiments show good agreement with the simulation, and hence, it can be concluded that the proposed DRA is a promising solution that can be used for various wireless communication applications. [ABSTRACT FROM AUTHOR]

In this Paper, a low-profile circularly polarized (CP) chamfered rectangular dielectric resonator antenna (RDRA) is designed and investigated for radio frequency energy harvesting (RFEH) applications. The proposed modified RDRA comprises of dielectric resonator (DR) made up of Alumina material (εr = 9.9) mounted on the PEC ground plane. Dual unequal triangular-shaped vertical slits are engraved on the rectangular DR for generating the orthogonal modes with CP characteristics. The optimized antenna offers an impedance bandwidth (IBW) of 51.4% (2.25–3.81 GHz) and axial ratio bandwidth (ARBW) of 14.8% (3.25–3.77 GHz), respectively. The peak realized gain and maximum radiation efficiency are 7.18 dBi and 97.8% in desired frequency bands. Due to the wide impedance and AR bandwidths with realized gain and radiation efficiency, the optimized antenna is suitable for integration with a rectifier circuit for RF energy harvesting applications. A rectifier circuit with a single shunt diode topology is also designed for rectification purposes. The rectifier achieved 67.16% RF-DC power conversion efficiency (PCE) at 3.5 GHz and 5dBm input power. At 0dBm input power, the rectifier achieved 60.26% PCE. The effective input power range, during which the PCE maintains above 50%, is calculated to be 15.2 dBm from −3.5 to 11.7 dBm. [ABSTRACT FROM AUTHOR]

This paper presents a novel Multiple Input Multiple Output (MIMO) circularly polarized stacked Cylindrical Dielectric Resonant Antenna design integrated with graphene and polarization switching, propelling significant advancements in THz wireless communication. The proposed antenna achieved a wideband Impedance bandwidth of 3.12 THz, complemented by an overlapping Axial Ratio (AR) bandwidth (ARBW) of 2.01 THz, respectively. The antenna incorporates a new Defected Ground Structure to generate a wideband frequency response. The integration of graphene on top of the DRAs further enhances the antenna's performance, significantly boosting gain and radiation efficiency. A standout feature of this antenna is its seamless switching capability between Left-Hand Circular Polarization and Right-Hand Circular Polarization, making it highly adaptable for diverse communication scenarios. Additionally, the resonant frequency of the antenna can be precisely tuned by varying the graphene chemical potential (µc), offering enhanced flexibility. The paper also investigates a 2 × 2 MIMO configuration with excellent performance parameters, showcasing its suitability for THz wireless communication. Furthermore, the proposed antenna exhibits very high isolation between the ports by varying µc. The key features of the antenna include wideband frequency response and AR response, polarization switching, tuning of resonant frequency, high gain, and high efficiency. These advantages mark a significant milestone in THz wireless communication, setting new benchmarks for efficiency, adaptability, and overall performance in this rapidly evolving field. [ABSTRACT FROM AUTHOR]

A new tri-band rectangular DRA is simulated and tested for wireless communication applications like ISM, Wi-Max, and WLAN. The dielectric resonator antenna structure is excited by a 50Ω transmission line. The rectangular DRA with concentric square rings is designed to acquire the operation of triple-bands. The investigated antenna parametric study has been accomplished on HFSS tool. The implemented design exhibits triple-band characteristics at 2.16-2.57 GHz, 3.35-4.45 GHz, and 5.35-5.95 GHz, with a fractional bandwidth of 17.3%, 28.1%, and 10.6%, respectively. The implemented concentric square rings are imposed on FR4-substrate material to emphasize the antenna parameters and to minimize the size. The designed antenna has a compact size, good radiation properties, and optimal operational bandwidth. To validate the antenna, it is fabricated, and the results match well with the simulated ones. The antenna is well suitable for wireless communication applications. The fabricated rectangular DRA is measured by using MS2037C Anritsu-Combinational Analyzer. [ABSTRACT FROM AUTHOR]

This paper presents a novel wideband circularly polarized millimeter-wave (mmWave) hemispherical dielectric resonator antenna (HDRA). Two distinct configurations of alumina dielectric resonator antennas (DRAs) are investigated, each featuring a different coating: the first configuration incorporates a polyimide layer, while the second involves a perforated alumina. Both configurations demonstrate promising characteristics, including impedance and axial ratio (AR) bandwidths of 58% and 17.7%, respectively, alongside a maximum gain of 10 dBic at 28 GHz. Leveraging additive manufacturing technology, the HDRA with the perforated coating layer is fabricated, simplifying assembly and eliminating potential air gaps between layers, thereby enhancing the overall performance. This innovative approach yields a circularly polarized (CP) HDRA suitable for Beyond 5G (B5G) communication systems. Agreement between measurements and simulations validates the efficacy of the proposed design, affirming its potential in practical applications. [ABSTRACT FROM AUTHOR]

