Search

In this work, we present a simple design of a compact and miniaturized wideband bandpass filter (BPF) based on substrate integrated waveguide (SIW) and microstrip line. Through the order extension, the filtering effect and the order of the Chebyshev response of the designed BPF can be indirectly controlled by preserving square notches (SNs) on the SIW. By introducing one or two SNs in the SIW structure, the resonance frequencies of different modes can be controlled, thus achieving dual- and tri-mode BPFs with wideband and low insert loss. The working principle of the designed BPFs was illustrated by modal analysis, field distribution, and equivalent circuit theory. Based on this, the dual- and tri-mode BPFs with center frequencies of 6.8 and 7 GHz were designed and demonstrated numerically. Further experimental results indicate that the proposed tri-mode BPF has low insertion loss (0.25 dB), compact size (0.27λg2), and wideband bandwidth (60%). In addition, the tri-mode BPF achieves a broadband out-of-band rejection of 1.5f0 (f0 is the center resonance frequency) below the −10 dB level, making it highly promising for various applications in related fields. [ABSTRACT FROM AUTHOR]

In this article, we present a polarization-insensitive terahertz metamaterial designed by stacking resonators capable of providing ultra-wideband terahertz transmissions. Our design includes a square ring resonator situated between two windmill-shaped resonators, separated by a polyimide spacer. We optimized the spacer thickness to achieve a broadband response in transmission. These optimized broadband metamaterial designs were fabricated through multiple steps of the photolithography process. Terahertz time-domain spectroscopy of the fabricated samples indicates broadband terahertz transmission, in agreement with both simulation findings and results calculated from the transmission line model for the multi-layered metamaterial geometry. Our research reveals a strong near-field coupling between resonators, leading to wideband transmission of terahertz waves. The stacking of these metamaterials is crucial in designing broadband bandpass filters and broadband modulators for terahertz photonics while keeping the resonance strength almost intact. [ABSTRACT FROM AUTHOR]

This study illustrates the successful achievement of tunable defect bands in one-dimensional defective phononic crystals (PnCs) through the incorporation of piezoelectric defects with synthetic negative capacitances (SNCs) for the first time. The efficacy of SNCs in creating tunable bandpass filters across a broad frequency range is thoroughly examined using the proposed analytical and numerical models. A newly developed electroelastically coupled transfer matrix that incorporates SNCs is presented, considering either series or parallel connection between bimorph piezoelectric elements. Defect band and transmittance analyses are conducted using the transfer matrix and S-parameter methods. Two key findings emerge from this investigation. First, when the total equivalent capacitance of the bimorph piezoelectric elements and SNC becomes zero, the defect band representing the point-symmetric defect-mode shape can be customized throughout the entire phononic bandgap. Second, the constant transmittance value, resembling short-circuit conditions, highlights the remarkable ability of SNCs to tune defect bands without energy dissipation, paving the way for fully tunable bandpass filters. To propel this research forward, future investigations could explore expanding the design space with double defects, adopting enhanced modeling techniques to account for lateral and shear effects, developing a control algorithm for the automatic optimization of SNC values in actively tunable bandpass filters, and incorporating artificial intelligence into design methods for piezoelectric defects with electrical connections. [ABSTRACT FROM AUTHOR]

Bandpass filters (BPFs) are optical filters with significantly high transmittance in a specific wavelength range and low transmittance on both sides. Infrared BPFs can reduce system losses and overheating caused by other light wavelengths owing to their ability to selectively transmit infrared light of the desired wavelength. This article discusses the potential of using a high refractive index material, β-FeSi2, in BPFs. To the best of our knowledge, no studies have applied β-FeSi2 to infrared BPFs. Simulation results showed that its high refractive index allows the excellent performance of the BPF to be achieved using a multilayer thin film structure with only three layers. Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy results showed that the β-FeSi2 thin film exhibited the lowest absorptance of approximately 0 when the correct stoichiometry (Fe:Si = 1:2) was achieved through co-sputtering. Based on these findings, a β-FeSi2/SiO2/β-FeSi2 multilayer thin film was designed to fabricate the BPF. The fabricated BPF exhibited a narrow peak and achieved a peak transmittance exceeding 80%. This suggested that β-FeSi2 is a promising material for fabricating infrared BPFs. Utilizing these filters is expected to yield significant efficiency improvements and reduce losses across various applications, including thermophotovoltaics and infrared heaters. [ABSTRACT FROM AUTHOR]

In this manuscript, a miniature high-temperature superconductor (HTS) bandpass filter (BPF) with multi-transmission zeros (TZs), high selectivity, and great attenuation of stopband is presented. A couple of dual-mode resonator (DMR) is employed to achieve the proposed BPF, which can be characterized by using the classical even-odd mode analysis technique. The presented cascaded DMR can excite four resonant modes, which can be individually managed. Plus, a pair of intrinsic transmission zeros can be yielded at both the lower and upper edges of the passband, which results in sharp shirt performance. As an example, the HTS BPF is designed, fabricated, and tested, in which the center frequency is centred at 3.95 GHz and the 3-dB fractional bandwidth (FBW) is 2.5%. The proposed HTS BPF is implemented by using Tl2Ba2CaCu2O8 (Tl-2212) thin films which are fabricated by two-step processing and the superconducting critical temperatures (Tc) of the HTS films can reach 103 K. The design methodology is confirmed since the experimental results are in good agreement with theoretical results, showing desired bandpass characteristics, high selectivity, and the attenuation of lower and upper stopbands above −50 dB. Further, the circuit size is only 0.4 cm2. [ABSTRACT FROM AUTHOR]

A compact simple structure bandpass filter based on terminated three coupled line structures with high selectivity is introduced through odd and even-mode analysis. The proposed filter consists of three coupled lines loaded by open and short circuit stubs. The parallel-coupled lines structure is used to obtain high selectivity with transmission zeros near the passband. Meanwhile, simultaneously tuning on bandwidth and center frequency are introduced by coupled line. One type of bandpass filter based on terminated coupled line structure is theoretically analyzed, simulated, and measured. The stepped impedance structures at the input and output ports have been used to improve the attenuation level at the stopband region and create the multiple attenuation poles. The center frequency of 1.3 GHz, the fractional bandwidth (FBW) of about 65%, the low insertion loss of 0.25 dB, and the high return loss of 30 dB are obtained. Also, a flat group delay lower than 1.4 ns is achieved. Experimental and simulated results are presented, which are in good agreement. [ABSTRACT FROM AUTHOR]

