Alexis Gomez

Handheld Microwave-Based Scanner for Foodborne Pathogen Detection

Senior Design Project

• Designed and built a handheld microwave sensing device using a NanoVNA (50 kHz–6.3 GHz), single PCB antenna, and Raspberry Pi control, enabling non-invasive reflection (S11) measurements for material and moisture characterizationSD1- Final (1)
• Developed fully automated measurement and classification workflows on Raspberry Pi, triggering VNA sweeps, processing S11 data, comparing results against stored reference stages, and providing real-time LED-based user feedback with a single button pressSD1- Final (1)
• Validated handheld performance against a $20,000 professional lab VNA, demonstrating 0.32–3.28% measurement error across multiple test objects, confirming the feasibility of low-cost microwave hardware for reliable electrical sensing applications

Improving the Quality of a Microwave Imaging System for Testing Small Live Animals

University of Central Oklahoma & University of Oklahoma Health Sciences Center

• Designed and implemented an automated near-field microwave imaging system using Arduino-controlled motion, VNAs, and PCB antennas, enabling ~12-minute fully automated scans with <40 s image reconstruction per sample.
• Developed MATLAB-based signal processing and image reconstruction workflows (baseline subtraction, averaging, filtering, back-projection with Hann window) to improve image contrast, repeatability, and reconstruction speed.
• Reconstructed and analyzed 2D cross-sectional dielectric intensity maps for phantom samples, demonstrating material differentiation based on dielectric contrast and validating system performance.

Optical Spectroscopy for Early Detection of Food Quality and Decay

University of Central Oklahoma & University

• Conducted optical spectroscopy experiments to detect early-stage food degradation (e.g., apples) by measuring intensity and absorbance changes across selected wavelength ranges over time.
• Collected and processed multi-day, multi-trial spectral datasets, applying averaging and baseline correction to identify repeatable spectral trends associated with moisture loss and decay progression.
• Evaluated spectroscopy as a non-invasive, rapid sensing technique for food quality assessment, generating reference datasets to support comparison with microwave-based sensing methods.

Wireless Robotic Hand

• Designed and built a wearable robotic hand using flex sensors, servo motors, and a custom PCB, enabling real-time motion tracking and actuation.
• Implemented embedded control logic for sensor acquisition and motor response, with wireless communication for user interaction.
• Integrated an OLED display for system feedback and debugging during development and testing.