This paper presents a high gain diagonally-probe-fed multi-layered dielectric resonator antenna (DPF-ML-DRA) designed for 77 GHz automotive radar applications. A comparison with the conventional probe-fed ML-DRA demonstrates that the proposed DPF-ML-DRA achieves higher antenna gain by 1 dB. The sub-array utilizing the proposed DPF-ML-DRA is tailored to meet specific radar system requirements, including a broad impedance bandwidth (> 5 GHz), high antenna gain (> 12 dBi), and wide half-power beamwidth (> ± 60°). Simulated results validate that the sub-array performance meets the aforementioned antenna requirements. To attain high azimuthal and elevational angular detecting resolution, 3 sub-arrays with 12 DF-ML-DRA for the Tx channel and 4 sub-arrays with 10 DF-ML-DRA for the Rx channel were designed and simulated. The fabricated radar system underwent field testing, demonstrating a maximum range of up to 160 m and a field of view of 120° for 100 m. Remarkably, the proposed DPF-ML-DRA exhibits equivalent radar performance while featuring a smaller form-factor compared to commercially available state-of-the-art automotive radar systems. Consequently, the proposed DPF-ML-DRA proves to be well-suited for 77 GHz automotive radar applications. [ABSTRACT FROM AUTHOR]

The design of three‐dimensional (3D)‐printed heterogeneous ceramics exhibiting isotropic and anisotropic dielectric permittivities at microwave frequencies is studied for dielectric resonator antenna (DRA) applications. The heterogeneous ceramics are engineered by using periodic structures made up of subwavelength unit cells filled with zirconia ceramic and air. Ceramic stereolithography (CSLA) allows the 3D printing of a one‐piece ceramic block mixing isotropic and anisotropic dielectric regions. In order to demonstrate the possibility of exploiting such 3D‐printed ceramics, a singly fed dual‐band circularly polarised DRA is presented. To achieve circular polarisation at both bands, the relative permittivity of the dielectric resonator is locally controlled by introducing anisotropic dielectric regions. The 3D‐printed DRA is finally measured, and its results agree well with the simulations. [ABSTRACT FROM AUTHOR]

Summary: In this communication, a dielectric resonator based dual‐port radiator is designed. Loading of meta‐surface over the dual‐port antenna creates two important features that make it unique to the proposed design: (i) conversion of the linear polarized plane waves into circularly polarized plane wave (ii) improve the isolation between the antenna port by more than 30 dB. Experimental measurement confirms that proposed design is working in the frequency range 5.14–5.55 GHz, and a 3‐dB axial ratio is produced from 5.36 to 5.45 GHz. Stable radiation pattern and good value of diversity performance are also achieved in the proposed radiator. All of these characteristics make the developed radiator appropriate for WLAN (5.4 GHz) applications. [ABSTRACT FROM AUTHOR]

We review dielectric resonator antenna (DRA) designs. This review examines recent advancements across several categories, specifically focusing on their applicability in array configurations for millimeter-wave (mmW) bands, particularly in the context of 5G and beyond 5G applications. Notably, the off-chip DRA designs, including in-substrate and compact DRAs, have gained prominence in recent years. This surge in popularity can be attributed to the rapid development of cost-effective multilayer laminate manufacturing techniques, such as printed circuit boards (PCBs) and low-temperature co-fired ceramic (LTCC). Furthermore, there is a growing demand for DRAs with beam-steering, dual-band functions, and on-chip alignment availability, as they offer versatile alternatives to traditional lossy printed antennas. DRAs exhibit distinct advantages of lower conductive losses and greater flexibility in shapes and materials. We discuss and compare the performances of different DRA designs, considering their material usage, manufacturing feasibility, overall performance, and applications. By exploring the pros and cons of these diverse DRA designs, this review provides valuable insights for researchers in the field. [ABSTRACT FROM AUTHOR]

This article presents a four-element directional multiple input multiple output (MIMO) rectangular dielectric resonator antenna (RDRA) equipped with strategically placed copper reflector plates to enhance port isolation. This design aims to achieve an extended coverage range without compromising the coverage area. The proposed MIMO antenna is 3D printed using biodegradable polylactic acid to ensure mechanical robustness and then integrated with the substrate to prevent mis-mounting issues. The proposed design exhibits good MIMO characteristics, registering a 3-GHz bandwidth (4-7 GHz) for |S11|≤-10 dB and a minimum radiation gain of 7 dBi for all four RDRAs. The antenna demonstrates a rotation of radiation patterns for different ports, thus enabling beam formation in specific directions. With a beam width of 71.2˚, the antenna covers all directions without any fade zones. The proposed 3D printed antenna offers simplicity, strong MIMO properties, and practicality for wireless communication systems, making it suitable for industrial, scientific, and medical band applications. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract A 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.

The Li2Mg3Ti1−xAl4x/3O6 (0 ≤ x ≤ 0.1) ceramics are synthesized using the solid phase method, showing excellent microwave dielectric properties with εr = 14.05, Q × f = 144 500 GHz, and τf = −43 ppm/°C at x = 0.04. Rietveld refinements, based on the XRD data, reveal that the Li2Mg3Ti1−xAl4x/3O6 ceramics crystallize in the rock salt structure with Fm-3m space group. The relationship between the crystal structure and intrinsic microwave dielectric properties is studied in detail. The variation in the dielectric constant is related to ionic polarization and relative density. The quality factor (Q × f) demonstrates a strong correlation with lattice energy, relative density, and concentration of Ti3+. The variation of τf is influenced by the bond thermal expansion coefficient and bond valence. The dielectric resonant antenna, manufactured from Li2Mg3Ti0.96Al0.0533O6-0.09TiO2 ceramic with near-zero τf, shows a bandwidth of 230 MHz at 7.40 GHz and a high radiant efficiency, which indicates that high-quality factor Li2Mg3Ti0.96Al0.0533O6 ceramic has significant potential in relevant fields such as 5G and smart driving. [ABSTRACT FROM AUTHOR]

