CHRIS TRASK
Analog/RF/Microwave Design Consultant
Principal Engineer
ATG Design Services
Chris Trask is a designer of analogue, RF, and microwave active and
passive circuits, and has performed a number of successful designs over
a period in excess of 18 years. In addition, Chris is the Principal Engineer
of ATG Design Services, a provider of analogue,
RF, and microwave circuit design service with an emphasis on low-cost and
high-efficiency designs of receivers, transmitters, and transceivers for
wireless communications.
Email:christrask@earthlink.net
DESIGN EXPERIENCE
- Performed theoretical design, computer-aided modeling, and scale model testing of the vertical-incident log-periodic antenna array for the Ionospheric Modification Facility at the Arecibo Observatory (Puerto Rico).
- Designed L-band and S-band oscillators and isolators for high-G enviroment artillery fuse telemetry transmitters.
- Designed VHF, UHF, and L-band multipliers, amplifiers, and filters, (lumped, distributed, and cavity) for TDRSS satellites.
- Designed low-noise oscillators and synthesizers for military airborne applications using both hybrid and discrete technologies. In addition to rigid specifications for phase noise, designs required performance under extreme environmental conditions, including temperature, humidity, and vibration.
- Designed microstrip edge-coupled, hairpin, SIR, interdigital, combline, and direct-coupled bandpass filters, as well as microstrip lowpass and bandstop filters at UHF, L-band, S-band, C-band, and X-band frequencies.
- Designed electronically-switched crystal oscillators for high-G vibration missile applications.
- Developed X-band to VHF/UHF satellite earth station upconverters and downconverters for military applications.
- Designed X-band intrusion alarms and short-haul data/audio/video links for military and commercial applications.
- Designed 70MHz 16-QAM modulators and demodulators.
- Designed airborne C-band GPS receiver for agricultural aircraft.
- Designed 70 MHz to L-band commercial telecommunications upconverters and downconverters.
- Developed VHF VCXOs for injection-locking local oscillators in commercial C-band telecommunications outdoor unit upconverter and transmitter.
- Developed 1-2 GHz satellite terminal modulator/upconverter and downconverter/demodulator for commercial applications.
- Developed high-efficiency (95%) Class-F switching power amplifiers for VHF and UHF frequencies.
- Designed voltage-controlled active filters for linear real-time ultrasound scanner.
- Developed low-cost TRF AM receiver for biomedical research telemetry system.
- Designed low-cost 11GHz, 13GHz, 15GHz, and 18GHz LMDS transceivers
- Developed and patented low-power linearized active mixers.
- Developed and patented high linearity lossless feedback amplifiers.
- Designed low-power active RFID tags for US and Japanese markets.
- Designed and developed RFID hardware for dairy cow rumen acidocis monitoring system.
EDUCATION
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BSEE, The Pennsylvania State University, 1973
MSEE, The Pennsylvania State University, 1979
PUBLICATIONS
- "A High-Gain Vertical-Beam Antenna Using Orthogonal Non-Planar Log-Periodic Structures in a Backfire Configuration," Master's Thesis, The Pennsylvania State University, 1979
"ALMOND - A Design, Analysis, and Optimization Programme for High-Frequency Networks," EE Public Domain Library, 1982
"Feedback Improves AGC Amplifier Harmonic Performance," RF Design, August 1996, pp. 81-84.
"Feedback Technique Improves Active Mixer Performance," RF Design, September 1997, pp. 46-49.
"The Forgotten Use of Saturable-Core Inductors (Transductors)," Applied Microwaves and Wireless, Sep/Oct 1997, pp. 76-82.
"Lossless Feedback Amplifiers," QRP Quarterly, January 1998, pp. 40-41.
"A Wide-Band Low-Distortion Ferrimagnetic Attenuator," Proceedings of the 1998 IEEE International Symposium on Microwave Theory and Techniques, Baltimore, Maryland, June 1998, pp. 1847-1850.
"A Linearized Active Mixer," Proceedings of the RF Design '98 Conference, San Jose, California, October 1998, pp. 13-24.
"Nonlinear Distortion in Bipolar Transistors," QEX, Nov/Dec 1998, pp.
37-42.
