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Unilateral radiating antennas are widely studied due to their ability to provide lateral or unidirectional radiation patterns, which are especially suitable for indoor and office Wi-Fi router applications. In this letter, a unilateral radiating rectangular dielectric resonator antenna (DRA) without a ground plane is proposed. A temperature stable low-loss 0.8MgTiO3–0.2Mg2SiO4–0.06CaTiO3 (MT–MS–CT) composite ceramic prepared via solid-state reaction and sintered at 1380 °C is utilized for the proposed DRA. Notably, the MT–MS–CT composite ceramic shows good dielectric performance with a permittivity of ε r ∼ 13 , a quality factor of Q × f 0 ∼ 115 , 000 , Q = 1/dielectric loss, f0 = 8.6 GHz, and a temperature coefficient of resonant frequency T C F ∼ + 4.6 ppm / ° C. Its unilateral radiation pattern is based on the complementary magnetic dipole and electric dipole, where the excited dominant TE111 mode of the rectangular DRA serves as the magnetic dipole and a probe acts as an electric dipole. The proposed prototype antenna fabricated using the composite ceramic has a unilateral radiation pattern with wide impedance bandwidth, reasonable gain, and radiation efficiency of 95%. [ABSTRACT FROM AUTHOR]

In this paper, the high-quality factor mullite microwave dielectric ceramic is employed to introduce in dielectric resonator antenna (DRA). The microwave dielectric properties of ɛr ∼ 5.8, Q × f ∼ 31 240 at 9.66 GHz, and loss tangent tanδ = 1/Q ∼ 2.7 × 10−4 can be obtained by the solid-state reaction method in mullite microwave dielectric ceramic sintered at 1700 °C. On this basis, the resonant modes of the proposed broadband high-gain rectangular DRA are analyzed by using a dielectric waveguide theoretical model and the antenna performance is evaluated by a commercial CST Microwave Studio 2021® software. It has been found that the proposed rectangular DRA can provide a broad bandwidth of 35.9%, a maximum gain of 10 dBi at 3.61 GHz, and a radiation efficiency of 90% in the range of 3.13–4.42 GHz. For demonstration, adequate consistency between the simulation results and the measurement results was achieved. The proposed DRA has great application potential and value in 5G communication scenarios requiring wideband and high-gain antenna. [ABSTRACT FROM AUTHOR]

This paper proposes the structured and investigation of multi‐port ceramic‐based aerial with filtering, high gain, and circular polarization features. The alumina ceramic is excited using a cross‐shaped microstrip line. Defected ground structure (DGS) is utilized to provide good impedance matching within the operating band. Metasurface suspension over the two‐port aerial improves the gain level by an amount of 10.2 dBi. The application of polarization diversity idea helps to improve separation between aerial ports by 25 dB. The prediction of |S11| and axial ratio using random forest and XGBoost‐built machine learning (ML) technique reduces the computational complexity. Fabricated prototype confirms that the designed antenna operates in between 2.55 and 3.45 GHz, and 3‐dB axial ratio is found in between 2.75 and 3.15 GHz. Directive far‐field attributes and suitable amount of diversity parameters confirm its applicability for sub‐6 GHz‐based 5G communication system. [ABSTRACT FROM AUTHOR]

A novel method is proposed to achieve a low-profile miniaturized dual-band dielectric resonator antenna (DRA) for wireless communication applications. The cylindrical dielectric resonator (DR) is fed by a microstrip loop on the top surface of the substrate and a mountain shaped ground on the bottom surface of the substrate. This structure not only effectively transfers energy to the DR but also plays a pivotal role in establishing a lower resonance frequency of 1.73 GHz, achieving this with a compact structure (0.21λ0 × 0.18λ0 × 0.02λ0, and λ0 is the free-space wavelength at 1.73 GHz). HEM11δ mode of the cylindrical DR is employed to cover the upper frequency band of 2.8 GHz. Ultimately, the effectiveness of our suggested approach and the antenna's performance are confirmed through the measurement. [ABSTRACT FROM AUTHOR]

This paper presents a slot antenna integrated with a split ring resonator (SRR) and feed line, designed to achieve a high Q-factor while maximizing channel capacity utilization. By incorporating a lens into the dielectric resonator antenna (DRA), we enhance both bandwidth and directivity, with the dielectric material's permittivity serving as a key control parameter for radiation characteristics. We explore water and ethanol as controllable dielectrics within the terahertz (THz) frequency range (0.5-1 THz), implementing these liquids through microfluidic techniques. This novel design serves two purposes, functioning as both an antenna system and a highly sensitive material sensing device. The antenna's performance is evaluated using the Debye model for pure water and ethanol, with electromagnetic full-wave simulations employing the Finite Integration Technique (FIT) to model both the antenna and microchannel structures. For predicting resonant frequencies based on antenna dimensions, we implement a Support Vector Regression (SVR) algorithm, comparing its performance against various models including Linear Regression, Regression Trees, Ensemble Bagged Trees, Ensemble Boosted Trees, and Three-layered Neural Network Models. The SVR demonstrates superior prediction accuracy by effectively capturing non-linear relationships between antenna dimensions and resonant frequencies. [ABSTRACT FROM AUTHOR]

A novel compact low-profile Conformal Dielectric Resonator Antenna (CDRA) for wideband applications is proposed. By employing a specially designed dielectric resonator in conjunction with an inverted-trapezoidal patch for feeding, an extensive Impedance Bandwidth (IB) around 51.5% is realized. The resonant frequencies of 6 GHz and 7.5 GHz correspond to the observation of the TE21δ mode and the second higher-order TE23δ mode, respectively. Moreover, a realized peak gain of 7.2 dBi is attained at 7.4 GHz. The proposed DRA offers a wide IB with more than 90% radiation efficiency throughout the bandwidth. Additionally, a good alignment is observed between the measured and simulated results. The proposed DRA is compact and has a low profile of 0.1λg, where λg represents the wavelength at the lower cut-off frequency. A CDRA with a conformal feed is an innovative design tailored for wireless communication systems operating within the frequency range from 5.2 GHz to 8.8 GHz. This antenna configuration is specifically engineered to exhibit conformal properties, enabling it for applications such as the exteriors of vehicles, aircraft, or other non-planar structures. [ABSTRACT FROM AUTHOR]

