Power Divider Research Articles

A circularly polarized graphene based wideband 1 × 2 array antenna for terahertz spectrum applications

A graphene-based 1 × 2 array antenna with circular polarization for terahertz applications is prescribed in this article. Initially, a novel concept of a folded quarter wave impedance transformer is utilized in the design process of a single element for minimizing the overall antenna size. The opposite corners of the patches have been truncated and structural modifications are performed with the insertion of four flower-shaped slots along with an additional circular slot for achieving a much-improved reflection coefficient and better impedance bandwidth. It also shows a much wider 3 dB axial ratio bandwidth, confirming circular polarization due to the suggested modifications in its geometry. Then, an array antenna has been formed to provide better gain. The configured patches are fed by a magic-T power divider to attain the required impedance matching. The results of the CP antenna array have been analyzed using the HFSS and CST simulators. The propounded 1 × 2 array antenna shows circular polarization with a 3 dB AR bandwidth of 205 GHz (2.345–2.55 THz) and wide spectral coverage of 210 GHz (2.345 − 2.555 THz) along with a maximum gain of 8.65 dB and 99.8 % radiation efficiency with a total size of 53.5 × 102 × 1.56 μm3. It could be utilized for high-speed data transmission, material characterization, terahertz spectroscopy, terahertz imaging, etc. applications.

Planar Rectangular Microstrip Patch Antenna Array with Corporate-Feed Network for Gain Enhancement

Abstract: The design and performance analysis of a inset-fed planar rectangular microstrip patch antenna array with corporatefeed network systems is presented in this paper. This design aims to increase the gain of the rectangular patch antenna through the use of a 16-element planar rectangular antenna array. Each element in this planar array is fed by T-junction power divider networks with quarter-wave transformer lines via the corporate-feed method. The antenna is designed over the operating frequency of 2.4 GHz using the substrate material FR-4, which has a dielectric constant of 4.4 and a loss tangent of 0.002. By the addition of radiating patches in the array design, the gain, directivity and bandwidth also has been improved significantly. The proposed antenna array provides a gain of 9.284 dB, a directivity of 16.2 dBi, and a bandwidth of 0.361 GHz. The designed antenna can be used for wireless applications.

A Single Layer Low Axial Ratio Circularly Polarized Planar Wide-Angle Scanning Phased Array

This paper proposes a circularly polarized planar wide-angle scanning phased array radar. The structure of the proposed array element is a windmill-type patch with an octagon-shaped series power divider. The proposed array exhibits a low axial ratio because the element has a wide 3-dB axial ratio beamwidth and the array topology uses the sequential rotation technique. Test results show that the proposed 8 × 8 uniform planar array can realize two-dimensional circularly polarized scanning from −60° to +60° in the working band of 3.43–3.48 GHz. The coverage gains of θ = ±60° are about 3 dB lower than the gain when the main beam points at θ = 0°. Moreover, in the scanning mentioned above airspace, the scanning beam axial ratio is below 0.5 dB in the xz-plane (φ = 0°) and yz-plane (φ = 90°) and below 1.4 dB in the D-plane (φ = 45°). Another notable feature is the single-layer structure, and its profile is only 0.08λ0 at the center wavelength. This good low- axial ratio and low-profile characteristics make the proposed array potentially applicable to low-orbit satellite communications.

General characteristics of investment law in India

The aim of the work is a comprehensive analysis of investment law in India. The methodological basis of the study are official websites of specialized institutions, laws, analytical reports, articles by other scientists, etc. According to the results of the conducted research, it was found that two main legislative acts regulate investment activities in India. The first piece of legislation is the Foreign Exchange Management Act, 1999, the main objective of which is to promote foreign trade and foreign exchange and to develop and maintain the foreign exchange market in India. According to Section 5 and 6 of the Law, operations with a current currency account are allowed only on the condition that they do not have any restrictions (criminal, state, etc.). Capital account transactions mean transactions during which changes in assets or liabilities occur (referring to liabilities of resident and non-resident persons in relation to assets). The second act – Consolidated Policy on Attracting FDI in India by the Department of Trade and Industry Promotion 2020 – includes clarification of all investment norms. The policy update is in line with the policy of need to attract FDI to India, as per the plans of the Department. In conclusion, it was found that the legal system of India is based on common law, which is based on English law. According to the Constitution of India, a quasi-federal structure has been approved, which provides for the division of legislative power between the central government and the individual states. Foreign direct investment in India is governed by two main pieces of legislation. The first is the Foreign Exchange Management Act of 1999, its main objective is to facilitate foreign trade and foreign exchange and to develop and maintain the Indian foreign exchange market. The second – Consolidated policy on attracting FDI to India. Attracting foreign direct investment in India is possible in two ways: automatic investment of FDI and obtaining permission for FDI.

