Multiple Notch Research Articles

Bandwidth Enhancement with Multiple Notch Bands and Cross-Polarization Suppression of Microstrip Patch Antenna for Modern Wireless Applications

A miniaturized UWB antenna with multiple notch bands is proposed for modern wireless applications. The proposed microstrip-line-fed antenna consists a Y-shaped strip supported by defected ground structure. Procedure of bandwidth enhancement with multiple notch bands is presented. 163.6% of impedance bandwidth ranging from 1.5 to 15 GHz with three notch bands at 3–3.6, 6–6.8 and 9.2–9.8 GHz is achieved with gain of 2–6 dBi within the band. Accurate equivalent circuit model is presented for proposed antenna structure. Proposed antenna shows good radiation characteristics with very large bandwidth including three notch bands and suppressed cross-polarization level up to − 35 dB. The designed antenna is tested experimentally and measured results are verified with the simulated and theoretical results.

A Compact Multiple Notched Ultra-Wide Band Antenna with an Analysis of the CSRR-TO-CSRR Coupling for Portable UWB Applications.

We present a compact ultra-wideband (UWB) antenna integrated with sharp notches with a detailed analysis of the mutual coupling of the multiple notch resonators. By utilizing complementary split ring resonators (CSRR) on the radiating semi-circular patch, we achieve the sharp notch-filtering of various bands within the UWB band without increasing the antenna size. The notched frequency bands include WiMAX, INSAT, and lower and upper WLAN. In order to estimate the frequency shifts of the notch due to the coupling of the nearby CSRRs, an analysis of the coupling among the multiple notch resonators is carried out and we construct the lumped-circuit equivalent model. The time domain analysis of the proposed antenna is performed to show its validity on the UWB application. The measured frequency response of the input port corresponds quite well with the calculations and simulations. The radiation pattern of the implemented quad-notched UWB antenna is nearly omnidirectional in the passband.

Six1 and Eya1 both promote and arrest neuronal differentiation by activating multiple Notch pathway genes

The transcription factor Six1 and its cofactor Eya1 are important regulators of neurogenesis in cranial placodes, activating genes promoting both a progenitor state, such as hes8, and neuronal differentiation, such as neurog1. Here, we use gain and loss of function studies in Xenopus laevis to elucidate how these genes function during placodal neurogenesis. We first establish that hes8 is activated by Notch signaling and represses neurog1 and neuronal differentiation, indicating that it mediates lateral inhibition. Using hes8 knockdown we demonstrate that hes8 is essential for limiting neuronal differentiation during normal placode development. We next show that Six1 and Eya1 cell autonomously activate both hes8 and neurog1 in a dose-dependent fashion, with increasing upregulation at higher doses, while neuronal differentiation is increasingly repressed. However, high doses of Six1 and Eya1 upregulate neurog1 only transiently, whereas low doses of Six1 and Eya1 ultimately promote both neurog1 expression and neuronal differentiation. Finally, we show that Six1 and Eya1 can activate hes8 and arrest neuronal differentiation even when Notch signaling is blocked. Our findings indicate that Six1 and Eya1 can both promote and arrest neuronal differentiation by activating the Notch pathway genes neurog1 and hes8, respectively, revealing a novel mechanism of Six1/Eya1 action during placodal neurogenesis.

CPW-Fed UWB antenna with sharp and high rejection multiple notched bands using stub loaded meander line resonator

This paper presents a CPW-fed UWB filter-antenna with sharp and high rejection multiple band notches for band-notched UWB communication applications. The band notch operation is achieved by employing a sharp bandstop filter (BSF) with multiple reject bands using only one element meander line resonator at the bottom layer through theoretical calculations and parametric studies. The adjustment of the notched bands is successfully accomplished by loading the meander line with open ended stubs to modify the harmonic frequencies to the desired bands. The structure of the proposed BSF is simple and compact so that the proposed filter-antenna is achieved with the same size of the reference UWB antenna without an extra area. Measurement results show that the proposed filter-antenna has two notches at the WiMAX systems operating in the 5.8GHz (5.725–5.85GHz) and at the international telecommunication union (ITU) operating in the 8.2GHz (8.025–8.4GHz). Also, it has sharp rejection characteristics at the edges of the federal communication commission (FCC) band for UWB communications. The experimental measurements are in good agreement with theoretical and simulation results for the BSF and the filter-antenna. Moreover, the filter-antenna exhibits stable omnidirectional radiation patterns except at the notched bands.