Microwave dielectric ceramics have drawn intensive interests in recent years due to the advanced development in communication area. High‐permittivity dielectric ceramics have thus become the highlight owing to dielectric ceramics with high permittivity could meet the demand of electronic components in both stabilization and miniaturization features. Bi2(Li0.5Ta1.5)O7 shows its great potential among various high‐permittivity dielectric ceramics with a suitable permittivity and a considerable quality factor. Based on previous studies, a series of rational optimizations were conducted on Bi2(Li0.5Ta1.5)O7 to manipulate the temperature coefficient of resonant frequency (TCF) and the sintering temperature for potential Low Temperature Co‐fired Ceramic (LTCC) applications. Two distinguished ceramics were obtained, Bi2(Li0.5Ta1.5)O7–0.03Bi2O3 (sintering temperature of 850°C, εr ∼ 64.1, Qf ∼ 8510 GHz, TCF—25.3 ppm/°C) and Bi2[(Li0.5Ta1.5)0.975Ti0.05]O7–0.015Bi2O3 (sintering temperature of 980°C, εr ∼ 66.2, Qf ∼ 10 950 GHz, TCF—8.5 ppm/°C). Dielectric resonator antenna (DRA) simulation was subsequently conducted and proved the ceramics holding excellent potential for microwave applications. [ABSTRACT FROM AUTHOR]

A solid-state sintering process is used to fabricate Li 4 Mg 2 SbO 6 F oxyfluoride ceramics. The sintering behavior, phase structure as well as microwave dielectric performances of Li 4 Mg 2 SbO 6 F sintered bodies were studied. The phase transformation from cubic to orthorhombic occurred for Li 4 Mg 2 SbO 6 F ceramics sintered above 750 °C. The values of ɛ r, Q × f and τ f for Li 4 Mg 2 SbO 6 F ceramics were closely related to density, and configurational entropy caused by the phase transformation. The perfect microwave dielectric performances (ɛ r = 12.6, Q × f = 59,000 GHz (at 11.3 GHz), τ f = −37.0 ppm/K) could be acquired in Li 4 Mg 2 SbO 6 F ceramics following densification at 750 °C. A cylindrical dielectric resonator antenna was fabricated from the 0.15Li 4 Mg 2 SbO 6 F-0.85Li 2 SnO 3 composite ceramics with close zero τ f , which showed good performances. [ABSTRACT FROM AUTHOR]

Summary: In this work, an offset microstrip line coupled bilateral rectangular‐shaped dielectric resonator antenna (RDRA) is designed for broadband circular polarization (CP), which is fabricated and experimentally verified. The vertical microstrip is added in an offset position to generate orthogonal modes and the fundamental modes TEx111 and TEy111. The generation of orthogonal modes designates the antenna structure as a CP antenna with orthogonal modes. Moreover, the location of the microstrip feed arrangement is used to control the polarization state in the proposed work. In the proposed design, the simulated and hand‐measured input impedance bandwidth(|S11| ≤ −10 dB) obtained is 32.6% (3.53–4.9 GHz) and 33.2% (3.56–4.98 GHz), respectively, whereas the simulated and measured axial ratio (AR ≤ 3 dB) shows 16.1% (3.71–4.36 GHz) and 17.03% (3.7–4.39 GHz) of axial ratio bandwidth, respectively. This design shows a consistent radiation pattern and good average gain, with acceptable agreement between simulation and hand‐measured results. The simulated result shows 94% radiation efficiency in the working frequency range. [ABSTRACT FROM AUTHOR]

In this paper, a novel dual-slot-fed dielectric resonator antenna (DRA) with rectangular and irregular elements, designed for 5G wireless applications, is presented. The DRA achieves wideband capability by combining the resonant modes of the rectangular and irregular DRA elements, which is a less common feature in conventional designs. A frequency ratio adjustment technique, based on the concept of inductive de-loading, is uniquely proposed for the independent frequency adjustment of the irregular DRA. Unlike traditional methods, an equivalent circuit presentation was developed to interpret the impedance characteristics of single-element DRAs, and to provide new insights into the presence of inductive de-loading from a circuit perspective. For verification, a dual-slot-fed prototype was fabricated through digital light processing (DLP)-based 3D printing technology, with the aim of customizable design and low-cost fabrication. The measured and simulated results of reflection coefficients and radiation patterns showed good agreements, with a measured bandwidth of 51.6% (2.96–5.02 GHz), effectively covering the desired 5G n77–n79 (3.3–5.0 GHz) frequency bands. [ABSTRACT FROM AUTHOR]

In pursuit of the objective of implementing fifth-generation communication technology, a LiMg 2 P 3 O 10 microwave dielectric ceramic was developed in this study, and an ultra-wideband dielectric resonant antenna was fabricated. Rietveld refinement confirmed that the monoclinic crystal structure of LiMg 2 P 3 O 10 ceramics is constituted of MgO 6 octahedral chains and shared angle PO 4 tetrahedra. The impact of chemical bond characteristics on properties was explored through P-V-L theory. The primary contributions to the intrinsic properties were investigated through infrared spectroscopy. The LiMg 2 P 3 O 10 ceramics sintered at 830 °C were found to have the best microwave dielectric properties (ε r = 6.16, Q × f = 33,573 GHz (at 15.538 GHz), and τ f = −35.6 ppm/°C). A novel ultra-wideband dielectric resonant antenna with 53.7 % relative bandwidth, 6.53 dBi maximum gain and 81.7 % radiation efficiency was designed and fabricated. Its wide ultra-wideband characteristics makes it suitable for signal transmission in modern wireless communication systems. [ABSTRACT FROM AUTHOR]

In this study, the far‐field characteristics of a plasma dielectric resonator antenna are investigated. The internal structure of the antenna is filled with a plasma material. Surface currents are obtained in an imaginary closed area formed at a certain point outside the plasma antenna. Then, the near field‐far field transformation is performed with the FFT method using the surface currents. The field distributions in the far field of the plasma antenna have been evaluated using three‐dimensional FDTD. The system has shown to work in multiband with wider bandwidths. [ABSTRACT FROM AUTHOR]