A quad-band microstrip bandpass filter (BPF) based on a 13-mode resonator is proposed in this article with compact size, high band‐to‐band isolation, and multiple transmission zeros (TZs). The proposed filter is constructed by two transmission paths from the input to the output port, which employs the transversal cancellation mechanism of two transition paths to introduce extra nine TZs. Therefore, a total of 12 TZs are located at 0.2, 1.8, 2, 3.88, 4.61, 5.24, 5.9, 9.26, 9.51, 12.32, 12.75, and 13.27 GHz, respectively, realizing high selectivity. Moreover, the designed filter can achieve quad passbands with centered frequency at 0.95, 2.78, 7.32, and 10.63 GHz for the requirement of multi-service in modern communication systems, with wide bandwidth of 235, 790, 2200, and 1540 MHz, respectively. The measured results agree well with the simulation results, which proves the feasibility of the design method. [ABSTRACT FROM AUTHOR]

We present an analysis method for determining signal amplitudes using a least squares method in combination with an optimally selected bandpass filter. This method has been developed to process heat and light signals obtained in the AMoRE-I experiment. We apply Butterworth filters with various combinations of passbands and filter orders to both the heat and light signals. Subsequently, we employ the least squares method to calculate signal amplitudes by comparing each signal template for the heat and light channels. Optimal filter conditions are identified to achieve the best resolution value. In this paper, we provide a detailed description of the signal processing approach, comparing it with the optimal filter method. [ABSTRACT FROM AUTHOR]

The design of a miniaturized dual-band bandpass filter featuring a broad bandwidth and a high center frequency ratio is demonstrated in this article. A novel symmetrically loaded shunt coupled line with dual stepped impedance stubs has been investigated for the first time and it is utilized to realize a dual-band bandpass filter with seven transmission zeros. The transmission zeros frequencies of the filter response have been theoretically verified using even-odd mode analysis. For experimental validation purposes, a dual-band filter with a center frequency ratio of 4.06 covering 5G applications is implemented using Rogers RT/duroid 5870 substrate and tested. The tested filter has wide 3 dB fractional bandwidths of 53.8% and 17.9% in the first and second passbands, respectively, and has a compact topology of 0.20 × 0.09 λg2. The full-wave simulated and tested magnitude and group delay responses of the proposed filter are in good congruence. [ABSTRACT FROM AUTHOR]

Background: Heart rate (HR) is a critical biomarker that provides insights into overall health, stress levels, and the autonomic nervous system. Pulse wave signals contain valuable information about the cardiovascular system and heart status. However, signal acquisition in wearables poses challenges, particularly when using electrical sensors, due to factors like the distance from the heart, body movement, and suboptimal electrode placement. Methods: Electrical bioimpedance (EBI) measurements using bipolar and tetrapolar electrode systems were employed for pulse wave signal acquisition from the wrist in both perpendicular and distal configurations. Signal preprocessing techniques, including baseline removal via Hankel matrix methods, normalization, cross-correlation, and peak detection, were applied to improve signal quality. This study describes the combination of sensor-level signal acquisition and processing for accurate wearable HR estimation. Results: The bipolar system was shown to produce larger Δ Z (t) , while the tetrapolar system demonstrated higher sensitivity. Distal placement of the electrodes yielded greater Δ Z (t) (up to 0.231 Ω) when targeting both wrist arteries. Bandpass filtering resulted in a better signal-to-noise ratio (SNR), achieving 3.6 dB for the best bipolar setup and 4.8 dB for the tetrapolar setup, compared to 2.6 and 3.3 dB SNR, respectively, with the Savitzky–Golay filter. The custom HR estimation algorithm presented in this paper demonstrated improved accuracy over a reference method, achieving an average error of 1.8 beats per minute for the best bipolar setup, with a mean absolute percentage error (MAPE) of 8%. Conclusions: The analysis supports the feasibility of using bipolar electrode setups on the wrist and highlights the importance of electrode positioning relative to the arteries. The proposed signal processing method, featuring a preprocessing pipeline and HR estimation algorithm, provides a proof-of-concept demonstration for HR estimation from EBI signals acquired at the wrist. [ABSTRACT FROM AUTHOR]

The traditional high-frequency resonance technology has two disadvantages: (1) The resonance frequency (RF) is obtained by using Fourier spectrum (FS) and the bandwidth is obtained based on experience, and the effect is often poor due to severe noise interference; (2) the separation of compound faults is not considered. After systematic research, a feasible fault detection methodology named enhanced adaptive high-frequency resonance technology is summarized and introduced, which is on the basis of power spectrum (PS) analysis, abbreviated as enhanced adaptive high-frequency resonance technique based on power spectrum (PS-EAHFRT), to realize the single fault detection and compound fault separation of bearing. Firstly, the theoretical values of various bearing fault modes are calculated to establish a database. Then, a series of spectral peaks are obtained by performing PS analysis, and each prominent spectral peak is considered as an alternative RF, that is, an alternative central frequency. Then, the bandwidth calculation formula of the bandpass filter is given, and the optimal bandwidth parameter is calculated by using the signal envelope kurtosis as a sparse measure. Finally, the original signal is denoised by the optimized band-pass filter, and then the filtered signal is demodulated by envelope PS analysis, and compared with the theoretical value in the library, and then the fault category is obtained. Simulated and real-world bearing cases are used to demonstrate the effectiveness and advantages of PS-EAHFRT. It is demonstrated that the PS-EAHFRT can effectively realize the bearing single fault detection and the compound fault separation. Moreover, the lower bound of the frequency interval in which this method can achieve bearing composite fault separation is explored. [ABSTRACT FROM AUTHOR]

This paper introduces a multimode hybrid continuous class power amplifier utilizing a band-pass filter. It integrates resistive response amplifiers operating in three modes: class F, class J, and class F-1. Instead of the traditional quarter-wavelength line for harmonic control, an interdigital band-pass filter is utilized to manage harmonic impedance, enabling broadband operation, high efficiency, reduced circuit size, and improved out-of-band rejection. To demonstrate the approach, a multimode hybrid broadband high-efficiency power amplifier designed for 2 to 3.8 GHz range, achieving drain efficiency from 56.3% to 75.5%, saturated output power ranging from 39.1 to 41.2 dBm, and gain between 11.1 and 13.2 dB, is detailed and fabricated in this paper. [ABSTRACT FROM AUTHOR]

