Cumbajín Alferez, Myriam
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Preferred name
Cumbajín Alferez, Myriam
Main Affiliation
Ambato
Email
myriamcumbajin@uti.edu.ec
ORCID
Scopus Author ID
57198450868

Research Output
Now showing 1 - 10 of 19
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Low-Cost Signal Generator: Design and Implementation

2025 , Sharon Solano , Kevin Diaz , Carlos Gordon , Cumbajín Alferez, Myriam

This document meticulously details the design and implementation process of a Low-Cost Signal Generator using the AD9833 module. This device can generate sinusoidal, triangular, and square signals with a high degree of precision, making it ideal for applications in electronics laboratories and educational projects. The methodology employed is divided into four main stages: circuit design, simulation, fabrication, and characterization tests of the signal generator. Operational tests demonstrated that the generator meets the design specifications, producing stable signals in a frequency range of 0.1 Hz to 12.5 MHz. The features of the AD9833 module allow for flexible configuration of waveforms and frequencies, facilitating its use in various testing and development applications. This work was developed to provide a solid foundation for the creation of economical and efficient signal generators, thus contributing to the accessibility of advanced tools in educational and research environments.

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Hybrid Storage System Based on Rectenna and Photovoltaic Cells for Low Power IoT Wireless Devices

2023 , Cumbajín Alferez, Myriam , Valle M. , Gordón C. , Peñafiel C.

This article presents the results of a research project, in which a system for harvesting Radio Frequency energy in the Wi-Fi frequency and a system for harvesting solar energy were developed, later they were connected. The two voltage sources collected in series to add them and an MT3608 circuit was added to its output, to have a regulated voltage between 5 to 27 V at the system output and charge a 3.7 V lithium battery at 300 mA, and a 9 V battery. The antenna that was designed was a patch-type Sierpinski carpet until the second interaction, which together with a two-stage Cockcroft Walton multiplier is improved to acquire up to 254 mV, the solar panel on the other hand was a 6 V at 150 mA, when implementing the entire system, 27 V were acquired at the output, a voltage that, thanks to the MT3608 regulator, can be regulated to obtain a sufficiently voltage at the output of the system. To carry out several systems loads tests in different day conditions such as: cloudy, sunny and at night, managing to charge 90% 3.7 V and 9 V batteries in 4 h. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

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Multiband Microstrip Antennas for Energy Harvesting Systems

2022 , Gordón C. , Criollo W. , Cumbajín Alferez, Myriam , Peñafiel C.

In this paper, the development of two microstrip antennas for electromagnetic energy harvesting systems is presented. The first one, is the Hybrid Resonator Planar Structure Antenna operating at a specific 900 MHz frequency, while the other is an Archimedean Spiral Multiband Antenna working in a frequency range of 1 to 3 GHz, both were developed for energy harvesting systems. Both antennas were designed using CST Studio software and fabricated in a low cost FR4 substrate with a thickness of 1.6 mm, dielectric constant of 4.4 and an input impedance of 50 Ω. The frequencies achieved with the antennas are very promising, as it offers good performance for electromagnetic energy harvesting applications since it operates at standard frequencies such as GSM, Wi-Fi, LTE and UMTS which are available in the environment and allow us to harvest energy at any place and any time. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.

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Rectenna Patch-Type Array for Capture of Electromagnetic Energy

2024 , Cumbajín Alferez, Myriam , Sánchez, Patricio , Fausto Tello , Carlos Gordón

This research project is focused on gathering information on rectennas, as well as on patch antenna arrays for Energy Harvesting Systems designed at frequencies up to 3 Ghz, in addition to a simulation and implementation of a rectenna consisting of elements and technology suitable for electromagnetic energy harvesting systems; and at the same time analyze the results obtained from the tests carried out in order to demonstrate its efficiency in the aforementioned systems. The design of this prototype was made in Ansys HFSS software, which allowed us to make a 2×2 array of rectangular patch antennas, in which λ/4 transformers are used to couple the transmission lines to a characteristic impedance of 50 Ω; at the same time the design of a multiplier and voltage rectifier for high frequencies is also performed, in this case for 2.4 Ghz; in such a way that by joining the antenna array with the rectifier, a useful rectenna for electromagnetic energy collection is obtained.

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Biosignal Monitoring System Through an Interface to Optimize People’s Emotional Well-Being

2025 , Kevin Gamboa , Dario Guaman , Carlos Gordon , Myriam Cumbajin

This document presents the development of a Node-RED application with an interactive graphical interface for the visualization of emotional biosignals, allowing users to monitor and analyze their emotional state. The objective is to record relevant information on the implementation of algorithms in real time and the integration of sensors such as the MAX30100 and AD8232 ECG, together with an ESP32 and electrodes to take the samples, in order to identify emotional patterns using predefined thresholds. The aim is to optimize the efficiency of the system by improving biosignal transmission algorithms, minimizing resource consumption, and guaranteeing fast and fluid visualization of emotions on OLED screens, to improve the overall user experience. In this study, a methodology divided into four phases was used: research, development, integration, and optimization. Once the application was implemented, the results obtained in the identification of emotional patterns were compared and the algorithms that offered the best performance were optimized. Finally, an intuitive graphical interface was created in Node-RED that allows users to efficiently visualize and monitor their emotional biosignals, functioning as a tool to optimize people’s emotional well-being.