Localized dark solitons and vortices in defocusing media with spatially inhomogeneous nonlinearity.

Recent studies have demonstrated that defocusing cubic nonlinearity with local strength growing from the center to the periphery faster than r^{D}, in space of dimension D with radial coordinate r, supports a vast variety of robust bright solitons. In the framework of the same model, but with a weaker spatial-growth rate ∼r^{α} with α≤D, we test here the possibility to create stable localized continuous waves (LCWs) in one-dimensional (1D) and 2D geometries, localized dark solitons (LDSs) in one dimension, and localized dark vortices (LDVs) in two dimensions, which are all realized as loosely confined states with a divergent norm. Asymptotic tails of the solutions, which determine the divergence of the norm, are constructed in a universal analytical form by means of the Thomas-Fermi approximation (TFA). Global approximations for the LCWs, LDSs, and LDVs are constructed on the basis of interpolations between analytical approximations available far from (TFA) and close to the center. In particular, the interpolations for the 1D LDS, as well as for the 2D LDVs, are based on a deformed-tanh expression, which is suggested by the usual 1D dark-soliton solution. The analytical interpolations produce very accurate results, in comparison with numerical findings, for the 1D and 2D LCWs, 1D LDSs, and 2D LDVs with vorticity S=1. In addition to the 1D fundamental LDSs with the single notch and 2D vortices with S=1, higher-order LDSs with multiple notches are found too, as well as double LDVs, with S=2. Stability regions for the modes under consideration are identified by means of systematic simulations, the LCWs being completely stable in one and two dimensions, as they are ground states in the corresponding settings. Basic evolution scenarios are identified for those vortices that are unstable. The settings considered in this work may be implemented in nonlinear optics and in Bose-Einstein condensates.

Association of tumor mutational burden in cutaneous squamous cell carcinoma with genomic alterations in Notch family receptors.

e13031 Background: In Cutaneous Squamous Cell Carcinoma (cSqCC), Notch1, Notch2, and Notch3 have been identified as tumor suppressors with a high rate of inactivating mutations early in cSqCC pathogenesis. Despite the high frequency of alterations, the biologic and therapeutic implications of Notch genomic alterations (GAs) in cSqCC are incompletely understood. Methods: 232 FFPE samples of cSqCC were evaluated by comprehensive genomic profiling (CGP) of 315 genes and analyzed for all classes of GAs, with diagnoses confirmed by central pathology review. Notch GAs with unknown functional impact were excluded. Tumor mutational burden (TMB) was calculated from 1.11 Mb of sequenced DNA and reported as mutations/Mb. Results: The cohort of 232 samples was 78% male and 22% female, aged from 17 to 88, with confirmed metastatic disease in 32% of cases. 115 (50%) samples had a Notch family member GA with a known or predicted functional impact. 96 cases had Notch1 GAs, 43 cases had Notch2 GAs, and 14 cases had Notch3 GAs with 40 cases having GAs in multiple Notch family members. These mutations were 41% missense, 34% nonsense, 15% splice site, 9% frameshift indels, and 1% non-frameshift indels alterations. Patients with Notch GAs were significantly older (median 70 years old vs median 64, p < 0.01). TMB was increased among samples with Notch GAs (median TMB of 63 mutations/mb versus 20 mutations/mb, p < 1x10-6), with similar differences for primary and metastatic samples. Cases with Notch GAs had more total GAs per case (mean 10.4 vs 7.4, p < 1.5x10-10); however, the top co-mutated genes were the same (TP53, CDKN2A, FAT1, MLL2). Both groups had a high proportion of C- > T/G- > A transitions, consistent with UV damage; however, the proportion was higher in cases with Notch GAs (median 83% vs 80%) - a difference seen in primary and metastatic samples. Conclusions: 50% of cSqCC cases had a Notch family member loss of function GA, which was associated with increased TMB in the primary and metastatic setting. With pre-clinical models and case studies showing responses to PD-1 inhibitors in cSqCC, further investigations are warranted into the associations of Notch GAs with mutational burden and response to immunotherapy.