ABSTRACT In this paper, a broadband high‐efficiency power amplifier (PA) with filtering characteristics is proposed. This PA is designed using a series of inverse continuous modes (SICMs) and adds a novel coupled microstrip line filter structure. The terminal of this structure is composed of microstrip lines cascaded to improve the out‐of‐band suppression effect. This filter can achieve low in‐band insertion loss, high passband selectivity, as well as deep stopband rejection performance simultaneously. A PA was designed and implemented using a 10 W GaN HEMT device, verifying its wideband characteristics. The measurement result shows that the 39.6–41.6 dBm output power (Pout), 61.6%–73.7% drain efficiency (DE), and 8.6–10.8 dB gain are achieved at 2.2–2.9 GHz. [ABSTRACT FROM AUTHOR]

In this paper, a new structure for wide-band rectangular waveguide bandpass filters with distinguished harmonic suppression is presented. The filter is realized by using ridged waveguides in both resonant cavities and coupling windows and a metal plate, which performs like a low-pass filter and makes it arduous to form parasitic passbands. According to the field analysis and out-of-band response, the ridge structure can expand pass bandwidth and obtain a wide stopband by harmonic suppression. The filter is designed to perform a passband of 67% fractional bandwidth at center frequency at 75 GHz. The harmonic suppression of the design is increased from 1.5 times to 3.6 times the center frequency of the filter with 20 dB suppression levels. Finally, the measurement results validate the proposed design. [ABSTRACT FROM AUTHOR]

Surface microseismic monitoring is widely used in hydraulic fracturing. Real‐time monitoring data collected during fracturing can be used to perform surface‐microseismic localization, which aids in assessing the effects of fracturing and provides guidance for the process. The accuracy of localization critically depends on the quality of monitoring data. However, the signal‐to‐noise ratio of the data is often low due to strong coherent and random noise, making denoising essential for processing surface monitoring data. To suppress noise more effectively, this paper introduces a novel denoising method that integrates the Ramanujan subspace with dynamic time warping and adaptive singular value decomposition. The new method consists of two steps: First, a Ramanujan subspace is constructed to suppress periodic noise. Then, dynamic time warping and adaptive singular value decomposition are applied to eliminate remaining coherent and random noise. The method has been evaluated using both synthetic and field data, and its performance is compared with traditional microseismic denoising techniques, including bandpass filtering and empirical mode decomposition. [ABSTRACT FROM AUTHOR]

In this paper, the design of a dual-band filter based on the band gap waveguide (BGW) is presented. In the low-frequency band, the TE201 mode rectangular waveguide cavity resonator was used to design the bandpass filter, which significantly reduces the impact of the high-frequency transmission line (TL). In the high-frequency band, a TE101 mode cavity resonator based on the gap waveguide (GW) structure was used to design the high-frequency band filter. A lower insertion loss can be achieved with the use of all-metal structure. A dual-band filter prototype was fabricated to verify its performance. According to the measurement results, the insertion loss is less than 1.3 dB and the return loss is better than 14 dB in the frequency range of 5.92–6.06 GHz; and the insertion loss is less than 1.77 dB and the return loss is better than 15 dB in the frequency range of 80.6–86.2 GHz. The frequency ratio is as large as 13.9, and because the high-frequency band filter is embedded in the cavity resonator of the low-frequency band filter, it saves space to a certain extent and realizes the integrated design of the dual-band filter, which is of great significance for the improvement of the performance of the dual-band communication system in higher-frequency bands. [ABSTRACT FROM AUTHOR]

ABSTRACT A novel balanced switchable bandpass filter with all‐port reflectionless characteristics is proposed in this paper. The balanced switchable bandpass filter comprises a balanced switchable filtering section with bandpass response and two absorptive networks. The absorptive network proposed in this paper adopts only one structure to achieve both differential‐ and common‐mode reflectionless characteristics. The proposed switchable resonators in the filtering section and the proposed absorption networks excited under even‐ and odd‐modes are analyzed in detail. For the purpose of verification, a prototype is manufactured based on the simulated results, and it has a good consistency. The experimental results exhibit that the proposed balanced bandpass filter exhibits a differential‐mode bandpass filtering function and all‐port reflectionless performance in the ON‐state, differential‐mode isolation function, common‐mode suppression, and reflectionless behavior in the OFF‐state, which verifies the feasibility of the design theory. [ABSTRACT FROM AUTHOR]

Summary: In this paper, an out‐of‐band suppression enhanced high‐efficiency millimeter‐wave (mm‐wave) gallium nitride (GaN) microwave monolithic integrated circuit (MMIC) filtering power amplifier (FPA) is presented. A modified elliptic response bandpass filtering (BPF) output matching network (OMN) is used to achieve low loss and high out‐of‐band rejection. The circuit of the presented BPF OMN is given and its synthesized method is introduced. The simulated S‐parameters show that the OMN has a low‐loss in‐band response and a desired out‐of‐band rejection performance with two transmission zeros (TZs). To demonstrate this idea, a two‐stage 24–28‐GHz GaN MMIC PA is designed and implemented in a 0.15‐μm GaN‐on‐SiC process, with a mask area of 2.4 × 1.0 mm2. Experimental results show that the realized MMIC PA achieves a small signal gain of 18.8 dB from 24 to 28 GHz with ±1.2‐dB gain flatness and 40‐dB rejection at 19.43 and 33.8 GHz. The saturated power‐added efficiency (PAE) is higher than 29% from 24 to 28 GHz, with a peak PAE of 36.3% at 27 GHz. The output power is within the range of 33.8 to 35.6 dBm in the operating band. For a 100‐MHz five‐carrier LTE signal, the PA can achieve ACLR better than −40 dBc over the band with digital predistortion. [ABSTRACT FROM AUTHOR]

A two‐channel high‐selectivity, wideband bandpass filter has been presented. This is based on a microstrip mixed‐impedance resonator and defected ground structure with the mixed coupling strategy. Two pairs of peripheral stepped‐impedance resonator (SIR) structures are used as stubs, achieving TZs at the immediate lower and upper cut‐off sides of the passband and control the bandwidth, while the other two transmission zeros on the upper cut‐off side are yielded through the defected ground structure, and the coupling between the SIR and uniform‐impedance resonators components, respectively. A prototype of the circuit is fabricated and measured for validation. The measured results exhibited insertion and return losses better than 1.1 and 20.5 dB, respectively, and high isolation levels exceeding 19 dB. In total, four transmission zeros are achieved. The designed filtering circuit realized a 3‐dB fractional bandwidth of 58.1%. There is a 0.95f0 stopband at the upper cutoff. The fabrication of the prototype shows good agreement between the simulated and measured performance. [ABSTRACT FROM AUTHOR]

