Ceramic Resonators Research Articles

A new hybrid metamaterial absorber composed of ceramic resonators stacked on thin conductive rubber layer

In this letter, a hybrid metamaterial absorber made of ceramic resonators stacked on the traditional thin conductive rubber layer (RAT) has been developed. While RAT has been proven to be an effective absorber with good absorption around 10.5 GHz, its ability to absorb electromagnetic (EM) waves is inconsistent due to its flexible characteristic. Meanwhile, the absorption bandwidth above 90 % for RAT is constrained by its dispersion, limiting the coverage across the entire X-band (8–12 GHz). To address these limitations, we have incorporated the ceramic artificial nanostructure to enhance absorption intensity and broaden the absorption bandwidth by leveraging the strong magnetic Mie resonance of the ceramic resonator. Simultaneously, the number of absorption peaks and the bandwidth of each absorption peak can be controlled by adjusting the offset distance of the ceramic resonators and by varying the sintering temperature of the ceramics. Through the integration of metamaterial design and ceramic materials optimization, we have experimentally demonstrated the feasibility of multi-band, high-absorption devices by utilizing the hybrid structure of ceramic resonators and RAT, which opens up new possibilities for the further development of absorber devices.

Quasi-BIC high-index resonators for liquid characterization and analysis

Capabilities to monitor the purity and mixture composition of liquids with the aid of low-cost portable devices can grant essential advantages in maintaining personal health safety. The overwhelming majority of consumer wireless devices operate at relatively small operational bandwidth, thus not allowing for retrieving material composition via dispersion characteristics. To mitigate the bandwidth limitations, resonant methods, granting precision in a small frequency window, might be of use. Here, we demonstrate a liquid sensor able to provide 90.5 kHz/RIU sensitivities owing to a resonator, supporting high-quality factor quasi-bound states in the continuum. The sensor's architecture encompasses a high-permittivity ceramic resonator and a capillary wrapped around it. The volumetric design increases the overlap between the electromagnetic mode and the liquid under test while maintaining resonant conditions within a relatively narrow frequency band. To demonstrate the capabilities of the proposed method, the UHF RFID band was considered, and temperature dependence of the distilled water permittivity was retrieved. Interfacing standalone low-cost electromagnetic sensors with widely available consumer-level wireless devices offers promising opportunities that contribute to the paradigm shift toward IoT.

Improving bonding strength between Ni/Cu/Ag coatings and MgTiO3 ceramic resonator by alumina thin-film grown by atomic layer deposition

A layer of nano-sized alumina thin-film was grown on MgTiO3 based ceramic resonator using atomic layer deposition (ALD) to improve the bonding between resonator and electroless plated and/or electroplated metal coatings. The hydroxylation of resonator surface ensures the strong bonding between alumina film and ceramic substrate, indicating by the bonding score to 10 from 0. However, it will not result in the degradation of the insertion loss of metalized resonators. The signal insertion loss of metalized ceramic resonator with alumina thin-film intermediate layer is significantly lower than that of resonators treated by traditional HF solution corrosion and/or laser scanning to achieve strong bonding between resonator and metalized coatings. It could be promising to metalize ceramic resonators with highly complex intricate geometric shape.

Experimental observation of diffractive retroreflection from a dielectric metasurface

The non-specular reflection scenario is considered important for many practical applications of gratings because this regime corresponds to the maximum efficiency of diffraction. Retroreflection is a particular case of a non-specular scenario when a grating returns a large portion of the incident light back to its source. We propose a detailed quasi-optic (microwave) experimental study of the retroreflection phenomenon in dielectric metasurfaces. Our study is supplemented by an analytical description and full-wave numerical simulation. The experimental sample of the metasurface is constructed as an array of disk-shaped low-loss ceramic resonators inserted in a host with air-like material properties. To ensure efficient reflection, the metasurface is coated on one side with a metallic foil. The conditions of retroreflection for any direction and polarization of an incident wave are demonstrated in both far-field and near-field experiments. The main contribution to the non-specular reflection of the Mie-type (HE 11) mode of the disk-shaped resonators forming the metasurface is revealed. The high efficiency of retroreflection in both TE (transverse electric) and TM (transverse magnetic) polarizations allows us to consider our metasurface as a prototype of planar grating rulers for high-precision displacement measurements.