This article proposes a novel compact wideband dielectric resonator antenna design that incorporates inhomogeneous material distribution in a cubic structure. Specifically, in this design, the cubic dielectric resonator antenna is divided into multiple small blocks, and a continuous genetic algorithm is employed to optimize the material property of each block in order to maximize the radiation bandwidth. As a result, a cubic dielectric resonator antenna with inhomogeneous material distributions is designed and tested. In measurement, the proposed compact dielectric resonator antenna design exhibits 64.9% impedance bandwidth (4.08–8 GHz), considerably higher than the bandwidth of the initial homogeneous dielectric resonator antenna. The maximum system gain achieved over the frequency range is 9 dB at 7 GHz, with a peak measured system efficiency of 90.6%. [ABSTRACT FROM AUTHOR]

New microwave dielectric ceramics of LiZnSbO4 were prepared by the reactive sintering method. Within the sintering temperature zone of 1350∘C–1385∘C, a single-phase LiZnSbO4 with an orthorhombic structure was identified by XRD refinement, which contains 10 molecular formula per unit cell (i.e., Z = 1 0). The relative density and average grain size had a main effect on ε r and Q × f value of the LiZnSbO4 ceramics, whereas the phase assemblage was responsible for its τ f . The 1375∘C-sintered LiZnSbO4 specimens owned comparable low ε r ∼ 6. 5 , but ultra-high Q × f ∼ 7 4 , 5 0 0 GHz (nearly three times) compared to LiZnPO4 and LiZnVO4 ultra-high Q × f ∼ 7 4 , 5 0 0 GHz (nearly three times) compared to LiZnPO4 and LiZnVO4 manufactured, which showed a return loss as low as 37.4 dB, maximum gain of 5.7 dB and a fractional bandwidth of 3.9% (11.95–12.43 GHz). [ABSTRACT FROM AUTHOR]

Radially embedded probe-fed circular disc dielectric resonator antenna (DRA) for ultrawideband applications is investigated. Initially, a single-layer probe fed DRA is developed. The probe length is adjusted to optimize S11 performance. For a probe length of 10 mm, a measured −10 dB bandwidth of 47.8% (4.75–7.74 GHz) is obtained. The design is modified with two concentric rings of different dielectric materials with a hollow center. The modified configuration improves the matching from an S11 value of −18 dB at 5.23 GHz to −24.2 dB at 4.56 GHz. However, the measured −10 dB bandwidth reduces to some extent to 38.4% (4.2–6.2 GHz). In another modified design, an air gap is introduced between two inner discs of Alumina supported by a solid outer ring of Teflon. The radially embedded feeding probe, therefore, protrudes into the circular air pocket sandwiched between the two Alumina discs. An improved measured bandwidth of 55.9% (6.66–11.83 GHz) is obtained. Measured S11 of −24.1 dB is similar to that obtained for the concentric ring design but at a higher frequency of 9 GHz. All three antenna designs feature a reduced size with a volume of approximately 1963.5 mm³, wider bandwidth, and consistent radiation patterns over the operating frequency band. It makes the proposed designs suitable for ultra-wideband (UWB) applications. [ABSTRACT FROM AUTHOR]

A circularly polarized (CP) filtering dielectric resonator antenna (DRA) array is proposed based on the magneto-electric currents combination (MECC) method in this paper. The array consists of four rectangular DRAs, four hook-shaped electric dipoles (HSED), and two layers of substrate integrated waveguide (SIW) cavities. The electric current (EC) on the HSED is excited by the slot aperture of the SIW cavity, and the equivalent magnetic current (MC) is simultaneously generated with HSED in the DRA. Based on the surface current regulation, the EC and MC are adjusted to achieve appropriate amplitudes and phases, thereby realizing wideband CP radiation. The filtering function is realized with the high-pass characteristics of the SIW and the effective suppression of the higher-order modes in the resonance cavity. Due to the presence of an air gap between the DRAs and HSED, the higher modes of the DRA are designed for bandwidth enhancement. The prototype of the DRA array has been fabricated and measured, exhibiting a relative bandwidth of 26.1% and an axial ratio bandwidth of 17.77%, with radiation nulls present at either side of the passband. With the advantages of wide bandwidth and high gain, the proposed DRA array can be applied to satellite communications. [ABSTRACT FROM AUTHOR]

Summary: A low profile, concave conformal ring cylindrical dielectric resonator antenna (CDRA) employing frequency selective surface (FSS) using split ring resonator (SRR) for wideband and high gain applications is presented. The ring CDRA loaded with the monopole is designed to excite the TM01δ mode to increase the antenna's bandwidth. The effect of a curved ground plane (GP) on the radiation performance of CDRA is studied. A 5 × 5 array of the SRR is placed above the conformal GP at a far‐field distance optimized to (2n ± 1) λ/4 from the radiating element to enhance the gain of the proposed structure. The planar CDRA with FSS is compared with the conformal CDRA with FSS and a 4.3 GHz improvement in bandwidth is observed due to the multiple reflection and surface reflection leading to a 3.2 dBi improvement in gain. An impedance bandwidth of 51.8% (5 to 8.5 GHz) with a maximum gain of 8.7 dBi at 7.3 GHz resonant frequency and 99% radiation efficiency at 5.9 GHz is offered by the proposed antenna with FSS. Additionally, the proposed CDRA has a low profile of 0.12 λ0 where λ0 is the lower cut‐off frequency's wavelength. A good agreement is observed between the simulated and measured results. [ABSTRACT FROM AUTHOR]

ABSTRACT In this article, a rectangular dielectric resonator (DR) based multiple input multiple output (MIMO) hybrid antenna with a machine learning (ML) optimization approach for 5G New Radio (NR), WiMAX, WLAN, Wi‐Fi 6, Vehicle to Everything (V2X), and C‐band uplink applications are presented. The proposed antenna provides a triple band. It covers n1, n2, and n39 5G NR at a lower frequency (1.59–2.26 GHz), n48 5G NR at the middle frequency (3.1–3.87 GHz), and n46, n47, n96, WiMAX, WLAN, and C‐band uplink at higher frequency (5.25–6.91 GHz). It achieved more than 20% impedance bandwidth and 20 dB isolation in all frequency bands. The maximum gain of the proposed antenna is 15 dBi. The calculated MIMO parameters are within the accepted range. It is optimized through various ML algorithms, including random forest (RF), K‐nearest neighbor (KNN), artificial neural network (ANN), extreme gradient boosting (XGB) and decision tree (DT). The RF ML algorithm gives 98.09% accuracy compared to other ML algorithms for S parameter prediction. [ABSTRACT FROM AUTHOR]