A novel slow‐wave half‐mode substrate integrated waveguide (HMSIW) bandpass filter (BPF) is proposed based on spoof surface plasmon polaritons (SSPPs) with loading capacitive patches (LCPs). The bandpass characteristics are achieved by etching complementary SSPPs on the metal patches of the HMSIW. SSPPs exhibit a slow‐wave effect, which effectively reduces the overall size of the filter. At the same time, using proper LCPs between the HMSIW metal via and the complementary SSPPs structure, the effective dielectric constant of the HMSIW can be changed, reducing the low cutoff frequency and further facilitating the miniaturisation of size. A prototype of the proposed filter is designed, fabricated, and measured. The measured results show that the proposed filter has the in‐band insertion loss of 1 and 3 dB passband range of 6.4–9.8 GHz. [ABSTRACT FROM AUTHOR]

In this paper, a plasmonic filter is realized which consists of a T-shaped stub resonator and two side-coupled rectangular cavities; forming an inverted E-type structure connected to the main waveguide. Initially, the device is investigated for the function of a band stop filter in the telecommunication band. Later, the proposed device is investigated for bandpass filtering application by using Vanadium dioxide as an active material to show the improvement in transmittance, modulation depth, quality factor, and tunability of the device. Vanadium dioxide is filled into all four arms of the inverted E shaped structure. For the OFF-state, the electric field is applied to the T shape structure which are; arm 2 and arm 4 whereas for the ON-state, the electric field is applied to the two-side coupled rectangular cavities named as arm 1 and arm 3. The device has shown its potential application in high-quality factor filtering, switching, and modulation applications in telecommunication bands. The quality factor of 208 and 138.18 is achieved for ON-state and OFF-state respectively, whereas the quality factor is further increased and a high value of 308 is obtained by optimizing the device parameters. An extension ratio of modulation of 18.45 dB is attained which can be further increased to 19.95 dB by changing the width of the cavities. Device optimization is performed to show that the bandwidth and transmittance of the spectrum can be manipulated by changing the device parameters like width, length, and height of the cavities. Additionally, the effect of the Elasto-optic effect is also shown which results in a huge tunability of 650 nm and an increase in the modulation depth to 25.8 dB. The device has demonstrated its potential for use in filtering and switching for photonic integrated circuits. [ABSTRACT FROM AUTHOR]

This study aimed to quantitatively analyze the combustion process of a boron/ethanol nanofuel droplet through optical and spectroscopic observations. Boron nanoparticles were added to ethanol at concentrations of 0 %, 2 %, 4 %, and 6 % by weight. Experiments were conducted under atmospheric pressure, and the droplet diameter was controlled at 1.1 ± 0.1 mm. Results indicated that the combustion of the boron nanofuel droplet was similar to that of the 0 wt.% boron nanofuel droplets at the beginning of the experiment, but the former actively combusted as the experiment progressed. Mass ejections, such as puffing and microexplosions, were observed at the late stage of combustion. Spectroscopic measurements revealed that boron oxide emissions were predominant at the late stage of droplet combustion, and this emission trend varied with changes in the boron concentration. Photomultiplier tube data obtained through a bandpass filter of 550 nm demonstrated temporal intensity fluctuations during combustion. The overall signal intensity was enhanced by high boron concentrations. [ABSTRACT FROM AUTHOR]

In this letter, the working mechanism of suggested bandpass filters with connected symmetric short‐circuit stub multimode resonators is described. Because of the design flexibility, the suggested bandpass filters' centre frequencies may be modified based on the design approach. Meanwhile, the suggested bandpass filters have reduced insertion losses and compact sizes. A prototype is built and tested with six passbands centred at 1.57/2.38/3.55/5.14/5.83/6.78 GHz to confirm the design and analysis. Good agreement between the simulated, and measured results is observed, indicating that the proposed structure can be applied in the field of communication, information, and automation. [ABSTRACT FROM AUTHOR]

The analysis of seismic events recorded by NASA's InSight seismometer remains challenging, given their commonly low magnitudes and large epicentral distances, and concurrently, strongly varying background noise. These factors collectively result in low signal-to-noise ratios (SNR) across most event recordings. We use a deep learning denoising approach to mitigate the noise contamination, aiming to enhance the data analysis and the seismic event catalogue. Our systematic tests demonstrate that denoising performs comparable to fine-tuned bandpass filtering at high SNRs, but clearly outperforms it at low SNRs with respect to accurate waveform and amplitude retrieval, as well as onset picking. We review the denoised waveform data of all 98 low-frequency events in the Marsquake Service catalogue version 14, and improve their location when possible through the identification of phase picks and backazimuths, while ensuring consistency with the raw data. We demonstrate that several event waveforms can be explained by marsquake doublets—two similarly strong quakes in spatio-temporal proximity that result in overlapping waveforms at InSight—and we locate them in Cerberus Fossae (CF). Additionally, we identify and investigate aftershocks and an event sequence consisting of numerous relatively high magnitude marsquakes occurring within hours at epicentral distances beyond CF. As a result of this review and interpretation, we extend the catalogue in event numbers (⁠|$+$| 8 per cent), in events with epicentral distances and magnitudes (⁠|$+$| 50 per cent), and events with backazimuths and a resulting full locations (⁠|$+$| 46 per cent), leading to a more comprehensive description of Martian seismicity. [ABSTRACT FROM AUTHOR]

A compact, low loss microstrip ultra-wideband (UWB) bandpass filter (BPF) with a narrow notch band is proposed in this article for using wireless communication applications within the unlicensed UWB range reported by the Federal Communications Commission. A systematic approach is presented to establish the UWB-BPF structure followed by a narrow notch within it. The UWB-BPF response is achieved by integrating a defected structures-based lowpass filter and a short-stepped impedance stub-based highpass filter. The narrow notch band is obtained by embedding two-stepped impedance stubs. The physical dimensions of the stubs can be optimized to select a specific frequency for the notch band. The UWB-BPF structure without the notched band, having a center frequency of 3.69 GHz, provides a fractional bandwidth (FBW) of 157%. The stopband suppression is −26 dB and it is broadened up to 15 GHz. On the other hand, the notched band response is obtained at 5.8 GHz with an FBW of 49.78% which is used for avoiding interference from the wireless local area network. The proposed structures are fabricated and measured for experimental validation. [ABSTRACT FROM AUTHOR]