Study on the Shear Lag Effect

Shear lag effect increase as we move away from the section thereafter, the effects becomes predominant especially for the unsymmetric structures. The force transmission between the structure and patch occurs through bond layer, via shear mechanism, invariably causing shear lag. In the present study, an attempt is made to correlate the average shear stress in the bond layer obtained using the Bhalla & Soh model (2004) & BSC(Bhatt Saxena Chaudhary) model. In BSC model overall deformation of the bond layer is considered. It is simplified model of the complex shear lag phenomenon as with force transmission among PZT (lead zirconate titanate) patch and host structure .PZT is one of the world’s most widely used piezoelectric ceramic materials. When fired, PZT has a perovskite crystal structure, each unit of which consists of a small tetravalent metal ion in a lattice of large divalent metal ions. PZT is used to make ultrasound transducers both for loudspeakers and microphones and other sensors and actuators, as well as high –value ceramic capacitors and FRAM chips. PZT is also used in the manufacture of ceramic resonators for reference timing in electronic circuitry. PZT has a high dielectric constant, ferroelectric, piezoelectric, & pyroelectric properties. The ideal properties of PZT have made its application to transducer, sensor and actuator devices ubiquitous. Piezoelectric ceramics, when mechanically activated with pressure or vibration, have the capacity to generate electric voltages sufficient to spark across an electrode gap. Piezoelectric energy harvester has good compression performance, fatigue resistance and waterproof performance. Piezoelectric effect is the ability of certain materials to generate an electric charge in response to applied mechanical stress. The word Piezoelectric is derived from the Greek piezein , which means to squeeze or press ,& piezo , which is Greek for “push”. The main advantage of BSC model is that it does not involve solving the complex differential equations. Shear stress distribution is practically independent of excitation frequency except near pressure. BSC model can be made use of for carrying out the preliminary design in structural control related problems.

Miniature Long-Range Ceramic On-Metal RFID Tag

Radio frequency identification (RFID) is a widely used wireless technology for contactless data exchange between a passive information carrier (tag) and an active interrogation device (reader). Being sensitive to a surrounding environment, RFID tags are usually designed per application. Here, we demonstrate an RFID tag with three essential functions available simultaneously, namely, small footprint, long reading range, and capability of on-metal labeling. Our design is based on a compact high-index ceramic resonator and an inductively coupled small metal ring functionalized with an RFID chip. The tag operates at magnetic dipolar resonance, which interacts with the metal object subject to labeling. Specifically, a 16.5 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times16.5$ </tex-math></inline-formula> mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times12$ </tex-math></inline-formula> mm footprint device, placed on a 40 cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times40$ </tex-math></inline-formula> cm metal sheet, was successfully interrogated from 22 m with no violation of international effective isotropic radiated power (EIRP) standards. Currently, it is the smallest on-metal RFID tag with a reading range of over 20 m. Multifunctional miniature long-range ceramic tags are attractive for use in numerous practical applications, including the Internet of Small Things (IoST) and many others.

Improving Luminous Efficacy of Ceramic Resonator Plasma Lamps by Using Microwave Pulse Modulation

The microwave plasma lamp is an electrodeless light source that uses radio frequency (RF) energy to excite gas discharge. By using the square wave pulse modulation, this article studies the luminous characteristics of the rectangular ceramic resonator plasma lamp so as to improve the system’s luminous efficacy. When the modulation frequency is 22 kHz and the duty ratio is 90% for a quartz bulb with color rendering index (CRI) of 92, the luminous efficacy can be increased by 15% steadily for the RF power of 180 W. The spectral power distribution is almost the same as the continuous wave (CW) 200 W, indicating that the luminous efficacy is improved without changing the luminous parameters and performance. The luminous flux is very sensitive to different modulation frequencies during the arc discharge state. This sensitivity is explained by the resonance between the pressure wave generated by pulse modulation and the reflected wave from the tube wall. Finally, the luminous efficacy of 90.4 lm/W for the light source and 60 lm/W for the system is achieved. This study provides a method to increase the luminous efficacy when the efficiency of the RF driver cannot be significantly improved, and it has a practical value to prolong the life of plasma lamps.

Novel compact bandpass filter using sextuple‐mode ceramic cavity resonator

This letter proposes a novel compact ceramic cavity bandpass filter with surface silver coating and air coupling apertures. It is constituted of a sextuple-mode ceramic cavity as the main resonator, two single-mode cavities to connect the sextuple modes transversely with source and load, and two single cavities to suppress higher harmonics. This proposed filter has the advantages of compact size, wide band, low insertion loss, high selectivity, wide spurious-free window, as well as coplanar source and load interfaces. There are no blind holes in the filter, which is beneficial for improving the machining accuracy. One prototype filter operating at 3.5 GHz is fabricated and measured. The minimum insertion loss in the passband is 0.65 dB. The inherent spurious mode of the sextuple-mode resonator at around 1.2fC (fC center frequency) is suppressed under −30 dB. The measured and simulated results are in good agreement.