This article presents the design, development, and testing of a two-port microstrip-fed dielectric resonator antenna (DRA) with a defective ground structure (DGS) for future smart phones. The proposed DRA array is fabricated on an FR-4 substrate with dimensions of 23 × 54 × 1.57 mm³. The top layer of the substrate consists of two inverted L-shaped alumina dielectric resonators, energized by a pair of L-shaped microstrip feed lines. The bottom layer of the substrate features two airplane-shaped structures to form the reduced ground DGS. Initially, a single-input single-output (SISO) rectangular dielectric resonator (DR) made of alumina material is placed over the feed network. This is later modified into an inverted L-shaped DR to enhance the antenna's bandwidth. Subsequently, a 2 × 2 array is devised from the proposed SISO, and two airplane-shaped DGS structures were introduced on the surface of the ground plane to achieve the desired impedance bandwidth of 6.3–12.6 GHz. This configuration provides a maximum gain of 4.5 dB at a frequency of 7.6 GHz with a high isolation value (S21 ≤ − 22.5 dB).The performance of the proposed DRA prototype in MIMO systems is validated by measuring various diversity parameters, such as a low envelope correlation coefficient (ECC), high diversity gain (DG), high mean effective gain (MEG), and better multiplexing efficiency, all within acceptable limits. [ABSTRACT FROM AUTHOR]

Summary: In this article, a two‐port multiple‐input multiple‐output (MIMO) hybrid rectangular dielectric resonator antenna (DRA) with machine learning (ML) approach for the n261 5G New Radio (NR) application is presented. The proposed antenna is designed on an RT/duroid 5880 (Ɛr = 2.2) substrate activated by 50 Ω, L‐shaped microstrip slot feeds beneath both DRAs. The isolation is more than 19 dB, and the gain is 10 dBi in the operating frequency range. The proposed antenna is optimized through knowledge‐based neural networks (KBNN), artificial neural networks (ANNs), and ML. The optimal design parameters of the proposed antenna are accomplished using the ML optimization approach, which includes ridge regression, ANNs, and KBNN. KBNN ML techniques provide 96.88% accuracy and correctly predict the S‐parameters of the proposed antenna. The MIMO diversity parameters like envelope correlation coefficient (ECC), diversity gain (DG), total active reflection coefficient (TARC), and channel capacity loss (CCL) are calculated and found within the limits. Hence, the proposed antenna is used for 5G NR mm‐wave application. [ABSTRACT FROM AUTHOR]

A substrate-integrated cylindrical cavity (SICC) fed polarization flexible cylindrical dielectric resonator antenna (CDRA) is presented in this literature. To excite the CDRA, a unique and simple feeding approach based on substrate-integrated waveguide (SIW) technology is demonstrated. This SICC is fed by two 50Ω microstrip lines, oriented orthogonally to each other. The SICC with a cross slot on its top metalized surface and the TM110 mode excites inside it act together to couple energy efficiently to the CDRA. Applying different phase combinations signals at the two input ports of the SICC, the CDRA can radiate in four different orientations linear polarization (LP) (along φ = 0°, 45°, −45°, and 90°), left-handed circular polarization (LHCP), and right-handed circular polarization (RHCP). A conventional cylindrical dielectric resonator having relative permittivity ϵd = 10 is preferred. Its diameter, height, and cross-slot dimensions are optimized to operate the CDRA over Ku-band with 12% impedance bandwidth, 2-dB axial ratio (AR) bandwidth of 11%, and 3-dB gain bandwidth of 12%. In this operating band, CDRA resonates at three different higher-order modes (HEM32δ, HEM113, and HEM12δ+2) with 8 ± 1.6 dBi/dBic gain for all the polarization states. The measurements of this antenna are conducted using two external phase shifters and one power divider. [ABSTRACT FROM AUTHOR]

A novel wide-band circularly polarized (CP) antenna with a step-like dielectric resonator (DR) is proposed, which features a two-order step-like dielectric resonator (TSDR) and fed by a Microstrip-slot structure. The parameter values of the TSDR are adjusted and the return loss (S11), axial ratio (AR), gain and radiation pattern are estimated by using HFSS. Results show that the new antenna has 10 dB S11 bandwidth of 56.3% (3.7 GHz-6.6 GHz), 3 dB AR bandwidth of 52.2% (3.78 GHz-6.45 GHz), and gain of 2 dBic-4.4 dBic, respectively. The usable bandwidth and peak gain are increased by 15% and 13%, respectively. [ABSTRACT FROM AUTHOR]

In this paper, a compact wideband filtering rectangular dielectric resonator antenna (RDRA) loaded with a pair of U-shaped metal strips is proposed. By using a slot-coupled feeding structure, a rectangular DR with a length–width ratio of 3:1 is selected to combine the resonant frequencies of the TE111 and TE121 modes to achieve the passband. Two pairs of transverse branches with different lengths are added to the longitudinal microstrip feeding line, and the TE111, TE11+δ1, and TE121 modes are successfully excited to enhance the bandwidth. The short pair of transverse branches can generate a null high-frequency radiation. A pair of U-shaped metal strips is loaded at both ends of the top of rectangular DR, introducing a low-frequency radiation null. Both radiation nulls can be independently adjusted. A pair of rectangular grooves is etched inside rectangular DR to boost the impedance matching level. The proposed filtering RDRA has been fabricated and measured for verification. The measured relative impedance bandwidth is 22.67% (4.34–5.45 GHz). The measured average gain and peak gain are 7.19 dBi and 8.06 dBi, respectively. RDRA filtering has broad application potential in modern communications, such as the N79 band. [ABSTRACT FROM AUTHOR]

