Magnetic Conductor Research Articles

Influence of Plasma Treatment Conditions on Structural-Phase Composition and Magnetic Properties of Barium Hexaferrite (M-type) Films on C-Sapphire

In the work investigated the influence of plasma treatment conditions on the structural-phase composition and magnetic properties of barium hexaferrite films (0001) BaFe12O19 on C-sapphire. Two treatment modes were used: with a weight average plasma temperature of 4-5 kK and 8-10 kK. It has been shown that the films obtained at the low treatment temperature have a pronounced magnetic anisotropy and saturation magnetization of 42 emu/g. The films obtained at high temperature have weak magnetic anisotropy, but have a higher saturation magnetization value of 62 emu/g. All films have low coercive fields of less than 500 Oe, which indicates the low magnetic hardness of barium hexaferrite samples and the possibility of their use as magnetic conductors of transformers, electromagnets, in measuring devices. The presented results demonstrate the promise of the plasma treatment technique in the formation of coatings with high anisotropy. Keywords: barium hexaferrite, sapphire, plasmatron, magnetization.

Design of Miniaturized High Gain Bow-Tie Antenna

A high gain low-frequency bow-tie antenna with artificial magnetic conductor (AMC) and metamaterial lens for ground penetrating radar (GPR) is proposed. First, a bow-tie antenna working in 348–772 MHz frequency band is designed. The substrate is a square with side length of 420 mm. A periodic AMC reflector is designed. The in-phase reflection region of the unit is 481 MHz–1.44 GHz. The results show that the gain of antenna loaded with reflector is increased by 5 dB. A metamaterial lens based on the zero-index metamaterial element is also proposed to improve the gain. The zero refractive index frequency point is 810 MHz, the unit size of the metamaterial is 60 mm, and the lens size is consistent with the antenna substrate size. The gain of the antenna loaded with AMC reflector and the metamaterial lens is increased by 6.5 dB and the front-to-back ratio is 23 dB. The directivity of the antenna is further optimized. The measured results are in good agreement with the simulations.

Rank-Full Arrays for 2-D Mirrored Aperture Synthesis

The arrangement of the antenna array of the mirrored aperture synthesis (MAS) determines the transformation matrix for solving the cosine visibilities. When the transformation matrix is rank deficient, the solved cosine visibilities will introduce the rank-deficient error. For the two-dimensional mirrored aperture synthesis (2-D MAS), the existing literature has discussed the relationship between the arrangement of the antenna array and the rank-deficient error but has not proposed an array that can achieve a full rank transformation matrix, which is call the rank-full array (RFA). Based on a new method for calculating the rank of the transformation matrix and the literature on one-dimensional (1-D) RFAs, this paper proves that 2-D RFA cannot be obtained when the reflectors are all metal, and by introducing a reflector made of magnetic conductor, 2-D RFA can be obtained. Besides, this paper obtained the existence conditions for 2-D RFA. Based on those conditions, two methods are proposed to obtain 2-D RFAs.

A New Arraying Technique for Band-Switchable and Polarization-Reconfigurable Antenna Arrays With Wide Bandwidth

Modern antenna arrays desire antenna apertures which can support a wide frequency range and reconfigurable polarization states. It is challenging to realize such antenna apertures with high isolation among different antenna elements when they are closely packed, particularly for wide-band (>2:1 frequency ratio) operations. In this paper, we demonstrated switchable-band antenna arrays which can be reconfigured from S to C band with an instantaneous bandwidth close to 2:1. The major novelty in this antenna array is that a new arraying technique is adopted to reduce the number of feeding ports by 50%. As a result, the isolation among antenna elements can be significantly improved, thereby increasing the overall radiation efficiency. It should be noted that vertical, horizontal and circular polarizations are supported by this antenna array when all ports are provided with appropriate phases. Herein two arrays are demonstrated. Array I is based on a fractal-shaped slot-ring structure. Each antenna element is fed by a microstrip along the diagonal direction. The common antenna aperture can be reconfigured to operate at 2.5-4.0 GHz or 4.2-7.2 GH, using PIN diode switches. Array II is extended from Array I but with an Artificial Magnetic Conductor (AMC) ground to enhance the instantaneous bandwidth to 2:1. The length of the microstrip feeding lines are reduced to enable modular design. In addition, PIN diode switches are embedded in the feeding lines to further improve the isolation and radiation efficiency. The return losses, port isolations, radiation patterns, gains, radiation efficiencies and IIP3 are simulated and measured.

