I have more than 20 years of design, analysis, and modeling experience with RF, antenna, communications, and EW/SIGINT systems to apply to your project. My time as a consultant is available on a part-time basis.
Bradden (Brad) K. Cowan 29152 Bowhill Road, Hayward, CA 94544 Santa Clara (650) 966-2069; home: (510) 293-8968 ; cell: (510) 326-6314 E-mail: bradden.cowan@gd-ais.com ; braddenkcowan@comcast.net Objective: Sr. RF/Antenna/Communication Systems Engineer/Consultant Synopsis: BSEE+20 years RF, antenna, communications & EW/SIGINT systems design/analysis/modeling
experience Expertise in satellite (space-based) communications (GPS, payloads, transceivers, antenna, earth station) and airborne/aircraft radio systems (Doppler navigation, direction finding, communications, range, altimeter) Active DoD Top Secret, current SSBI (TS/SCI with polygraph reinstatement in progress) Enrolled in Naval Postgraduate School MSEE with Sensor Systems Engineering option Experienced with system architecture design, requirements analysis, performance optimization Experienced with simulation/synthesis simulation tools (Matlab/Simulink, ADS, MWO, Eagleware, CST) Knowledge of digital modulation techniques and complex IQ signal processing for comm & EW Design knowledge of antennas, receivers, up/downconverters, tuners, PLLs, frequency synthesizers Excellent technical (proposal) writing and communication/presentation skills
Professional Experience: January 2006 to present Sr. Lead System Engineer General Dynamics Advanced Information Systems, Santa Clara, CA Linear distortion analysis, dynamic range and noise cascade analysis, system block diagram, and requirements compliance for ground based beam former element separator. Supported Business Development effort for airborne SIGINT/DF/EW/IO platform that integrates SIGINT, IO, and MASINT capabilities for UAV platforms, including direction finding (DF), imaging, cross-queuing, targeting, geolocation, and signal ID. Support system architecture, RF front end, apertures. Used STK to generate 3D and 2D earth coverage plots for classified missile defense system. Analyzed requirements, and generated RF front end design, for handheld UHF satellite terminal, including antenna design trade (patch, dipole, quad helix), modem, RF up/down converter, and high efficiency SSPA. Analyzed and modeled V-band GPS III QPSK crosslink with digital Costas PLL phase tracker implemented in receiver to assess BER impact of transmitted carrier phase noise profile. Wrote Matlab script to generate FMCW signals with user-specified windowing/filtering in frequency domain to compensate nonlinear amplifier AM/AM and AM/PM and reduce spectral regrowth. Designed microstrip edge-coupled band pass filters at C/Ku-band on Roger RO4003 using MWO and CST. Analyzed patch antenna using MWO for input and radiation impedance, VSWR and far-field pattern. Wrote Matlab program for development of SIGINT receiver DF algorithms to generate 30 MHz instantaneous bandwidth multi-carrier sampled spectrum with user-specified modulation (CW, digital, analog), carrier frequency, data rate, SNR, and AOA. Wrote Matlab program to compute link degradation vs. untracked phase noise vs. modulation type (BPSK, QPSK, 8PSK, MSK, GMSK, CPFSK) using closed-form equations.
December 2001 to December 2005 Communication Systems Engineer, Senior Staff Lockheed Martin ISS, San Jose, CA (6/04 12/05); Space Systems, Sunnyvale, CA (12/01 6/04) PI for High-Rate Communications Modeling and Simulation IRAD: Led team of five engineers investigating distortion mitigation techniques (FEC coding, interleaving, site diversity) for free-space optical communications link. Responsible for schedule, budget and documentation. Project on-schedule, on-budget. Principle Investigator for Communications-On-The-Move IRAD: Analyzed receiver tracking and acquisition requirements to support T1 data rates between GEO processed payload and land mobile terminals driving up to 50 MPH on various types of terrain. Areas of study include EHF propagation channel modeling, Doppler correction, error correction coding, interleaving, acquisition/tracking for frequency hopped waveform. Space-Based Infrared Systems (SBIRS): Analyzed communications Bit Error Rate (BER) performance requirement for GEO space-to-ground telemetry link and land line relay between earth stations. Mobile User Objective System (MUOS): Led team of five engineers/consultants to develop waveform simulation RF models and communication subsystem requirements for a high-profile system definition study for mobile geosynchronous satellite spread spectrum (WCDMA) communications system. Responsible for schedule, budget and documentation in proposal. Project on-schedule, and on-budget. LM won program. Airborne Defensive Missile: Analyzed RF preamplifier noise figure, gain, isolation requirements for missile-borne GPS receiver. National Polar-orbiting Operational Environmental Satellite System (NPOESS): Analyzed transmit/receive filter requirements to mitigate payload electromagnetic self-interference from multiple scientific sensor, radar, command and telemetry transponders.
