High Conversion Ratio Research Articles

An interleaved high step‐down coupled inductor based quadratic DC‐DC converter

AbstractA high step‐down direct current‐direct current (DC‐DC) buck converter with a coupled‐inductor in its topology is presented in this study. The switching pattern of the proposed converter is interleaved; therefore, the voltage stress on the semiconductors and the components is low since the primary high voltage will be divided between the blocking capacitors on the primary side. Thus, the voltage stress on semiconductor elements will be low. As a result, the preselected elements can be chosen with low voltage ratings. In addition, there are cells with coupled inductors utilized in the structure that helps the converter to provide improved voltage gain in its output terminal. Typically, narrow duty cycles are needed to achieve high gain in conventional buck converters, but the proposed converter has obtained a high conversion ratio even with wider duty ratios. Besides, the proposed converter has a constant equation for the voltage gain for the whole range of duty cycles. Theoretical analysis and comparison with other recent converters of similar types have been conducted to demonstrate the proposed converter performance. Furthermore, to verify the theoretical analysis, a 600 W prototype of the proposed converter with 820 V/30 V is implemented, and experimental results are presented.

A High Conversion Ratio DC–DC Boost Converter with Continuous Output Current Using Dual-Current Flows

Recently, the demand for small, low-cost electronics has increased the use of cost-effective tiny inductors in power-management ICs (PMICs). However, the conduction loss caused by the parasitic DC resistance (RDCR) of a small inductor leads to low efficiency, which reduces the battery usage time and may also cause thermal problems in mobile devices. In particular, these issues become critical when a conventional boost converter (CBC) is used to achieve high-output voltage due to the large inductor current. In addition, as the output voltage increases, a number of issues become more serious, such as large output voltage ripple, conversion-ratio limit, and overlap loss. To solve these issues, this paper proposed a high-voltage boost converter with dual-current flows (HVDF). The proposed HVDF can achieve a higher efficiency than a CBC by reducing the total conduction loss in heavy load current conditions with a small inductor. Moreover, because in the HVDF, the current delivered to the output becomes continuous, unlike in the CBC with its discontinuous output delivery current, the output voltage ripple can be significantly reduced. Also, the conversion gain of the HVDF is less sensitive to RDCR than that of the CBC. To further increase the conversion gain, a time-interleaved charge pump can be connected in series with the HVDF (HVDFCP) to achieve higher output voltage beyond the limit of the conversion gain in the HVDF while maintaining the advantages of a low inductor current and small output voltage ripple. Simulations using PSIM were performed along with a detailed numerical analysis of the conduction losses in the proposed structures. The simulation results were discussed and compared with those of the conventional structures.

A modified configuration of high step‐up non‐isolated DC‐DC converter with low voltage stress: Analysis, design, and implementation

SummaryThis study develops a novel DC‐DC converter with an extremely high voltage conversion ratio that utilizes just one switch, a voltage multiplier circuit (VMC), and a coupled‐inductor. Two diodes and two capacitors comprise the VMC, employed to reach high voltage gain. Consequently, the conduction loss is minimized by using a low voltage rated switch with lower RDS(on). Due to the coupled inductor's leakage inductance, the output diodes' reverse recovery trouble is solved. Moreover, the passive clamp technique stores and recycles leakage energy at the output. The proposed DC‐DC converter features are high conversion ratio, low maximum voltage on semiconductors, remarkable efficiency, the existence of only one active low voltage switch, and simple circuit topology with common ground between the input and the output. This paper outlines CCM, BCM, and DCM's operating concept and steady‐state analysis in great detail. Furthermore, the suggested structure's capability is indicated by mathematical analysis and comparative findings with other earlier structures. Eventually, experimental findings with 210 W output power and 25 kHz switching frequency demonstrates that the proposed converter can be used successfully.