A Wearable Circularly Polarized Antenna Backed by AMC Reflector for WBAN Communications

A new flexible circularly polarized (CP) wearable antenna is proposed for Wireless Body-Area Network systems (WBAN) operating at 5.8 GHz. The circular polarization is enabled by combining a microstrip-line monopole feed and an inverted L-shaped conformal metal strip extended from a coplanar waveguide. The proposed antenna shows satisfactory performance in terms of gain and specific absorption rate (SAR) at a separation of 12 mm from a human body model. To minimize body-antenna separation, a flexible <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2 \times 2$ </tex-math></inline-formula> artificial magnetic conductor (AMC) was used as a reflector to achieve good performances in terms of gain and SAR. The total footprint of the proposed antenna is only <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$34.4\times34.4$ </tex-math></inline-formula> mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.384 \lambda _{0}^{2}$ </tex-math></inline-formula> ) board of semi-flexible Rogers RT-Duroid 5880 substrate. The final design provides a peak gain of 7.6 dBi and an efficiency of 94.7% when worn on the body. Furthermore, evaluation results indicate that the maximum SAR level decreased by up to 20.42% in comparison with the CP antenna without the AMC. Full-wave EM simulation and experimental results are performed, both in free space and proximity to the human body under different bending scenarios. Overall, the proposed antenna performance has been shown to be robust to structural deformation along the x-axis in comparison to previously reported designs. These features demonstrate that the proposed antenna is a strong candidate for off-body wearable applications.

Застосування методу головних компонент в задачі аналізу спектрів вільних коливань

This article addresses the main methods used for analysis, distribution, and classification of input data space. The main aspects of applying these methods are analyzed and determined. In this study it is found that the method of the principal components analysis (PCA) is the most suitable. Possible principal components analysis algorithms are described. A combination of these algorithms is used to distribute the input data in the analysis of signals and their spectra obtained by non-destructive testing after applying a free oscillations method. The article aims to study the possibility of reducing the vector of informative features after applying principal components analysis without losing the quality of recognition of the state of objects. The objects of study may be components of electric motors (shunt magnetic conductor), parts of aircraft made of composite materials and other structures that require analysis by non-destructive testing methods. Spectra taken during non-destructive testing by the method of free oscillations of samples of carbon fiber panels from defective and defect-free zones were studied. The analysis of three, five and ten harmonics was conducted and the maximum number of the principal components and the values of maximum dispersions of these components for the input values set of amplitudes were determined. The Mahalanobis distance was used to analyze the quality of the distribution of the input data space into classes (defect-free and defect zones of the sample). The quality of the separation of values from the damaged and undamaged zones of the sample into two classes was improved. Therefore, the use of principal component analysis, in this study, can increase the reliability of the recognition of the state of objects.

Research on the Design of Axial Uniform Coils for Residual Field Compensation in Magnetically Shielded Cylinder

A novel method to design highly uniform axial coils inside a closed magnetically shielded cylinder (MSC) is presented. The proposed method has two major advantages over existing methods. First, based on the coupling model of coil and MSC with finite permeability and finite thickness, and the image method and target-field method (TFM) are introduced to provide a flexible design method for the coil inside the MSC. Second, a backpropagation neural network (BPNN) model and particle swarm optimization (PSO) algorithm are used to predict and optimize the coil parameters, thus reducing the magnetic field deviation caused by the use of discrete wires to approximate the continuous current density. Simulations indicate that this method reduces the magnetic field deviation within the target region from 2.63&#x00D7;10^-3 to 1.13&#x00D7;10^-4 compared with the coils designed using the TFM without consideration of the coupling effect. The magnetic field deviation is reduced from 1.42&#x00D7;10^-4 to 1.13 &#x00D7; 10^-4 compared with the coils designed in the ideal magnetic conductor. Moreover, the field deviation is reduced to 2.43&#x00D7;10^-5 after optimization using the BPNN and PSO method. The experimental results also verify the effectiveness of the design method and its practicability in compensating for the residual field of the MSC. The method proposed in this research has major significance for the establishment of practical magnetoencephalography and magnetocardiography measurement systems.