October-December 2001 Consultant Teraburst Networks, Campbell, CA October 2000 to October 2001 Hardware System Engineer for 60 GHz Gigabit Radio Project Agilent Technologies, Wireless Semiconductor Division, Santa Clara, CA Designed millimeter wave 60 GHz coplanar waveguide antenna using Momentum and HFSS. Antenna design was coplanar waveguide fed, l/2 slot dipole, with hyper-elliptic ceramic lens and hemispherical antireflection shell. Analyzed input impedance, radiation pattern, sidelobes, gain and subharmonic rejection for parametric perturbations in lens geometry and single vs. dual slots. Generated far field 3D plots and 2D plots. Supervised testing of prototype and comparison with simulated data. Modeled and simulated 2.5 GHz FSK modem using Agilent ADS to determine FM modulation index, baseband, IF and RF filter requirements, and frequency discriminator circuit design requirements to meet FCC out-of-band emission and receiver timing jitter requirements. Allocated requirements to RF components (FM modulator, filters, oscillators, frequency discriminator).
March 1997 to October 2000 Advanced Programs Analyst (4/98-10/00) Payload Engineer (3/97-4/98) Space Systems/Loral, Palo Alto, CA Designed CD Radio/XM/Sirius S-band high-power transmit payload including Monte Carlo analysis/simulation to assess phase matching requirements for multi-port antenna. Allocation of phasing requirements to payload RF components Layout of waveguide combining and redundancy ring to minimize phase dispersion Analysis of harmonic filter rejection requirements for CDMA vs TDMA waveforms. Developed budgets for phase, gain, noise figure, intermodulation distortion, AM/PM etc. Developed test requirement documents
Analyzed spectral regrowth for CDMA traffic through linearized TWT. Analyzed adjacent channel interference (ACI) for three QPSK carriers through non-linear transponder Analyzed carrier-to-interference ratio (C/I) and NPR as a function of carrier position and number of carriers for multiple QPSK signals through satellite transponder. Developed spectral plots and 99% BW estimates for analog FM/PM and digital M-PSK signals for meteorological and aeronautical payload. Co-authored IRAD report, Higher order modulation signals for satellite, investigating QPSK, 8PSK, 16QAM, Trellis-coded 8-PSK, determination of optimum backoff for fixed BER Performed analysis/simulation for Globalstar CDMA system with phased array S-band transmit antenna to determine compliance with ITU spectral mask* (*received Employee Recognition Award) Analyzed automatic gain control requirements for Globalstar linearizer module.
Additional Engineering Experience 6/95-3/97 ArgoSystems, Test and Measurement Division, Sunnyvale, CA Principle RF engineer for Global Broadcast System (GBS) airborne burst receiver development RF system analysis and specification of antenna, RF up/down converters Modification to COTS LNB to accept phase locked external reference Generation of QPSK IF test vectors with Gaussian or root raised cosine pulse shaping Analyzed RF system and filter requirements for C band frequency modulated continuous wave (FMCW) aircraft radio altimeter system Developed Test Requirements Documents (TRDs) for frequency discriminator circuit card and LO frequency synthesizer assemblies used in airborne AWACS E-3 ESM System
8/92-6/95 Stanford Linear Accelerator Center, Menlo Park, CA Designed RF signal generation, detection, control, and interlock circuitry for test of UHF high power klystron amplifier using analog and digital circuitry.
2/89-8/92 Loral (now Lockheed) Western Development Labs, Wideband Receiver Design, Palo Alto, CA Designed 3 GHz OQPSK multi-rate modulator Performed RF system design/analysis and specified phase locked LO phase noise requirements Designed wideband amplifier/select module, Designed analog/digital control & status card.
10/88-2/89 Litton Applied Technology Division, San Jose, CA 2/88-9/88 Microwave Modules & Devices (now Spectrian), Mountain View, CA Education: In process MSEE w/Sensor System Engineering option, Naval Postgraduate School, Monterey, CA. Course work in Antenna/Radiowave Propagation, Network-enabled Electronic Warfare Systems 1989-90 Santa Clara U., Santa Clara, CA, graduate courses in Fourier analysis, Active Microwave Circuits 1987 BSEE, San Jose State U., San Jose, CA (electromagnetics, microwaves, fiber optics, communications) Clearances: Active DoD Top Secret with current SSBI TS/SCI w/polygraph (reinstatement in process) Modeling/Simulation Tools: Proficiency in each of the following Satellite Tool Kit (STK) Matlab/Simulink Agilent/EEsof Genesis/Eagleware, Advanced Design System (ADS), Ptolemy Signal Processing Workstation (SPW) CST Microwave Studio Ansoft HFSS AWR Microwave Office/Visual System Simulator
Hardware-In-The-Loop Simulation Experience: Downloaded complex I/Q samples generated in Matlab to Agilent E4438C for use in developing SIGINT detection algorithms. Interfaced WCDMA waveforms to prototype SSPA using Agilent ADS and Matlab using Agilent ESG signal generator and 89600 vector signal analyzer. Experienced with the following instruments: Vector Signal Analyzer, Network Analyzer, Spectrum Analyzer, Phase Noise Test Set, Digital Oscilloscope
Awards & Achievements: STAR Employee Achievement Award, GDAIS, Phase Noise vs. Modulation Analysis Employee Recognition Award, Space Systems/Loral, CDMA Spectral Emissions Mask analysis
References: Available Upon Request |