High‐selectivity wideband four‐way filtering power divider with input absorptive feature

AbstractIn the paper, a high‐selectivity wideband four‐way filtering power divider with input absorptive feature is presented. It consists of two parallel‐coupled lines (CLs), two three‐coupled lines (TCLs), two open‐ended stepped branches, one absorptive branch, and two isolation resistors. The wideband filtering response is achieved by cascading the TCLs and CLs. While high selectivity is obtained by loading the open‐ended stepped branch, where two extra transmission zeros are generated. In addition, wide absorptive bandwidth with good isolations between adjacent output ports are realized by combining the absorptive branch with the isolation resistors. Equations are derived by using the two‐parity mode analysis, and main parameters are investigated in detail. For validation, a prototype was designed and fabricated. Test results show that the 3‐dB FBW can reach 87% with a 10‐dB input absorptive FBW of 200%. Besides, for the output ports with 10‐dB return loss and 10‐dB isolation, the FBWs are 94% and 91.5%, respectively. It also features high frequency selectivity and low insertion loss.

Two CMOS Wilkinson Power Dividers Using High Slow-Wave and Low-Loss Transmission Lines.

This work presents two Wilkinson power dividers (WPDs) using multi-layer pseudo coplanar waveguide (PCPW) structures. The PCPW-based WPDs were designed, implemented, and verified in a standard 180 nm CMOS process. The proposed PCPW features high slow-wave and low-loss performances compared to other common transmission lines. The two WPDs are based on the same PCPW structure parameters in terms of line width, spacing, and used metal layers. One WPD was realized in a straight PCPW-based layout, and the other WPD was realized in a meandered PCPW-based layout. Both the two WPDs worked up to V-band frequencies, as expected, which also demonstrates that the PCPW guiding structure is less susceptible to the effects of meanderings on the propagation constant and characteristic impedance. The meandered design shows that the measured insertion losses were about 5.1 dB, and its return losses were better than 17.5 dB at 60 GHz. In addition, its isolation, amplitude imbalance, and phase imbalance were 18.5 dB, 0.03 dB, and 0.4°, respectively. The core area was merely 0.2 mm × 0.23 mm, or 1.8 × 10-3λo2.

A distributed coordinated control strategy for isolated AC microgrids based on consensus algorithm considering communication delay

AbstractIn the multi‐paralleled converter microgrid system, the traditional hierarchical control strategy can eliminate the bus voltage amplitude and frequency deviation from the rated value. However, isolated AC microgrids may face extreme scenarios such as communication delays and interruptions in data transmission due to the use of low‐bandwidth communication (LBC) lines. Additionally, the inconsistent line impedance of each distributed generation (DG) unit may result in the inaccurate division of reactive power in multi‐paralleled converter systems, thus affecting system stability. To address these issues, this paper presents a distributed coordinated control strategy for isolated AC microgrids based on the consensus algorithm. The proposed strategy first replaces LBC lines with a filter to alleviate the effects of communication delays. A small‐signal model is established in its state space, and stability of the microgrid system under the proposed control strategy is verified through eigenvalue analysis. Furthermore, based on the above theoretical analysis, a consensus algorithm is introduced, and a distributed control strategy for isolated AC microgrids based on the consensus algorithm is proposed to solve the issue of inaccurate equalization of the system's reactive power. Finally, factors that influence the dynamic convergence performance of the consensus algorithm are analyzed through simulation in PLECS software. Also, the maximum tolerable communication delays of the microgrid system under different communication topologies are also compared, and the system's robustness is evaluated under the condition of sudden communication interruption in a DG unit and sudden weather variation. These analyses confirmed the robustness of the proposed strategy against communication delays, output power fluctuation, and communication interruptions.