Investigation on Antenna with Artificial Magnetic Conductor for Repeater in Fire Fighting Support System

Investigation on Antenna with Artificial Magnetic Conductor for Repeater in Fire Fighting Support System

Влияние условий плазменной обработки на структурно-фазовый состав и магнитные свойства пленок гексаферрита бария (M-типа) на c-сапфире

In the work investigated the influence of plasma treatment conditions on the structural-phase composition and magnetic properties of barium hexaferrite films (0001) BaFe12O19 on C-sapphire. Two treatment modes were used: with a weight average plasma temperature of 4÷5kK and 8÷10kK. It has been shown that the films obtained at the low treatment temperature have a pronounced magnetic anisotropy and saturation magnetization of 42 emu/g. The films obtained at high temperature have weak magnetic anisotropy, but have a higher saturation magnetization value of 62 emu/g. All films have low coercive fields of less than 500 Oe, which indicates the low magnetic hardness of barium hexaferrite samples and the possibility of their use as magnetic conductors of transformers, electromagnets, in measuring devices. The presented results demonstrate the promise of the plasma treatment technique in the formation of coatings with high anisotropy.

A Dual-Band High-Gain Subwavelength Cavity Antenna with Artificial Magnetic Conductor Metamaterial Microstructures.

This paper presents dual-band high-gain subwavelength cavity antennas with artificial magnetic conductor (AMC) metamaterial microstructures. We developed an AMC metamaterial plate that can be equivalent to mu-negative metamaterials (MNMs) at two frequencies using periodic microstructure unit cells. A cavity antenna was constructed using the dual-band AMC metamaterial plate as the covering layer and utilizing a feed patch antenna with slot loading as the radiation source. The antenna was fabricated with a printed circuit board (PCB) process and measured in an anechoic chamber. The |S11| of the antenna was −26.8 dB and −23.2 dB at 3.75 GHz and 5.66 GHz, respectively, and the realized gain was 15.2 dBi and 18.8 dBi at two resonant frequencies. The thickness of the cavity, a sub-wavelength thickness cavity, was 15 mm, less than one fifth of the long resonant wavelength and less than one third of the short resonant wavelength. This new antenna has the advantages of low profile, light weight, dual-frequency capability, high gain, and easy processing.

Low profile and miniaturized dual‐band antenna based on graphene assembled film for wearable applications

Wearable electronic devices are the basic components of wireless human body local area network. Due to their close contact with the human body, it is necessary to improve the flexibility and isolation of the antenna to maintain high signal transmission performance. In this paper, a flexible wearable antenna based on highly conductive graphene assembled film (GAF) and polydimethylsiloxane dielectric material is proposed. The planar combination of the powerful novel materials and supple polymer maximizes the flexibility and chemical stability of the antenna. In addition, the coplanar waveguide feeding and artificial magnetic conductor (AMC) structure enhance the efficiency and isolation with an easier preparation process. In the wearing measurement, the GAF antenna operates at 3.5 GHz for 5G communication frequency band and 5.8 GHz for ISM (Industrial, Scientific, Medical) frequency band. The GAF antenna has a minimizes SAR level, which in accordance with IEEE C95.1 International standard, by taking up a small space with 50.5 × 48.5 × 2.08 mm3. Furthermore, the GAF antenna has good radiation performance both under several different bending conditions and human body conditions.

Single-Port Coherent Perfect Loss in a Photonic Crystal Nanobeam Resonator.