The transformer is an important component of electrical engineering for many applications including those for integrated circuits. For integrated circuit applications, the use of a synthetic transformer has been recognised to be a viable option for a number of applications. This paper presents two new designs of electronically-controllable CMOS active transformers. The first preposition is based upon a capacitive T-network embedded between two active CMOS gyrators each of which has been obtained by a parallel back-to-back connection of one non-inverting and other inverting electronically-controllable CMOS transconductor. This circuit requires thirty-two MOSFETs, all operating in saturation region. The second design simulates an inductive T-network using two CMOS electronically-controllable floating inductors and one electronically-controllable CMOS grounded inductor thereby employing eighty MOSFETs. The first design offers the advantage of realising a step up as well as step down transformer by appropriate selections of the transconductances of two transconductors. The second design although uses a larger number of MOSFETs than the former but has the advantage of using three grounded capacitors which is a desirable from the view point of IC implementation. It may also be mentioned that using more MOSFETs does not increase layout area significantly since the capacitors require more layout area than all the MOSFETs put together. The workability of both the designs, along with their various performance characteristics and non-ideal analysis, has been well corroborated by computer simulations using SPICE software using 0.18 µm CMOS technology parameters. The application of the proposed circuits in the design of double tunned band pass filter has also been shown and its workability too has been validated by computer simulations using SPICE software. [ABSTRACT FROM AUTHOR]

This work presents a Brillouin amplification performance comparison of seed generation techniques using double-sideband suppressed carrier (DSB-SC) and single-sideband suppressed carrier (SSB-SC) modulations. The SSB-SC is obtained using an optical bandpass filter (OBPF) and in-phase and quadrature Mach-Zehnder modulator (IQ-MZM). All three techniques provide high amplification performance with optical signal-to-noise ratio (OSNR) enhancement of 37.47 dB, 33.14 dB, and 32.67 dB using DSB-SC, SSB-SC/OBPF, and SSB-SC/IQ-MZM, respectively. The best seed generation technique is using the DSB with a signal amplification of 62.47 dB. The technique presents ~4 dB higher OSNR enhancement due to the dual-energy transfer obtained from the beating process of the DSB than SSB. A ~3 dB OSNR reduction is found when pump linewidth (LW) was changed from 1kHz to 50 MHz, which suggests using a low-cost pump source whenever the OSNR reduction is not critical. The work also shows that the three techniques required 10 dBm stimulated Brillouin scattering threshold (SBST) to stimulate the process. An additional analysis of DSB-SC shows that a high-carrier suppression during the seed generation technique using MZMs is insignificant to the amplification performance. The high-carrier suppression produces a high seed signal power that distorts the Brillouin gain spectrum (BGS) and the pump depletion region, hence reducing the Brillouin gain (BG). Since carrier suppression is not a primary consideration, a cost-effective MZM with a modest extinction ratio requirement is allowed. The relaxed requirement of the pump's linewidth and MZM's extinction ratio suggest a cost-effective development of the SBSbased optical amplifier with narrow filter bandwidth. [ABSTRACT FROM AUTHOR]

This article presents a machine vision system for measuring the arithmetic average roughness of shot- and sand-blasted surfaces. In the developed system, a digital microscope was used for capturing surface images after shot- and sand-blasting processes. The captured grayscale images were analyzed with the proposed algorithm using Otsu's global thresholding and a size bandpass filter. The algorithm detected white regions associated with the specular reflection of light on a binary image, and then calculated the size of selected regions. One-way ANOVA was used to identify the relation between the size of the regions and the arithmetic average roughness of blasted surfaces. It was noted that the average size of white regions showed a linear relation to the arithmetic average roughness of both shot- and sand-blasted surfaces. Different abrasives (shot or sand) were found to bring about differences in the rate of change of the average size within a chosen roughness range. When a surface image with unknown roughness is given, it is possible to predict the arithmetic average roughness on the basis of the relation. This machine vision system enables the fast and low-cost roughness measurement of shot- and sand-blasted surfaces. Thus, it could be useful in a quality inspection for shot- and sand-blasting. [ABSTRACT FROM AUTHOR]

This article presents a multiband bandpass filter structure with an in-line topology based on substrate-integrated waveguide (SIW) technology. A multi-layer configuration is employed to achieve circuit miniaturization. By constructing the coupling matrix, the coupling relationships among all resonators are quantitatively characterized, enabling the extraction of the theoretical frequency response and guiding circuit modeling and optimization. We designed and fabricated a third-order tri-band SIW filter and a third-order quad-band SIW filter, achieving a return loss of nearly 20 dB across all passbands. The close agreement between simulated and measured results validates the proposed design model. Additionally, the high in-band isolation of over 40 dB is demonstrated between all adjacent bands, highlighting the potential applicability of this technology in multiband scenarios. [ABSTRACT FROM AUTHOR]

This paper presents and validates a compact dual-band bandpass filter with independent controllable passbands and isolation. The proposed filter is constructed by two transmission paths from input port to output port. Based on the transversal cancellation mechanism of two transmission paths, dual passband with independent controllable characteristics can be approached. The transversal cancellation techniques yield extra transmission zeros, which are located at 2.56 GHz, 3.58 GHz and 4.43 GHz respectively. Therefore, two passbands centered at 2.25/3.9 GHz are divided by triple transmission zeros. These transmission zeros also improve the out-of-band suppression performance of proposed filter. The designed prototype filter is implemented and tested, the measured 3 dB passband fractional bandwidths are 12.4 % and 7.5 %, respectively, and the minimum insertion losses are 0.48 dB and 0.88 dB respectively. Additionally, the dual-band transversal filter only occupies 0.012 λ g 2 , which λg is the guided wavelength at 50 Ω microstrip line at 2.25 GHz. [ABSTRACT FROM AUTHOR]