In this paper, a wideband circularly polarized (CP) filtering dielectric resonator antenna (FDRA) is proposed. The proposed antenna consists of a microstrip-Y-shaped slot line coupled feeding structure and a grooved DRA. The Y-shaped slot line not only serves as an energy coupling structure to excite the orthogonal modes (TEx 111 mode and TEy 111 mode) of DRA, forming the CP radiation effect, but also generates two resonant modes, thereby broadening the antenna impedance bandwidth. In addition, due to the groove engraved on the diagonal of the DRA top wall, the antenna CP performance within the passband is enhanced. Finally, by loading a shorting stub and a spur line on the microstrip feedline, radiation nulls are generated on both sides of the antenna passband, resulting in a quasi-elliptical filter response in the antenna gain curve. To further verify the performance of the antenna design, a prototype CP FDRA is fabricated and measured. The measurement results indicate that the antenna achieves a -10 dB impedance bandwidth of 46.1% (2.67-4.27 GHz) and an axial ratio (AR) bandwidth of 23% (3.08-3.88 GHz), with an average measured gain of approximately 4.9 dBi. This antenna exhibits high-frequency selectivity and an out-of-band suppression level exceeding 10 dB. [ABSTRACT FROM AUTHOR]

The research describes a novel method for boosting gain in quantum CDRAs that involves replacing the silicon dioxide substrate with a Teflon substrate. The enhanced gain results are analyses and compared to earlier research findings. CST software was used to create and simulate a quantum CDRA. The antenna structure includes cylindrical dielectric resonators with a greater antenna gain at a frequency of 504 THz. The quantum CDRA has an impedance bandwidth of 9.41 percent. The reported quantum CDRA has a gain of 6.3 dB and a return loss of − 27.5 dB. Terahertz applications are feasible with the suggested quantum CDRA. [ABSTRACT FROM AUTHOR]

This review article provides a detailed overview of current techniques in the field of Dielectric Resonator Antennas (DRA). The primary aim of study aims electrical size downsizing, retrofitting bandwidth to meet commercial needs, and radiation pattern stability by managing the modes in the DRA with the evolution starting from rectangular shape to contemporary investigations. Various research strategies for miniaturizing the physical and electrical size, mode excitation by various mechanisms such as a probe, microstrip, slot, and others, along with increasing bandwidth and radiation characteristics have been mentioned. In this review, the innovative geometries and fractal notions introduced to the DRAs are also discussed. [ABSTRACT FROM AUTHOR]

In the advancing field of 5G technologies, particularly at the 60 GHz band, dielectric resonator antennas (DRAs) stand out for their low conduction loss and high radiation efficiency. However, the traditional design process for DRAs, predominantly reliant on intuitive reasoning and trial‐and‐error methods, is notably inefficient and resource‐intensive. Addressing this critical challenge, our research introduces a pioneering approach: a generative adversarial network (GAN)‐based model specifically tailored for automating DRA structure design. This novel model represents the first of its kind in the domain, marking a significant departure from conventional methods. Our GAN model uniquely integrates a simulator for DRA modeling and a generator for DRA structure design, streamlining the design process. To effectively train this model, we created a simulated data set comprising pattern–annotation pairs of geometric shapes and S11 parameters. This data set enabled the GAN to capture the intrinsic principles underlying DRA design. The practical impact of our model is profound; it significantly expedites the DRA design process, aligning it more closely with specific user requirements while conserving valuable time and resources. This breakthrough approach not only enhances the efficiency of DRA design but also sets a new standard in antenna technology development for future wireless communications. [ABSTRACT FROM AUTHOR]

A novel simple decoupling technique is proposed to suppress the mutual coupling of a millimeter‐wave multiple‐input‐multiple‐output dielectric resonator antenna (DRA). The design to be decoupled consists of two microstrip‐line fed rectangular DRAs placed side‐by‐side on an RT‐Duroid substrate and operates near 26 GHz. First, the DRAs are placed at an appropriate separation distance to avoid any close coupling. Second, to reduce coupling further, a set of square ring cell loaded slot is employed on the ground plane in between the DRAs. These two arrangements together, potentially reduce the mutual coupling between the DR elements and substantially improves the in‐band isolation from 14 to 23 dB (min)/34 dB (max) between them. The design is very simple, compact, and easy to fabricate. The model is prototyped and characterized to demonstrate its feasibility for operation. This can be a suitable technique for fifth‐generation compact handheld microwave devices. [ABSTRACT FROM AUTHOR]

This article presents a four-port Multi-Input Multi-Output (MIMO) antenna based on Dielectric Resonators (DR), showcasing excellent filtering characteristics, high isolation between ports, and strong diversity performance. The initial step introduces a single-port filtering Dielectric Resonator Antenna (DRA) utilizing the HEM11δ mode, featuring a complementary split ring resonator (SRR) feed structure that excites the cylindrical DR. This feed structure enables the independent adjustment of one resonance frequency and two radiation nulls. The experimental results confirm that the designed radiator works in between 2.35 and 2.57 GHz with an isolation level of more than 25 dB. The value of the gain is around 5.0 dBi within the operating band, while it is less than −15 dBi outside the working band. All these features make the designed MIMO radiator applicable for IoT applications. [ABSTRACT FROM AUTHOR]