Compact circular Wilkinson power divider for wireless applications

Abstract This manuscript introduces an innovative 1-to-4 modified Wilkinson power divider designed to operate at a frequency of 3.5 GHz. The configuration of the proposed divider is fabricated on Rogers RT/Duroid 5,880, featuring a relative permittivity of 2.2 and a thickness of 0.565 mm, respectively. The circular shape employed in the design minimises size and enhances power handling capability. To achieve a 4-way power division with equal power distribution at each output port, a 1:2 power divider at 3.5 GHz is cascaded. Furthermore, we present and analyse a 1:4 WPD implemented on a microstrip line utilised as a power supply for measuring a four-port MIMO antenna. This divider exhibits excellent impedance matching at all ports and consistent phase and amplitude characteristics between the output ports. The performance metrics of the presented divider, as detailed in both experimental and simulated results, include a return loss of 27.92 dB (1:2) and 29 dB (1:4), isolation of 33.046 dB (1:2) and 35.56 dB (1:4) and insertion loss of 3.17 dB (1:2) and 6.6 dB (1:4) respectively. These proposed power dividers hold potential applications in microwave and communication systems, mainly where power division is imperative with minimal signal loss and robust impedance matching.

Design of a microstrip Wilkinson power divider using a low pass filter with the particle swarm optimization algorithm

In this paper, a microstrip Wilkinson power divider (MWPD) based on particle swarm optimization (PSO) algorithm is designed, simulated, and fabricated using novel resonators. In addition, attenuators and open-ended stubs are incorporated to generate a broad cut-off band and reduce unwanted harmonics. The proposed power divider has a central frequency of 1 GHz. The performance of each used resonator is analyzed based on lumped-element circuit models.The L and C parameters of the equivalent circuit of the used resonators are predicted and optimized with the assistance of the PSO method. The subsequent phase was the fabrication of the proposed MWPD, after which its performance was evaluated in the light of the results obtained from the simulation. It was discovered that there was a high degree of concordance between the two. On the other hand, the fabricated circuit has several benefits, including a suitable S12 of − 3.15 dB, a high return loss of less than − 24 dB at the operating frequency, a compact size of 0.058 λg\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\varvec{\\lambda}}_{{\\varvec{g}}}$$\\end{document} × 0.064 λg\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\varvec{\\lambda}}_{{\\varvec{g}}}$$\\end{document}, and the ability to remove undesired harmonics. The results show a high level of suppression of the unwanted harmonics (up to the 16th harmonic) and a great responsiveness in the passband, while having very low ripple. As a result, the proposed circuit may be used in a wide variety of electronic devices, such as radar transmitter and receiver circuits, and many other high-frequency systems.

Broadband Eight-Way High-Isolation Cavity Power Divider with Low Insertion Loss for MIMO Communication Systems

Broadband Eight-Way High-Isolation Cavity Power Divider with Low Insertion Loss for MIMO Communication Systems

Compact circular microstrip 1:4 power divider/combiner with defected ground plane

This letter presents a methodology for the design of high-performance miniaturized Circular Power Dividers (CPDs) for wideband applications. To accomplish this objective, annular slots are strategically incorporated into patch and the ground plane of CPDs. This, in turn, increases the effective path length of the surface current flowing across the patch. This yields miniaturization, improved impedance matching, reduced insertion loss and increased isolation over a larger bandwidth. A mathematical model is developed for the design of the proposed configuration called Circular power dividers with Defected Ground Plane(CDGP). The presented model has been verified through various simulations and practical measurements. By implementing this approach, a substantial miniaturization of approximately 83% and more than threefold increase in bandwidth has been achieved when compared with non-slotted CPDs. Moreover, there is improvement in insertion loss, isolation, and return loss as well. There is good agreement between the mathematical model, simulation results and measured parameters.

Compact, wide-stopband filtering power divider based on a single shielded circular patch resonator

Compact, wide-stopband filtering power divider based on a single shielded circular patch resonator

A novel design of a Wilkinson power divider based on the circular-shape resonator

Abstract This paper describes the general properties of power dividers, in particular matching and isolation. This original works relates to three different divider structures based on the circular-shaped resonator. These prototypes resemble the Wilkinson power divider due to their geometric configuration. These power dividers provide very good isolation between their output ports of −51.26 dB. In fact, the originality of these new structures stems from the idea of minimizing the size of this classic power divider. The required design parameters for the three proposed dividers came from a simulation study using the Ansoft HFSS tool in addition to a design theory. The experimental prototypes are well presented and operate at 2.4 GHz. They demonstrate excellent performance in adaptation, which refers to impedance matching, ensuring consistent impedance at the component terminations. Additionally, they exhibit low insertion losses and high isolation at 2.4 GHz. The measurement results agree well with those of the simulation. The benefits demonstrated by this study are significant, justifying the preference for these components.

