GENERATION OF COHERENT ELECTROMAGNETIC SIGNAL IN THE LOW AND SUBMILLIMETER RANGE. Technical Note No. 2

Technical Report · Fri Dec 01 04:00:00 EST 1961

OSTI ID:4786120

Hakki, B W

Three schemes were studied as a means of generating coherent electromagnetic energy in the low and submillimeter region. A Doppler frequency shift device used a megavolt tightly bunched beam as a moving reflecting surface from which 3 kmc power was reflected. The theoretical magnification in frequency was 27.6 times. In order to enhance the reflectivity of the electron bunches a longitudinal magnetic field was used such that the cyclotron frequency was equal to the frequency of the electromagnetic fields in the moving frame of reference. Cherenkov radiation was produced in a prebunched beam in a plasma column waveguide. The prohibitively high plasma density necessary for operation below one millimeter precluded the use of this device in the submillimeter region. Coherent inner-brenmsstrahlung radiation was produced in the millimeter region at power levels in excess of a hundred milliwatts by the use of a tightly bunched relativistic electron beam. A prebunched beam was completely stopped on the flat surface of a conducting plate or a dielectric material whose permitivity was chosen such that the velocity of light in the medium was close to the beam velocity. If the physical dimensions of the device were made much larger than a wavelength then it was found that the radiation resistance was a constant independent of frequency. Furthermore, the inner-bremsstrahlung scheme used was free of physical size limitations, mode interference problems and attenuation difficulties which limited the utility of other schemes in the low and submillimeter region. Thus the only frequency limitation is the size of the bunches of the beam. Therefore, it appeared that the inner-bremsstrahlung radiation scheme is ideally suited for the generation of coherent electromagnetic power in wavelengths below one millimeter. (auth)

• Research Organization: Illinois. Univ., Urbana. Electrical Engineering Research Lab.
• NSA Number: NSA-16-013684
• OSTI ID: 4786120
• Report Number(s): ASD-TDR-62-39
• Country of Publication: United States
• Language: English

Related Subjects

BREMSSTRAHLUNG
CHERENKOV RADIATION
CYCLOTRON FREQUENCY
CYCLOTRON RADIATION
DENSITY
DIELECTRICS
ELECTRIC CONDUCTIVITY
ELECTROMAGNETIC WAVES
ELECTRON BEAMS
ENERGY RANGE
FREQUENCY
GENERATORS
INNER BREMSSTRAHLUNG
INTERFERENCE
MAGNETIC FIELDS
MICROWAVES
PERMITTIVITY
PHYSICS
PLASMA
PLATES
POWER
RADIATION EFFECTS
REFLECTION
SPECTRA
SPECTRAL SHIFT
SURFACES
VELOCITY