A 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. [ABSTRACT FROM AUTHOR]

This paper proposes a compact dielectric resonator-based high gain dual-band hybrid antenna. The antenna is proposed to work in a dual ISM (industrial, scientific, and medical) band, i.e., at 2.40 - 2.48 GHz and 5.725 - 5.875 GHz. The designed antenna can work as a radiator in the lower band (2.37 - 2.49 GHz) and as a sensor in the upper band (5.34 - 6.00 GHz). The non-invasive blood glucose sensing application is chosen at a higher frequency band, and a lower band is chosen for wireless communication. From a single transmission feed line, both frequency bands are generated by the fundamental mode T M 10 of radiating slot and H E M 11 mode inside cylindrical DRA, respectively. The designed antenna is optimized and simulated to get the best possible results in terms of S-parameter, bandwidth, gain, radiation pattern, efficiency in a lower band, and sensitivity toward blood permittivity in a higher band. This work performs regression analysis and fasting experiments for blood glucose sensing. The link budget analysis is also done at different data rates for wireless communication. The Specific absorption rate (SAR) value is calculated in finger tissue to ensure safety. The simulated and measured results of the designed antenna suggest that it can be used for non-invasive blood glucose sensing and wireless communication applications. To the author's knowledge, no antenna was reported prior for radiating as well as sensing applications. [ABSTRACT FROM AUTHOR]

A dual-band dual-sense (DBDS) circularly polarized (CP) filtering dielectric resonator antenna (FDRA) with a quasi-elliptic band-pass response is proposed in this paper. The proposed antenna consists of a rectangular dielectric resonator (DR) with a Z-shaped strip at the top, a ground plane with a rectangular slot, and a microstrip feedline etched with a section of the spur line. By using the microstrip coupled slot line structure to excite DR with a Z-shaped strip, different senses of circular polarization are achieved in the two bands. The results show that the lower and upper bands are independently controlled by the strip and the DR, respectively. In addition, three radiation nulls are generated at the passband's edge by elaborately designing a half-wavelength open stub and etching the spur line. For demonstration, a prototype DBDS CPFDRA is fabricated and measured. The measurements illustrate that the antenna achieves a wide impedance bandwidth of 38.2%, as well as a dual axial ratio (AR) bandwidth of 2.2% for the left-hand circular polarization (LHCP) and 4% for the right-hand circular polarization (RHCP). The realized gain exhibits a decline of 25 dB at the passband edge, indicating high selectivity. [ABSTRACT FROM AUTHOR]

This article presents a quad port multi-input multi-output (MIMO) antenna based on arrays of rectangular dielectric resonators for intelligent automotive applications. The proposed MIMO antenna configuration is formulated by integrating four rectangular dielectric resonator antenna (RDRA) arrays. Two RDRAs are configured asE-plane arrays and the other two asH-plane arrays. Each array consists of two radiating elements, evenly spaced apart. Direct microstrip line (DML) feeding, a novel kind of feeding technique to cope up with back radiation issue which occurs owing to discrete grooves on ground plane is employed to feed RDRA. The orthogonal mode in individual arrays (H-plane and E-plane) results in increased isolation. The overall dimension of the suggested quad port MIMO antenna is (2.21λ0 × 1.32λ0). The prescribed RDRA array operates at 5.9 GHz with an impedance bandwidth of 6.9% for Port1 and 8.1% for Port2, respectively. The measured isolation is more than -24 dB. For this MIMO antenna measured peak gain of 9.6 dBi is noticed. Various MIMO performance metrics such as the total active reflection coefficient (TARC), diversity gain (DG), channel capacity loss (CCL), and envelope correlation coefficient (ECC) have been studied in detail and discussed in this article. It is noteworthy that these measurements continue to fall within allowable threshold ranges, indicating the appropriateness of the prescribed MIMO antenna for the intended applications in intelligent automotive system. [ABSTRACT FROM AUTHOR]

A novel stacked rectangular structure with surface-mounted short rectangle dielectric resonator antenna (SRSMSR) with an E-shaped microstrip feed through a wide aperture slot was investigated for C-band operation in wireless communication and tracking radar applications. The developed design uses copper for SMSR to improve return loss up to -46 dB, gain up to 10.7 dB, and an observed impedance bandwidth of 20.6% in the broad frequency range of 5.69 GHz-7.0 GHz. The 3 dB beamwidth achieved in the E-plane is 89.82°, while that in the H-plane is 24.31°. [ABSTRACT FROM AUTHOR]

This paper introduces a novel design of an embedded stacked Rectangular Dielectric Resonator Antenna (RDRA). The antenna structure incorporates two distinct materials, namely PLA (Polylactic Acid) and Alumina, possessing dielectric constants of 3.45 and 9.9, respectively. A coaxial probe is employed to feed the antenna, enabling efficient signal transmission. The simulated results indicate the presence of two distinct resonance frequencies, which are 9.4 GHz and 10.6 GHz. Furthermore, the simulated antenna exhibits a maximum gain of 7.7 dB at 10.6 GHz, while demonstrating a wideband characteristic spanning approximately 22.7% of the frequency band between 8.75 GHz and 11 GHz on the measurement. The design and simulation of the RDRA are carried out using CST 2020 microwave studio, ensuring accurate and reliable results. The proposed antenna configuration is well suited for X-band applications such as radar and satellite systems. [ABSTRACT FROM AUTHOR]

