Slot Parameters Research Articles

Design and Analysis of 150° Bend SIW and Corrugated SIW Bandpass Filter with Multiple Transmission Zeroes Using Reactive Periodic Structures Suitable for Microwave Integrated Circuits (MICs)

Microwave multi-band bandpass filter using substrate integrated waveguide (SIW) and corrugated SIW (CSIW) over Neltec NH9320 with dielectric constant of 3.2, thickness 30 mil and loss tangent tanδ = 0.0024 are presented in this paper. Firstly, 150° bend in the SIW BPF has been provided in SIW multi-band filters in view of its overall size reduction compared to planar un-bend structures and integration ability as required in microwave integrated circuits. Secondly, Reactive periodic slots are introduced over the SIW surface to obtain multiple transmission zeroes within the passband. These slots are bend to 150° in alignment to the 150° bend within the waveguide section. The method presented is further extended for designing CSIW multi-band BPF. Impacts of several parameters of the periodic slots (which are also 150° bend in accordance with the SIW structure) are analyzed. The measured results ensure improved filter performance like low reflection as well as improved isolation. The angular bend used in the BPF enables it to be integrated with other planar circuits within the same PCB material. Passbands obtained within the microwave Ku-bands are suitable for use in Direct Broadcasting Satellite communication systems.

Slot Optimization Design of Induction Motor for Electric Vehicle

Slot design of induction motor has a great influence on its performance. The RMxprt module based on magnetic circuit method can be used to analyze the influence of rotor slot type on motor characteristics and optimize slot parameters. In this paper, the authors take an induction motor of electric vehicle for a typical example. The first step of the design is to optimize the rotor slot by RMxprt, and then compare the main performance of the motor before and after the optimization through Ansoft Maxwell 2D. After that, the combination of optimum slot type and the optimum parameters are obtained. The results show that the power factor and the starting torque of the optimized motor have been improved significantly. Furthermore, the electric vehicle works at a better running status after the optimization.

Assessment of Elbow Torque and Other Parameters During the Pitching Motion: Comparison of Fastball, Curveball, and Change-up

To assess the precision of a new wearable device in detecting medial elbow torque during the pitching motion in competitive baseball pitchers and to determine the differences in torque across pitch types and thrower demographic characteristics. High school and collegiate baseball pitchers were recruited from August 1, 2016, to January 31, 2017, through direct request by athletic trainers and coaches. Body dimensions and throwing arm measurements of the participants were collected. The sensor was positioned directly over the medial elbow and pitchers were instructed to throw 8 fastballs, 8 curveballs, and 8 change-ups in a standard, randomized sequence. The sensor reported elbow torque, arm speed, arm slot, and shoulder rotation, whereas a radar gun measured peak ball velocity. Precision was calculated by measuring outlier rate, and mixed model regression analysis was performed to detect differences in throwing biomechanics among pitch types. In total, 37 competitive baseball pitchers were included in the study. The device had a precision of 96.9% for fastballs, 96.9% for curveballs, and 97.9% for change-ups. The device was sensitive enough to distinguish pitches according to elbow torque, arm speed, arm slot, and shoulder rotation. Fastballs caused the greatest relative torque across the medial elbow (average= 45.56Nm), compared with change-ups (43.77Nm; P= .006) and curveballs (43.83Nm; P= .01). Ball velocity contributed most to medial elbow torque (P= .003), followed by elbow circumference (P= .021), where smaller elbow circumference predicted greater medial elbow torque. The sensor is a precise and reproducible device for measuring torque across the medial elbow, as well as additional parameters of arm speed, arm slot, and shoulder rotation. Torque was significantly relatively higher in fastballs than curveballs and change-ups. Level III, comparative study.

A compact dual frequency double U-slot rectangular microstrip patch antenna for WiFi/WiMAX

This letter presents design of a compact (0.32λg × 0.15λg) dual frequency rectangular microstrip patch antenna for wireless applications. Dual frequency operation is achieved by inserting a pair of symmetric face-to-face U-slots, which results in excitation of and modes, on a narrow radiating patch upon appropriate offset coaxial feeding. In addition to compactness, the embedded slots provide two degrees of freedom for tuning the resonant frequencies independently. A physics based approach is adopted in deriving empirical expressions for lower and upper resonant frequencies by analysing the surface current distribution on the patch. Parametric studies of the slots' dimensions show that it can cover the frequency ranges from 1.72 to 4.1 GHz without giving rise to any grating lobes. This antenna geometry can be used for various standards like GSM (1800–1900 MHz), DCS (1710–1880 MHz), PCS (1880–1990 MHz), UMTS (1920–2170 MHz), LTE2300 (2300–2400 MHz), WiFi (2400–2480 MHz), WiMAX (3467–3521 MHz), etc. by appropriately choosing slot parameters. Many typical designs of the proposed antenna geometry are possible with different slot dimensions according to the requirement of these bands. One such design which supports WiFi and WiMAX has been fabricated on FR4 substrate. The measured results for this antenna are also included here.