Modelling of methane sorption enhanced reforming for blue hydrogen production in an adiabatic fixed bed reactor: unravelling the role of the reactor's thermal behavior

Methane sorption enhanced reforming (SER) is investigated in this work as a promising route for blue H2 production. A 1-D dynamic heterogeneous model is developed to evaluate the thermal behavior of a fixed bed reactor under adiabatic conditions. The heterogeneous model allows to decouple the feed gas temperature from the initial solid one in order to investigate the behavior of the reforming step in a temperature swing reforming/regeneration process. The effects of the feed gas temperature, the initial bed temperature, and the bed thermal capacity are studied by evaluating the global impact of each parameter through a set of key performance indices (CH4 conversion, H2 yield and purity, carbon capture ratio) calculated as integrals over the duration of the reforming step. The results highlight the minor effect of the initial bed temperature on the process performances showing the potential of minimizing the extent of a cooling step between regeneration and reforming stages. Besides, due to the endothermic nature of the methane sorption enhanced reforming process at high temperatures, thermal energy must be provided to the SER process to achieve high CH4 conversion and high carbon capture ratio. This can be made either in the form of high feed temperature or by utilizing the energy stored in the bed benefiting from the bed thermal capacity.

A Wide Conversion Ratio Bidirectional Modified SEPIC Converter with Non dissipative Current Snubber

This article presents a wide conversion ratio bidirectional dc-dc converter based on a bidirectional modified Single-ended primary-inductor converter (SEPIC converter). A key feature of this modified SEPIC converter is the non-dissipative current snubber circuit, which is used to achieve zero current switching and to suppress voltage spikes that occur during MOSFET switching. The snubber is made up of a capacitor, an inductor, and a diode that work together to form a resonant circuit that absorbs the voltage spike and returns it to the circuit without dissipating it. Even with conventional MOSFETs, high efficiency is achieved. The SEPIC converter differs from other bi-directional DC-DC converters in that it provides continuous output current, has fewer components, and can provide high conversion ratios of step-up and step-down voltage without exceedingly low or high duty-cycle. This paper presents a theoretical analysis with stages of operation in both step-up and step-down modes, theoretical waveforms, and the design procedure, as well as a comparison with other bidirectional dc-dc converter topologies. The experimental results are presented to validate the performance of the proposed converter using a 500-W prototype with Voltage Source V1 = 48 V and Voltage SourceV2 = 300 V.

Effect of Pulsed Feeding of GIFT Strain of Tilapia in Biofloc System Using Inland Saline Water

Feed is one of the major inputs in aquaculture system and constitutes 60%–80% of total production costs of tilapia. Inappropriate selection of feed quality and the feeding strategy affects the feed utilization resulting in high food conversion ratio (FCR). A 60 days experiment was conducted to evaluate the growth performance and immuno-physiological responses of GIFT tilapia, (Oreochromis niloticus) by pulsed feeding under biofloc culture system in inland saline water. For the experiment, feeding pattern in pulsed was followed viz., in situ biofloc with daily feeding (T1), in situ biofloc with alternate day feeding (T2), in situ biofloc with every third day feeding (T3), in situ biofloc with no feeding (T4), and clear water control with daily feeding (C) each in triplicates. Biofloc based treatment receiving daily feeding (T1) resulted in significantly (P<0.05) higher average body weight, weight gain, and specific growth rate (SGR) compared to control. T1 and C showed a significantly similar feed conversion ratio (FCR) and protein efficiency ratio (PER). Fish maintained in T4 grew the least and survival was lowest (85%). The immunological parameters showed a significant difference (P<0.05) for nitroblue tetrazolium (NBT) and myeloperoxidase content whereas no significant difference (P>0.05) for lysozyme activity was observed. Higher NBT activity was observed in biofloc based treatments compared to control. Activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activity were considerably higher (P<0.05) in biofloc based treatments than control. Among biofloc based treatments the antioxidant activities were lower in T1. The carbohydrate metabolism enzymes lactate dehydrogenase (LDH) and malate dehydrogenase (MDH) were lower in T1, T2, and T3 compared to control and T4. In conclusion, in-situ biofloc with daily feeding is found to be effective in growth improvement and to elicit immune-physiological responses in GIFT tilapia under pulsed feeding using biofloc based system.

Changes in Japanese quail (Coturnix coturnix japonica) blood gases and electrolytes in response to multigenerational heat stress