This paper explores the potential use of fused deposition modeling (FDM) technology for manufacturing microwave and millimeter-wave dielectric resonator antennas (DRAs) for 5G and beyond communication systems. DRAs operating at microwave and millimeter-wave (mmWave) frequency bands were simulated, fabricated, and analyzed in terms of manufacturing quality and radio frequency (RF) performance. Samples were manufactured using a 3D printer and PREPERM® ABS1000 filament, which offers a stable dielectric constant ( ε r = 10 ± 0.35) and low losses (tan δ = 0.003) over wide frequency and temperature ranges. Surface profile tests and microscope measurements revealed discrepancies in the dimensions in the xy-plane and along the z-axis, consistent with the observed shift in resonant frequency. Despite these variations, reasonably good agreement between RF-simulated and measured results was achieved, and the DRA array successfully covered the intended mmWave band. However, challenges in achieving high precision may restrict applications at higher mmWave bands. Nevertheless, compared with conventional methods, FDM techniques offer a highly accessible and flexible solution with a wide range of materials for home and micro-manufacturing of mmWave DRAs for modern 5G systems. [ABSTRACT FROM AUTHOR]

In this paper, a compact 2 × 1 dielectric resonator antenna (DRA) array with circular polarization (CP) agility array is presented. The array is formed of two novel resonating elements, and each is composed of a pentagonal slot (PS) coupling a rectangular dielectric resonator (RDR). The proposed resonating element emits two degenerate orthogonal modes TExd 11 and TEy d21, confirming the CP radiation performance. The proposed resonator is utilized to portray a 2×1 sequentially rotated (SR) array with the ability to alter the CP polarization orientation. The signal at the feeding network input splits into two paths with equal magnitudes and phase progression phase by means of Wilkinson power divider (WPD). To obtain the 90 phase shifting between the WPD output signals, a single branchline coupler (BLC) is utilized. Considering the fact that the shifting orientation of the BLC output depends on which of the two BLCs is used as in input, the signal phase at the BLC can be controlled to yield a right hand circular polarization (RHCP) or left hand circular polarization (LHCP). To control the switching between the BLC output ports phase state, two PIN diodes are used at the BLC input ports. The 50 × 50 mm2 archetype achieves a bandwidth of 5.17% with a maximum realized gain of 7 dBic and a polarization purity of 4.4%. The findings of the proposed array make it a decent candidate for application using a 5.8 GHz band. [ABSTRACT FROM AUTHOR]

Abstract The authors propose a novel yet simple way of passive beamforming using a liquid antenna. A hemispherical dielectric resonator antenna filled with a dielectric liquid is considered to realise the fundamental TE111 mode, and a small, weighted metal ball is dropped inside the hemispherical container. This metal ball functions as a movable director and passively steers the realised fundamental mode of the DRA always towards the ground. The proposed design finds its applications in static‐subject‐based applications such as indoor base stations, and beam‐stabilisation/pattern‐correction works in case of dynamic‐subject‐based applications. The overall profile of the antenna is 0.60λ0 × 0.60λ0 × 0.19λ0 targeting the ISM band at 2.4 GHz with decent efficiency and far‐field characteristics. The working prototype is developed and experimentally verified.

This study presents experimental investigations and numerical simulations of the microwave (MW) dielectric and evaluation of the electrical properties in the radiofrequency region (RF). The ceramic matrix Li2LaNbTiO7 (LLNT) is obtained through the solid‐state reaction method. The synthesis of LLNT is confirmed using the X‐ray diffraction technique. In the complex impedance spectroscopy study, permittivity (ε′r) and loss tangent (tanδ) values are analyzed at room temperature. The study of the conductivity spectrum at different temperatures demonstrates that the conduction process is thermally activated, presenting a value of 0.65 eV for the activation energy. Numerical simulations are employed to evaluate the behavior of the LLNT matrix as dielectric resonator antennas (DRA), whereas this ceramics demonstrated a reflection coefficient of less than −10 dB at the resonant frequency, achieving a gain of 3.71 dBi, a bandwidth of 144 MHz and a radiation efficiency greater than 97%. The results indicate that the LLNT matrix would be a promising candidate for RF and MW operating devices. [ABSTRACT FROM AUTHOR]

This study presents experimental investigations and numerical simulations of the microwave (MW) dielectric and evaluation of the electrical properties in the radiofrequency region (RF). The ceramic matrix Li2LaNbTiO7 (LLNT) is obtained through the solid‐state reaction method. The synthesis of LLNT is confirmed using the X‐ray diffraction technique. In the complex impedance spectroscopy study, permittivity (ε′r) and loss tangent (tanδ) values are analyzed at room temperature. The study of the conductivity spectrum at different temperatures demonstrates that the conduction process is thermally activated, presenting a value of 0.65 eV for the activation energy. Numerical simulations are employed to evaluate the behavior of the LLNT matrix as dielectric resonator antennas (DRA), whereas this ceramics demonstrated a reflection coefficient of less than −10 dB at the resonant frequency, achieving a gain of 3.71 dBi, a bandwidth of 144 MHz and a radiation efficiency greater than 97%. The results indicate that the LLNT matrix would be a promising candidate for RF and MW operating devices. [ABSTRACT FROM AUTHOR]

A low-profile broadband circularly polarized (CP) dielectric resonator antenna (DRA) is proposed, utilizing DR reutilization and metasurface (MS) techniques. Two resonant frequencies and an AR minimum are achieved simultaneously, by exciting a rectangular DR with an inclined corner-truncated coupling slot, for it generates nearly degenerated TE111 modes. For significant bandwidth enhancement and low profile, a new resonator is formed by reusing the DR and loading an MS above, which works in orthogonal TM modes. To increase the axial ratio bandwidth (ARBW) further without enlarging the antenna size， two parasitic patches are printed on two adjacent side walls of the DR. To verify the rationality and feasibility, the antenna is fabricated and measured. The fabricated prototype possesses the profile of 0.06λ0 (λ0 is the free-space wavelength at the center frequency). The measured impedance bandwidth (IBW) and ARBW are 36.05% (4.23 ~ 6.09 GHz) and 22.46% (4.9 ~ 6.14 GHz), respectively. The proposed antenna has both broadband characteristics and a low profile, making it easy to integrate into space-limited wireless communication systems with high data rates. [ABSTRACT FROM AUTHOR]