Wideband slotted substrate integrated waveguide cavity‐backed antenna for Ku – band application

AbstractIn this article, a wideband substrate integrated waveguide (SIW) cavity‐backed antenna with multi‐resonance slots for band application is presented and experimentally investigated in terms of antenna performances including S‐parameter, optimized parameter values, gain, and radiation pattern. With the proper placement of multi‐resonant slots on the backside of the cavity, the hybrid modes are generate in the frequency band of interest. These modes can be tuned by varying the slot parameters which result the merging of different resonant frequencies, therefore the simulated impedance bandwidth is substantially enhanced to 1.46 GHz, ranging from 12.7 to 14.16 GHz with a gain of 6.0 to 8.0 dBi. The measured result showing the fractional bandwidth of the proposed antenna is 11.8% and 11% achieved at the resonant frequencies of 13 and 14 GHz, respectively. Moreover, the antenna has the features of simple‐single layer structure, resonant frequency flexibility with multi‐resonance characteristics over a wide impedance bandwidth.

Integrity Testing of a Polyvinyl Chloride Slotted Liner for Horizontal Coalbed-Methane Wells

Summary Steel slotted liners are often used in horizontal coalbed-methane (CBM) well completions. However, the disadvantages associated with these liners, such as high operation costs, corrosion susceptibility, and safety considerations in subsequent mining processes, can limit their performance. One possible alternative is a plastic slotted liner. A major challenge for designing a plastic slotted liner is providing sufficient structural integrity without creating a significant restriction for gas that flows into a wellbore. In this paper, we present an optimization design for polyvinyl chloride (PVC) slotted liners. Our design couples the influence of the mechanical integrity of the liner and the inflow performance. The optimization parameters are the slot geometrical parameters. The boundary conditions are identified by the failure criteria and the influence of various slot-parameter adjustments through laboratory compression experiments. Two models—a collapse-bearing-capacity model and a skin-factor model (Furui et al. 2005)—are used to optimize the design of the PVC slotted liners. A genetic algorithm is used to maximize the collapse-bearing capacity and minimize the skin factor. Finally, a selection guide for the optimal combination of slot parameters is provided. The key findings of this work are beneficial for determining the design criteria of plastic slotted liners in horizontal CBM wells. In addition, the proposed “cross-disciplinary” evaluation method is expected to provide a valuable optimization approach for slotted-liner completions.

Subwavelength T‐slot waveguide optical interconnect

A T-slot waveguide optical interconnect is proposed that can be realised on a photonic integrated circuit with sub – wavelength silicon slot waveguides and can redirect optical power to optical devices placed perpendicular to each other. In the proposed configuration, all critical parameters of high index waveguide and low index slot of all three arms are optimised. A power splitting efficiency of 54% is achieved which is almost independent of operating International Telegraph Union (ITU) grid C Band wavelengths. By judicious modification in T-slot waveguide configuration, power splitting efficiency is enhanced up to 73%.

Heuristic algorithm-based estimation of rotor resistance of an induction machine by slot parameters with experimental verification

Heuristic algorithm-based estimation of rotor resistance of an induction machine by slot parameters with experimental verification

Presentation of Design Equations for Array of Circumferential Slot on Cylindrical Waveguide

In this paper the design equations for an array of circumferential slots on a cylindrical waveguide are obtained, following the procedure introduced by Elliott for slots on rectangular waveguides. The minimization of the error function is achieved for optimization of slot array parameters. The optimization of slot parameters is not goal of this paper but a numerical example are presented as illustrations of the proposed synthesis method. The results of array designs by the method of the least squares are verified by two computer simulation softwares, namely CST and HFSS.

Influence of Slot Parameters on the Structure Performance of Slotted Tunnels under the Internal Chemical Explosion

The chemical explosion is a complicated process with the coupling action of the temperature field and pressure field. Under the internal chemical explosion, tunnels with different slot parameters such as the slot area ratio and the slot depth have different structure performance. In this paper, the influence of slot parameters on the structure performance of slotted tunnels under the internal chemical explosion was studied numerically. 3 schemes were conducted to obtain the structure performance of slotted tunnels, which were different slot area ratios, different slot depths and their different combinations respectively. Based on the finite element analysis software LS-DYNA, the peak vertical acceleration and the peak maximum principal stress of the tunnel roof under different slot parameters were calcutated to obtain the structure performance, which can help provide a reference for the explosion resisting design of slotted tunnels.

