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In this paper we discussed the new design, fabrication and testing of a mechanical can crusher taking into deliberation the force analysis and ergonomic factors that will enable people to use this mechanical can crusher especially in Botswana rural areas. The process of crushing cans is of vital importance as it saves a percentage of space for can disposal and also makes it easier for these cans to be transported to recycling centers or landfill areas. The methods and processes used to bring this project to life include welding, cutting, bending, drilling and assembly operations. This project study is mainly about generating a new concept of a mechanical can crusher that is compact to transport from one location to another and makes can crushing easy and fascinating to the general public so as to promote people buy into crushing in Sub-Sahara market. Even though there are numerous sorts of the mechanical would crusher be able to as of now in presence, this model provides a more practical usage than previous one with the desired mechanical advantage of 10, machinability to crush the entire cans to 25% of their original size and 100% efficiency for the entire rounds.

Size reduction homogenizes the bulk biomass and facilitates downstream feedstock handling, transportation, and storage. Effects of feeding rate, mill-type (hammer and knife mill), screen size, and moisture content on comminution energy consumption of commercial Douglas-fir ( Pseudotsuga menziesii ) pulp chips were quantified. The resulting particles were characterized by geometric mean diameter, size distribution, aspect ratio and bulk density. We also employed scanning electron microscopy (SEM) to visualize the dominant fracture surface features. A linear regression was used to describe the relationship between specific energy consumption (SEC) and comminution ratio, which can be used for estimating SEC of various particle sizes of feedstock. Results demonstrated that with a screen size of 3.18 mm, the hammer mill consumed 141 kJ kg −1 , while the knife mill consumed 345 kJ kg −1 . Selecting the feeding rate, which allows the machine reach its rated power, can result in lowest total SEC. SEC also increased substantially with an increase in moisture content from 11% to 17% (fraction in total mass basis). Analysis of the particle morphology revealed that the dominant fracture mechanism was across lumen for hammer milling and along middle lamella for knife milling. [ABSTRACT FROM AUTHOR]

ABSTRACT In this study, the relationship between ground slot length and operating guided wavelength of a rectangular microstrip patch antenna for different dielectric substrates is investigated. The microstrip antenna structure taken into consideration is consist of one open ended slot embedded inside the patch and one rectangular slot placed inside the ground plane. For each of the dielectric substrates ( εr = 2.2, 2.4, 3.2, 3.55, 4.2, 4.4, 4.8, 6, and 8) simulation results in terms of resonance frequency, bandwidth, gain, and size reduction are found for different values of ground slot length. From the each stage of the antenna (for each dielectric substrate) the relationship between ground slot length and guided wavelength is formed by the help of simulated results and finally all these relations are combined into the proposed relationship. Four prototypes are fabricated (two prototypes using PTFE substrate and two using FR4 substrate) and tested. Good agreements are found between simulated and measured results. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2859-2864, 2016 [ABSTRACT FROM AUTHOR]

Size reduction is an unavoidable operation for preparing biomass for biofuels and bioproduct conversion. Yet, there is considerable uncertainty in power input requirement and the uniformity of ground biomass. Considerable gains are possible if the required power input for a size reduction ratio is estimated accurately. In this research, three well-known mechanistic equations attributed to Rittinger, Kick, and Bond available for predicting energy input for grinding pine wood chips by hammer mill were tested against experimental grinding data. Prior to testing, samples of pine wood chips were conditioned to 11.7 % wb, moisture content. The wood chips were successively ground in a hammer mill using screen sizes of 25.4, 10, 6.4, and 3.2 mm. The input power and the flow of material into the hammer mill were recorded continuously. The recorded power input vs. mean particle size showed that the Rittinger equation had the best fit to the experimental data. The ground particle sizes were four to seven times smaller than the size of the installed screen. Geometric mean size of particles were calculated using two methods: (1) Tyler sieves and using particle size analysis and (2) Sauter mean diameter calculated from the ratio of volume to surface that were estimated from measured length and width. The two mean diameters agreed well, pointing to the fact that either mechanical sieving or particle imaging can be used to characterize particle size. Specific energy input to the hammer mill increased from 1.4 kWh t (5.2 J g) for large 25.1-mm screen to 25 kWh t (90.4 J g) for small 3.2-mm screen. [ABSTRACT FROM AUTHOR]

