A TECHNIQUE OF FABRICATING INHOMOGENEOUS MEDIA AND THE BEHAVIOR OF A DIPOLE IN SUCH A MEDIUM.
Interim technical rept.,
HARVARD UNIV CAMBRIDGE MASS DIV OF ENGINEERING AND APPLIED PHYSICS
Pagination or Media Count:
It is shown that an inhomogeneous medium to be used for antenna experiments can be fabricated using the diffusion profile of NaCl into agar agar. Various problems relating to the construction of a 380 Gallon agar agar tank are described. The production of a desired profile of the electrical properties of the medium is discussed together with the experimentally determined driving-point admittance and current distribution of a dipole antenna when immersed in the inhomogeneous conducting medium. The measured electrical properties of the agar agar when dissolved in tap water are epsilon sub r 78, tan delta 0. 13 at 114 Mcs and a conductivity of 0.8 millimhos cm at 1000 cs the diffusion constant D of NaCl into 1.3 agar agar is 0.000008 to 0.00002 sq cm sec at 25C. The range of change in the loss tangent is large one profile varied from tan delta 0.13 to tan delta 3.3 which corresponds to a factor of twenty six in the distance of a wavelength. The periods of diffusion were one to three weeks. The properties of a dipole antenna measured in an inhomogeneous conducting medium are compared with those in a homogeneous conducting medium. Author
- Electrical and Electronic Equipment
- Test Facilities, Equipment and Methods