In order to meet the demand of high capacity and high speed transmission of satellite communication system, a wideband dual-circularly polarized dielectric resonator antenna (DRA) array is proposed based on the traveling wave principle. Four DRA elements with slot-coupling excitation are sequentially placed on the ground, and the feeding network is designed to realize the two orthogonal circular polarization radiation waves. A notched copper loop (NCL) around the antenna array is adopted to improve the radiation performance. Depending on the operation of the two ports, the NCL generates the induced currents which rotates clockwise/counterclockwise, increasing the axial ratio bandwidth. In order to further improve the gain stability, the copper sheets are embedded on the top surface of each radiation element, and the copper cylinders perturb the internal field distribution of the DRA to introduce higher-order modes. The measurement results show that the left-hand circular polarization and the right-hand circular polarization operating bandwidths are 11.8% (14.97–16.85 GHz) and 12% (14.91–16.82 GHz). The antenna gain achieves 9.0 dBic. This DRA array can be applied for the vehicle mounted RF terminals in satellite communication. [ABSTRACT FROM AUTHOR]

Dielectric resonator antennas have been demonstrated to be an efficient radiator, especially with the possibility of fabricating it at low cost based on 3-D printing technologies. However, they have two main limitations which are: their relatively small gain (about 5dBi) and narrow bandwidth. To enhance the gain of DRA, higher-order mode excitation can be utilized; however, typically this has a limit of a few dB increments besides its negative effects on the bandwidth. This study employs a cavity-backed slot to provide an appropriate feeding method for a cylindrical dielectric resonator antenna (CDRA). This design effectively facilitates the excitation of higher-order modes, resulting in a significant gain of up to 15 dBi, which is essential for many wireless systems that are unable to support larger aperture sizes through the standard use of arrays. Additionally, two modes are excited to keep a relatively broadband of about 15 %. The proposed design consists of a cylindrical dielectric placed on top of a cavity-backed slot that is excited by a coaxial probe soldered to the top patch of the cavity. With this feeding, a good matching is achieved for different dielectric resonator heights, hence, the gain can be adjusted easily without the need of reoptimizing the antenna or the feed structures. The design process is explained in addition to performing a sensitivity analysis of fabrication tolerances which confirms that the 3-D printer provides enough accuracy with a negligible effect on the antenna's performance. Then a prototype with a medium length is fabricated and measured to provide high realized gain and impedance bandwidth of 11 dBi and 14.5 %, respectively. The measured data demonstrate the good performance of the antenna with great matching compared to the simulated ones. Furthermore, the antenna presents a good performance in terms of sidelobes and polarization. This proposed design outperforms other DRA designs based on higher-order modes. [ABSTRACT FROM AUTHOR]

In this work, a cylindrical-shaped dielectric resonator antenna (DRA) with four elements is designed and presented at 28 GHz for millimeter-wave applications. The microstrip line is designed to excite the dielectric resonator (DR) with a relative permittivity of 8.3, and then the proposed single cylindrical DR antenna has been mounted on a FR4-Epoxy substrate with a relative permittivity of 4.4 and a thickness of 1.8 mm. However, the optimized single element was used to create a particular array for improving the gain and achieving the required antenna performance. The resulting antenna enabled a response range for the reflection coefficient from 26.8 GHz to 30.6 GHz, which covers the operational frequency. This allows for a maximum gain of 19.07 dB, an impedance bandwidth of 3.8 GHz, and a total efficiency of 80.62%, meeting the requirements for millimeter-wave and fifth-generation applications. [ABSTRACT FROM AUTHOR]

Summary: This 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. [ABSTRACT FROM AUTHOR]

Summary: In 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. [ABSTRACT FROM AUTHOR]

Summary: Developing 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. [ABSTRACT FROM AUTHOR]

Samples with compositions of Sr2Sn1−xMnxO4(SSM) with 0 ≤ x ≤ 0.10 are prepared by conventional ceramic route via heat treatment at 1350 °C. Phase and crystal structure analysis is studied using X‐ray diffraction and Rietveld refinement to confirm the crystallization of samples in the tetragonal structure under space group I4/mmm. The size‐strain plot method is employed to identify the role of Mn on crystallite size/microstrain/dislocation density. The scanning electron microscope and energy‐dispersive X‐ray spectroscopy analysis confirm a significant change in the grain size and compositional homogeneity of all samples with Mn‐doping. Dielectric properties of samples are explained in terms of interfacial and orientation polarization of dipoles SnSn4+2+″−VO⋅⋅;2Mn2Mn3+2+′−VO⋅⋅$S n_{\left(\text{Sn}\right)^{4 +}}^{2 +} ^{&aposx; &aposx;} - V_{O}^{\cdot \cdot} ; 2 M n_{2 \left(\text{Mn}\right)^{3 +}}^{2 +} ^{&aposx;} - V_{\text{O}}^{\cdot \cdot}$. Modulus studies show the exclusion of electrode contribution from the electrical properties. The single‐segment circular dielectric resonator antenna is designed with the help of experimental dielectric parameters and showed two major resonant frequencies at 3.6 and 6.7 GHz. The reduction in the S11 parameter and −10 dB reflection coefficient bandwidth with Mn‐doping observed due to overlapping of the E‐field line suggests the application in patch array antenna for radar and satellite communication applications. This study also enables to explore Sr2SnO4‐based Ruddlesden Popper oxide for antenna and mm‐wave communication applications. [ABSTRACT FROM AUTHOR]

This study investigates the synthesis, structural analysis, and microwave dielectric characteristics of ZnZrNb2O8 ceramics, prepared via solid-state reaction method and subjected to sintering at temperatures ranging from 1,000°C to 1,200°C for 4 h. X-ray diffraction (XRD) analysis confirms the successful formation of ZnZrNb2O8 phase, with a monoclinic wolframite phase. Scanning electron microscopy (SEM) investigations unveil microstructural features such as grain size and porosity, reveals material's morphological details. Dielectric properties conducted in the microwave frequency regime show a correlation between dielectric constant (εr) and relative density of the ceramics. Importantly, the ceramics exhibited a suitable dielectric constant and low dielectric loss, indicative of their suitability for microwave applications. Remarkably, ZnZrNb2O8 ceramics sintered at 1,150°C for 4 h exhibit excellent microwave dielectric properties (εr = 27.2, Q × f = 54,500 GHz, and τf = -60 ppm/°C). These findings underscore the potential of ZnZrNb2O8 ceramics as advanced materials for high-frequency applications, including filters, resonators, and other microwave devices, thus contributing significantly to the advancement of next-generation telecommunications technologies. [ABSTRACT FROM AUTHOR]