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Health and Educational Impacts Reduction Using a Supervisory Control and Data Acquisition Web System

2018 , Davila L. , Robalino F. , Gordon C. , Cumbajín Alferez, Myriam

We present the design and implementation of a Supervisory Control and Data Acquisition SCADA web system of pollution factors such as Nitrogen Dioxide (NO2), Carbon Dioxide (CO2) and Carbon Monoxide (CO) in order to manage them, providing comfort in indoor environments. The SCADA web system allows a comparative analysis of the recorded information with the alert, alarm and emergency levels, established in the Ecuadorian air quality regulations, annex 4 of Book VI of the Unified Legislation of Secondary Legislation of the Ministry of the Environment., The SCADA web system performs the comparison of the registered information, with the physical agents of environmental comfort, established in the ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers) standards. In the process of stabilization of the pollution factors, in indoor environments, air ionizers are used, which emit negative ions to maintain the standardized range in micrograms per cubic meter (3). Finally, we have been able to develop a SCADA web system for controlling pollution factors in indoor environments thanks to the integration of firebase (Android Studio), authentication (Facebook), notification (Database and Web Server), control and monitoring (Android Studio) interfaces. Besides, the SCADA web system allows preventing long term health problems such as allergic reactions, physical exhaustion and respiratory diseases, which influence academic performance during study days in educational institutions. © 2018 IEEE.

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Technical Comparisons of Antennas at a Frequency of 3 GHz

2024 , Yessika Jaramillo , Alex Calle , Cumbajín Alferez, Myriam , Carlos Gordón

This paper presents a detailed performance comparison between two widely used antenna types: the Patch Antenna with Insert Field and the 1×4 Linear Array, operating at a frequency of 3 GHz. Using Ansoft Designer software, simulations and modeling were conducted for both antennas, analyzing key parameters such as directivity, gain, reflection coefficient, and radiation pattern. The results show that the 1×4 Linear Array exhibited higher directivity and gain compared to the Patch Antenna with Insert Field. Furthermore, the 1×4 Linear Array demonstrated greater flexibility in controlling the beam pointing angle. On the other hand, the Patch Antenna with Insert Field stood out for its ease of implementation and its capability for more omnidirectional radiation

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Software for Horns, Reflectors and Antennas in RF Circuits

2024 , Jorge Unapucha , Ruales, María Belén , Carlos Gordón , Cumbajín Alferez, Myriam

The software developed in Python, fulfills the main objective of facilitating the calculation, graph, design and analysis of horns, reflectors and antennas. Through an intuitive and dynamic graphical interface, with text boxes, users can enter calculation parameters, among which can be the operating frequency, physical dimensions and electrical characteristics, this depending on the type of element that is or will be manipulated within the software, this to configure and observe the different values of the metrics of the different elements of the circuit. The program has numerical modeling and simulation algorithms that allow the analysis of the behavior of horns, reflectors and antennas in the radio frequency domain. Among the aspects evaluated are the radiation, gain, directivity, efficiency and bandwidth of the devices

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Machine Learning Algorithms for Filtering Data Acquired by Arduino

2024 , Mateo Llerena , Jessica López , Cumbajín Alferez, Myriam , Carlos Gordón

In this paper, we developed an artificial intelligence-based data filtering algorithm to improve the accuracy and reliability of MPU6050 sensor measurements. Using the Edge Impulse platform, we trained and optimized the machine learning model for real-time processing of accelerometer and gyroscope readings. The solution was implemented on the ESP32 with a sampling rate of 600 Hz. The experimental results validated the effectiveness of the solution, highlighting its relevance in applications requiring real-time monitoring

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Multiband Broadband Modulator Implementation on Field-Programmable Gate Array

2020 , Castro, C. , Gordón, C. , Encalada, P. , Cumbajín Alferez, Myriam

The proper management of resources available in FPGA’s is one of the main issues that designers must consider when implementing a high bandwidth communications system. For this reason, we report the hardware-efficient implementation, for mapping stages and pulse shaping, of broadband multi-level QAM signals, in Field-Programmable Gate Array (FPGA) devices. The process for designing the system is based on the large capacity of analog-digital (ADC) converters that exist today, in this case the ADC has a sampling rate of 5 GSPS, which allows the transmission of signals with bandwidths of about 2.5 GHz. The model implements in the same polyphase FIR structure multiplier-less the mapping schemes Q-PSK, 16-QAM, 64-QAM y 256-QAM together with the RRC filter. As a result, this implementation shows that the proposed architecture eliminates the use of dedicated multipliers which would be around 3150 if conventional methods were used. The Error Vector Module is used as a figure of merit in the selection of the RRC filter and the digital quantization levels. We achieved the target frequency for hardware operation at 312.5 MHz con un factor de interpolation de 16 and an EVM < 2%. Also, Hardware Description Language (HDL) models are validates in test benches with reference to the finite precision models of Simulink. © 2020, Springer Nature Switzerland AG.

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