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The purpose of this research is to efficiently separate incident terahertz (THz) waves into distinct transmission and reflection channels by minimizing the absorption ratio. So, the optical systems operating within the THz frequency range can developed. To achieve a multi-band response, four different periodic arrays of graphene patterns are used. These arrays are strategically stacked on both sides of three SU-8 photoresists, serving as dielectric materials. Consequently, each layer exhibits a unique influence on the device's response, and by applying four external bias voltages, the behavior of the device can be precisely controlled and adjusted.

A novel optoelectronic device operating in the THz frequency range is introduced, using periodic arrays of graphene patterns and SU-8 photoresist dielectrics. The design of this device is based on meta-surface principles, using both the equivalent circuit model (ECM) and transmission line concept. The output of the device is a THz coupler implemented by analyzing the reflection and transmission channels. The structure is characterized using the ECM and validated through comprehensive full-wave simulations. By representing the electromagnetic phenomenon with passive circuit elements, enabling the calculation of absorption, reflection and transmission through the application of the theory of maximum power transfer.

Based on simulation results and theoretical analysis, the proposed device exhibits sensitivity to gate biasing, enabling efficient reflection and transmission of THz waves. The device achieves reflection and transmission peaks exceeding across the five distinct THz bands 90%, and its behavior can be tuned by external gate biasing. Moreover, the device's sensitivity to variations in geometrical parameters and chemical potentials demonstrates its reliable performance. With its outstanding performance, this high-performance meta-surface emerges as an ideal candidate for fundamental building blocks in larger optical systems, including sensors and detectors, operating within the THz frequency band.

The proposed device covers a significant portion of the THz gap through the provision of five adjustable peaks for reflection and transmission channels. Additionally, the ECM and impedance matching concept offers a simplified and time-efficient approach to designing the meta-surface. Leveraging this approach, the proposed device is effectively represented using passive circuit elements such as inductors, capacitors and resistors, while its performance is validated through the utilization of the finite element method (FEM) as a full-wave simulation tool. This combination of circuit modeling and FEM simulation contributes to the robustness and accuracy of the device's performance evaluation.

The purpose of the present study is to investigate the antecedents of export performance and branding advantage, as a key type of competitive advantage in export markets among entrepreneurs and managers of agri-food exporters.

A sample of entrepreneurs from 182 exporting firms of the agriculture and food industry participated in a cross-sectional survey. The data were collected by a self-reporting questionnaire and partial least squares were used to analyse the data and assess the path model.

Results revealed that experiential resources strongly promote communication capabilities. Also, communication, distribution and product development capabilities contribute to the creation of the branding advantage in export markets. In addition, a positive relationship between the branding advantage and export performance of agri-food products is confirmed.

The study targets exporters of agri-food products. Hence, the results should be interpreted regarding the context of low-technology firms. Further, this paper delineates branding advantage considerations that managers need to account for to achieve effective exporting. Practitioners can efficaciously exploit resources to achieve a competitive advantage, considering that they focus on building capabilities, and in particular, communication capabilities.

The present study highlights the role of the branding advantage as an important type of competitive advantage in international entrepreneurship and export markets. It attempts to examine the combined relationships of resources and capabilities with branding advantage and export performance.