Title :
Round spiral antennas printed on a grounded dielectric substrate with a single surface wave mode
Author :
Nakano, H. ; Hirose, K. ; Kerner, S.R. ; Alexopoulos, N.G.
Author_Institution :
Coll. of Eng., Hosei Univ., Tokyo, Japan
Abstract :
Frequency characteristics of two types of spiral antennas printed on a grounded dielectric substrate are investigated under the condition that a single surface wave mode (TM mode) is allowed to exist. The currents on the spiral arms are evaluated by using the method of moments and the radiation characteristics are examined over a frequency range 1:1.19. The bandwidth in which the axial ratio is less than 3 dB is calculated to be 15% for a printed spiral antenna of one center source and 10% for a spiral antenna of two off-center sources. These two antennas have nearly pure resistances of 330 and 350 Omega , respectively.<>
Keywords :
antenna radiation patterns; dielectric-loaded antennas; microstrip antennas; 330 ohm; 350 ohm; TM mode; bandwidth; center source; currents; frequency characteristics; grounded dielectric substrate; method of moments; microstrip antennas; off-center sources; printed spiral antenna; radiation characteristics; resistances; round spiral antennas; single surface wave mode; spiral arms; Antenna radiation patterns; Coplanar waveguides; Current distribution; Dielectric substrates; Frequency; Impedance; Moment methods; Polarization; Spirals; Surface waves;
Conference_Titel :
Antennas and Propagation Society International Symposium, 1988. AP-S. Digest
Conference_Location :
Syracuse, NY, USA
DOI :
10.1109/APS.1988.94170
