INITIATIVES

SLC workshops at pre-college engineering summer camp

SLC workshops EDUCUA Summer Camp

Keysight ADS workshop

Thesis proposal writing workshop

Student Leadership Council Organizational Meeting

Educua Summer Camp

Examining the Integration of CUA & DEI within CARSE Initiatives:

One of the objectives of the Center for Advanced Radio Sciences and Engineering (CARSE) is to provide opportunities for undergraduate and graduate students in STEM disciplines so they can further their career and research experiences. Moreover, CARSE includes an outreach component through a collaboration with the Center for University Access (CUA), which seeks to provide opportunities to bridge inequality gaps for underserved youths enrolled in public schools in Mayagüez. This investigation is centered on documenting the overall impact of the integration of social and educational justice and diversity equity and inclusion (DEI) content on CARSE/STEM participants. To achieve this, individual interviews, focus groups, observations and surveys will be administered. This research project will explore how the DEI and outreach components focusing on issues of social and educational justice impacts the research and work conducted by CARSE participants This poster will present the current stage of the project and the future plan for data collection and findings.

Educational Justice for Youth in Mayagüez:

The Center for University Access (CUA) is an educational justice initiative that began at the University of Puerto Rico-Mayagüez (UPRM) in 2007. Undergraduate and graduate students collaborate with faculty and other experts to support socioeconomically disadvantaged youth from Mayagüez. The school-level component offers free tutoring and mentoring as well as an interdisciplinary array of workshops aimed at fostering college aspirations of first-generation middle and high school students. The college-level component supports participants to ensure their retention, persistence and graduation from college. The Center provides a safe and inclusive space where aspiring first-generation college students can grow intellectually, professionally and personally as we promote college access and help them build an educational foundation for success in their university careers.

The purpose of this poster is to present the progress in developing a planar near-field system for characterizing the radiation properties of high directives antennas. Near-field measurements enable performance evaluation of large antennas at greatly reduced distances. A recently completed, planar near-field system with a 1 m x 1 m scan area. The work that is being conducted is the creation of a window application to create an automated system for said planar near-field system. The application is capable of controlling the scanner and acquisition instruments, storing data, and reusing previously stored near-field data as well as having the necessary controls for accurate prediction of the far field radiation. The methodology for this investigation consists of 1) building a 4-axis positioner system using parts from Velmex inc., 2) creating an automated program to control the positioner system. 3) Adding adsorber materials to the scanner system walls to reduce reflections and improve data quality, 4) Measuring the near-field characteristic of an AUT using a waveguide probe mounted on the 4-axis scanner.

Measurements made will be acquired by a 67 GHz Vector Network Analyzer controlled via Local Network, 5) Generating the far-field radiation pattern and extracting the antenna parameters from measured data using near-field to far-field transformation algorithms. A windows program is being developed in C with different window processes for the creation of the GUI for the system. Different tabs are created for ease of use for the different options. The expected outcome for this GUI being the creation of a processed signal with the collected information that is latter to be used in the creation of a plot chart, with the purpose of studying the electrical field generated by the radiation of the pair of antennas being used.

Radio frequency propagation measurements across wireless commercial bands (39 GHz, 28 GHz, Sub 6 GHz, Sub 3 GHz, and Sub 1 GHz) play a critical role when designing wireless networks. Understanding propagation characteristics allows more efficient  communication networks design, through base station placing for optimum coverage. Path loss and link quality measurements are both necessary to understand the system performance under different propagation environments. Through this project we propose to investigate the propagation characteristics at 1.9, 3.7, 28 and 39 GHz in different indoor and outdoor locations across campus, using Software Defined Radios (SDRs), signal generators and spectrum analyzers to measure the path loss and link quality.

This research presents a Low Noise Amplifier (LNA) design, operating between the L & S bands of the RF spectrum (1-2GHz & 2-4GHz respectively) using heterojunction materials. A comparison between Silicon (Si) and Gallium Arsenide (GaAs) is presented that covers
electron mobility and thermal noise, as well as a programmable level detector circuit to avoid external interference in Si. Migration from Si to GaAs is presented. Circuit simulations are illustrated with design parameter results.

This work outlines a methodology for designing feed networks for single and dual-polarized
aperture-coupled microstrip patch (ACMP) antennas with dual-offset microstrip feedlines. The challenge to be addressed is matching the antenna effective impedance to the feedline, which is an area with limited literature. This study demonstrated that ACMP antennas can be coupled to dual-offset feedlines with λ/4 transformers and T-junctions with infinite combinations of impedance for the λ/4 transformer. Equations were developed to relate the effective impedance to the feed geometry, allowing the design of the patch antenna’s feedlines. Using this approach, two 10 GHz ACMP antennas, with single and dual-polarization, were designed and implemented obtaining satisfactory excellent impedance matching and isolation and cross-polarization level.