Building a Robust Federalism in India: Constitutional Provisions, Practical Challenges, and Pathways to Overcome

This study explores the intricacies of India's federalism, examining both the actual challenges encountered in implementing the system and the legal structure that establishes and governs it. The Indian Constitution aims to establish a balance of authority and responsibility between the central and state governments. It combines unique characteristics of unitary government with federal government. This study looks at the key constitutional provisions and amendments that specify the organizational structure of the federal government, including the division of legislative power, budgetary relationships, and administrative processes. Federalism cannot actually be implemented in India due to significant barriers, despite a constitution designed to maintain a careful balance. Administrative inefficiencies, political tensions, and economic disparities sometimes lead to strained relations between centers and states. This essay looks at these problems, highlighting instances of conflict and cooperation between different levels of government. This study aims to understand the evolution of Indian federalism by a critical analysis of case laws, policy decisions, and intergovernmental discussions. The paper also covers the effects of regionalism, coalition politics, and economic liberalization on the federal framework. The study aims to provide a comprehensive understanding of the practical aspects of constitutional federalism and the necessary modifications to enhance its efficacy by means of an examination of these characteristics. The findings underscore the necessity of continuous deliberation and adaptation to ensure that India's federalism is resilient and responsive to the aspirations of its diverse citizenry.

Konstitusi Myanmar Tahun 2008: Pembagian Kekuasaan Antara Sipil-Militer pada Masa Pemerintahan Sipil Usdp (2011-2016) & Nld (2016-2021) di Myanmar

This study aims to analyze civil-military relations during the USDP and NLD governments, as well as analyze the democratic transition in Myanmar that led to the division of power during the civilian rule. This research was conducted using qualitative research methods. That is, a method that is used by providing an overview of the problem being discussed by arranging the facts in such a way that it forms a configuration of the problem that can be understood clearly. This approach has an assumption by seeing social reality as an ever-changing condition and is the result of social construction between actors and social institutions. As a result, under the 2008 Constitution, the military in Myanmar remains dominant in security and defense with 25% of legislative seats reserved for the Tatmadaw. This division of power is unequal, resulting in military dominance, as the democratic transition is controlled by the military through a "seven-step roadmap to democracy," without the significant role of the NLD. Civilian control over the military during the 2011-2021 civilian rule was not achieved, with the military having sovereign authority in top-down policies and weak political representation.

High gain quasi-omnidirectional dipole array fed by radial power divider for millimeter-wave IoT sensing

This article presents the design and implementation of a dipole array antenna based on a radial waveguide power divider for millimeter-wave IoT sensing applications. The dipole array and radial waveguide power divider techniques are used in tandem to achieve high gain with omnidirectional radiation properties. The proposed antenna is comprised of eight non-uniform array dipole structures, a circular radiating loop, and shorting vias. The one-to-eight power divider is created with the shorting vias to feed the circularly arranged eight non-uniform dipole arrays simultaneously. The proposed antenna is simulated and manufactured on Rogers-RO3003C substrate with a thickness of 8 mils. Both simulated and tested results confirm that the proposed method enables the antenna to offer a quasi-omnidirectional pattern with a high peak gain of 5.42 dBi. The antenna offers an impedance bandwidth (S11 < ‒ 10 dB) of more than 1 GHz ranging from 27.93 to 29.13 GHz. Moreover, by optimizing the parameters of the power divider network the proposed antenna can be tuned between a wide bandwidth range of 14.53 GHz as the designed dipole array offering the operating bandwidth from 25.56 to 40.09 GHz. Due to its comprehensive set of performance attributes, particularly for the quasi-omnidirectional radiation characteristics, the presented antenna is a viable candidate for the 5G millimeter wave wireless IoT sensing applications. Additionally, this work will accommodate other researchers to explore the proposed method for developing high-gain omnidirectional antennas for millimeter-wave applications.

Constitutional Court Decree No 90/Puu-XII/2023 Provisions on Age Requirements for Presidential and Vice Presidential Candidates in the Principles of the State of Law and Pancasila Democracy

Purpose: This study aimed to determine whether Constitutional Court Decision Number 90/PUU-XII/2023 concerning the Age Requirements for Presidential and Vice Presidential Candidates is in accordance with the principles of the rule of law and Pancasila democracy. Method: This article was prepared using normative juridical research methods with statutory, case, and conceptual approaches. In this approach, several primary legal materials are used, namely statutory regulations that are relevant to the object of study, especially Constitutional Court Decision Number 90/Puu-XII/2023. In addition, the researcher used a case approach to understand the decidendi ratio, namely the legal reasons used by the judge to arrive at his decision, and a conceptual approach used by the researcher to understand the concept of the rule of law and the democratic principle of Pancasila, which refers to the doctrine that developed in the views of the Ulama or legal doctrine. Results: The results of this research indicate that the procedures or mechanisms for implementing Constitutional Court Number 90/Puu-XII/2023 concerning Age Requirements for Presidential and Vice Presidential Candidates must be in accordance with the procedures regulated in the constitution as a concept of a legal state (rehstsstat) where there is a division of power. From this concept it can be seen that the decision of the Constitutional Court Number 90/Puu-XII/2023 concerning the Age Requirements for Presidential and Vice Presidential Candidates violates authority because the decision is an open legal policy entrusted by the drafters of the third amendment to the Constitution 1945 to the legislators to "... be further regulated by law based on Article 6 paragraph (2) of the 1945 Constitution of the Republic of Indonesia.