A Design for a Modified Circular Slot Antenna with a Fork-like Tuning Stub for UWB Operations

This paper proposes and experimentally tests a modified circular slot antenna fed by a fork-like tuning stub for ultra-wideband (UWB) operation. The proposed antenna consists of a modified circular slot model and fork-like tuning stub. The proposed antenna is printed on a 34.0 mm × 30.0 mm FR4 substrate with thickness of 1.0 mm and relative permittivity of 4.4. The effect of various parameters of the circular slot and fork-like tuning stub is investigated for UWB operation. The modified circular slot and fork-like tuning stub are fabricated on the substrate to achieve wideband operation and good impedance matching. Experimental results demonstrated that the measured return loss exhibits an acceptable agreement with the simulated return loss and satisfies the -10 dB impedance bandwidth requirement while simultaneously covering the UWB bands. In addition, the proposed antenna shows good radiation characteristics and gains in the UWB bands.

Multifrequency Seashell Slot Antenna With Cold-Electron Bolometers for Cosmology Space Missions

A novel type of the “seashell” multichroic polarized antenna is proposed for cosmology space missions. The polarized slot antennas are arranged in the compact form of a seashell with individual slots for each frequency and each polarization. Such an arrangement gives a unique opportunity for independent adjusting individual parameters of slots with microstrip lines (MSLs) and bolometers. For each frequency band, the seashell antenna contains two pairs of orthogonal slots for each polarization connected by MSLs with a bolometer in the middle for in-phase operation. To fit slots in the $\lambda/2$ area for the best beam shape, lumped capacitances in the form of the H-slot were introduced. Ellipticity of a beam was improved to the level of better than 1%. The seashell antenna gives a unique opportunity to select the needed bandwidth using two options. The first option is the frequency selection by resonance properties of slots with MSLs and resistive cold-electron bolometer (CEB). The second option is the frequency selection by resonant CEB with an internal nanofilter organized by a kinetic inductance of the NbN superconducting nanostrip and a capacitance of the nanoscale superconductor–insulator–normal tunnel junction.

A PROXIMITY-FED ANTENNA FOR DUAL-BAND GPS RECEIVER

A new design of dual-band L1/L2 GPS antenna is proposed. The antenna generates dual- band circularly polarized radiation by exciting a cross-slot and ring-slot of a concentric circular aperture using a proximity-coupled feed. Parametric studies show that the matching and axial ratio bandwidth of L1 (1.575 GHz) and L2 (1.227 GHz) bands can be independently tuned by alternating the ring radius and slot length. The range of frequency ratio and 3 dB center frequency can be highly adjusted by slot's parameters. The size of the antenna is 73 mm × 73 mm × 6.4 mm including the ground, corresponding to 0.29λ × 0.29λ × 0.026λ at 1.227 GHz.

Leaky Rectangular Waveguide With Circular Polarization Property

A leaky rectangular waveguide with novel composite slots cut into the broad wall, for use in generating a circular polarization wave along the waveguide, is proposed and investigated. A hybrid method involving a full-wave method for near-field computation and an integration approach for far-field computation is used to analyze the polarization properties of the leaky waveguide. Results show that the proposed leaky-wave structure can generate circular polarization radiation along the waveguide if the structural parameters of the composite slots are properly designed. The theoretical results on axial ratios are verified by the measurements.

Impact of Slot Parameters on the Three Resonant Frequencies of a Rectangular Microstrip Antenna: Study of the impact of the slot length, width, and position

Due to the importance that reconfigurable antennas have in modern designs of low-profile antennas, a comprehensive study of the impact of slot parameters on the resonant frequencies of a rectangular microstrip antenna (RMA) has been undertaken and the results have been presented here. The changes exhibited in the first three resonant frequencies were graphed with respect to the changes in the values of the specific slot parameter. The impact of the slot length, width, and the position was thoroughly documented. Following the computational results, a few models were selected for manufacturing and the measurements performed on them showed a good agreement with the computational results.

Influence of coupled effect among flaw parameters on strength characteristic of precracked specimen: Application of response surface methodology and fractal method

Hydraulic slotting is an effective method for enhanced coalbed methane (ECBM) recovery, and it has been widely employed in China. Although there have been many studies of this technique, the influence of slot parameters on the strength characteristic of the coal, which is an important factor that affects the permeability enhancement effect, has rarely been studied. Thus, only limited information is available regarding the pressure relief and permeability enhancement mechanisms of this technique. In the current study, the influence of flaw parameters on the compressive strength of a precracked sample under biaxial compression is discussed. The results indicate that an increase in the flaw length and width has a negative effect on the compressive strength, whereas an increase in the flaw inclination angle has a positive effect on the compressive strength. The results of the response surface methodology (RSM) indicate that the interactions among the flaw parameters have a significant influence on the compressive strength. The propagation patterns of cracks are quantified by the fractal dimension, which is used to explore the mechanism of compressive strength variation with changes in the flaw parameters. The study results indicate that the variation in the flaw parameters changes the propagation pattern of cracks, resulting in different compressive strengths. In addition, an opposite variation trend of the compressive strength and fractal dimension with flaw parameters is also observed. The research results are expected to guide the field application of hydraulic slotting.

