TITLE:
Modal Resistance of Spiral Antenna
AUTHORS:
Teng-Kai Chen, Gregory H. Huff
KEYWORDS:
Spiral Antennas; Modal Resistance; Quasi-Static Analysis
JOURNAL NAME:
Journal of Electromagnetic Analysis and Applications,
Vol.5 No.5,
May
24,
2013
ABSTRACT:
This paper proposes a quasi-static
conformal mapping analysis to analytically evaluate the input resistance of
Archimedean spiral
antenna at its radiation region. The deviation from the original constructs of
band theory for two-wire spiral antennas leads to the concept of common
slot-line mode radiation. The per-unit-length capacitance and the characteristic impedance of the quasi-TEM
fundamental propagating mode in periodic coplanar waveguide (PCPW) structure are obtained in terms of spiral
parameters including substrate properties. This formula enables little computational
effort on the computation of input resistance at the radiation mode of
balanced-excited two-arm Archimedean spiral antennas. The numerical simulation
demonstrates the accuracy of derived formulas both in free space and when a dielectric
layer is presented.