Resonance characteristic analysis and damping control for LCL-filter-based voltage source converter during bus transfer

This paper investigates a new resonance issue of LCL-filter-based voltage source converters (VSCs). Unlike the traditional resonance issue under normal operating condition, the new potential issue is exposed in the application of automatic bus transfer system (ABTS), due to a temporary change of LCL filter structure during bus transfer. The resonance-induced current and voltage spikes may cause damage or nuisance tripping to sensitive equipment, leading to failure of the automatic transfer and interruption of the continuous process. To solve this problem, the transformation of resonance characteristics during bus transfer is analyzed in this paper. Furthermore, the influence factors to the system stability are obtained, and the stable regions of the factors are derived with Nyquist criterion. Besides, when the system parameters locate within the unstable region, a comprehensive damping scheme with an all-pass filter based multiple notch filter is proposed to solve both resonance issues. With the proposed damping strategy, a smooth bus transfer can be achieved without additional hardware. Finally, the experiments are provided to confirm the stability analysis and validate the effective damping scheme developed in this paper.

A novel cost-effective parallel narrowband ANC system with local secondary-path estimation

Many noise reduction applications are targeted at multi-tonal disturbances. Active noise control (ANC) solutions for such problems are generally based on the combination of multiple adaptive notch filters. Both the performance and the computational cost are negatively affected by an increase in the number of controlled frequencies. In this work we study a different modeling approach for the secondary path, based on the estimation of various small local models in adjacent frequency subbands, that greatly reduces the impact of reference-filtering operations in the ANC algorithm. Furthermore, in combination with a frequency-specific step size tuning method it provides a balanced attenuation performance over the whole controlled frequency range (and particularly in the high end of the range). Finally, the use of small local models is greatly beneficial for the reactivity of the online secondary path modeling algorithm when the characteristics of the acoustic channels are time-varying. Several simulations are provided to illustrate the positive features of the proposed method compared to other well-known techniques.

Notch signaling pathway and transplantation immunology

Notch signaling pathway plays a key role in the development and fate of T lymphocytes and B lymphocytes, and may be a therapeutic target in alloimmunity.In this paper, we reviewed the functions of Notch signaling pathway in the activation and differentiation of T lymphocyte and formation of memory T cell subsets, and its role in the alloimmunity.Selective inhibition of multiple Notch receptors and ligands in a solid organ transplantation model can successfully modulate the allograft immune response and influence the balance between immune effector cells and regulatory cells, which suggests that selective targeting of Notch signaling pathway is expected to become a new immunomodulatory therapy for organ transplantation. Key words: Notch; Signaling pathway; Alloimmunity; Rejection; T lymphocytes

Design and Fabrication of a Microstrip Antenna with Multiple Notch Functions

Design and Fabrication of a Microstrip Antenna with Multiple Notch Functions

Analysis and design of notch filter-based PLLs for grid-connected applications

Using multiple notch filters (NFs) inside the control loop of a standard PLL is a basic strategy to improve its filtering capability. Often, adaptive NFs (ANFs) are employed for this purpose as they can block the disturbance components even under off-nominal grid frequencies. This advantage is at the cost of a rather considerable increase in the PLL implementation complexity and computational effort, particularly when ANFs have their own frequency estimation mechanism. The non-adaptive NFs (NNFs), contrary to ANFs, are easy to implement. They, however, have received a little attention in PLL applications. Therefore, their performance characteristics are rather unclear. To gain insight about the advantages and disadvantages of NNF-based PLLs (NNF-PLLs), analysis and design of these PLLs is conducted in this paper. This procedure includes: (1) selecting the appropriate number of NNFs inside the PLL control loop, (2) approximating dynamics of cascaded NNFs with a simple first-order low-pass filter, which simplifies the tuning procedure, (3) applying the symmetrical optimum method for selecting the control parameters of the NNF-PLL, and (4) performing extensive experimental results. The obtained results indicate that NNFs can sufficiently mitigate disturbances caused by the presence of harmonics in the PLL input while maintaining a fast dynamic response for the PLL. To be more exact, the NNF-PLL can provide a settling time around 2 cycle of the nominal frequency during phase and frequency jumps while having a peak-to-peak phase error less than 0.2° under a heavily distorted grid condition (THD=15%). It, however, may not be able to effectively reject the double-frequency disturbance component caused by the grid voltage unbalance. To deal with this problem, a hybrid combination of adaptive/nonadaptive NFs is suggested in this paper. The experimental results show that the resultant PLL, which is called the HNF-PLL, completely removes the grid voltage unbalance, effectively suppresses harmonics, and offers a fast dynamic response (a settling time around 1.5 cycle of the nominal frequency). The ease of implementation is kept in the HNF-PLL as only one of the NFs is adaptive and this NF does not require a separate frequency estimation mechanism.