The primary objective of this study is to improve the efficiency of dielectric resonator antennas (DRAs) by the manipulation of their geometric and material characteristics. Two distinct cylindrical dielectric resonator antenna (DRA) with microstrip patch antenna designs chosen, and deliberate modifications implemented in a systematic manner to enhance crucial characteristics including gain, bandwidth, S-parameters, voltage standing wave ratio (VSWR), and directivity. Furthermore, an investigation was conducted to assess the efficacy of incorporating additional layers into the design of the DRA to achieve increased gain and enhanced efficiency at a frequency of 28 GHz. The research encompassed the process of collecting and designing and simulating CDRA and microstrip patch antenna antennas utilizing the CST framework. The study investigates different configurations of apertures and alterations or holes in the patch geometry to improve both the gain and efficiency. A comparative analysis between both antennas was carried out utilizing performance criteria such as S-parameters, gain, directivity, bandwidth, and VSWR and efficiency. The discourse explores the progress made in the field of technology pertaining to the improvement of gain and bandwidth. This includes the utilization of high-dielectric-constant materials, modifications in resonant frequencies, and the implementation of metamaterial (MTM) cells. The CST program is utilized for conducting realistic trials and assessments. The research highlights the advantages of CDRA antennas and microstrip patch antennas, including improved radiation efficiency, smaller size, lower profile, and lightweight design. The integration of photonic crystal layers into the design of the cylindrical dielectric resonator antenna (CDRA) was emphasized as a noteworthy enhancement, resulting in amplified gain. The significance of considering both intrinsic characteristics and external factors, such as surface Plasmon waves, in the computational modeling of DRA antennas to achieve maximum efficiency is emphasized by the research. [ABSTRACT FROM AUTHOR]

This article presents a novel double - layered, dual band and dual polarized hybrid substrate integrated half cylindrical dielectric resonator antenna (SICDRA) for IRNSS satellite base station and various wireless applications. The SICDRA comprises of a unique top semi cylindrical dielectric resonator (DR) with top and side copper strips, circular hybrid substrate integrated waveguide (SIW) cavity and an inner circular ring type air gap cavity on upper FR4 substrate. To produce circularly polarized (CP) fields, two tilted rectangular cross slots of dissimilar size is etched in the middle layer. Also, the tilted cross slot and DR is excited through underneath microstrip feed line in the bottom of lower Rogers 5880 substrate. Due to the hybridembedded assembly, the fundamental mode TM01d excited at L5-band (1.164-1.188 GHz) and the other higher order TM02d mode excited at S-band (2.48-2.5 GHz) simultaneously. The proposed archetype has provided improved S11 < -25 dB for L5 band and < -15 dB for S-band, axial ratio (AR) more than 3 dB for L5 band. Moreover, a novel circularly arrange substrate integrated metallic and non metallic vias has boosted the realized gain at 5.63 dbic for circularly polarized L5 band and 4.81 dbi for linearly polarized S-band. The proposed structure is fabricated and tested in the anechoic chamber also. Also, the detail parametric analysis is carried out to achieve the desire results. Comparative result analysis shows proposed novel design has miniaturized DR radiating aperture, better reflection coefficient, dual polarization, improved realized gain and radiation performance compare to earlier techniques stated in the literature. [ABSTRACT FROM AUTHOR]

This manuscript presents a novel aperture-coupled fed slotted dumbbell-shaped (SDS) dielectric resonator antenna (DRA) with enhanced bandwidth for 5G sub-6 GHz, short-range wireless communications, and C-band applications. The DRA is excited by HEM11δ mode. The proposed SDS-DRA is designed by assembling the four frustums of conical DRAs with the base and apex of one on top of another. The measured operating frequency of SDS-DRA is from 3.5 GHz to 9.6 GHz (impedance bandwidth of 93.1 %). The SDS-DRA shows a peak gain of 9.7 dBi in the operational frequency range, with an average peak gain of 6.02 dBi. The antenna's average radiation efficiency is found to be 84.6 %. The proposed SDS-DRA produces omnidirectional-like radiation patterns with significantly low cross-polarization in the broadside direction. The size (l × w × h) of the proposed SDS-DRA is 1.55λg × 1.55λg × 0.67λg where, λg is the guided wavelength in mm at 3.5 GHz for effective permittivity (ϵeff), 7.1. To validate the simulation results, the proposed antenna structure is built, and its performance is measured. The findings of simulation and measurement results are found to be quite congruent. [ABSTRACT FROM AUTHOR]