This paper describes a concept of stepped impedance resonators (SIR) built from two coaxial structures fitted inside one another. The resonator is built out of a succession of two coaxial sections in cascade, where the ground conductor of the first one is the central core of the next, or vice-versa. An advantageous property of SIR is that they allow a substantial reduction in size, while keeping away the first harmonic and without strongly degrading the quality factor. After describing the theoretical behavior of the resonator, we will then present the specific properties of this approach in second order filter, conceived, and realized in the UHF band. With this example, we will also address flexibility and tunability aspects, which are the other potentially useful properties of the structure. Measurements and simulations are presented and discussed. The architecture resembles a set of two Russian dolls that fit inside one another. [ABSTRACT FROM PUBLISHER]

Cone crushers are used in the aggregates and mining industries to crush rock material. The pressure on cone crusher liners is the key factor that influences the hydraulic pressure, power draw and liner wear. In order to dynamically analyze and calculate cone crusher performance along with liner wear, a series of experiments are performed to obtain the crushed rock material samples from a crushing plant at different time intervals. In this study, piston die tests are carried out and a model relating compression coefficient, compression ratio and particle size distribution to a corresponding pressure is presented. On this basis, a new wear prediction model is proposed combining the empirical model for predicting liner wear with time parameter. A simple and practical model, based on the wear model and interparticle breakage, is presented for calculating compression ratio of each crushing zone along with liner wear. Furthermore, the size distribution of the product is calculated based on existing size reduction process model. A method of analysis of product size distribution and shape in the crushing process considering liner wear is proposed. Finally, the validity of the wear model is verified via testing. The result shows that there is a significant improvement of the prediction of cone crusher performance considering liner wear as compared to the previous model. [ABSTRACT FROM AUTHOR]

Solubility and bioavailability of drug molecules are the key factors influencing their therapeutic effectiveness in-vivo. The desired drug concentration in systemic circulation can be achieved through the required dissolution of the drug in the biological environment which ultimately affects the pharmacological response. Efavirenz is an anti-HIV molecule with low solubility and variable bioavailability (<45%) and prescribed as first line drug with 800 mg dose. The objective of the study was to develop polymeric nanoparticles of Efavirenz and assess the dissolution enhancement, safety and efficacy using T-lymphatic cell lines infected with HIV-1 IIIB strain. The nanoparticle formulations were developed using solvent evaporation method and characterized for its size (110–283 nm), charge (−21 to −33 mV), % entrapment efficiency (57–95%), viscosity of nanosuspension (2.39–4.2 cP) and surface area of the particles (1.4 m 2 /g). The fourier transform infrared analysis and differential scanning calorimetry analysis of the pure drug and nanoparticles revealed the compatibility and stability of drug in nanoparticles. The in-vitro dissolution studies of the nanoparticles in distilled water media using type-1 USP dissolution apparatus at 100 rpm showed improved drug release based on the polymer composition, as compared with marketed formulations (capsules). The cytotoxicity and therapeutic activity of nanoparticles was studied by MTT assay in C8166 cell lines and syncytium formation assay using HIV-1 IIIB strain infected cell lines, respectively. Cell uptake of the nanoparticles was studied by confocal microscopy. The formulated nanoparticles were found to be safe and exhibiting 2-fold increase in therapeutic activity compared to pure drug, which could be attributed to improved dissolution and high cell uptake. [ABSTRACT FROM AUTHOR]

Size reduction is an essential but energy-intensive process for preparing biomass for conversion processes. Three well-known scaling equations (Bond, Kick, and Rittinger) are used to estimate energy input for grinding minerals and food particles. Previous studies have shown that the Rittinger equation has the best fit to predict energy input for grinding cellulosic biomass. In the Rittinger equation, Rittinger's constant (kR) is independent of the size of ground particles, yet we noted large variations in kR among similar particle size ranges. In this research, the dependence of kR on the physical structure and chemical composition of a number of woody materials was explored. Branches from two softwood species (Douglas fir and pine) and two hardwood species (aspen and poplar) were ground in a laboratory knife mill. The recorded data included power input, mass flow rate, and particle size before and after grinding. Nine material properties were determined: particle density, solid density (pycnometer and x-ray diffraction methods), microfibril angle, fiber coarseness, fiber length, and composition (lignin and cellulose glucan contents). The correlation matrix among the nine properties revealed high degrees of interdependence between properties. The kR value had the largest positive correlation (+0.60) with particle porosity across the species tested. Particle density was strongly correlated with lignin content (0.85), microfibril angle (0.71), fiber length (0.87), and fiber coarseness (0.78). An empirical model relating kR to particle density was developed. [ABSTRACT FROM AUTHOR]