The average surface temperature is predicted to rise 0.5 to 6˚C by the year 2100. When Japanese quail (Coturnix coturnix japonica), a source of protein for many, are subjected to heat stress, their blood acid-base equilibrium and ability to regulate electrolytes may change. This disequilibrium may influence egg-shell quality, enzyme functions, and synthesis of tissue proteins. To determine effects of multi-generation heat stress on Japanese quail, the following treatments were applied (1) control (TN, non-sibling random mating at thermoneutral temperature [22.2˚C]); (2) thermoneutral siblings (22.2˚C, TNS); (3) heat stress (HS, non-sibling random mating at 31.1˚C); and (4) heat stressed siblings (HSS, siblings of TNS with high feed conversion ratios (FCR), 31.1˚C). Body weights (BW), blood gases, and electrolytes of quail were measured during the first 4 hours (acute) and after 3 weeks (chronic) of heat exposure (31.1˚C) in generation 10. ANOVA was used to determine statistical significance at P≤0.05. Models included treatments, length of exposure, sex, and their interactions. Results showed that acute and chronic heat stress did not have a clear effect on blood electrolytes, acid-base regulation, and oxygen transport. However, acute HSS males or females were significantly different than chronic TN males in BW, PCO2, PO2, sO2, and Na+. Chronic HS males and females did not have significantly different blood electrolytes, acid-base regulation, and oxygen transport than chronic HSS males and females. Thus, selection for low FCR in heat stress at 31.1˚C did not incur a fitness advantage when considering these parameters. Sexually mature males had significantly higher levels of hematocrit and hemoglobin compared to sexually immature quail and sexually mature females. Future studies using higher temperatures (32 to 34˚C) could inform producers when to expect significant physiological changes in quail, lending to adaptions of feeding regiments according to environmental temperature and age.

High Step-Up IPOS DC/DC Converter Based Efficiency Optimization Control Strategy

This article introduces a symmetrical, high step-up, input-parallel output-serial (IPOS), dc–dc converter based on voltage multiplier (VM) cells and active clamp circuits to obtain a very high voltage conversion ratio. The VM using a switched capacitor and the coupled inductor makes high voltage gain achievable, which results in reduced voltage stress on power switches. Meanwhile, the IPOS structure also makes great improvements in the above aspects. Importantly, by incorporating active clamp circuits, not only voltage spikes caused by leakage inductance are restrained but also the clamped circuit plays a role in energy transfer to boost the gain. Especially, zero voltage switching for all switches can be obtained. Furthermore, the optimization control strategy is proposed to further improve the overall efficiency. A detailed mathematical analysis of the proposed converter is conducted for systematizing its design. Finally, a prototype of 768 W output power and the 480 V output voltage is implemented to verify the excellent performance of the proposed converter.

Sensitive Detection of Nitrite and Nitrate in Seawater by 222 nm UV-Irradiated Photochemical Conversion to Peroxynitrite and Ion Chromatography-Luminol Chemiluminescence System

Sensitive detection methods for nitrite (NO2-) and nitrate (NO3-) ions are essential to understand the nitrogen cycle and for environmental protection and public health. Herein, we report a detection method that combines ion-chromatographic separation of NO2- and NO3-, on-line photochemical conversion of these ions to peroxynitrite (ONOO-) by irradiation with a 222 nm excimer lamp, and chemiluminescence from the reaction between luminol and ONOO-. The detection limits for NO2- and NO3- were 0.01 and 0.03 μM, respectively, with linear ranges of 0.010-2.0 and 0.10-3.0 μM, respectively, at an injection volume of 1 μL. The results obtained by the proposed method for seawater analysis corresponded with those of a reference method (AutoAnalyzer based on the Griess reaction). As luminol chemiluminescence can measure ONOO- at picomolar concentrations, our method is expected to be able to detect NO2- and NO3- at picomolar concentrations owing to the high conversion ratio to ONOO- (>60%), assuming that contamination and background chemiluminescence issues can be resolved. This method has the potential to emerge as an innovative technology for NO2- and NO3- detection in various samples.

Zootechnical Performance and Growth Curve Modelling of the Niamey Local Chickens in Niger

The Niamey region in Niger depends on imports to meet its chicken meat needs. Although consumers appreciate local poultry products, they cannot fulfill their needs. The reluctance of modern producers to use local chickens on their farms is linked to a lack of knowledge of the production characteristics of local strains, which have been little studied. Thus, this study aimed to determine the growth profile of traditional chickens from villages in the Niamey region (Niger). In doing so, 100 local chicks whose parents were collected in the surrounding villages of the Niamey region were followed from hatching until the age of 140 days. The chickens were raised in cages with 10 per compartment of 3 m length and 1.5 m width. Food consumption was recorded daily, and weights were measured weekly. The parameters of the growth curves were obtained using the Gompertz equation. Female and male chickens had a significant weight difference at the third week of age. The mean weight of chicks at hatching was 24.90 ± 0.36 g. At the end of the follow-up, males, with a mean weight of 1523.05 ± 26.22 g were significantly heavier than females (1052.73 ± 14.04 g). Over the entire period of the experiment, the average daily gain and consumption indices were 9.5 g/d and 5.12, respectively. Asymptotic weights were 2096.78 g and 1313.26 g for males and females, respectively. The maturation factor of the Gompertz equation was higher in females (0.0196 g/d) than in males (0.0181 g/d), and the inflection age averaged 75 days for both sexes. In conclusion, Niamey local chickens are slow growing and have a high feed conversion ratio compared to the modern broiler or layer strains.

