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 of 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 Ω, respectively.
|ジャーナル||IEEE Antennas and Propagation Society, AP-S International Symposium (Digest)|
|出版ステータス||Published - 1988 12 1|
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