Background: Chia (Salvia hispanica L.) seeds have been described as a good source of lipids, protein, dietary fiber, polyphenolic compounds and omega-3 polyunsaturated fatty acids. The consumption of chia seed oil helps to improve biological markers related to metabolic syndrome diseases. The oil yield and fatty acids composition of chia oil is affected by several factors such as pre-treatment method and size reduction practices. Therefore, the main mandate of present investigate was to study the effect of different seed pre-treatments on yield, fatty acids composition and sensory acceptability of chia oil at different storage intervals and conditions. Methods: Raw chia seeds were characterized for proximate composition. Raw chia seeds after milling were passed through sieves to obtain different particle size fractions (coarse, seed particle size ≥ 10 mm; medium, seed particle size ≥ 5 mm; fine, seed particle size ≤ 5 mm). Heat pre-treatment of chia seeds included the water boiling (100 C°, 5 min), microwave roasting (900 W, 2450 MHz, 2.5 min), oven drying (105 ± 5 °C, 1 h) and autoclaving (121 °C, 15 lbs, 15 min) process. Extracted oil from pre-treated chia seeds were stored in Tin cans at 25 ± 2 °C and 4 ± 1 °C for 60–days and examined for physical (color, melting point, refractive index), oxidative (iodine value, peroxide value, free fatty acids), fatty acids (palmitic, stearic, oleic, linoleic, α-linolenic) composition and sensory (appearance, flavor, overall acceptability) parameters, respectively. Results: The proximal composition of chia seeds consisted of 6.16 ± 0.24 % moisture, 34.84 ± 0.62 % oil, 18.21 ± 0.45 % protein, 4.16 ± 0.37 % ash, 23.12 ± 0.29 % fiber, and 14.18 ± 0.23 % nitrogen contents. The oil yield as a result of seed pre-treatments was found in the range of 3.43 ± 0.22 % (water boiled samples) to 32.18 ± 0.34 % (autoclaved samples). The oil samples at day 0 indicated the maximum color (R and Y Lovibond scale) value for oven drying while at storage day 60 (25 ± 2 °C), the highest color value was found for autoclave pre-treatment. The slightly increasing trend of color values for all treatments was observed during the storage period. The lowest iodine value (182.83 ± 1.18 g/100 g at storage day 0 & 173.49 ± 1.21 g/100 g at storage day 60, 25 ± 2 °C) was calculated for autoclaved samples while the maximum iodine value (193.42 ± 1.14 g/100 g at storage day 0 & 190.36 ± 1.17 g/100 g at storage day 60, 25 ± 2 °C) was recorded for raw chia samples. The significant increasing trend for all treatments was observed in case of peroxide value and free fatty acids production during storage. Maximum decrease in linoleic (35 %) and α-linolenic (18 %) fatty acids was observed in autoclaved samples. The oil from pre-treated seed samples obtained decreasing scores for sensory parameters throughout the storage period at different conditions. Conclusions: As a result, chia seeds are an important source of lipids and essential fatty acids. The water boiling and high temperature processing of chia seeds provides instability to lipids during storage at room temperature. However, detailed investigation is required on the processing performance and storage stability of food products supplemented with pre-treated chia seeds and furthers their effect on biological system. [ABSTRACT FROM AUTHOR]

Mechanized coal mining generates a substantial amount of fines that represents significant economic value. Coal fines had several applications, such as gasification, liquefaction, combustion, and beneficiation, but also pose health and safety hazards. Particle size and particle size distribution (PSD) literature on fine coal are highly limited. In this study, PSD of laboratory ball- and gyro-milled lignite and hard coal using machine vision analyzes was determined and compared with standard mechanical sieving. The developed machine vision ImageJ plugin utilized length- and a new width-based sieveless volume-based analysis for PSD evaluation. The plugin automated PSD analysis with high speed, and produced better insight of the fine coal (− 300 μm) PSD characteristics through textual and visual outputs. The method of analysis, coal, and mill types, produced statistically significant differences between these variables more on cumulative undersize and less on PSD parameters using pooled data. Ground fine coal PSD exhibited an unimodal normal distribution, and can be classified poorly-graded, positively skewed and leptokurtic, very well-sorted, symmetrical, and platykurtic to mesokurtic. Mechanical sieving PSD characteristics, in general, fell between machine vision width- and length-based characteristics. Unlike limited standard sieves of mechanical sieving, the machine vision methods, with limitless virtual sieves, accurately analyzed the PSD with the necessary number of sieves. The outlined machine vision methods can be readily utilized to analyze similar particulate materials. [ABSTRACT FROM AUTHOR]