This project consists in the development of a millimeter-wave receiver front-end, characterized by its Size, Weight, and Power plus Cost (SWaP-C) requirements. The front-end encompasses a low-noise amplifier and a self-oscillating mixer that will be seamlessly integrated with the antenna system. For the receiver design, a MMIC PH15 process based on a 0.15 microns gate Pseudomorphic High Electron Mobility Transistors (0.15 microns P-HEMT) technology from UMS has been selected. This is a type of field-effect transistor (FET) commonly used in high-frequency and have been shown to be ideal for the design of low-noise amplifiers (LNAs). The cascode topology was selected for the LNA, which makes it unconditional stable. Through parameter optimization, we successfully designed a Low Noise Amplifier (LNA) with a peak gain of 8.4 dB for single stage and noise figure of 0.75 dB. Additionally, a Voltage- Controlled Oscillator (VCO) was designed using the varactor diode model to generate frequencies with a bandwidth of 10 GHz. The subsequent phase involves integrating the VCO with the mixer in a current reuse topology. These advanced receiver systems are specifically tailored for employment within distributed spectrum monitoring systems, as well as integrated arrays designed for the purpose of interference mitigation.

Operations on a finite field are closed under summations and multiplications thus eliminating errors caused by rounding. This benefit of finite field arithmetic has the potential of improving signal-to-noise ratios for radio frequency interference (RFI) mitigation. We study the impact on performance of the use of finite fields on RFI mitigation algorithms. An implementation on a Field Programable Array (FPGA) is proposed to validate results with respect to traditional fixed-point or floating-point representations.

Water vapor is a greenhouse effect gas vital for atmospheric predictions. We use microwave radiometers to obtain water vapor profiles from the atmosphere by calculating brightness temperature, which reflects the energy absorption at specific frequencies, especially between the 22-30 GHz (K-band) range where the absorption rate of water vapor is higher. Vehicle collision radars, 5G New Radio, and FCC licensed bands emit signals within K-band range that can interfere with microwave radiometers, potentially distorting the water vapor profiles they are trying to measure. We propose a new method using autoencoders and transfer learning to deal with the mentioned interferences in order to obtain clean water vapor profiles

This research focuses on achieving real-time radio frequency interference (RFI) mitigation in astronomy signals. The study explores the use of Modified-LMS and Wavelet transformation for adaptive filtering across L to S frequency bands. Our aim is to develop a mathematical model that assesses the impact of algorithmic changes while detecting transient interference events with
a low mean square error (MSE) and a high signal-to-noise ratio (SNR). The effect of algorithmic variations on the estimation of spectral coefficients is evaluated in digital backend data processing, with special focus on the recognition of transient interfering events and monitoring of low-power spectral density scenarios in radio astronomy receivers. Hardware validation will be performed on a processing system with a radio frequency system-on-chip (RFSoC) and a graphics processing unit (GPU) as hardware accelerators.

The Atmospheric Science Testbed is based upon the Radiometrics MP3000A mm-wave radiometer at UPRM Physics Building for high-temporal resolution monitoring of coastal atmospheric boundary layer (ABL) of western Puerto Rico. A low SWaP, low-cost spectrum monitoring system from K- to V-bands (22-30 and 50-59 GHz) is being developed to check for RFI that could affect the radiometer observations.

We present details of the construction of a wideband, cryogenic receiver and its successful commissioning on the Arecibo 12m telescope. The cryogenic receiver works in the 2.5-14 GHz frequency range. The receiver is built around a Quadruple-Ridged Flared Horn (QRFH) developed by Akgiray et al. (2013)[2]. To mitigate strong radio frequency interference below 2.7 GHz, we installed a high-pass filter before the first stage low noise amplifier (LNA). The QRFH, high-pass filter, noise coupler and LNA are located inside a cryostat and are cooled to 15 K. The measured receiver temperature is 25 K (median value) over 2.5 to 14 GHz. The system temperature measured at zenith is about 40 K near 3.1 and 8.6 GHz and the zenith antenna gains are 0.025 and 0.018 K/Jy at the two frequencies respectively.