Slot Parameter Optimization for Multiband Antenna Performance Improvement Using Intelligent Systems

This paper discusses bandwidth enhancement for multiband microstrip patch antennas (MMPAs) using symmetrical rectangular/square slots etched on the patch and the substrate properties. The slot parameters on MMPA are modeled using soft computing technique of artificial neural networks (ANN). To achieve the best ANN performance, Particle Swarm Optimization (PSO) and Differential Evolution (DE) are applied with ANN’s conventional training algorithm in optimization of the modeling performance. In this study, the slot parameters are assumed as slot distance to the radiating patch edge, slot width, and length. Bandwidth enhancement is applied to a formerly designed MMPA fed by a microstrip transmission line attached to the center pin of 50 ohm SMA connecter. The simulated antennas are fabricated and measured. Measurement results are utilized for training the artificial intelligence models. The ANN provides 98% model accuracy for rectangular slots and 97% for square slots; however, ANFIS offer 90% accuracy with lack of resonance frequency tracking.

Numerical analysis of centered-inclined coupling slots in rectangular waveguides

Numerical analysis is presented for the characteristic parameters of centered-inclined coupling slot in rectangular waveguides, taking into account the transverse distribution of the electric field across the slot aperture. Integral equations are formulated based on dyadic Green’s function theories and solved using the method of moments. Trigonometric basis functions are adopted. It is found that the method will converge with up to ten basis functions. The characteristic parameters can be easily obtained for different slot sizes. Resonant length and resonant resistance of the coupling slots are calculated. It is shown that the calculated results have very high accuracy, compared with simulated results obtained from commercial software. Therefore, it can be effectively applied in the synthesis of antenna arrays. Effects of the transverse distribution on calculating resonant parameters of the coupling slot are also analyzed. The results show that if the transverse distribution of the electric field is neglected, the calculated error tends to become larger when the slot gets wider or thinner.

Bandwidth enhancement in coplanar waveguide‐fed slot antennas designed for wideband code division multiple access/wireless local area network/worldwide interoperability for microwave access applications

A multiband coplanar waveguide-fed slot antenna design is proposed for use in wireless and mobile communication applications. This antenna was designed on a single-layer printed circuit board FR4 substrate featuring a permittivity ɛ r = 4.4, a loss tangent tan δ = 0.0245 and a thickness of h = 1.6 mm. The antenna consists of a T-shaped signal strip and a U-shaped conducting strip placed on the upper side of the T-shaped signal strip. After simply tuning the slot parameters of the ground plane, the proposed antenna can be used in the following operations: wireless local area networks at 2.4/5.2/5.8 GHz, worldwide interoperability for microwave access at 2.5/3.5/5.5 GHz and wideband code division multiple access at 1.92–2.17 GHz. The −10 dB bandwidth measured for the proposed antennas was 109.2% (1.85–6.3 GHz). The bandwidth was enhanced by choosing suitable combinations of the upper and lower ground slots. The geometrical parameters were examined to optimise the performance of the proposed antenna. The results of the return loss, far-field H- and E-planes radiation patterns, gain and radiation efficiency of the proposed antenna are presented and discussed herein. The antenna size of the radiation area and the ground plane was 50 × 50 mm2. Detailed simulations and experiments were conducted to optimise broadband operations, and the measured results concurred with the simulated results.

Design of Bandwidth Enhancement CPW-Fed Slot Antennas

A multi-band coplanar waveguide (CPW)-fed slot antenna design for wireless/mobile communication applications is proposed. This antenna is designed on single-layer PCB FR4 substrate with permittivity er = 4.4, loss tangent tanδ = 0.0245, and thickness h = 1.6mm. The antenna consists of T-shaped signal strip and U-shaped conducting strip in the upper side of T-shaped signal strip. With the simple tuning slot parameters of the ground plane, the proposed antenna is suitable for WLAN 2.4/5.2/5.8, WiMAX 2.5/3.5/5.5, and WCDMA 1.92-2.17 GHz operations. The -10 dB bandwidth of the proposed antennas from measurement is about 109.2% (1.85-6.3GHz). The bandwidth enhancement is obtained by choosing suitable combinations of the upper and the lower ground slots. The elaborate analysis of geometrical parameters has been studied to optimize the performance of the designed antennas. The results for return loss, far-field H- and E-plane radiation patterns, gain, and radiation efficiency of the proposed antennas are presented and discussed. The antenna size of radiation area and ground plane is 50×50mm^2. The detailed simulation and experiment are investigated to optimize for broadband operation. The measured results show a good agreement with the simulated results.