Fracture Mechanism of Brazilian Discs with Multiple Parallel Notches Using PFC2D

This study presents crack initiation, propagation and coalescenceat or near pre-existing open cracks in a numericalmodel under Brazilian test. Firstly, Particle Flow Code intwo dimensions (PFC2d) was calibrated with respect to thedata obtained from experimental laboratory tests to ensurethe conformity of the simulated numerical models response.Brazilian discs contain one, two, three, four, and five parallelcentred cracks (45° to the horizontal) under compressiveline loading. Models containing two and three cracks havedifferent joint spacing and joint configuration. In model consistingone flaws, tensile cracks initiated from notch tip andpropagates in direction of compressive loading till coalescewith model edge. By increasing the number of notch, first typeof tensile crack initiated at the tips of outer flaws and coalescedwith model edge. Also second type of tensile cracksinitiates from middle of inner flaws and coalesce with tip ofthe neighbouring flaws. The results show that joint spacingand joint configuration has important effect on the failure patternin model consisting two and three notch. Experimentaland numerical results rendered by other researchers showed agood agreement with the numerical results in the coalescencecharacteristics in cracked model. In addition, crack initiationand coalescence stresses in models were analyzed and comparedwith those in the single-flawed model.

Multiple band notch and Dual-Band filter using concentric and contiguous split ring resonators (CCSRR)

A novel, compact, multiple band notch filter and dual-band filters are presented. Contiguous and concentric split ring resonators (SRRs) and Ring resonator are used to achieve desired multiple narrow band notches. These band notches have been designed to avoid the undesired interference between co-existing wireless channels. The dual-band filter consists of a dual SRR having splits on the opposite sides with Inductive Short Stub Split Ring Resonator. Even- and odd-mode analyses have been performed to calculate the resonance frequencies. Three transmission zeros are achieved between the two passbands by both dominant electric or dominant magnetic coupling and also cancellation effect of electric and magnetic coupling. This results in high passband selectivity and improved band-to-band isolation. The proposed dual-band pass filter has the advantages of being compact with more degree of freedom to achieve desired passbands by controlling the electric and magnetic coupling independently. Proposed filter is implemented on RT/Duroid 5880 (εr = 2.2) substrate of thickness 0.785 mm and surface area of 0.27λg × 0.27λg. Insertion loss of the proposed filter at notch bands is high (>13 dB) and low (<0.8 dB) in pass band. Measured results correlate with the simulated results and thus ensure that the proposed filter is a suitable candidate to mitigate interference caused by the co-existing and emerging wireless technologies.

A perfect diagnosis of Ellis-van Creveld syndrome by oral manifestations: a case report

Ellis-van Creveld syndrome is an extremely rare congenital genetic disorder having autosomal recessive inheritance. The characteristic features of this syndrome are bilateral postaxial polydactyly, acromesomelic dwarfism, ectodermal dysplasia affecting nails, congenital cardiac malformation, edentulous maxillary and mandibular incisors, non-appearance of mucobuccal fold, congenitally missing teeth, slight serrations of the alveolar ridge and multiple small alveolar notches. The present case describes the oral manifestations of the patient which leads to a perfect diagnosis of this syndrome. Ellis-van Creveld syndrome requires a multidisciplinary management and, hence the dental surgeons play an important role in these cases.

Elastic-plastic defect interaction in (a)symmetrical double edge notched tension specimens

Interaction of defects tends to intensify their crack driving force response compared to the situation where these defects act independently. The interaction between multiple defects is addressed in engineering critical assessment standards like BS7910 and ASME B&PV Section XI. Nonetheless, the accuracy of these rules is open to debate since all of them are based on re-characterization procedures which in essence introduce conservativeness. The authors have developed a fully parametric finite element (FE) model able to generate multiple notches in different topologies, in order to investigate their interaction effect. An experimental validation study is conducted to verify the FE model in terms of CTOD response and surface strain distribution. To that end, symmetrically and asymmetrically double edge notched tension specimens are tensile tested and their deformation monitored by means of 3D digital image correlation. In this study the CTOD is opted as a local criterion to evaluate the interaction between notches. These results are compared with an evaluation of strain patterns on a specimen’s surface, as a global interaction evaluation. Through this comparison a deeper understanding is gained to allow us to develop a novel approach to address flaw interaction. Moreover, the validation of the FE model allows future studies of interaction between other defect types (e.g., semi-elliptical, surface breaking) in plate-like geometries.