Transmission expansion planning (TEP) is an important and computationally expensive decision‐making process in power systems. Expression of the power flows using power transfer distribution factors (PTDFs) could potentially reduce the size and computational cost of the TEP. However, this formulation does not lend itself easily for this problem as the system topology changes in the course of the optimisation procedure. This study presents a PTDF‐based TEP model devoid of voltage angles and nodal power balances, while producing the same solution as angle‐based TEP models. The proposed model is capable of monitoring a limited number of transmission lines that have significant impact on the system's reliable and optimal operation. It thus considerably reduces the number of constraints and results in a scalable optimisation problem. The proposed model is highly advantageous especially for the TEP of large‐scale power systems. The numerical results provide an indication for the effectiveness of the proposed model. [ABSTRACT FROM AUTHOR]

ABSTRACT This article proposes the stepped impedance line Wilkinson power divider (SIL WPD) and extracts the design formulae of SIL WPD. In the process of forming the WPD and executing a simulation based on the calculated design parameters, this study found that the SIL WPD improves stop-band performance compared to the conventional one. In addition, it is useful in reducing the size due to the characteristics of SIL. Finally, the consistency of the simulated and measured results confirmed the validity of the SIL structure. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1607-1610, 2016 [ABSTRACT FROM AUTHOR]

By shunting a susceptance at the middle of the branch of a conventional Wilkinson power divider, the size can be reduced and the harmonic components can be suppressed. Further, miniaturization can be achieved by optimal layout of the internal area of the conventional power divider. In this article, simple design methods to implement miniaturized Wilkinson power dividers with harmonic suppressions are presented. To validate the design methodology, two power divider prototypes are optimally designed and examined from electromagnetic simulations and experiments. As compared to conventional types, the circuit sizes of the demonstrators are effectively reduced to 15.6 and 24.98%, respectively, and the spurious suppressions are over 20 dB at the desired harmonic frequencies. Meanwhile, the mechanisms of spurious suppression are studied herein. The achieved performance simply confirms the presented design methodology. [ABSTRACT FROM AUTHOR]

Cutting tool parameters such as edge-sharpness and speed of cut directly influence the shape of final samples and the required cutting force and specific energy for slicing or cutting operations. Cutting force and specific energy studies on different vegetables help to design the appropriate slicing or cutting devices. Peak cutting force and specific energy requirements for the transverse cutting of nine vegetables, differing in their textural characteristics of rind and flesh, were determined at cutting speeds of 20, 30, 40 mm min-1 and single-cut knife-edge angles of 15, 20 and 25° using a Universal Testing Machine. Low speed (20 mm min-1) cutting with a sharper knife-edge angle (15°) required less peak force and specific energy than that of high-speed cutting (40 mm min-1) with a wider knife-edge angle (25°). The vegetables with the maximum and minimum variation in the average peak cutting force were aubergine, at 79.05 (for knife speed 20 mm min-1 and edge angle 15°) to 285.1 N (40 mm min-1 and 25°), and cucumber, at 11.61 (20 mm min-1 and 15°) to 21.41 N (40 mm min-1 and 25°), respectively. High speed (40 mm min-1), with a large knife-edge angle (25°), required the highest force and specific energy to cut the vegetables, however, low speed (20 mm min-1), with a small knife-edge angle (15°), is preferred. Effects of cutting speed and knife-edge angle on peak force and specific energy responses were found significant (p<0.05). Linear or quadratic regressions gave a good fit of these variables. [ABSTRACT FROM AUTHOR]

Petroleum coke (PC) blend with coal is an attractive feedstock for combustion process. The present work investigates the grinding characteristics of PC blend with coal in a laboratory ball mill to meet an industrial tube mill conditions. Tests were carried out using a laboratory batch ball mill for optimal production of −200 mesh size product. The ground products at different combinations were subjected to sink-float tests. Experimental results suggested that the petcoke with coal at 5.0% blend ratio was optimum for generation of −200 mesh size product. It was also observed that increasing coal/petcoke blend ratio beyond 5.0% leads to a decrease in −200 mesh size generation. The better performance could be achieved at the blending ratio of 5%, perhaps resulting from the synergistic effect of the blends. With the aforementioned blend ratio, the optimal condition of the milling time was found to be 3 h. The percentage of coal to the total charge and percentage of petcoke to the total charge of the ball mill product at various blends were also calculated for all the blends and at all grinding time intervals. The results obtained could provide a useful insight to predict the industrial mill performance. [ABSTRACT FROM PUBLISHER]

