Title :
On the theory of eccentric spiral antennas
Author :
Gloutak, R.T., Jr. ; Alexopoulos, N.G.
Author_Institution :
Dept. of Electr. Eng., California Univ., Los Angeles, CA, USA
Abstract :
The authors discuss the theory of eccentric spiral antennas and show numerical results for a planar eccentric spiral that generates a circularly polarized wave whose main beam is off-normal to the spiral plane. The input impedances and radiation characteristics are calculated from the current distribution generated by a method of moments solution. The method used involves the reaction-matching technique employing piecewise sinusoids and a bent dipole as the fundamental element. Calculations for the eccentric spiral show that, for both polarizations, the main beam is directed 25 degrees off-normal in the phi=325 degrees plane. The power gain is a maximum at 6.6 dB and the axial ratio is a minimum of 0.3 dB at this off-normal angle.<>
Keywords :
antenna radiation patterns; antenna theory; dipole antennas; electric impedance; 6.6 dB; antenna theory; axial ratio; bent dipole; circularly polarized wave; current distribution; eccentric spiral antennas; input impedances; method of moments solution; numerical results; off-normal angle; piecewise sinusoids; planar eccentric spiral; power gain; radiation characteristics; reaction-matching technique; Antenna theory; Antennas and propagation; Arm; Broadband antennas; Feeds; Frequency; Impedance; Polarization; Spirals; Wire;
Conference_Titel :
Antennas and Propagation Society International Symposium, 1992. AP-S. 1992 Digest. Held in Conjuction with: URSI Radio Science Meeting and Nuclear EMP Meeting., IEEE
Conference_Location :
Chicago, IL, USA
Print_ISBN :
0-7803-0730-5
DOI :
10.1109/APS.1992.221453