Broadband and high-efficiency of garnet-typed ceramic dielectric resonator antenna for 5G/6G communication application

Garnet-typed ceramics of Y3Mg1-xMnxAl3SiO12 (0 ≤ x ≤ 0.2) have been synthesized using the traditional solid-state reaction method. The optimal microwave dielectric properties (εr = 10.73, Q׃ = 62,824 GHz, τf = −34.8 ppm/°C) are obtained for Y3Mg0.9Mn0.1Al3SiO12 (x = 0.1) sintered at 1575 °C for 5h. A millimeter-wave dielectric resonator antenna is designed and fabricated using Y3Mg0.9Mn0.1Al3SiO12 as a dielectric unit due to its excellent characteristics of low dielectric constant and high Q׃. The designed DRA resonates at 24.94 GHz with a bandwidth ∼2.20 GHz (S11 < −10 dB). The simulated gain and efficiency are 6.64 dBi and 91.08%, respectively. The results indicate that the Y3Mg0.9Mn0.1Al3SiO12 ceramic has a potential application as an antenna for the 5G/6G millimeter wave frequency band.

Dual-Band Circularly Polarized Hybrid Dielectric Resonator Antenna for 5G Millimeter-Wave Applications

This paper proposes a dual-band circularly polarized (CP) rectangular dielectric resonator antenna (DRA) for 5G millimeter wave wireless communications. The proposed DRA consists of a novel modified cross-flower exciting (MCF) slot and a rectangular ceramic dielectric resonator (DR). With the help of the compact MCF feeding slot, the fundamental modes TEδ11x/TE1δ1y and higher-order modes TEδ13x/TE1δ3y of the DR can be excited to achieve CP dual-band characteristics. In addition, the MCF slot works as a radiator at 26 GHz and 39 GHz to enhance the DRA bandwidth. More importantly, these two operational bandwidths can be controlled independently at the lower and upper bands. The proposed DRA is designed, fabricated and measured. The measured results show that the proposed dual-band CP DRA achieves 3 dB axial-ratio (AR) bandwidths of 19.8% and 7.8% with peak gains of 5.62 dBic and 6.74 dBic for the lower and upper bands.

Self-aligning roly-poly RFID tag

Radio frequency identification (RFID) is a mature technology that allows contactless data readout via a wireless communication link. While numerous passive RFID tags are available on the market, accurate alignment between tags and readers is required in a vast majority of cases to mitigate polarization mismatches. We show that enhancing electromagnetic designs with additional mechanical degrees of freedom allows bypassing fundamental limitations and approach ideal performances. Here, we demonstrate a new miniature tag, accessible from any direction and immune to rotations in space. Our tag is made of a high permittivity ceramic resonator, inductively coupled to a metal ring, which contains an RFID chip. The structure is placed inside a spherical plastic holder. In this architecture, the ceramic resonator serves several functions. First, it allows reducing the device footprint without significant bandwidth degradation. Second, it acts as a bob, aligning the electromagnetic structure parallel to the ground, regardless of its initial orientation in space. The bob is designed to slide inside the plastic holder. This roly-poly effect relaxes the constraint on a mutual tag-reader orientation, including the polarization mismatch, and provides next to perfect long-range operation. Being only 55 mm in diameter, our device can be interrogated from a 12 m distance, regardless of the tag’s orientation in space. Introducing mechanical degrees of freedom into electromagnetic designs allows obtaining new functionalities, contributing to applications where a mutual orientation between transvers is required.

Design and Realization of Chebyshev Bandstop Filters Based on Ceramic Resonators

Abstract. Distributed bandpass or band-reject filters generally become larger as the design center frequency decreases. To achieve suitable filters with small dimensions even at center frequencies below 2 GHz, ceramic resonators can be used. These components essentially represent transmission lines with a specified, potentially large permittivity, making them physically short while maintaining a desired electrical length. In this paper, Chebyshev-approximated band-reject filters using capacitors and transmission lines, the latter being represented by ceramic resonators, are investigated. Three filter prototypes are built and their performance is evaluated by measurements. Reasonable bandstop filter properties are found, which are the better the narrower the filter bandwidth is.