The planetary boundary layer (PBL) is a region of the atmosphere that is directly influenced by the Earth’s surface. The PBL height is important for a variety of atmospheric processes, including cloud formation, precipitation, and air quality. This study aims to determine the height and characteristic behavior of the PBL in western Puerto Rico. To do this, we will analyze data from the MP3000a radiometer located at the University of Puerto Rico, Mayagüez. This data will be used to determine and analyze variables such as the dew point, virtual potential temperature, and others. We will then develop an algorithm to calculate the PBL height as a function of time. This algorithm will be based on the stability of meteorological variables, and will use a neural network to make predictions. The results of this study will be made available to the meteorological community in real time through the website of the Puerto Rico Climate Office.

We are conducting a study of atmospheric opacity in the skies of Puerto Rico, based on the collection of meteorological profiles through the Radiometrics Corporation’s MP-3000A ground-based radiometer in the 22-30 GHz range. Various atmospheric components such as water vapor, aerosols, clouds, and dry air need to be considered in the calculations related to atmospheric opacity. The radiative transfer method with multiple absorption processes throughout the atmosphere can be characterized in terms of three fundamental absorption coefficients: the coefficient of dry air, the coefficient of water vapor, and the coefficient of water present in clouds. These coefficients are inherently linked to meteorological profiles. It is important to note that the absorption coefficient and opacity are closely connected. Opacity is the medium’s ability to allow the propagation of electromagnetic waves. The higher the opacity, the lower the capacity for wave propagation. The results of this work allow us to calculate opacity on a quasicontinuous basis at the site of the radiometer.

Dr. Jorge Morales Ortiz, University of Puerto Rico at Río Piedras, Survey of outflow-envelope interactions in low-mass protostars in the Orion A molecular cloud, This project will provide an unprecedented observational dataset that will be used to study the evolution of the dense circumstellar gas associated with the star formation process. The low-mass protostars in the dataset were chosen because they are located in the same molecular cloud, which ensures a consistent resolution in the ALMA observations and the existence of the same ancillary data for all of them, therefore guaranteeing a consistent analysis. The rich dataset, which will allow us to address the challenges previously described, are essential steps to understanding the star formation efficiency in molecular cloud cores and the origin of stellar masses. jorge.morales15@upr.edu

Dr. Mayra Lebrón Santos and Dr. Carmen Pantoja Pantoja, University of Puerto Rico at Río Piedras, CARSE Visiting Scientists Program. The CARSE Visiting Scientists Program promotes the visit of scientists who are experts in areas of interest of the astrophysics group at UPR-Río Piedras and promoted by CARSE. The visiting scientists will contribute to the training of faculty and students and give talks to the community at large. These visits also aim to promote new collaborations among colleagues. This program will expose new areas of research related to astronomy for project participants. Visiting scientists will teach mini-courses, workshops and seminars for the students and scientific community at UPR and beyond. mayra.lebron3@upr.edu, carmen.pantoja1@upr.edu

Dr. Emmanuel Morales Butler, University of Puerto Rico at Utuado, Radio Frequency Interference (RFI) mitigation at S-band with Statistical Techniques, The 3.3-GHz transitions of the Methylidyne (CH) molecule are important for understanding the interstellar medium of our galaxy, yet they lie in a frequency range that is particularly polluted by radio transmissions of common devices. The commissioning projects for the upgraded 12-m antenna at the Arecibo Observatory site demonstrated that the S-band environment is no different there than elsewhere– RFI contamination is prominent. In an effort to salvage RFI-affected data from the commissioning studies, we developed an imple- mentation of a statistical method, known as the Generalized Spectral Kurtosis (GSK) Estimator, to confront this issue, maximize the use of our existing data, and preserve the utility of future data. emmanuel.morales13@upr.edu

Dr. Desiree Cotto Figueroa, Dr. Alex J. Camacho Martínez, University of Puerto Rico at Humacao, Radio Astronomy at the UPR Humacao Astronomical Observatory. Establishment of an L-band Educational 3.7 m Radio Telescope Facility at UPR Humacao to establish a radio astronomy educational and research training component and provide a much needed hands-on introduction on radio astronomical techniques. This will allow the team to attract, train, and retain students into STEM fields and to also naturally complement the research training of the UPR Humacao Astronomical Observatory. desiree.cotto@upr.edu, alex.camacho@upr.edu 

Neurodiversity – Oct. 2022

Racism and Racialization in Puerto Rico – 7 March

Inclusive Language: What is it and how to use it – 13 April

Women in Research and Academia – 18 April

Gender Identity and Sexual Orientation – 25 April

DEI Bootcamp – 6-8 June