We numerically demonstrated single-port coherent perfect loss (CPL) with a Fabry–Perot resonator in a photonic crystal (PC) nanobeam by using a perfect magnetic conductor (PMC)-like boundary. The CPL mode with even symmetry can be reduced to a single-port CPL when a PMC boundary is applied. The boundary which acts like a PMC boundary, here known as a PMC-like boundary, and can be realized by adjusting the phase shift of the reflection from the PC when the wavelength of the light is within the photonic bandgap wavelength range. We designed and optimized simple Fabry–Perot resonator and coupler in nanobeam to get the PMC-like boundary. To satisfy the loss condition in CPL, we controlled the coupling loss in the resonator by modifying the lattice constant of the PC used for coupling. By optimizing the coupling loss, we achieved zero reflection (CPL) in a single port with a PMC-like boundary.

High gain, high isolation, and low‐profile two‐element MIMO array loaded by the Giuseppe Peano AMC reflector for wireless communication systems

A low-profile printed dipole antenna (PDA) backed by a broadband Giuseppe Peano fractal artificial magnetic conductor (AMC) is introduced for wireless communications. A suggested PDA with a pair of microstrip dipoles excited by an E-shaped microstrip feedline is used to expand the bandwidth range of 5.5–6.96 GHz (S11 ≤ −10 dB). Then, the suggested Giuseppe Peano fractal AMC surface as a reflector of the antenna is inserted into the PDA to improve radiation efficiency. The PDA with the 4 × 4 Giuseppe Peano AMC array exhibits −10 dB measured impedance bandwidth from 4.25 to 7.10 GHz (50.2%) for the wireless local area network and worldwide interoperability for microwave access (WiMAX) applications. The suggested PDA with AMC compared to the PDA without AMC exhibits a size reduction of 50.5%, enhanced gain up to 8.2 dBi, and excellent impedance matching (at least −19 dB) with uni-directional radiation patterns. The novel AMC unit cell is realized based on the Giuseppe Peano fractal patch to operate at 6.10 GHz with an AMC bandwidth of 5.15–7.10 GHz (32%). Besides, by loading a 4 × 8 AMC reflector into the two-element array with diverse polarisations, a low profile wideband printed structure with enhanced radiation properties is achieved. The measured results show the broad bandwidths from 4.3 to 7.05 GHz for two elements with enhanced gains and good isolations between the elements (more than 28.5 dB) for multiple-input multiple-output (MIMO) systems.

Multilayered metamaterials array antenna based on artificial magnetic conductor's structure for the application diagnostic breast cancer detection with microwave imaging

In this work, a small multilayer ultra-wideband (UWB) patch antenna for microwave breast imaging (MWI) applications was developed both theoretically and experimentally. However, to improve the antenna performance relating to the bandwidth (BW), the radiating element of the suggested initial antenna is modified by adding a modified split ring resonator (SRR) and slits in the patch as well as the ground plane. Then, to achieve the requisite antenna properties for MWI applications such as the gain and directivity, the antenna is equipped with a uniplanar artificial magnetic conductor (AMC) structure made up of a 3 × 3 array of square modified SRR unit cells. The final proposed prototype has a relatively small size of 20 × 19 × 1.6 mm3 and it accomplishes a return loss below -10 dB (S11< -10 dB) at overall BW of 7 GHz (4.1 – 9.7 GHz) with more than 5 dBi realized gain. In this way, the characteristics of the fabricated antenna are measured to examine the antenna performance. Indeed, the fidelity factor of face-to-face (FtF) and side-by-side (SbS) scenarios are also noticed for the same frequency range. In the final analysis, a simulation model of the antennas, which operate as a transceiver, and a breast phantom model with tumor sample are proposed for detecting cancerous tumor cells within the breast.Hence, the proposed design is suitable in the biomedical applications such as tumor cell detection.