A Coupled-Inductor-Based Bidirectional DC–DC Converter With High Voltage Conversion Ratio and Sensorless Current Balance

In this article, a coupled-inductor (CI)-based bidirectional dc–dc converter with a high voltage conversion ratio (VCR) and low voltage stress is proposed. The topology can achieve high VCR by employing two CIs; moreover, the interleaved technique overcomes the defect of large current ripple in CI. A sensorless current balance between the two CIs is also realized without an auxiliary circuit and complex control method. The pulsewidth modulation plus phase-shift control is employed, where the duty cycle <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</i> is used to adjust the VCR, and the phase-shift angle <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ϕ</i> is used to control the direction and amount of the transferred power. In addition, all switches can achieve soft-switching under a wide operation range. The steady-state analysis of the proposed converter is analyzed in detail, followed by comprehensive experimental verification under a 1-kW prototype.

A Distributed Multimode Control Strategy for the Cascaded DC–DC Converter Applied to MVAC Grid-Tied PV System

The cascaded dc–dc converter is a popular topology for large-scale medium-voltage photovoltaic (PV) system with the advantages of high voltage conversion ratio, high efficiency, great flexibility, and independent control capability. However, the absence of optimal string maximum power point tracking (MPPT) operation under power mismatch is a big issue in common centralized control. Furthermore, the cost and time delay are unacceptable resulting from the distance among PV strings in the large-scale PV station and the cascaded dc–dc converter needs to adopt the distributed control method without real-time communication. To this end, by introducing other necessary constraints including voltage constraints, power constraints, and gain constraints on the basis of the distributed MPPT control strategy, a distributed multimode control scheme is proposed in this article. Each submodule (SM) can be switched flexibly between multiple operation modes to maximize the extracted solar energy. Individual string MPPT and autonomous distribution of output voltage are achieved without communication under the proposed distributed control strategy. In this way, optimal operation range is wider, mode switching is simpler, and applicability and robustness are improved. A downscaled prototype and a 35-kV/6-MW simulation system are constructed to verify the effectiveness of the proposed control strategy.

Firms' financial structure with contingent convertible debt, risky debt and multiple growth options

PurposeThe objective of this paper is twofold: first, to model the value of the firm in the presence of contingent capital and multiple growth options over its life cycle in a stochastic universe to ensure financial stability and recover losses in case of default and second, to clarify how contingent convertible (CoCo) bonds as financial instruments impact the leverage-ratio policies, inefficiencies generated by debt overhang and asset substitution for a firm that has multiple growth options. Additionally, what is its impact on investment timing, capital structure and asset volatility?Design/methodology/approachThe current paper elaborates the modeling of a dynamic problem with respect to the interaction between funding and investment policies during multiple sequential investment cycles simultaneously with dynamic funding. The authors model the value of the firm in the presence of contingent capital that provides flexibility in dealing with default risks as well as growth options in a stochastic universe. The authors examine the firm's closed-form solutions at each stage of its decision-making process before and after the exercise of the growth options (with and without conversion of CoCo) through applying the backward indication method and the risk-neutral pricing theory.FindingsThe numerical results show that inefficiencies related to debt overhang and asset substitution can go down with a higher conversion ratio and a larger number of growth options. Additionally, the authors’ analysis reveals that the firm systematically opts for conservative leverage to minimize the effect of debt overhang on decisions so as to exercise growth options in the future. However, the capital structure of the firm has a substantial effect on the leverage ratio and the asset substitution. In fact, the effect of the leverage ratio and the risk-shifting incentive will be greater when the capital structure changes during the firm's decision-making process. Contrarily to traditional corporate finance theory, the study displays that the value of the firm before the investment expansion decreases and then increases with asset volatility, instead of decreasing overall with asset volatility.Research limitations/implicationsThe study’s findings reveal that funding, default and conversion decisions have crucial implications on growth option exercise decisions and leverage ratio policy. The model also shows that the firm consistently chooses conservative leverage to reduce the effect of debt overhang on decisions to exercise growth options in the future. The risk-shifting incentive and the debt overhang inefficiency basically decrease with a higher conversion ratio and multiple growth options. However, the effect of the leverage ratio and the risk-shifting incentive will be greater when the capital structure changes during the firm's decision-making process.Originality/valueThe firm's composition between assets in place and growth options evolves endogenously with its investment opportunity and growth option financing, as well as its default decision. In contrast to the standard capital structure models of Leland (1994), the model reveals that both exogenous conversion decisions and endogenous default decisions have significant implications for firms' growth option exercise decisions and debt policies. The model induces some predictions about the dynamics of the firm's choice of leverage as well as the link between the dynamics of leverage and the firm's life cycle.

