David McDermott

Research Engineer, Department of Applied Science, University of California, Davis


MAIL: LLNL // PO Box 808 (L-637) // Livermore, CA 94550

TEL: (925) 422-8572

FAX: (925) 424-5114



B.S., Physics, University of California, Davis, 1976

M.A., Applied Physics, Columbia University, 1977

M.Phil., Applied Physics, Columbia University, 1979

Ph.D., Applied Physics, Columbia University, 1979



An intense relativistic electron beam at the Naval Research Laboratory in Washington, D.C., was used in Dr. McDermott's thesis research to generate high power, submillimeter-wave radiation through the free-electron-laser instability. After two years in a postdoctoral position at Columbia, Dr. McDermott joined the Electrical Engineering Department at UCLA as an Assistant Research Engineer under Prof. Luhmann. In 1994, Dr. McDermott transferred with Prof. Luhmann to the Department of Applied Science at the University of California at Davis as a Research Engineer.

Dr. McDermott has remained actively involved in the field of electron/wave interaction since he began his graduate research in 1976. At UCLA, his research resulted in the development of moderate power, millimeter-wave, high-harmonic gyrotron oscillators and amplifiers driven by gyroresonantly rf accelerated electron beams; a dielectic-loaded wideband gyroTWT amplifier; gyrofrequency multipliers; and a high power, second-harmonic gyroTWT amplifier. He is particularly interested in the relation between harmonic interaction and symmetry and has also contributed to the evolution of microwave and quasi-optical components, including broadband, overmoded couplers, mode convertors and low loss transmission lines.

Before actually testing their innovative devices in full-scale experiments, Dr. McDermott's research group first makes extensive use of simulation codes to design the electromagnetic circuits and then precise network-analyzer measurements to optimize them. His current projects include a high-performance W-band (94 GHz) gyro-TWT amplifier and three harmonic gyro-devices driven by low-voltage axis-encircling-electron Cusp guns: a sixth-harmonic slotted gyrotron; an extremely efficient, second-harmonic slotted peniotron; and a second-harmonic gyro-TWT amplifier. David McDermott is a member of APS and a Senior Member of the IEEE.


Recent Major Publications

"Demonstration of Marginal Stability Theory by a 200 kW Second-Harmonic Gyro-TWT Amplifier," Q.S. Wang, D.B. McDermott and N.C. Luhmann, Jr., Phys. Rev. Lett., vol. 75, 4322 (1995).

"Broadband Linearly-Polarized Beat-Wave TEm1/TE11 Mode Converter," D.B. McDermott, J. Pretterebner, C.K. Chong, C.F. Kinney, M.M. Razeghi, and N.C. Luhmann, Jr., IEEE Trans. Microwave Theory Tech., vol. 44, 311 (1996).

"Periodic Permanent Magnet Focusing of an Annular Electron Beam and its Application to a 250 MW Ubitron Free-Electron Maser," D.B. McDermott, A.J. Balkcum, R.M. Phillips and N.C. Luhmann, Jr., Phys. Plasmas, vol. 2, 4332 (1995).

"Experimental Investigation of a Broadband Gyro-TWT Amplifier," K.C. Leou, D.B. McDermott, C.K. Chong, and N.C. Luhmann, Jr., IEEE Trans. on Electron Devices, vol. 43, 1016 (1996).

"Marginal Stability Design Criterion for Gyro-TWT's and Comparison of Fundamental with Second Harmonic Operation," A.T. Lin, K.R. Chu, C.C. Lin, C.S. Kou, D.B. McDermott, and N.C. Luhmann, Jr., Int. J. Electronics, vol. 5, 873 (1992).


Research Projects


Gyrotrons and Peniotrons

High-Harmonic Gyrotrons (Third-Eleventh Harmonics, 1 kW, 10% efficient)

Sixth-Harmonic Slotted Gyrotron (94 GHz, 50 kW, 20% efficiency predicted)

High-Efficiency Second-Harmonic Peniotron (33 GHz, 130 kW, 50% efficiency predicted)

Compact CW High-Harmonic Gyrotrons (35 and 95 GHz, 25 kW with 20% efficiency predicted)

Prebunched Gyrofrequency Multipliers (Third-Sixth Harmonics, 1 kW, 15% efficient)


Gyroklystron Amplifiers

Fifth-Harmonic Gyroklystron (0.5 kW, 5% efficient, 30 dB gain)

High Performance TE0n Gyroklystron (under test, 250 kW with 40% efficiency predicted)

Third-Harmonic Gyroklystron (70 kW with 20% efficiency predicted)


GyroTWT Amplifiers

Second-Harmonic GyroTWT (210 kW, 13% efficiency, 2% bandwidth, 16 dB gain)