A compact triple band‐notched UWB printed antenna with multistep patches integrated by multitype slots

ABSTRACTA novel compact low‐profile printed antenna is designed and analyzed for wireless communication applications. The proposed antenna is composed of a four‐steps patch and a three‐steps segmental ground plane with two small rectangular slits. To enhance the antenna bandwidth and generate multiple notches, a circular split‐ring slot integrated with double strip slots is introduced in the multistep radiating patch, and a inverted‐L shaped slot is embedded onto the defected ground plane. The simulated and measured results show that the antenna achieves a wider bandwidth ranging from 3.0 to 16.5 GHz (the return loss &lt;–10 dB) with triple notches of 3.3–3.8 GHz (WiMAX band), 5.1–5.8 GHz (WLAN band), and 7.2–7.8 GHz (X‐band). Furthermore, the proposed antenna obtains relative high gain (&gt;4.0 dBi), lower group delay (&lt;2.5 ns) and stable radiation patterns. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:270–275, 2017

Flexible ultra-wideband antenna incorporated with metamaterial structures: multiple notches for chipless RFID application

A coplanar waveguide (CPW) ultra-wideband (UWB) antenna incorporated with metamaterial—split ring resonator structure—that operates from 3.0 to 12.0 GHz is proposed for chipless RFID tag. The 30 mm × 40 mm flexible chipless RFID tag is designed on the fleece substrate (er = 1.35, thickness = 1 mm and tan \( \delta \) = 0.025). A six-slotted modified complementary split ring resonator (MCSRR) is introduced into the ultra-wideband antenna to produce multiple band notches at 3.0, 4.0, 5.0, 6.0 and 7.0 GHz. The frequency shifting technique is introduced for designing a high-capacity chipless RFID tag with compact size. Each MCSRR is able to code in four different allocations (00, 01, 10 and 11). To achieve encoding of 10-bits data (10,234 number), six MCSRRs are proposed with three-slotted MCSRR in the radiator and three-slotted MCSRR in the ground plane.

Enhanced Frequency-Locked Loop With a Comb Filter Under Adverse Grid Conditions

To improve the performance of frequency-locked loops (FLLs) under distorted grid conditions, the technique of harmonic decoupling with multiple notch filters was usually employed to remove the harmonic components, which, although offering good filtering abilities, suffers from complexity, high computational burden, and deteriorated dynamics. To alleviate these problems, this letter proposes an enhanced adaptive notch-filter-based FLL, which incorporates a comb filter and improves the filtering abilities by introducing purely imaginary zeros to achieve notch peaks and harmonic cancellation. In comparison with the typical existing solutions of multiple notch-filter-based FLLs for distorted grid systems, the proposed FLL features simple structure and low computational load, and it can completely block the dc component, odd and even harmonics of the input grid voltage without sacrificing the FLL dynamics. Experimental results and comparisons are presented to validate the effectiveness of the proposed FLL.

Harmonic Current Suppression of an AMB Rotor System at Variable Rotation Speed Based on Multiple Phase-Shift Notch Filters

An active magnetic bearing (AMB) rotor system has such advantages as no friction and active vibration control. However, harmonic current caused by mass imbalance and sensor runout of magnetically suspended rotor system will lead to harmonic vibration. The harmonic current frequency is changed with the variation of rotation speed. The harmonic current suppression at variable rotation speed is a challenging research topic. In order to suppress harmonic current in AMB whose frequencies are integer multiples of the rotation frequency of rotor and to maintain system stability, multiple phase-shift notch filters are proposed in this paper. The closed-loop stability is ensured by adjusting the phase at variable rotation speed. Experiments are carried out on vibration measurement table and magnetically suspended flywheel prototype to show the effectiveness of the proposed method.

Optical Signal Filtering Using Phase-Sensitive Amplification and De-Amplification

We utilize for the first time, to the best of our knowledge, the amplification and de-amplification properties of a fiber-based optical phase-sensitive amplifier (PSA) to implement a flexible, multiple notch filter with optical power extinction ratio given by the internal amplifier gain squared. Our PSA-based filter is completely realized in the optical domain, permitting further downstream optical signal processing, if desired. Direct detection leads to an additional gain-squared enhancement, resulting in electrical filter extinction that is a biquadratic function of the PSA gain. This suggests that the PSAs with even modest optical gains can be used to realize filters with extremely large electrical extinction ratios or notch depths. We characterize filter performance using bit error rates, and demonstrate highly effective isolation of a signal-of-interest from neighboring interferers. Finally, we measure filter extinctions of 20 and 40 dB in the optical and electrical domains, respectively.