A Compact Metamaterial-Based Antenna for Multiband Phased Array Applications

In this communication, we present a miniaturized multiband metamaterial (MTM)-based antenna for array applications, operating with good radiation performance over the long term evolution (LTE) and Universal Mobile Telecommunications System (UMTS) uplinks within the 800–3000 MHz range. Each antenna element consists of a radiator and an MTM reflector. The former is a miniaturized Archimedean spiral antenna with an integrated matching line. The latter is placed 39 mm below the radiator and is shared among the multiple elements in the array application. The radiator is very compact, a square of 75 mm per side, equivalent to only 0.2 (0.75) times the free-space wavelength at 800 MHz (3000 MHz). The reflector is incorporated to achieve half-space radiation and is implemented with a novel multilayered MTM structure to improve the radiation efficiency. The MTM, moreover, is used in a nonconventional way. In fact, we take advantage of its complete phase-response function, behaving, thus, as a magnetic or electric conductor in different parts of the band. In this way, the in-phase reflection is not limited by the typical narrow bandwidth of artificial magnetic conductors. The measured <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S_{11}$ </tex-math></inline-formula> parameter is less than −8 dB and the simulated gain is greater than 4.2 dBi in a range exceeding the one covered by the UMTS and LTE uplinks. Furthermore, a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times 2$ </tex-math></inline-formula> antenna array was also built. The reflections of each element are similar to those obtained in the single-element antenna.

Numerical Green’s Function-Based Method for Modeling Radiated Emission From PCBs in Shielding Enclosures

Due to stringent electromagnetic compatibility (EMC) regulations, all electronic devices need to go through rigorous radiated emission tests before launching to market. Thus, efficient, accurate, and cheap characterization approaches are quite of interest. Instead of utilizing the time-consuming and expensive direct far-field measurement, in this work, a novel methodology on the basis of numerical Green’s function (NGF) is proposed to acquire the parasitic EM emissions from PCBs placed in a shielding enclosure with ventilation slots. Referring to Schelkunoff’s equivalence principle, the whole modeling procedure can be decomposed into two steps in order to obtain the emissions in the entire space. For the first step, the tangential electric fields over the surface of ventilation slots are sampled first; then, the NGF over a spherical surface tightly enclosing the perfectly electric conductor (PEC) filled shielding box is numerically evaluated; finally, the tangential component of the magnetic field over the spherical surface enclosing the shielding box is calculated in terms of the NGF and the sampled near electric field. As for the second step, by filling the sphere with a perfectly magnetic conductor (PMC) first, the pertinent Green’s function is further expanded by the spherical modal functions; later, the radiated emission outside this sphere can be analytically evaluated in terms of the previously obtained tangential magnetic field and the modal function expanded Green’s function. Therefore, the novelty of the proposed method has two folds: 1) only the tangential electric field over the ventilation slots is required, thus saving a lot of time in near-field measurement and 2) the NGF is independent of the PCBs in the shielding enclosure and, thus, only needs to be calculated once even though the PCBs inside the shielding enclosure is changed. To validate and verify the effectiveness of this proposed modality, several representative examples are presented.

A Low-Profile Broadband Dual-Polarized Base Station Antenna Array With Well-Suppressed Cross-Polarization

Next-generation wireless communication requires antennas with excellent performance and low-profile structures. A low-profile broadband dual-polarized base station antenna array with an artificial magnetic conductor (AMC) reflector and cross-polarization suppression structures is proposed. Cross-polarization is effectively suppressed by introducing the structures among the antenna elements with almost no impact on the other antenna performances, and the cross-polarization suppression mechanism is analyzed theoretically. The AMC reflector reduces the antenna profile only <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.12\lambda _{0}$ </tex-math></inline-formula> ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{0}$ </tex-math></inline-formula> is the free-space wavelength at 4 GHz). Prototypes of the antenna element and the five-element antenna array are fabricated, and the simulated and measured results indicate that both achieve good performance over the entire operating frequency band. The antenna array has high isolation (>28 dB), a wide operating bandwidth (3.14–5.32 GHz, 51.5%), and stable radiation performances (XPD >29 dB, gain >15 dBi, FBR >37 dB). The proposed antenna array with good performance and a low profile may be a candidate for 5G communication applications.