The current paper reports on the crystal structure, microwave dielectric properties as well as the antenna parameters of (1-x)MgTiO 3 - xSrTiO 3 (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 SrTiO 3 was introduced to MgTiO 3 as a τ f compensator for developing a tunable τ f 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 (τ f) 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. [ABSTRACT FROM AUTHOR]

This review offers an extensive examination of the evolving landscape of Long Range (LoRa) Microstrip Patch Antennas (MPAs), highlighting their crucial role in optimizing LoRa systems within the Internet of Things (IoT). As the demand for energy-efficient standards like LoRa grows with the expanding IoT market, this research becomes increasingly relevant. This comprehensive review, the first of its kind, serves as a foundational resource for researchers seeking to optimize LoRa systems within the IoT. The study has categorized these LoRa MPAs – including monopole, Planar Inverted F Antenna (PIFA), dipole, yagi-uda, and array – into single band, dual-band, multiband, and wearable antennas, thus providing substantial viewpoints on their diverse design architectures and performance characteristics. Through systematic tabulation, the review facilitates a thorough comparison of antenna advancements. Notably, the review addresses inherent challenges in LoRa MPAs, emphasizing critical aspects that necessitate attention, including the need for miniaturization and integration, advancements in substrate materials and fabrication techniques, and the imperative for reconfigurable and adaptive antennas. Various approaches to enhance antenna performance are explored, including the metamaterial incorporation, slot-based enhancements, Electromagnetic Band Gap (EBG), dielectric resonator antennas (DRAs), substrate material considerations, and corrugation techniques. Looking ahead, the paper explores the future trends and subtle considerations that are poised to shape the trajectory of LoRa MPAs. To the best of our knowledge, this paper represents the first comprehensive review on the multifaceted topic of LoRa MPAs, serving as a foundational resource for researchers in the field. [ABSTRACT FROM AUTHOR]

Summary: In this article, a dual port Multiple Input Multiple Output (MIMO) cylindrical Dielectric Resonator (DR)‐based frequency tunable antenna with a machine learning (ML) approach for a 5G New Radio (NR) application is presented. According to the author's best knowledge, it is the first time‐frequency tunable MIMO hybrid DR with ML is reported. A dual port MIMO DRA is placed in the orthogonal configuration with the connected ground to obtain higher isolation S12<−19dB in the entire frequency range. The proposed dual port antenna provides a total spectrum (TS) and tuning range (TR) of 98.99% and 80.93%, respectively. The different MIMO parameters, Envelope Correlation Coefficient (ECC), Total Active Reflection Coefficient (TARC), and Diversity Gain (DG) are investigated and found within the acceptable limits. The optimization of the proposed dual port tunable antenna is done through the various ML algorithms, including Artificial Neural Network (ANN), K‐Nearest Neighbor (KNN), Decision Tree (DT), Random Forest (RF), and Extreme Gradient Boosting (XGB). The KNN ML algorithm provides more than 98% accuracy for predicting the S‐parameters in all configurations. Hence, the proposed antenna is suitable for 5G NR applications. [ABSTRACT FROM AUTHOR]

This paper puts forward a low-profile, circularly polarized (CP), wideband Euler's Spiral Dielectric Resonator Antenna (ES-DRA) having a footprint of 0.68 λ × 0.68 λ × 0.096 λ and operating in X and Ku-band (8.26–14 GHz). A cross-shaped aperture is used to couple the power from 50 Ω walking stick-shaped microstrip line to the ES-DRA. The antenna generates circular polarization radiation in the frequency band 10.47–11.69 GHz and has a peak gain of 8.1 dBic. There is a good matching between radiation and total efficiency in the operating band. The antenna can be put to use in weather mapping and detecting, long-range tracking radar and missile applications. The prototype has been fabricated and tested for experimental validation and the results are in good coherence with the simulated ones. [ABSTRACT FROM AUTHOR]

The authors propose a novel yet simple way of passive beamforming using a liquid antenna. A hemispherical dielectric resonator antenna filled with a dielectric liquid is considered to realise the fundamental TE111 mode, and a small, weighted metal ball is dropped inside the hemispherical container. This metal ball functions as a movable director and passively steers the realised fundamental mode of the DRA always towards the ground. The proposed design finds its applications in static‐subject‐based applications such as indoor base stations, and beam‐stabilisation/pattern‐correction works in case of dynamic‐subject‐based applications. The overall profile of the antenna is 0.60λ0 × 0.60λ0 × 0.19λ0 targeting the ISM band at 2.4 GHz with decent efficiency and far‐field characteristics. The working prototype is developed and experimentally verified. [ABSTRACT FROM AUTHOR]

This study investigates the dielectric properties of ceramic waste derived from roof tiles and bricks commonly used in civil construction. The materials were analyzed by grinding them into a fine powder, followed by producing of cylindrical samples through uniaxial pressing on a steel matrix. The samples were sintered at temperatures of 1000 °C, 1050 °C, and 1100 °C to analyze the effect of temperature on the electrical characteristics of the ceramics. XRD and SEM analyses were performed to evaluate microstructural parameters and coalescence behavior. The dielectric characterization aimed to obtain the real relative electrical permittivity with average values of 2.85, 3.56, and 3.65, correlated with apparent porosity levels of 30.74 %, 20.54 %, and 9.11 %, and the loss tangent of 7.5 × 10−5, 3.9 × 10−5, and 12 × 10−5, respectively. The loss tangent values are lower than those obtained in commercial dielectrics from 1 to 6 GHz frequency range. The dielectric characteristics of samples manufactured from ceramic waste from bricks and tiles can serve as sustainable alternatives to produce dielectric resonator antennas (DRA), applicable to fifth-generation wireless communication devices in the sub-6GHz band. [ABSTRACT FROM AUTHOR]

A Rectangular Dielectric Resonator Antenna (RDRA) design for mmWave-frequency-band MIMO metrics is proposed, with a compact, low-complexity, high-gain structure that is easy to fabricate and offers reduced inter–port isolation. The RDRA operates in the mmWave spectrum, featuring a compact size of 1.307 λ 0 × 1.307 λ 0 , an impedance bandwidth of 6%, and a resonant frequency of 28 GHz, with a peak gain of 7 dBi. A four element MIMO system iteration was developed while maintaining the performance of the single element antenna. Additionally, a simple, low-complexity slot-etching technique was applied to achieve an average inter-port element isolation of 14 dB. The design also achieved a novel four-beam petal-splitting radiation pattern. The MIMO metrics, with an envelope correlation coefficient (ECC) of <0.5 and a diversity gain (DG) < 10, were successfully met. The simulated and measured results are in good agreement. [ABSTRACT FROM AUTHOR]