A novel non-isolated high gain multiport DC-DC converter for integrating fuel cell/solar PV and battery energy storage system

ABSTRACT This paper presents a novel non-isolated capacitor-assisted quasi-Z-source (CA-QZS) multiport DC-DC boost converter, which operates as a dual-input single-output high gain boost converter. It consists of a bidirectional port for the smooth operation of the energy storage system, and a unidirectional port for the solar/fuel cell to deliver power to the battery and the load. The availability of common ground between input and output ports, high voltage conversion ratio, and continuous current of the unidirectional port are the main features of this novel design, making it suitable for a wider range of applications. A typical switching strategy is followed to regulate the output voltage as well as control input power from the sources. As a battery-incorporated system, the converter’s performance is determined by its selection between three operating modes. Therefore, the CA-QZS converter offers a viable interface for the management of battery energy storage systems. A comparative study is performed with other multi-port converters to highlight the advantages. It is observed that the voltage conversion ratio of 10, can be achieved at a low duty ratio of 0.3. To evaluate the effectiveness of the proposed topology, a prototype is developed with a nominal output power rating of 200W and an output voltage of 200 V.

Preheated combustion characteristics and fuel-nitrogen conversion paths for bituminous coal and anthracite in wide-range preheating temperature

In this study, the characteristics of preheated combustion and fuel-nitrogen (fuel-N) conversion paths in wide-range preheating temperature (700 °C −900 °C) for bituminous coal and anthracite were revealed during the preheated combustion. The conversion of fuel-N mainly underwent three procedures, including the conversion from fuel-N to char-nitrogen (char-N), tar-nitrogen (tar-N) and gas-nitrogen (gas-N) in the PCFB, the reduction from preheated fuel-N to N2 in the reduction region of combustor and the release of NOx from the char-N in the oxidation region of combustor. During the preheating, the highest conversion ratio from fuel-N to tar-N was 9.94% at the preheating temperature of 700 °C for bituminous coal. However, the conversion ratio from fuel-N to tar-N was below 2% for anthracite from 700 °C to 900 °C. Most of fuel-N was transformed into char-N and N2 during the preheating. Although higher preheating temperature promoted the conversion of fuel-N during the preheating, the reduction of char-N was inhibited due to the lower temperature of reduction region in the combustor for anthracite. The lowest concentration of NOx emission was 226.01 mg/m3(@ 6% O2) at the preheating temperature of 850 °C for anthracite.

Single‐switch coupled‐inductors‐based high step‐up converter with reduced voltage stress

AbstractThis paper proposes a non‐isolated DC‐DC high step‐up converter. To achieve a high voltage conversion ratio and overcome the problems related to near unity duty‐cycle of the conventional boost converter in high step‐up applications, coupled‐inductors along with switch‐capacitor techniques are merged in this topology. The proposed converter provides continuous input current with low ripple without using any current ripple cancellation method and the voltage across the switch is limited inherently. In order to reduce the control circuit complexity, the proposed converter uses only one switch. These features decrease the complexity of the proposed converter structure. The voltage stress of the semiconductor components is reduced significantly; thus, high‐quality elements (fast power MOSFET switches with low on‐state resistance and Schottky diodes with low forward voltage drop along with low power losses) can be used, which minimizes the switching and conduction losses and improves the converter efficiency. To confirm the converter operation and theoretical analysis, a 200‐W prototype converter with 24‐to‐200‐V input and output voltages operating at 100‐kHz is implemented in the laboratory.