In this paper, a Bow-tie antenna with size reduction, impedance matching and radiation pattern improvement characteristics is designed with an encircling ring. Moreover, further size reduction is achieved by utilizing two symmetric split rings with more frequency tuning flexibility. Research found the ring loaded Bow-tie antenna (RLBA) shows better performance than the referenced Bow-tie antenna (RBA), and the mechanisms of performance improvements are also investigated and found to be the loading ring acts as two symmetric dipoles in the direction of the antenna's polarization. Then, using two symmetric split rings on the opposite side of the substrate as replacement of the encircling ring will prolong the length of the dipoles, and achieves further size reduction. The antenna is denoted as dual split ring loaded Bow-tie antenna (DSRBA). The low cutoff frequencies of RBA, RLBA and DSRBA with identical antenna size are 2.65 GHz, 2.27 GHz and 2.06 GHz, respectively. Then, the corresponding diameters of the antennas are 0.353 λc, 0.303 λc, and 0.275 λc, where λc are their corresponding wavelength of the lower cutoff frequencies. Furthermore, a notched-band is generated as a byproduct of the split rings, and it is owing to the new resonance of the overlap areas of the split rings. The notch can be used to alleviate interference of WiMAX band by carefully choosing the split rings' size. Radiation patterns of RLBA and DSRBA are also improved as current distributions of the high frequencies are trained in order by the ring/split-rings. Measurements are performed to verify the designs. [ABSTRACT FROM AUTHOR]

Pulp and paper solid waste (PPSW) originating from paper industry, was experimented for the production of fumaric acid (FA) through submerged and solid state fermentation by utilizing the filamentous fungus Rhizopus oryzae 1526 . Physicochemical characterization, pH and moisture content analysis of PPSW was carried out. Pre-treatment of PPSW by size reduction resulted in particles of different size ranges (1.7 mm < x ≤ 3.35 mm, 850 μm < x ≤ 1.7 mm, 300 μm < x ≤ 850 μm, 75 μm < x ≤ 300 μm and 33 μm < x ≤ 75 μm). In submerged fermentation with all particle size ranges, a maximum of 23.47 ± 0.70 g/L of FA was obtained with 33 μm < x ≤ 75 μm under the fermentation conditions of 30 °C, 200 rpm, 5% pre-cultured inoculum ( v/v ) and at 48 h. Viscosity measurement and analysis of by-product of the fermented broths were performed. Microwave-phosphoric acid mediated hydrolysis of 33 μm < x ≤ 75 μm particle size produced hydrolysate with maximum glucose (11.2 ± 0.8 g/L) and xylose (20.22 ± 0.85 g/L) contents. Submerged fermentation with this hydrolysate confirmed the utilization of xylose for both FA production and fungal growth. Solid state fermentation with 75 μm < x ≤ 300 μm particle size resulted in highest FA production (41.45 g/kg dry weight) after 21 days. Scanning electron microscopy revealed the morphological features of the fungus grown on the particles. The results of the present study confirmed the utilization of PPSW as a source of carbon and trace elements by the fungus R. oryzae 1526 and also the bioconversion into FA during fermentation. FA being a high value platform chemical, its bioproduction from the low cost PPSW, is a value addition approach. [ABSTRACT FROM AUTHOR]

Space traveling wave tubes (TWTs), which are used in satellite communications, need to be compact and light weight, and have high overall efficiency. In a typical TWT, $\sim 45$ % of the weight is due to the collector, which is normally made bulkier to dissipate the waste heat. Hence, reduction in size and weight of the collector will lead to huge savings in the weight of the entire TWT, thereby impacting significantly on the launch cost of the satellite. However, reduction in size and weight of the collector has several associated bottlenecks and challenges. Here, we have successfully addressed those challenges and have developed a novel, compact, and light-weight multistage depressed collector (MDC). The novelty of the MDC is in the shape of the electrodes, which has been modified to have internal corrugations. Due to this geometry modification, the MDC offers $\sim 76$ % weight reduction that, in turn, translates into $\sim 35$ % weight reduction of the TWT, which greatly impacts the launch cost of the communication satellite. Furthermore, no deterioration in electrical and thermal performance has been observed in this compact MDC design. [ABSTRACT FROM AUTHOR]