This paper presents a circularly polarized hybrid cylindrical dielectric resonator antenna (HCDRA) over a modified Minkowski unit-cell-based metasurface for 5G n79 band (4.4–5 GHz) and IEEE 802.11n WLAN (5 GHz) applications. The location of the perturbed probe feed mechanism and the asymmetric nature of the metasurface are the factors that influence the circularly polarized (CP) radiation within the DR element. The magnitude of E-field distribution and parametric study of the antenna to obtain the optimized feed location are the pieces of evidence of CP radiation. The return loss (RL) and axial ratio (AR) bandwidths produced by the proposed antenna are 1.837 GHz and 750 MHz with a peak gain of 7.04 dBic. The gain obtained is more than 5 dBic across the offered bandwidth of the proposed antenna. The proposed antenna is fabricated and tested in an anechoic chamber for measured results, and these results closely match with the simulation results. [ABSTRACT FROM AUTHOR]

This investigation introduces a MIMO antenna using cylindrical shaped dielectric resonators and discusses both the design and implementation approaches. The proposed antenna design employs a CSRR structure and L-shaped metallic reflectors to improve isolation across many frequency bands. The typology operates at five different frequency ranges: 2.48, 3.92, 5.36, 7.4, and 8.56 GHz. It provides isolation levels of 39, 52.5, 33.8, 42.9, and 37.2 dB, respectively. The semi-circular tapered feed enables for circular polarization between 5.3 and 5.75 GHz. The simulated results indicate that the specified antenna is appropriate for usage in five frequency ranges: 2.1–2.6, 2.7–4.4, 4.9–5.8, 6.9–7.8, and 8.1–9.1 GHz. In a multiple-input multiple-output configuration, antenna performance is evaluated using a variety of diversity indicators, including the envelope correlation coefficient, mean effective gain, diversity gain, channel capacity loss, and total active reflection coefficient. Both simulations and measurements reveal that the proposed antenna can handle Wi-Fi 6, Wi-Max, and W-LAN services, including X-band. [ABSTRACT FROM AUTHOR]

The frequency diverse array (FDA) is a very interesting technique in wireless communications. Many research papers are introduced in this field. A lot of them is concerned with linear point sources array. In this paper, a design of a time-modulated planar frequency diverse array architecture is proposed for tracking single or multi-target for the first time. The time-modulation array (TMA) and FDA are combined for detecting single and multi-target. The effectiveness of this combined scheme is demonstrated through simulation results that compared with a point source case to show its superior performance. Authors introduce planar FDA array instead of linear FDA array and realize the planar array using cylindrical dielectric resonator antenna array (CDRA). A planar array consists of 8 × 8 CDRA is used to enable the detection of single target/multi-target. The operating frequency of the antenna is set at 10 GHz, aligning with its applications in the FDA radar. The radiation characteristics of the CDRA antenna element are introduced. High maximum gain of 6 dBi is achieved with a remarkably high efficiency. A set of representative results is reported and analyzed to assess the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

In this paper, a Substrate-Integrated Waveguide (SIW)–based Cylindrical Dielectric Resonator Antenna (CDRA) is designed for 6G THz applications. This antenna provides a Quad-band response at 2.14 THz, 3.41 THz, 5.61 THz, and 9.02 THz respectively. The unique feature of the proposed SIW-CDRA is its ability to exhibit Circular Polarization (CP) behavior across three frequency bands. Graphene material is added onto the top of the proposed CDRA to achieve tunability in the antenna's resonant frequency. CP tuning is also achieved by varying the graphene potential of the antenna. Furthermore, this proposed antenna shows both Right Hand Circular Polarization (RHCP) and Left Hand Circular Polarization (LHCP) behavior at different resonant frequencies. The antenna exhibits a maximum gain of 6.97 dB and a maximum radiation efficiency of 84.53%. Notably, the antenna showcases a 3 dB Axial Ratio (AR) bandwidth of 11.05% (1.968–2.195 THz), 4.58% (5.483–5.734 THz), and 5.22% (8.843–9.313 THz) is achieved. Moreover, the CDRA generates two higher-order modes, specifically HEM11δ at 5.61 THz and HEM12δ at 9.02 THz. Additionally, the antenna exhibits a unique feature of converting multiband response to wideband response by changing the length of the aperture slots. All these results show that the proposed multiband SIW with CDRA is unique and suitable for THz applications. [ABSTRACT FROM AUTHOR]

Dielectric resonator antennas (DRAs) use dielectric material as a resonator to accomplish high radiation efficiency and avoid severe conductor loss. The dielectric material that behaves as a resonator is plagued by a number of limitations, including strong cross-polarised (XP) radiation and difficulties integrating with any development platform. Yet, it also offers a lot of benefits, including compact size, lightweight, affordable price, and diversity in form, including cylindrical, rectangular, conical, and ring. A discussion of DRAs, covering DRA propagation modes, geometries, feeding mechanisms, and different bandwidth augmentation approaches, is presented. A stacked arrangement with two or more DRs has achieved the widest impedance bandwidth (BW). The perforated topology is a straightforward alternative for increasing the DRA's bandwidth while maintaining a small, discrete size. [ABSTRACT FROM AUTHOR]

This research examines the performance of two Z-shaped dielectric resonator antenna designs that employ silicon substrate material and operate at a frequency of 10 terahertz. CST software was used to simulate and create a two-Z shape DRA. Results of enhanced gain are analyzed and compared with earlier research. The suggested Two Z shape DRA has a gain of 7.31 dB and a return loss of -15.9 dB.The two Z-shaped dielectric resonator antennas have an impedance bandwidth of 66.66%.The VSWR of two Z-shaped dielectric resonator antennas is around 2 dB, which is acceptable. This proposed approach may be suitable for a wide range of communication applications, including wireless and terahertz applications. [ABSTRACT FROM AUTHOR]