Ceramic‐elements‐based distributed resonators and filters

The aim of this paper is to introduce a new family of low-profile resonators and filters that achieve high performance and low insertion loss without the need for post-production tuning. The new resonator is termed ceramic-element based distributed resonator and consists of a matrix of subwavelength-length ceramic posts connected in the inter-digital fashion to the top and bottom ground planes. Such a disposition of elements is beneficial for two main reasons. First, the frequency of operation of such a resonator becomes a function of its height, unlike in the case of standard ceramic resonators. Second, the ceramic element matrix performs inherent dimensional averaging, resulting in a filter that requires no post-production tuning. As a demonstrator of the proposed technology, a two-pole filter using a ceramic with a dielectric permittivity of 37 and a loss tangent of 0.0033 and operating at a centre frequency of 3.5 GHz was designed, fabricated and tested. The measured and predicted results are in excellent agreement and are extensively discussed.

Millimeter-Wave Measurements and Applications of Dipole Modes in Spherical Alumina Dimer

Dielectric dimers composed of spherical Alumina ceramic resonators are studied. The electromagnetic scattering of dimer configurations is analyzed through spherical multipole decomposition. Different configurations of dimer operation are addressed with respect to propagation direction and polarization of the incident wave. In context to forward scattering caused by dipole interaction, measurements are performed in V-band (50–75 GHz) to quantify the corresponding electromagnetic signature of the dielectric dimer. Based on the fundamental dipole modes excited in the subwavelength free-space gap along the dimer axis, electric and magnetic hotspots are proposed, which can be exploited for near-field enhancement-based applications at millimeter-wave frequency. A dedicated frequency-scaled measurement setup is designed to measure the field-enhancement factor between 25 and 30 GHz in the free-space dimer gap, corresponding well to simulated results.

Determination of the PIC700 Ceramic's Complex Piezo-Dielectric and Elastic Matrices from Manageable Aspect Ratio Resonators.

Achieving good piezoelectric properties, such as the widely reported d33 charge coefficient, is a good starting point in establishing the potential applicability of piezoceramics. However, piezoceramics are only completely characterized by consistent piezoelectric-elastic-dielectric material coefficient matrices in complex form, i.e., including all losses. These matrices, which define the various alternative forms of the constitutive equations of piezoelectricity, are required for reliable virtual prototyping in the design of new devices. To meet this need, ten precise and accurate piezoelectric dielectric and elastic coefficients of the material, including all losses, must be determined for each alternative. Due to the difficulties arising from the coupling of modes when using the resonance method, this complete set of parameters is scarcely reported. Bi0.5Na0.5TiO3-based solid solutions are already commercially available in Europe and Japan. Here, we report a case study of the determination of these sets of material coefficients (diα, giα, eiα and hiα; sE,Dαβ and cE,Dαβ; εTik and εSik; and βTik and βSik), including all losses, of the commercial PIC700 eco-piezoceramic. Plate, disk, and cylinder ceramic resonators of a manageable aspect ratio were used to obtain all the material coefficients. The validation procedure of the matrices is also given by FEA modeling of the considered resonators.

A Novel 5G Band Filter Based on Ceramic Dielectric

The construction of 5G system is in the works. In order to improve the anti-interference and reduce the volumes of 5G system, it is important to design a filter with better filtering performance and smaller volume. At present, the research of 5G filter is almost base on metal resonator. This paper designs a ceramic dielectric resonator, and on the basis of the designed dielectric resonator, a 5G band dielectric filter is designed after theoretical calculation and analysis by using rf/microwave simulation software HFSS. The coefficients are realized by the distance between two resonators, and the Q value is realized by the distance between the input port and the first resonator. The results show that in the pass-band (3.4 ∼ 3.5GHz), the return loss is more than 15dB, the insertion loss is less than 0.35dB, and the VSWR is 1.62. The filter has the advantages of small insertion loss, small size and good rejection out of pass-band, which can be applied to 5G band wireless communication system with better suppression performance to improve the communication quality of the communication system.

