Mohamed Mohamed

Lower Hybrid Transmitter at DIII-D National Facility 4.60 GHz

• Conducted overhaul of existing low level RF source to drive to eliminate amplitude and phase errors at high attenuation
• Upgraded RF source design with modern oscillators, amplifiers, attenuators, and phase shifters
• Designed methods with improved accuracy of controlling and measuring amplitude and phase difference between klystron tubes at 10 MHz to minimize cables losses and temperature dependence at higher frequencies
• Modeled multiple chassis to house RF components and connectors on SolidWorks
• Assembled RF source in a standalone rack with independent power supplies
• Successfully commissioned and integrated rack with transmitter overall control system

Lower Hybrid Transmitter Assembly

• Oversaw Lower Hybrid 2 MW disassembly at MIT
• Successfully reassembled transmitter at General Atomics facility
• Performed analysis for high voltage power supply (50 kV, 208A) water load by using a mixture of DI and tap water to vary resistance of the load

Ion Cyclotron Range of Frequencies (ICRF) 2 MW 120 MHz

• Analyzed multiple vendor proposals for 175 kW solid-state driver amplifier
• Oversaw multiple peer reviews and FAT of sub-stages of solid-state amplifier
• Worked on converting two 40-80 MHz tube amplifier stages (100 kW and 2 MW respectively)
• Modified resonant RF cavity structures to tune to 120 MHz
• Successfully operated 100 kW stage using control ladder after 10 years without operation

Reconfigurable and GPU Computing Lab

• Researched coexistence of Wi-Fi, LTE, and ZigBee protocols using a single RF front-end as part of my Master's thesis
• Developed spectrum coexistence methods to receive Wi-Fi, LTE, and ZigBee protocols in the ISM band on the same RF front end using AD9361 RF transceiver
• Successfully implemented detection and synchronization on MATLAB for each protocol to meet bit error rate (BER) and error vector magnitude (EVM) requirements
• Published and presented this research at Crowncom 2018 conference in Ghent, Belgium

• Developed QPSK baseband Tx and Rx blocks on Simulink for AD9361 RF transceiver models to match datasheet modulation accuracy requirements
• Worked closely between Analog Devices and MathWorks engineers to develop efficient software modeling of AD9361 RF transceiver
• Presented completed Simulink project to Analog Devices engineers for approval
• Designed QA tests for updated RF transceiver Simulink models to test model before submission
• All models passed QA tests and were successfully on Matlab 2018b release

Senior Design Project

• Worked in a team of four to develop an RF radiometer to analyze soil moisture
• Designed an RF receiver using connectorized components including an LNA, PA, switch and a band-pass filter and performed link budget analysis
• Analyzed a 2x2 microstrip patch antenna by measuring S-parameters on a vector network analyzer to calculate resonant frequency and bandwidth
• Simulated antenna radiation patter on HFSS to measure antenna beamwidth
• Developed a thermal map to model brightness temperature and position using GPS locations on MATLAB