A highly miniaturized bandpass filter with quad-band response is demonstrated in this article. The proposed quad-band bandpass filter has a novel topology comprising series quarter wavelength transmission lines loaded with tri-stepped impedance openended resonators and a dual-stepped impedance short-ended resonator. The proposed quad-band bandpass filter configuration is validated by theoretically verifying the transmission zeros and pole frequencies using even-odd mode analysis. A prototype operating at 0.475 GHz, 1.695 GHz, 3.48 GHz, and 4.53 GHz is designed, implemented, and experimented. The tested insertion losses at these center frequencies are 0.38 dB, 0.71 dB, 1.03 dB, and 1.22 dB, and the return loss is better than 10 dB in each passband. Each passband is isolated by a transmission zero with a rejection better than 40 dB. The proposed quad-band filter occupies a compact size of 0.146 × 0.087λ²g and is distinguished by its high compactness, wide bandwidth, multiple transmission zeros and poles, and high performance compared to benchmark designs making it more suitable for multi-band wireless applications. [ABSTRACT FROM AUTHOR]

A novel bandpass-to-all-stop switchable absorptive filter with an ultra-wideband reflectionless range is proposed in this paper. The bandpass section of the filter consists of a dual-mode resonator and two L-shaped feeding lines. The dual-port reflectionless characteristic is achieved by loading absorption networks at the end of the open stubs of the feeding lines, which are composed of two parallel coupled lines and absorption resistors. The switching of the reflectionless bandpass filter (RBPF) to the all-stop filter (ASF) is realized by controlling the on/off behavior of the PIN diode through the bias voltage. Measurements show that the filter prototype at the center frequency of 2.43 GHz with the 3-dB fractional bandwidth (FBW) is 8.23%. For the RBPF state, the filter has an ultra-wideband reflectionless FBW of 214% and upper stopband rejection better than 33 dB up to 6 GHz. Besides, the rejection is better than 30 dB from 0 to 5.32 GHz in the ASF state. [ABSTRACT FROM AUTHOR]

A compact ultra-wideband (UWB) bandpass filter is realized with the combination of dual-split square complementary split ring resonator (DSS-CSRR) and substrate integrated waveguide and is investigated in this paper. Three DSS-CSRRs are carved on the top and bottom layers of SIW to achieve the required passband and enhance the selectivity of the filter. Slots are etched in the ground to improve the return loss characteristics and to lower the insertion loss. The proposed filter offers a fractional bandwidth of 107% (3.1–10.3 GHz) and an insertion loss range of 0.6–1.6 dB in the entire passband. The prototype was fabricated on an FR-4 substrate, with dimensions of 0.35λgL×1.06λgW. The group delay variation is almost flat over the entire passband. The prototype was fabricated and validated the measured results. [ABSTRACT FROM AUTHOR]

The biophysical characterization and engineering of optogenetic tools and photobiological systems has been hampered by the lack of efficient methods for spectral illumination of microplates for high-throughput analysis of action spectra. Current methods to determine action spectra only allow the sequential spectral illumination of individual wells. Here we present the open-source RainbowCap-system, which combines LEDs and optical filters in a standard 96-well microplate format for simultaneous and spectrally defined illumination. The RainbowCap provides equal photon flux for each wavelength, with the output of the LEDs narrowed by optical bandpass filters. We validated the RainbowCap for photoactivatable G protein-coupled receptors (opto-GPCRs) and enzymes for the control of intracellular downstream signaling. The simultaneous, spectrally defined illumination provides minimal interruption during time-series measurements, while resolving 10 nm differences in the action spectra of optogenetic proteins under identical experimental conditions. The RainbowCap is also suitable for studying the spectral dependence of light-regulated gene expression in bacteria, which requires illumination over several hours. In summary, the RainbowCap provides high-throughput spectral illumination of microplates, while its modular, customizable design allows easy adaptation to a wide range of optogenetic and photobiological applications. [ABSTRACT FROM AUTHOR]

This study proposes a novel simple structure based on evanescent‐mode theory for the design of miniaturized filters with good out‐of‐band rejection and controllable passband number characteristics. The filter structure is realized by embedding serpentine microstrip resonators in the upper metal surface of the substrate‐integrated waveguide (SIW). These resonators are composed of upper and lower parts, which form a single‐passband filter when the lengths are equal and a double‐passband filter when the lengths are unequal. This paper proposes a novel method for switching between single‐ and dual‐passband configurations by modifying the length of the serpentine microstrip resonators without altering the overall SIW dimensions. Furthermore, finite transmission zeros are incorporated into the filter to augment the out‐of‐band rejection capability of the filter and the isolation effect between the passbands of the dual‐passband filter. To ascertain the viability of the proposed design, a two‐stage single‐passband filter and a two‐stage dual‐passband filter were fabricated and tested in this study. The experimental results align closely with the simulation outcomes, effectively validating the efficacy of this design. [ABSTRACT FROM AUTHOR]

This article presents an ultrathin chiral metasurface which can exhibit multiband asymmetric absorption as well as symmetric transmission in a specific frequency band outside the absorption regions. Unlike most electromagnetic metasurface absorbers, the proposed structure does not have a continuous conducting sheet at the bottom which also allows it to act as a bandpass spatial filter. The metasurface has a substrate thickness of only λhigh/62.5 and λlow/34 at the highest and lowest operational free‐space wavelengths, respectively. The transmission band is centered at 5.5 GHz, and the asymmetric absorption bands are centered at 3, 3.33, and 4.5 GHz, respectively. The operational bands can be tuned as per user requirements. The metasurface has an angular stability of 45° for both TE and TM incidence. It can be used for radar cross‐section (RCS) reduction, electromagnetic shielding, and as a spatial bandpass filter. [ABSTRACT FROM AUTHOR]

This research focuses on the development of a machine learning-based approach for the early diagnosis of blade rubbing in rotary machinery. In this paper, machine learning-based diagnostic methods are used for blade rubbing early diagnosis, and the faults are simulated using experimental models. The experimental conditions were simulated as follows: Excessive rotor vibration is generated by an unbalance mass, and blade rubbing occurs through excessive rotor vibration. Additionally, the severity of blade rubbing was also simulated while increasing the unbalance mass. And then, machine learning-based diagnostic methods were applied and the trends according to the severity of blade rubbing were compared. This paper provides a signal processing method through feature analysis to diagnose blade rubbing conditions in machine learning. It was confirmed that the results of the unbalance and blade rubbing represent different trends, and it is possible to distinguish unbalance from blade rubbing before blade rubbing occurs. The diagnosis using machine learning methods will be applicable to rotating machinery faults like blade rubbing; furthermore, the early diagnosis of blade rubbing will be possible. [ABSTRACT FROM AUTHOR]