Subnanoliter Sensing of Dielectric Properties of Liquid-in-Flow at 190 GHz

Dielectric properties (permittivity and loss tangent) of various liquids (water, methanol, propanol, acetone, and isopropanol) are determined by analyzing the frequency detuning effects of different millimeter-wave resonators exposed by the liquid-under-test. Alumina ceramic spherical dielectric resonators, fed from a thin-film circuit, form a resonator fixture operating at 190 GHz. Subnanoliter amount of liquid, carried in a glass tube, is exposed to the resonator. Analysis of the setup by means of electromagnetic field simulations reveals the liquid’s dielectric properties. Extracted data match well with properties obtained from Debye models. Measurement sensitivity is discussed with respect to frequency shift, sensed volume, and dielectric contrast. Obtained sensitivity figure-of-merit outperforms alternative techniques at such high frequency.

Dielectric resonator antenna with Y3Al5O12 transparent dielectric ceramics for 5G millimeter‐wave applications

AbstractMicrowave dielectric ceramics are considered to be one of the key materials for dielectric resonators (DR) and have very broad application prospects in the fifth generation (5G) mobile communication system. Here we have prepared high‐quality factor Y3Al5O12 (YAG) transparent dielectric ceramics using high‐purity α‐Al2O3 and Y2O3 powders by cold isostatic pressing of the vacuum sintered with tungsten meshes as the heating elements. Optimum relative permittivity () ~10.53, quality factor Q × f (Q = 1/dielectric loss, f = resonant frequency) ~95, 270 GHz (at =7.37 GHz), and temperature coefficient of resonant frequency (TCF) ~ −51.7 ppm °C−1 were obtained at a sintering temperature of 1780°C for 12 h. For the first time, YAG transparent ceramic dielectric resonator antenna (DRA) is designed as a dominant mode and a higher‐order mode using the aperture coupling feeding configuration excitation. The proposed transparent dielectric ceramic DRA can provide a broad impedance bandwidth of 4.193 GHz (ranging from 21.90 to 26.09 GHz) for S11 &lt; −10 dB, radiation efficiency of 92.1%, and compact DR unit. The proposed DRA can be used potentially as a 5G millimeter (mm)‐wave multiple‐input‐multiple‐output (MIMO) antenna unit.

High-order and tunable balanced bandpass filters using mixed technology resonators

AbstractThis paper reports on high-order balanced bandpass filters (BPFs) that are continuously tunable in terms of frequency and bandwidth and can be intrinsically switched-off. They use a hybrid integration scheme based on two different types of capacitively loaded resonators—ceramic coaxial and microstrip—that reduce the filter size, enhance its out-of-band selectivity and common-mode suppression, and allow for multiple levels of transfer function tuning. High selectivity is obtained in the differential mode due to the high number of poles and transmission zeros present. The common mode is highly suppressed through the introduction of additional transmission zeros and resistively loaded resonators. Furthermore, the use of ceramic coaxial resonators results in supplementary transmission zeros that are used to lower the out-of-band transmission in the differential mode. Multiple levels of tuning are obtained by reconfiguring only the frequency of the BPF's resonators. For experimental validation, a tunable mixed-technology microstrip prototype was manufactured and measured at S-band. It exhibited frequency tuning between 2.22 and 2.94 GHz, bandwidth tuning between 104 and 268 MHz, and an intrinsically switched-off mode with isolation &gt;50 dB in the differential mode. For all states, the common mode was suppressed by at least 35 dB at the center frequency and within a wide range.

All‐Dielectric Toroidal Metasurfaces for Angular‐Dependent Resonant Polarization Beam Splitting

AbstractAn all‐dielectric metasurface exhibiting a strong toroidal resonance is theoretically designed and experimentally demonstrated as an angular‐dependent resonant polarization beam‐splitter in the microwave K‐band. The metasurface is fabricated by embedding a square periodic array of high‐permittivity ceramic cuboid resonators in a 3D‐printed substrate of polylactic acid. It is demonstrated that by properly selecting the resonator geometry and by tuning the angle of incidence through mechanical rotation, the metasurface can switch between a polarization beam splitting and bandpass or bandstop operation. Such performance is achieved by exploiting the highly asymmetric Fano spectral profile of the toroidal resonance and the very low (high) dispersion of the associated p‐(s‐) polarized mode resulting from the resonant toroidal dipole mode's field profile, as evidenced by both full‐wave and band structure simulations. Theoretically infinite extinction ratios are achievable for polarization beam splitting operation with very low insertion losses and adjustable bandwidth. The experimental demonstration of such a compact, all‐dielectric metasurface expands the research portfolio of resonant metasurfaces toward not only the investigation of the intriguing physics of toroidal modes but also to the engineering of functional millimeter‐wave components for polarization control, for instance, in the context of 5G wireless communication networks.