The increasing volumes of data generated by social networking, cloud computing, e-commerce, and online video broadcasting necessitate the implementation of higher data rates. As the current 4G network encounters congestion and potentially struggles to accommodate the substantial data demand, there is a growing interest in millimeter wave (mmWave) technology. The 30-300 GHz mmWave spectrum is characterized by its broad bandwidth and low latencyÍ? it is having many applications in communication domains, also includes 5G cellular. Despite its atmospheric attenuation and non-line-of-sight (NLOS) propagation, the majority of nations have begun to implement mmWave 5G in the band of 28/38 GHz as a result of its reduced path loss exponent, minimal signal spread, and decreased atmospheric attenuation. While the patch antenna (single-element) is a compact and easily transportable choice for mmWave applications, its radiation efficiency, gain, and bandwidth are all subpar. Array antennas have effectively addressed these limitations by exhibiting significant enhancements in bandwidth, gain, and radiation efficiency. It is still limited in the maximum data rates it can accommodate. The rate of data can be increased by a factor of one thousand using Multiple-Input-Multiple-Output (MIMO) technology, which is enabled by geographical diversity and multiplexing techniques. As a result, the comprehension of structures of MIMO antennas operating at mmWave is imperative for the continued enhancement of performance. In comparing the efficacy of these designs, bandwidth, isolation, efficiency, gain, and radiation pattern are considered. In this paper, the most recent planar MIMO antenna designs, which are categorized as defected ground structures, Slot/Patch/Stub, MIMO Antenna Array, Dielectric Resonator Antenna, and Meta-Surface/Metamaterial Structures, are described. This paper also addresses the effects that slots, partial ground, and decoupling structures have on levels of isolation, bandwidth, and impedance matching. A comprehensive analysis of the design considerations and subsequent advancements is also provided in this paper. [ABSTRACT FROM AUTHOR]

Low 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. [ABSTRACT FROM AUTHOR]

This article reports the Modified Microstrip Feed Hybrid Rectangular Dielectric Resonator Antenna (RDRA). The proposed structure has a ground plane with a plus-shaped slot on an FR4 substrate with a height of 1.6 mm and dimensions of 38 mm x 35 mm. The proposed Dielectric resonator antenna is made of a material with 10 as its dielectric constant, and the dimensions of the DR are 19 x 20 x 18 mm3. The DR is connected to a modified microstrip feed with an octagonal ring through the plus-shaped slot in the ground. The proposed structure operates in frequencies from 2.60 GHz - 2.74 GHz, 3.12 GHz - 3.37 GHz, and 4.25 GHz - 4.37 GHz. The resonant frequency of the final proposed RDRA is 2.68 GHz, 3.26 GHz, and 4.31 GHz, which covers WLAN, WIMAX and Wireless Avionics Intra-Communications (WAIC) applications, respectively. The entire structure was simulated using the CST microwave studio. The simulated results agree with the measured results and both are presented. The compact size, stable radiation pattern and reasonable gain make this antenna suitable for the proposed applications. [ABSTRACT FROM AUTHOR]

This paper presents a pure water antenna with frequency reconfigurability, which is composed of a water resonator, L‐shaped feeder, and metal ground pad. An L‐shaped feeding structure is designed so that the working frequency can be adjusted by changing the water level of the resonator. The cross‐stack periodic water radiator structure improves the radiation efficiency by 2–4 dB compared with simple rectangular structure. The working frequency of this antenna is around 1 GHz, and will decrease by 17 MHz for every 5 mm increase in water level, which proves the feasibility of this antenna for water level monitoring. It has the potential for application in the field of wireless environmental monitoring for the Internet of Things. [ABSTRACT FROM AUTHOR]

In this article we present a ring Dielectric Resonator Antenna (DRA) fabricated on three-dimensional (3D) printed Acrylonitrile Butadiene Styrene (ABS) filament. The 3D printer offers antenna easy to fabricate and the possibility to design new antennas shapes more complex. The simulation performed using CST software 2020 shows that the proposed ring DRA has two resonance frequencies 23.5 GHz and 26.4 GHz with an obtained great gain 9.5 dB and 10.5 dB, respectively. A wideband about 42.4% was measured. [ABSTRACT FROM AUTHOR]

In this paper, a two-port alumina-based filtering antenna is designed and investigated. The feeding structure of the proposed antenna creates dual radiation nulls inside the cylindrical ceramic, which in turn produces the filtering characteristics. A metasurface is suspended over the two-port radiator to convert linear waves into circular waves. The designed metasurface also reduces the mutual coupling between two ports by an amount of −15 dB because it acts as a single negative material. Experimental results are in good agreement with simulated outcomes. It works efficiently between 2.31 GHz and 2.62 GHz with an isolation level of more than 35 dB. 3 dB axial ratio is obtained between 2.4 GHz and 2.61 GHz. Out of the frequency band, the gain value is less than −15 dB, while it is 4.28 dBi in the functioning frequency range. Stable radiation properties make it suitable for B41/n41 (2.5/2.6 GHz) applications.a standard retrieval procedure. [ABSTRACT FROM AUTHOR]

This work studies the dielectric properties in the microwave region (MW) of the Ba2TiSi2O8 (BTS) ceramic with TiO2 additions and its applications as a dielectric resonator antenna (DRA). In this study, structural characterization through x-ray diffraction (XRD) is performed and the Rietveld refinement is used to confirm the phases formed. Analysis of the morphology of the materials is performed using scanning electron microscopy (SEM). The resonant frequency temperature coefficient (τf) reveals a variation from − 47.0 ppm°C−1 to + 16.5 ppm°C−1. The dielectric properties in the MW region reveal an increase in the dielectric permittivity (εr) and a decrease in the loss tangent (tanδ) of the samples. Numerical simulation shows good fits of the experimental data, with gain and directivity standing out, ranging from 4 dBi to 6 dBi and radiation efficiency below 80%. The results demonstrate that the samples can operate in C-band electronics, Wi-Fi devices, meteorological radar systems, etc. [ABSTRACT FROM AUTHOR]