This research introduces a novel approach to resampling periodically correlated time series using bandpass filters for frequency separation called the Variable Bandpass Periodic Block Bootstrap and then examines the significant advantages of this new method. While bootstrapping allows estimation of a statistic's sampling distribution by resampling the original data with replacement, and block bootstrapping is a model-free resampling strategy for correlated time series data, both fail to preserve correlations in periodically correlated time series. Existing extensions of the block bootstrap help preserve the correlation structures of periodically correlated processes but suffer from flaws and inefficiencies. Analyses of time series data containing cyclic, seasonal, or periodically correlated principal components often seen in annual, daily, or other cyclostationary processes benefit from separating these components. The Variable Bandpass Periodic Block Bootstrap uses bandpass filters to separate a periodically correlated component from interference such as noise at other uncorrelated frequencies. A simulation study is presented, demonstrating near universal improvements obtained from the Variable Bandpass Periodic Block Bootstrap when compared with prior block bootstrapping methods for periodically correlated time series. [ABSTRACT FROM AUTHOR]

The stepped‐impedance combline band pass filter (BPF) with novel input and output networks based on a new proposed J‐inverter, which increases the center frequency tuning range with constant bandwidth (BW), is discussed. The even and odd mode analysis shows that the stepped resonators provide the necessary conditions for the appropriate coupling coefficient to keep the BW constant. In order to create an appropriate quality factor, the new proposed J‐inverter is used. In the frequency response of the stopband region, three transition zeros (TZs) are generated, which two of TZs are controllable. The proposed tunable BPF has been fabricated on RO4003 substrate with a dielectric constant of 3.38 and 0.813 mm thickness. The size of the filter is compact and is only 0.31λg×0.1λg$$ 0.31{\lambda}_{\mathrm{g}}\times 0.1{\lambda}_{\mathrm{g}} $$, where λg$$ {\lambda}_{\mathrm{g}} $$ is the guided wavelength at the lower center frequency. The center frequency is equal to 1.723 GHz and a frequency tuning range from 1.2 GHz to 2.246 GHz with 100 MHz constant 3 dB absolute BW, the insertion loss of 1.4–3.17 dB and return loss of 17.8–25.9 dB is achieved. [ABSTRACT FROM AUTHOR]

This article has designed a bandpass filter using a coplanar stripline stub (CPS) resonator consisting of open and short‐ended strip lines connected to the PIN diode switches. The use of spurline stub resonators inside CPS results in bandpass and bandstop filters, depending on the PIN diode switch configurations. The work presents a novel circuit architecture aimed at reducing the parasitic resonance of the spurline resonators and acquiring the necessary series stub characteristics. The proposed filter resonates at 6.9–9, 1.7–4.7, and 8.4 GHz when the PIN diodes are forward and reverse‐biased, respectively. It also resonates at 1–2.1, 4.8–5.3, and 6.9–9 GHz when one diode is reverse‐biased, and the other is connected in forward bias. An insertion loss below −0.55 dB and a return loss less than 10 dB have been obtained during simulation and measurement. The designed filter can find different applications for the 1.8 GHz GSM band, 2.4/5.8 GHz (WLAN), 3.6 GHz (WiMAX), long‐term evolution (LTE), and WIFI. The filter can be used in various multi‐frequency systems owing to its compact size. The measured and simulated findings of the proposed CPS spurline stub resonator wideband bandpass filters are substantially consistent. [ABSTRACT FROM AUTHOR]

The bandwidth enhancement of the acoustic‐wave‐lumped‐element resonator (AWLR)‐based filter has been investigated for a long time. However, few researches are focused on the maximum bandwidth analysis. Based on a universal circuit structure of the AWLR‐based filter, we proposed the maximum bandwidth analysis of the hybrid filter. In the analysis process, the universal filter structure can be transformed into a novel AWLR‐based filter structure by incidentally excluding most of the other structures (including the reported hybrid filter structures) under the defined electrical characteristics. The novel hybrid filter obtains the maximum fractional bandwidth (FBW). Moreover, the proposed calculation results are better than the simulation results without artificial intervention. They are 2.12kt2 and 1.63kt2, respectively. kt2 is the electromechanical coupling coefficient of the acoustic wave resonator (AWR). Third‐order AWLR‐based bandpass filters with five‐type circuit structures have been manufactured and measured. They include the proposed novel AWLR‐based filter and the hybrid filter with the reported structure based on the universal AWLR‐based filter structure. The experimental results indicate that the proposed novel AWLR‐based filter has the maximum FBW. [ABSTRACT FROM AUTHOR]

This paper provides a compact, noncontiguous, high isolation, manifold triplexer operating from 25.8 to 49.5 GHz, a 62.95% wide fractional operating bandwidth. The triplexer is composed of three waveguide bandpass filters with Chebyshev responses. The initialization and loop optimization strategy of the triplexer are given. To eliminate undesired high‐order mode transmission between common port and filters, ridged‐waveguide topology, tuning screws, capacitive windows, and narrowing the wide edges of resonant cavities for the third filter are employed. The measured results and simulated ones are in good agreement. To our knowledge, this is the most broadband, high‐power triplexer demonstrated to date. [ABSTRACT FROM AUTHOR]

During the service life of bridge structures, they will be affected by various physical and environmental changes, which comprehensively manifest on different time scales. In other words, structural effects will have different variation patterns at different time scales, which will be reflected in the multi-scale characteristics of structural mechanical properties over time. However, most of the existing bridge performance indicators are defined on a time scale corresponding to a single factor. Therefore, it is necessary to analyze, process, and apply bridge monitoring signals differently at different time scales and components of different factors. This article proposes a signal decomposition and reconstruction method that extracts signals of different components from strain monitoring signals of bridge structures. On this basis, different feature extraction and indicator recognition are carried out for different extracted components. Among them, for component A related to bridge vibration, this paper proposes a strain mode identification method based on statistical stability. This method is based on the assumption that the strain mode under random noise has approximate time invariant characteristics, and noise is eliminated through statistical averaging. The component B of the vehicle induced effect is obtained through empirical mode decomposition (EMD) and bandpass filtering, and the lateral collaborative performance of the assembled beam bridge is characterized based on the correlation coefficient of component BA bridge hinge joint damage identification method based on temperature strain is proposed for component C of temperature effect. The effectiveness and feasibility of the above workflow were verified through real bridge data. [ABSTRACT FROM AUTHOR]