Negative Photochromic 3-Phenylperylenyl-Bridged Imidazole Dimer Offering Quantitative and Selective Bidirectional Photoisomerization with Visible and Near-Infrared Light

Selective bidirectional photoisomerization reactions with high conversion ratios between stable and metastable isomers by irradiation of photochromic molecules with visible light of different wavelengths have been an important issue for many years. For negative photochromic molecules known so far, metastable isomers also absorb UV or visible light in the same region as stable isomers, making it difficult to selectively achieve the reverse reaction by visible-light irradiation. We have demonstrated that the absorption bands of the stable and metastable isomers of 3-phenylperylenyl-bridged imidazole dimer are largely separated by more than 140 nm and that almost quantitative and selective bidirectional photoconversion can be achieved by 660 and 460 nm light. Furthermore, the forward reaction can be achieved completely with near-infrared light of 785 nm.

Bipolar Membrane Electrodialysis for Cleaner Production of Diprotic Malic Acid: Separation Mechanism and Performance Evaluation.

Bipolar membrane electrodialysis (BMED) is a promising process for the cleaner production of organic acid. In this study, the separation mechanism of BMED with different cell configurations, i.e., BP-A, BP-A-C, and BP-C (BP, bipolar membrane; A, anion exchange membrane; C, cation exchange membrane), to produce diprotic malic acid from sodium malate was compared in consideration of the conversion ratio, current efficiency and energy consumption. Additionally, the current density and feed concentration were investigated to optimize the BMED performance. Results indicate that the conversion ratio follows BP-C > BP-A-C > BP-A, the current efficiency follows BP-A-C > BP-C > BP-A, and the energy consumption follows BP-C < BP-A-C < BP-A. For the optimized BP-C configuration, the current density was optimized as 40 mA/cm2 in consideration of low total process cost; high feed concentration (0.5-1.0 mol/L) is more feasible to produce diprotic malic acid due to the high conversion ratio (73.4-76.2%), high current efficiency (88.6-90.7%), low energy consumption (0.66-0.71 kWh/kg) and low process cost (0.58-0.59 USD/kg). Moreover, a high concentration of by-product NaOH (1.3497 mol/L) can be directly recycled to the upstream process. Therefore, BMED is a cleaner, high-efficient, low energy consumption and environmentally friendly process to produce diprotic malic acid.

Machine learning based fault detection and state of health estimation of proton exchange membrane fuel cells

In fuel cells, chemical energy is directly converted into heat and electricity without any emissions which makes them an attractive substitute for various energy needs. Fuel cells have high energy conversion ratio and high-power densities which make them suitable for automotive applications. However, these fuel cell systems suffer with low reliability and durability as system components develop faults during operation resulting in degradation and diminished system performance. In this context, fault detection and fault mitigation strategies are being extensively developed. Diagnostic approaches like electrochemical impedance spectroscopy, cyclic voltammetry, and galvanostatic analysis offer a truthful representation of the State of Health (SOH) of the fuel cell. However, these approaches are intrusive and require pausing the operation of the fuel cell effecting its integrity. Machine learning based fault detection and SOH estimation is a non-intrusive approach where a mapping function is established between the indicators and SOH. The SOH of a fuel cell can be correlated to the patterns in sensor signals or indicators. Indicators that influence SOH are cell voltages, current density distribution, impedance spectra, acoustic emission and magnetic fields. Developing an accurate fault detection and state estimation technique through data driven machine learning approaches will allow corrective measures to avoid irreversible faults and improve the reliability and durability of fuel cells.

A Broadband Transmissive Type Metasurface Cross-Polarization Converter for EMC Application

In this article, the design of a cross-polarization converter (CPC) using metasurface has been presented for electromagnetic coupling applications. The proposed structure is able to convert a linearly polarized incident wave into its cross-polarized counterpart over a wide frequency range covering the C, X, and Ku bands. The present structure is a transmissive type CPC consisting of a thin layer of periodic structure sandwiched between two orthogonally oriented metallic patterns. The simulation of the proposed structure has predicted a high polarization conversion ratio above 95% between 4.6 and 14.8 GHz. The structure has the periodicity of 0.17 λ, while maintaining an ultra-thin feature of 0.12 λ concerning the lower frequency of the conversion band. A prototype of the structure with 20 × 20 unit cells has been fabricated and experimentally tested for its propagation behavior. The simulated and the measured results are found to be in excellent agreement.