This article introduces two new compact ultra-wide band (UWB) rectangular dielectric resonator antennas (RDRAs) with enhanced bandwidth (BW), gain, and directivity. The RDRAs are designed at 10 GHz resonant frequency. The proposed RDRAs are compactly designed using resonating dielectric material (RDM) of Alumina_96 pct (εr = 9.4, tanδ = 0.006) with overall dimensions of 30 × 20 × 4.6 mm3. The RDMs are mounted on FR4 substrate (εr = 4.4, tanδ = 0.02) with defected ground structure (DGS). The DGS are comprised of rectangular and circular ring slots on it. These compact DGS-RDRAs provides enhanced BW. Prototypes of the two suggested RDRAs are fabricated. The fabricated RDRAs are validated by experimental set-ups. The RDRA with rectangular-ring slot DGS provides impedance BW (S11 < −10 dB) of 33.97 % (8.6658–12.071 GHz). The impedance BW of the other RDRA is 27.97 % (9.08–11.869 GHz). The rectangular-ring slotted RDRA offers radiation efficiency and peak realized gain of 86.4 % and 6.27 dBi, respectively within the band of operating frequencies. The radiation efficiency and realised gain of circular-ring slotted RDRA are 86.18 % and 5.9 dBi, respectively. Good agreements are achieved in between the simulated results and measured results. The results are compared with some recently developed antennas available in literature. The comparison shows that the proposed RDRAs can be suitable candidate for various X-band applications such as satellite downlinks, synthetic aperture radar, weather monitoring by military and some government organizations. [ABSTRACT FROM AUTHOR]

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

In this communication, dual-band circularly polarized radiator is structured and investigated in THz regime. The unique properties of proposed radiator are: (1) dual band circularly polarized aerial is designed in THz regime; (2) application of graphene layer over ceramic makes the radiator reconfigurable in terms of both frequency range and axial ratio; and (3) asymmetrical dumbbell shape helps to create dual radiating mode i.e. HEM11δ and HEM12δ mode. For verification, optimized outcome obtained from Ansys HFSS is compared with CST-MWS. There is good agreement between them. The designed radiator works well between 2.4 THz–3.0 THz and 4.4 THz–5.15 THz. The value of axial ratio below 3-dB is achieved between 2.6 THz–2.8 THz and 4.6 THz–4.8 THz, respectively. Broadsided radiation patterns and good gain characteristics create the designed aerial suitable for different wireless applications in the optical domain. [ABSTRACT FROM AUTHOR]

In this article, a dual port dielectric resonator antenna is modeled using various machine learning algorithms i.e. deep neural network (DNN), Random Forest, and XG boost. The unique properties of proposed article are as follows: (i) two different diversity techniques i.e. pattern (with the help of metallic wall) and polarization (mirror image of the aperture) improves the isolation value between the ports; (ii) machine learning (ML) algorithms are used to optimize and predict the reflection coefficient as well as mutual coupling of proposed antenna. The accuracy of ML algorithms is verified by using HFSS EM simulator as well as experimental validation. Error is less than 1–2% between the value predicted from ML algorithms and HFSS/Experimental results. The proposed design is working well in between 2.4–4.02 GHz with 3-dB axial ratio from 2.84–2.95 GHz. All these features make the radiator employable to sub-6.0 GHz frequency band. [ABSTRACT FROM AUTHOR]

This work proposes a novel dielectric resonator antenna design for 5G-based IoT applications that operates in the sub-6 GHz frequency range. The DR antenna is built on a 1.6-mm-thick FR-4 substrate with dimensions of 30*50 mm2. The proposed dielectric resonator antenna is made of alumina and is excited using a microstrip feedline of 50 Ω. Because of the hybrid arrangement of cylindrical and rectangular dielectric resonator elements on the FR4 substrate, this proposed structure has improved the radiation mechanism. The antenna design process begins with creating the antenna in the Ansys HFSS EM simulator, which is then optimized using machine learning based on the antenna geometry's target factors. A data set of 2625 sample data values is generated in HFSS and fed to various machine learning algorithms for further optimization based on data trends. Post-optimization, the antenna design is fabricated and tested. The proposed antenna offers a wide bandwidth of 1.1 GHz between 3.5 and 4.6 GHz and resonates at 3.9 GHz making it suitable for 5G sub-6 GHz IoT applications. [ABSTRACT FROM AUTHOR]

(1– x)BaV 2 O 6 - x LiF (x = 0.025, 0.05, 0.10, 0.15) ceramics with an ultra-low sintering temperature of 475 °C were synthesized using the standard solid-state reaction method. The ceramics demonstrated a remarkable enhancement in the quality factor (Qf), reaching a maximum value of 16,800 GHz at x = 0.10, which is 5.6 times higher than that of pure BaV 2 O 6 ceramics obtained in this work. A near-zero temperature coefficient of resonant frequency (τ f = 1.44 ppm/°C) was simultaneously achieved, together with a dielectric constant ε r of 11.54. Additionally, the chemical compatibility between the present ceramics and the Al electrode was confirmed. Moreover, a millimeter-wave antenna with an excellent S 11 value of −50.3 dB, and a large bandwidth of 3.44 GHz was fabricated using the 0.9BaV 2 O 6 -0.1LiF ceramic as the dielectric resonator. These results highlight the potential application prospects of (1– x)BaV 2 O 6 - x LiF ceramics in the ultra-low temperature co-fired ceramic technology and 5 G millimeter-wave antennas. [ABSTRACT FROM AUTHOR]