This article presents an ultrawideband (UWB) bandpass filter (BPF) using integrated passive device technology on a GaAs substrate. This bandpass filter uses a multistage coupled line to achieve an ultrawide passband. The filter with a 3 dB fractional bandwidth can achieve a UWB of 106.1% (11.8–38.5 GHz). Introducing short‐circuit capacitors and two open microstrip lines between coupling lines achieved two transmission zeros on both sides of the passband and excellent frequency selectivity. Furthermore, to improve impedance matching performance within the ultrawide passband, a step impedance resonator (SIR) structure was adopted for the coupling line. To demonstrate the working mechanism of the proposed BPF, an LC equivalent circuit model was proposed and analyzed to investigate transmission poles and zeros. The suggested filter was fabricated into a small size of 1.4 × 0.85 mm2. According to the measurement results, the filter's insertion loss in the 13–34 GHz range was less than 2 dB, and its return loss exceeded −12 dB. The improved performance of the suggested filter was validated by the consistency between simulation results and measured findings. [ABSTRACT FROM AUTHOR]

This paper designs a bandpass filter for D‐band and 0.18 μm complementary metal oxide semiconductor (CMOS) process. The bandpass filter is composed of an inverted L‐shaped coupling microstrip line and a cross‐coupled resonator, and is coupled to produce two controlled transmission zeros. A defected ground structure is used to make a good impedance match. The designed filter has a 3 dB impedance bandwidth of 52 GHz (149–201 GHz) with a center frequency of 175 GHz and an insertion loss of 3.23 dB. The design of this paper is a CMOS 0.18 μm process capable of applying the D‐band bandpass filter with the advantages of lower insertion loss, broadband, and compact size. [ABSTRACT FROM AUTHOR]

This letter presents a new circularly polarized (CP) active antenna for global navigation satellite systems (GNSS) operating in the L1‐band (1.164–1.28 GHz) and L2‐band (1.525–1.615 GHz). The active antenna consists of a passive antenna and a two‐channel low‐noise amplifier (LNA) circuit. To achieve wideband coverage of the L1/L2 bands while maintaining a low profile, a new electroplating process is utilized in fabricating the passive antenna. Additionally, to realize CP performance, the passive antenna is sequentially fed by four ports with a wideband feeding network. To minimize phase variations, a 90° phase shifter loaded with open‐short‐stub is integrated into the feeding network. Furthermore, to improve noise immunity, out‐of‐band rejection, and amplify GNSS signals, the LNA circuit cascades two‐stage dielectric bandpass filters and three‐stage LNAs. Consequently, the circuit features a low noise figure of below 1.65 dB, a maximum out‐of‐band rejection level of 60 dB, and a stable active gain of 30 dB. The performance of the active antenna is evaluated in an outdoor open field using a GNSS receiver. [ABSTRACT FROM AUTHOR]

A series of fourth‐order bandpass filters (BPFs) with compact footprints, broad bandwidth, high selectivity, linear phase and notched response are proposed. The sketch of these BPFs is in accordance with the combination of the eighth‐mode substrate integrated waveguide (EMSIW) and dual‐mode microstrip line (DMML) resonators. The DMML resonator is constructed by means of metallic via‐holes and pad in the double‐layered structures. Among them, the DMML resonator can provide two transmission poles. Besides, the cross coupling is introduced through the vertical slot or fan‐shaped aperture in the dual‐layered substrates. The coupling schemes of the proposed BPFs can introduce two transmission zeros in the vicinity of operating passband, and the coupled scheme also exhibits a relatively flat in‐band group delay. Notched frequency responses have been obtained by exploiting the U‐shaped resonator and folded‐ring resonator embedded with the mixed EMSIW and DMML BPFs. To validate the conceptual design, the proposed BPFs are simulated, fabricated and measured. Both the simulation and measurement have reached to a satisfactory agreement. [ABSTRACT FROM AUTHOR]

The ability to analyze blunt-force trauma is crucial for deciphering valuable clues concerning mechanisms of injury and as evidence for medico-legal investigations. The use of alternate light sources (ALS) has been studied over the past decade, and is proposed to outperform conventional white light (CWL) during bruise assessments. In response to the growing interest of the technology worldwide, a systematic review of the literature was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) to address the ability of ALS to detect and visualize bruising. From an initial 4055 records identified, ten studies met the eligibly criteria and were selected for this review. Evaluation also included a novel framework, referred to as SPICOT, to further systematically assess both scientific evidence and risk of bias in forensic literature. Analysis reveals that narrowband wavelengths within in the infrared or ultraviolet spectral ranges do not significantly outperform CWL in visualizing or detecting bruising. However, wavelengths within the visible spectrum, particularly 415 nm combined with longpass or bandpass yellow filters, are more effective. However, the majority of selected studies only address the sensitivity of ALS, and therefore, results may only be considered valid when the location of a bruise is known. Further investigation is required to understand the specificity of ALS, in particular how the use of topical cosmetic products, previous wounds/scar-tissue, tattoos, moles and freckles may affect detection. The ethical concern regarding the interpretation of enhanced visualized trauma should also be considered in prospect discussions prior to implementing ALS into routine practice. Nevertheless, this review finds that narrowband ALS within the visible spectrum demonstrates potential for improved injury documentation, outperforming CWL in the detection and visualization of bruising. [ABSTRACT FROM AUTHOR]

This paper presents, a novel second order E-plane planar insert based dual band bandstop waveguide filter. The circular shape with two T-shape resonators are printed on Roger RO4350 dielectric substrate to form planar insert. The insert are placed in such a way that positioned in E-plane of the standard WR-90 rectangular waveguide. The independent resonant frequency and bandwidth of the stopband can be adjusted by tuning the resonators. To achieve second order dual band bandstop filter response four asymmetrical circular shape with two T-shape resonators are designed on dielectric substrate to form different stopbands and separated by some specific distance to eliminate the unwanted coupling between them. The numerical analysis of the proposed filter is carried out using CST microwave studio. To validate the numerical analysis of the proposed filter, resonator, WR-90 rectangular waveguide is fabricated and measured. The measured results shows stopband characteristics having centre frequencies f01g = 8.56 GHz and f02 = 11.21 GHz and exhibits the bandwidth of 0.4146 GHz and 0.3824 GHz. The simulated and measured result are in good agreement. [ABSTRACT FROM AUTHOR]