THE LWA SOFTWARE LIBRARY Jayce Dowell – LWA Users’ Meeting – July 27, 2012.
Lwa Phase Velocity
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Transcript of Lwa Phase Velocity
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• Space harmonics are expansion of field similar to fourier expansion but are not power orthogonal due to mutual coupling
• Spatial harmonics converge easily in evaluating field integrals and helps in accurate estimation of properties of radiation pattern and thereby designing antenna
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Floquet theoremTranslational symmetry of axially periodic structures in which mode is guided axially.
Cross-sectional complex field distribution of a periodic structure remains unchanged under an axial translation of observational point through period d , while amplitude multiplies itself by a complex constant
Macroscopic field Microscopic field
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Fourier expansion of a Bloch wave indicates that field of a normal mode of axially periodic structure is expressible in terms of an infinite number of travelling waves
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Each spatial harmonic has a phase velocity given by
For sufficiently large values of abs(n) all harmonics are axially slow n >= 0 forward travelling wavesLarge negative values if n backward travelling waves
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Orthogonal polarization – end fire scanning possibleWave number – key for all radiation characteristicsLeakage – interruption of current flow by slots on top wall
Wide microstrip shorted by vias at edges to form SIWEasy integration with planar circuits as a promising antenna for integrated microwave and millimeter wave applications
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[17] Collin, R. E., & Zucker, F. J. (1969). Antenna theory. 2 (1969). McGraw- Hill, ch. 19 and 20.
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