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Spiral Leaky-Wave Antennas Based on Modulated Surface Impedance.
- Source :
- IEEE Transactions on Antennas & Propagation; Dec2011, Vol. 59 Issue 12, p4436-4444, 9p
- Publication Year :
- 2011
-
Abstract
- Different kinds of spiral planar circularly polarized (CP) antennas are presented. These antennas are based on an interaction between a cylindrical surface-wave excited by an omnidirectional probe and a inhomogeneous surface impedance with a spiral pattern. The surface impedance interaction transforms a bounded TM0 surface wave into a circularly polarized leaky wave with almost broadside radiation. The problem is studied by adiabatically matching the local 2D solution of a modulated surface-impedance problem to the actual surface. Analytical expressions are derived for the far-field radiation pattern; on this basis, universal design curves for antenna gain are given and a design procedure is outlined. Two types of practical solutions are presented, which are relevant to different implementations of the impedance modulation: i) a grounded dielectric slab with a spiral-sinusoidal thickness and ii) a texture of dense printed patches with sizes variable with a spiral-sinusoidal function. Full wave results are compared successfully with the analytical approximations. Both the layouts represent good solutions for millimeter wave CP antennas. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 0018926X
- Volume :
- 59
- Issue :
- 12
- Database :
- Complementary Index
- Journal :
- IEEE Transactions on Antennas & Propagation
- Publication Type :
- Academic Journal
- Accession number :
- 67669757
- Full Text :
- https://doi.org/10.1109/TAP.2011.2165691