"LC Oscillators - A Brief History," QRP Quarterly, April 1999, pp. 44-45.
"Class-F Amplifier Loading Networks - A Unified Design Approach," Proceedings of the 1999 IEEE International Symposium on Microwave Theory and Techniques, Anaheim, California, June 1999.
"Distortion Improvement of Lossless Feedback Amplifiers Using Augmentation," Proceedings of the 1999 IEEE Midwest Symposium on Circuits and Systems, Las Cruces, New Mexico, August 1999.
"Common Base Amplifier Linearization Using Augmentation," RF Design, October 1999, pp. 30-34.
"High Dynamic Range Double-Balanced Active Mixers Using Lossless Feedback," Proceedings of the 2000 International Symposium on Circuits and Systems (ISCAS 2000), 30 May 2000, Geneva, Switzerland, Vol. 3, pp. 41-44.
"A New Low-IMD Mixer," Electronics World, September 2000, pp. 680-685.
"Wideband Transformers: An Intuitive Approach to Models, Characterization and Design," Applied Microwave & Wireless, Vol. 13, No. 11, November 2001, pp. 30-41.
"Low Noise, High Linearity Double-Balanced Active Mixers Using Lossless Feedback," Proceedings of the 2002 International Symposium on Circuits and Systems (ISCAS 2002), 27 May 2002, Phoenix, Arizona, Vol. 1, pp. 133-136.
"High Efficiency Broadband Linear Push-Pull Power Amplifiers Using Linearity Augmentation," Proceedings of the 2002 International Symposium on Circuits and Systems (ISCAS 2002), 28 May 2002, Phoenix, Arizona, Vol. 2, pp. 432-435.
"Powdered Iron Magnetic Materials," Workshop on Passive Components for RF Applications, IEEE 2002 International Microwave Symposium (IMS 2002), 4 June 2002, Seattle, Washington (invited).
"Active Loop Aerials for HF Reception, Part 1: Practical Loop Aerial Design," QEX, Jul/Aug 2003, pp. 35-42.
"Active Loop Aerials for HF Reception, Part 2: High Dynamic Range Aerial Amplifier Design," QEX, Sept/Oct 2003, pp. 44-49.
"Designing Wide-Band Transformers for HF and VHF Power Amplifiers," QEX/ Mar/Apr 2005, pp. 3-15.
"Transmission Line Transformers: Theory, Design and Applications - Part 1," High Frequency Electronics, December 2005, pp. 46-53.
"Transmission Line Transformers: Theory, Design and Applications - Part 2," High Frequency Electronics, January 2006, pp. 26-33.
BOOKS
- John L.B. Walker, Daniel P. Meyer, Frederick H. Raab, and Chris Trask, "Classic Works in RF Engineering: Combiners, Couplers, Transformers, and Magnetic Amplifiers," Artech House, 2006, ISBN 1-58053-056-7
PATENTS
- Active Double-Balanced Mixers with Embedded Linearizing Amplifiers, US Patent 6,140,849, 31 Oct 2000.
- Lossless Feedback Amplifiers with Linearity Augmentation, US Patent 6,172,563, 9 January 2001.
- Low-Distortion Lossless Feedback Double-Balanced Active Mixers Using Linearity Augmentation, US Patent 6,242,964, 5 June 2001
- Common-Base Amplifiers with Linearity Augmentation, US Patent 6,271,721, 7 August 2001.
- Lossless Feedback Double-Balanced Active Mixers, US Patent 6,393,267, 21 May 2002.
- Low-Noise Lossless Feedback Double-Balanced Active Mixers, US Patent 6,400,936, 4 June 2002.
- A Simplified Doherty Amplifier (patent pending).
- Low Noise Linear Vairiable Gain Amplifiers Using Lossless Feedback and Augmented Predistortion (patent pending).
- High Dynamic Range Double-Balanced Active Mixers Using Lossless Feedback and Augmentation (patent pending).
OTHER EXPERIENCE
- Pilot, C-130E/EII/H/EC transports, United States Air Force, 1975-1979.
- Lab Instructor, Electrical Engineering, The Pennsylvania State University, 1977-1979.
- Technical Editor, QRP Quarterly 1997-1999
TECHNICAL RESOURCES
Send email to: christrask@earthlink.net