A polarization reconfigurable tri-band dielectric resonator antenna (DRA) is designed and numerically investigated for THz applications. The designed rectangular DRA made of silicon is excited by a silver nanostrip feed. The unique feature of the proposed DRA is the incorporation of dual split ring resonators (SRRs) connected with graphene layer. The SRRs are used to excite orthogonal modes required to achieve circular polarization response in the THz bands. The tunability in polarization is achieved by varying the chemical potential of the graphene layer used to connect the outer ring of the two SRRs. The proposed circularly polarized DRA (CPDRA) achieves a triple band with an impedance bandwidth of 4.96–5.52 THz, 6.85–7.12 THz, and 8.5–9.4 THz. The dual 3-dB axial ratio bandwidth of 5–5.6 THz and 8.8–9.4 THz with a peak gain of 7 dBi is obtained by the proposed design. The CPDRA exhibits stable left-hand circular polarization radiation pattern with RHCP below 15 dB in the boresight directions. This novel approach for tuning the polarization and triple band impedance bandwidth makes the proposed design a suitable candidate for THz communication, imaging, and sensing applications. [ABSTRACT FROM AUTHOR]

A comprehensive design of an ultra-broadband circularly polarized (CP) dielectric resonator antenna (DRA) array operating in the C-band for fifth-generation (5G) communication systems is presented in this paper. The objective is to achieve a compact antenna size capable of receiving and transmitting CP electromagnetic waves over a wider bandwidth. The material chosen for the dielectric resonator (DR) is Alumina (Al 2 O 3) ceramic, known for its low dielectric loss and exceptional mechanical properties, making it an ideal candidate for the DR. The proposed design utilizes a 2 × 2 array of cross-shaped DRs, fed by a compact circular phase-shift feeding network with double-point feeding. This configuration results in a 3-dB axial ratio (AR) bandwidth of 48.7 % and an impedance matching bandwidth (IMB) of 53.2 %. The antenna's horizontal size is reduced to 1.17 × 1.17λ 0 2, and the gain is significantly enhanced by exciting multiple Mie resonances in the stacked DRs, yielding a measured peak gain of 12.48 dBic. These outstanding features position the CP DRA array as an excellent choice for 5G communication systems. [ABSTRACT FROM AUTHOR]

This document is a summary of a special issue in the journal Micromachines that focuses on new trends in microwave/millimeter antennas and filters. The issue includes 19 papers from authors in various countries, covering topics such as MIMO antennas, RFID, and filters. The papers discuss the design of antennas for 5G and wireless applications, multiband antennas with high isolation, and reconfigurable antennas for wireless communications. Two papers also explore circularly polarized dielectric resonator antennas. The issue presents cutting-edge research findings in the field of microwave/millimeter antennas and filters, providing readers with an overview of the latest developments in this area. [Extracted from the article]

A circularly polarized (CP) multiple-input multiple-output (MIMO) dielectric resonator antenna (DRA) is presented in this paper for 5G millimeter-wave (mm-wave) applications. This MIMO antenna consists of two high-order mode CP DRAs, which use the modified cross slots to generate the CP fields. Two complementary split ring resonators (CSRR) are used to isolate the surface current on the metal ground, which can increase the antenna isolation and optimize the axial ratio when each port is excited. The proposed MIMO antenna obtains a simulated impedance bandwidth from 25.41 to 31.18 GHz and an axial ratio (AR) bandwidth (AR < 3 dB) from 25.49 to 29.52 GHz for the 5th generation wireless communication applications. The measured results show that the antenna covers the overlapped bandwidth of 11% and isolation less than −25 dB over the frequency band range. The measured average (peak) gain is 5.84 (6.24) dBic at 26.5 GHz to 29.5 GHz for port 1 and 6.90 (7.27) dBic for port 2. [ABSTRACT FROM AUTHOR]

In this article, a wideband ceramic-based dual port MIMO (Multi Input Multi Output) antenna is investigated and analyzed. Wideband features are obtained with the assistance of asymmetrical dumbbellshaped cylindrical ceramic. Triple-band circular polarized waves are also obtained with an S-shaped aperture having unequal strip length. Other special characteristic of the proposed MIMO radiator is to achieve bidirectional pattern diversity by placing radiators in opposite direction. Measured outcomes confirm that the proposed radiator offers a fractional bandwidth of 65.04% (4.02 to 7.89 GHz) with less than -25 dB mutual coupling between two identical ports. In between the three frequencies range, i.e., 4.75 to 5.02 GHz, 5.75 to 6.2 GHz, and 7.55 to 7.82 GHz, the value of axial ratio is well below the value of 3 dB. Measured far-field pattern and diversity parameters authorize the appropriateness of the proposed radiator in MIMO system. [ABSTRACT FROM AUTHOR]

A 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. [ABSTRACT FROM AUTHOR]