Slotted Third-Harmonic GyroTWT (13 dB small-signal gain with 3% bandwidth)

Eighth-Harmonic Gyro-TWT (1 kW, 4% bandwidth, 2% efficiency, 10 dB gain)

Dielectric-Loaded Broadband GyroTWT (12% bandwidth, 55 kW, 11% efficiency, 27 dB gain)

Disk-Loaded Broadband GyroTWT (100 kW with 25% bandwidth predicted)

Second-Harmonic Cusp-Gun Gyro-TWT (50 kW at 30 GHz, 3% bandwidth, 20% efficiency, 30 dB gain is predicted)

High-Performance W-band Gyro-TWT (100 kW at 94 GHz, 4% bandwidth, 20% efficiency, 40 dB gain is predicted)


Free Electron Lasers

700 GHz FEL (Ph.D. thesis, 1 MW)

Low-Voltage, Broadband Disk-Loaded FEL Amplifier (20% bandwidth predicted)

High Power 11 GHz FEL Amplifier for 1 TeV Colliders (250 MW with 40% efficiency predicted)

High Power 3 GHz FEL Oscillator for Directed Energy (1 GW with 21% efficiency predicted)


Electromagnetic Circuits

Bragg Reflectors (98% reflection with 10% bandwidth)

Overmoded Couplers (1 dB coupler for TE21 mode with 20% bandwidth)

Beat-Wave TEm1/TE11 Mode Converters (98% conversion efficiency for TE31 into TE11 mode)

Mode Selective Circuits (100:1 attenuation selectivity between even and odd order TEm1 modes)


RF Accelerators

Gyroresonant RF Accelerator (0.5 MeV, 0.3 A, 45% efficient, helical electron beam

Linear RF Accelerator (0.5 MeV, 0.1 A linear electron beam)


Current Students


John McNally


Ph.D. Thesis: High Performance TE0n Gyroklystron Amplifier


Ron Stutzman


Ph.D. Thesis: Sixth-Harmonic Slotted TE61 Gyrotron


Steve Harriet


Ph.D. Thesis: Second-Harmonic Cusp-Gun TE21 Gyro-TWT


Larry Dressman


Ph.D. Thesis: High Efficiency Second-Harmonic TE31 Peniotron


Former Students


A. Kupiszewski, M.S., 1983



Current Address: Westinghouse Electric, PO Box 746, MS 491, Baltimore, MD 21203


D.S. Furuno, Ph.D., 1987



Current Address: Lockheed Martin, Missiles and Space Communications, Santa Clara, CA.


C.S. Kou, Ph.D., 1991


Assistant Professor

Current Address: Department of Physics, National Tsing Hua University, ROC.


K.C. Leou, Ph.D., 1993


Assistant Professor

Current Address: Department of Engineering and System Science, National Tsing Hua University, ROC.


Q.S. Wang, Ph.D., 1994



Current Address: Micramics, Inc., Santa Clara, CA 95051


C.K. Chong, Ph.D., 1995



Current Address: Hughes Electron Dynamics Division, Torrance, CA


A.J. Balkcum, Ph.D., 1998



Current Address: CPI, 811 Hansen Way (M/S B-450), PO Box 50750, Palo Alto, CA 94303-0750




Solenoid Magnets

50 kG, 50 cm length, 15 cm bore, refrigerated superconducting solenoid

60 kG, 40 cm length, 10 cm bore, superconducting solenoid

40 kG, 15 cm length, 8 cm bore, superconducting solenoid

30 kG, 10 cm length, 10 cm bore, superconducting solenoid

30 kG, 5 cm length, 10 cm bore, superconducting solenoid

4 kG, 100 cm length, 15 cm bore, copper solenoid

3 kG, 150 cm length, 20 cm bore, copper solenoid

7 kG, 25 cm length, 15 cm bore, copper solenoid


High Voltage Modulators

400 kV, 500 A, 2 Hz

100 kV, 50 A, 2 Hz

100 kV, 20 A, 2 Hz

50 kV, 20 A, 2 Hz


Electron Guns

350 kV, 400 A, SLAC linear-beam guns

80 kV, 10 A, commercial magnetron injection guns

100 kV, 20 A, custom magnetron injection guns

50 kV, 20 A custom linear-beam guns


Millimeter-Wave Hardware

Kilowatt-level pulsed sources

Watt-level CW sources

Continuous multi-mW coverage from DC-170 GHz

Abundant waveguide components (bends, tuners, transitions, etc. )



Computers (inc. Sun, Pentium, HP-Apollo, Macintosh, DEC-Net, Cray-Access)

Software (inc. MAGIC, HFSS, EGUN)


Current Funding

AFOSR under Grant F49620-99-1-0297 (MURI)