The paper presents a new design methodology for a novel compact rectangular microstrip patch antenna. The initial patch antenna consists of a rectangular-shaped patch using air as substrate, which is primarily used for cost-effectiveness and ease of fabrication. The size reduction procedure started with inserting triangular slots, parallel to the non-radiating edge, properly on the patch. Then gradually slots of different shapes are introduced on the microstrip patch to decrease the resonant frequency and adjusting the patch dimensions so as to alter the surface current path in such a way keeping the resonant frequency constant, and care is also taken to keep the radiation properties unchanged. The antenna parameters depend exclusively on the triangular slot dimensions, their relative positions and orientations relative to each other. The simulated and measured results show that the size reduction is achieved by 78% compared to the conventional rectangular patch antenna operating at the same center frequency. The results obtained provide a workable compact antenna design for incorporation in energy harvesting systems where the aim is to use the rectenna to transfer DC power through wireless links for long distance. [ABSTRACT FROM AUTHOR]

SUMMARY We designed a miniaturized permanent magnet synchronous motor with a magnetic gear by using an optimal design technique based on thermomagnetic field coupling analysis. To construct an even smaller motor, investigating the heat dissipation from the motor and increasing its rotation speed are necessary. We manufactured and tested the designed motor with a magnetic gear. The measured torque and motor efficiency demonstrated the high precision of the proposed design. [ABSTRACT FROM AUTHOR]

A half-mode substrate integrated waveguide (HMSIW) with developed microstrip polyline unit cells etched on the waveguide surface is investigated in this letter. Modified analysis of the effective electrical parameters analysis is proposed. By applying the modified retrieval method, effective permittivity and permeability are extracted accurately to further describe the influence of the proposed structure, as well as slow-wave effect. Then, a compact 3-dB Wilkinson power divider/combiner based on polyline-patterned slow-wave HMSIW is developed for broadband microwave applications. The prototype achieves a fractional bandwidth of 91.7%, with the amplitude and phase variations less than 0.5 dB and ±4°, respectively. Compared with some reported SIW and HMSIW power divider, this letter achieves a size reduction of 40% and a bandwidth enlargement over 50%, illustrating its suitability for practical broadband applications. [ABSTRACT FROM AUTHOR]

A new design of microstrip power‐divider (PD) diplexer with simple layout is presented. The proposed design is directly formed up by two independently designed dual‐mode filtering PDs without any additional matching network at the common port, thus bringing significant design flexibility and size reduction to the design process. For validation, a prototype PD diplexer working at 2.45 and 2.98 GHz is finally implemented and measured. Measured results agree well with the simulated ones. Results indicate that the PD diplexer exhibits sharp passband selectivity, good port‐to‐port isolation and high channel isolation, which is very attractive for applying to the multi‐standard wireless communication systems. [ABSTRACT FROM AUTHOR]

In this letter, a compact two-via hammer spanner-type polarization-dependent electromagnetic bandgap (TVHS-PDEBG) structure is proposed. Asymmetrical structure of the TVHS-PDEBG results in different bandgap properties in the $x$ - and $y$ -directions. Compactness of the structure is achieved because of the usage of two-via per unit PDEBG cell, U-shaped rectangular slot, stretched strip, and square EBG patch with central located via embedded in adjacent PDEBG cell. The simulation of the TVHS-PDEBG is carried out using Ansoft high-frequency structure simulator, and it is validated experimentally. These results are compared with fabricated central located via EBG having similar parameters. Simulated and experimental results prove that, compared with complementary split ring resonator-based PDEBG and dual asymmetrical U-shaped-type PDEBG, the TVHS-PDEBG presents a 35.48% and 16.66% reduction in the center frequency of the lower bandgap. [ABSTRACT FROM PUBLISHER]

A compact broadband circularly polarised (CP) aperture antenna is proposed. In order to broaden the CP bandwidth, a pair of perturbation slots is introduced to generate a higher order mode (quasi‐TE31) for CP radiation. With three resonant modes working simultaneously a wider CP bandwidth is obtained. Besides, with some modifications to the ground plane, the antenna is miniaturised while keeping its wideband CP performance. The measured CP working bandwidth is 76.6% (2.9–6.5 GHz) with the antenna size of 43 mm × 43 mm, which means a 71% CP bandwidth increment and a 47% size reduction compared with the original CP aperture antenna. [ABSTRACT FROM AUTHOR]