Wideband Gain Enhancement of an AMC Cavity-Backed Dual-Polarized Antenna

A novel low-profile wideband antenna is proposed with high-gain, high-isolated, and dual-polarized properties. It consists of two mutually-orthogonal bowtie-shaped dipole radiators, four rectangular parasitic elements, and a cylindrical artificial magnetic conductor (AMC) cavity. By introducing parasitic elements, additional resonance is generated, and the bandwidth is widened. The gain is mainly improved by the cylindrical metallic wall and wideband AMC of the cavity. The AMC operates in ±90 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sup> reflection phase band-gap bandwidth of 2.35-4.25 GHz, and its equivalent circuit model is developed to understand the working mechanism. The orthogonal placement of two dipole radiators ensures polarization diversity and high isolation. The impacts of various environmental conditions on antenna performance are investigated. To verify the concept of design and demonstrate its excellent performance features, a prototype is fabricated and measured. The proposed wideband antenna has a height of 0.18 wavelength at the center frequency. The measured -10-dB impedance bandwidth is from 2.16 to 3.96 GHz, where the realized gain is 8.34-10.96 dBi and the radiation efficiency is more than 81.8%. High isolation of > 28.65 dB and low envelop correlation coefficient (ECC) of < 2.74 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> are also achieved between antenna elements. It can be used in the base station for intelligent Internet of Vehicle (IoV) applications, covering the bands of WLAN, WiMAX, Bluetooth, LTE, and 5G sub-6 GHz.

Dual-band all textile antenna with AMC for heartbeat monitor and pacemaker control applications

Abstract All textile integrated dual-band monopole antenna with an artificial magnetic conductor (AMC) is proposed. The proposed design operates at 2.4 and 5.8 GHz for wearable medical applications to monitor the heartbeat. A flexible and low-profile E- shaped CPW dual-band textile antenna is integrated with a 4 × 4 dual-band textile AMC reflector to enhance the gain and specific absorption rate (SAR). The SAR is reduced by nearly 95% at both 1 and 10 g. The design was measured on the body with a 2 mm separation. The simulated and measured results appear in high agreement in the case of with and without AMC array integration. The measurement was performed in the indoor environment and in an anechoic chamber to validate the design based on reflection coefficient and radiation pattern measurements.

Dual-Band Circularly Polarized Antenna With Two Pairs of Crossed-Dipoles for RFID Reader

In this article, a low-profile high-efficiency dual-band 0.915/2.45 GHz circularly polarized (CP) antenna and its array are designed for radio frequency identification (RFID) reader applications. First, a dual-band antenna element is introduced to achieve dual-sense CP radiation using two pairs of crossed-dipoles for the first time. The right-hand CP (RHCP) wave at lower band is mainly produced by the first-order mode on longer dipole, while the left-hand CP (LHCP) wave at upper band is generated by the combination of first-order mode on shorter dipole and third-order mode on longer dipole. An artificial magnetic conductor (AMC) is used to improve the antenna directivity with low profile and makes this antenna easy to integrate into RFID system. Then, a rotated sequential phase feed CP array is proposed, fabricated, and measured. Measured impedance bandwidth (IBW) for <inline-formula> <tex-math notation="LaTeX">$\vert \text{S}_{11}\vert &lt; -10$ </tex-math></inline-formula> dB is more than 40.0&#x0025; at these two bands. Measured 3 dB axial ratio bandwidths (ARBWs) are 32.0&#x0025; (0.77&#x2013;1.06 GHz) and 27.8&#x0025; (2.22&#x2013;2.95 GHz). Compared with other dual-band CP reader antennas, which work in 0.915/2.45 GHz RFID systems, this new antenna array has a simpler configuration to achieve dual-band CP radiation. In addition, the 3 dB ARBWs are much wider than the previous antennas. Moreover, because the feeding network of this array is quite simple, the radiation efficiency is very high (&#x003E;90&#x0025;), and the peak gains are more than 9.0 and 15.0 dBic at corresponding bands.