Substrate-Integrated Cylindrical Cavity Controlled Hexa-Polarization Flexible Cylindrical Dielectric Resonator Antenna for Ku-Band Applications

A substrate-integrated cylindrical cavity (SICC) fed polarization flexible cylindrical dielectric resonator antenna (CDRA) is presented in this literature. To excite the CDRA, a unique and simple feeding approach based on substrate-integrated waveguide (SIW) technology is demonstrated. This SICC is fed by two 50Ω microstrip lines, oriented orthogonally to each other. The SICC with a cross slot on its top metalized surface and the TM110 mode excites inside it act together to couple energy efficiently to the CDRA. Applying different phase combinations signals at the two input ports of the SICC, the CDRA can radiate in four different orientations linear polarization (LP) (along φ = 0°, 45°, −45°, and 90° ), left-handed circular polarization (LHCP), and right-handed circular polarization (RHCP). A conventional cylindrical dielectric resonator having relative permittivity ϵd = 10 is preferred. Its diameter, height, and cross-slot dimensions are optimized to operate the CDRA over Ku-band with 12% impedance bandwidth, 2-dB axial ratio (AR) bandwidth of 11%, and 3-dB gain bandwidth of 12%. In this operating band, CDRA resonates at three different higher-order modes (HEM32δ, HEM113, and HEM12δ+2) with 8 ± 1.6 dBi/dBic gain for all the polarization states. The measurements of this antenna are conducted using two external phase shifters and one power divider.

A tunable versatile metasurface in terahertz frequency based on graphene–metal hybrid structures

The increasing demands for device integration and reusability have led to the development of freely switchable and dynamically tunable diverse functions in both modern optics and wireless communications. This study proposes a versatile metasurface that integrates with four tunable functions in the terahertz region based on graphene patch and metal split-ring hybrid structures. By adjusting the Fermi level of the graphene patches through electrostatic gating, the proposed metasurface can effectively achieve free switching among four different functions and dynamic tuning of each function's characteristics over a broad frequency band. Moreover, the metasurface operates smoothly in reflection mode for x-polarization, y-polarization, and left-hand and right-hand circular polarization illuminations. All expected performances, including resonant absorption with tunable frequency (relative bandwidth is about 20 %) and regulable absorbance (from 10 % to 100 %), arbitrary interconversion of four polarization states (relative bandwidth is over 48 %), regulation of cross-polarization conversion rate (from 0 % to 100 %), tunable spatial power division (three-way outputs), and dual-channel high-efficiency signal modulation (modulation depth is over 81 %), are demonstrated through full-wave simulation experiments. This study opens up a new avenue for exploring tunable multifunctional integrated devices with graphene materials, with potential applications in various domains, such as wireless communication, terahertz sensing, and imaging.

Design and Implementation of a Microstrip Six-Port Reflectometer (SPR) with Enhanced Bandwidth

A compact microstrip six-port reflectometer (SPR) with extended bandwidth is proposed in this paper. The design is based on using 16-dB multi-section coupled line directional couplers and a multi-section 3-dB Wilkinson power divider operating from 1 to 6 GHz. The proposed SPR employs only two calibration standards: a matched load and an open load. As compared to other dielectric substrates, fabricating the proposed SPR involves using a low-cost (FR4) substrate. A novel algorithm is also proposed to estimate the complex reflection coefficient over the frequency ranges at which the standard performance of the circuit components is not fully satisfied. The new algorithm is based on the circles’ intersection points, which have been derived from basic SPR equations, to estimate the complex reflection coefficient. To validate the SPR performance, a multiband microstrip patch antenna has been measured and the resulted reflection coefficient is compared with those obtained using a vector network analyzer (VNA). Results show that the proposed SPR provides a good estimation of the complex reflection coefficient within the frequency range of 1 GHz to 8 GHz. Owing to its compact size and ease of fabrication, the proposed reflectometer is suitable for various microwave broadband applications.