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No metal boundaries ==> hybrid modes beam waveguide. y. Waveguides. x. z. modes. E z = 0 and H z = 0 ==> TEM mode - plane wave - ideal coax or strip line E z = 0 and H z 0 ==> TE mode E z 0 and H z = 0 ==> TM mode E z 0 and H z 0 ==> hybrid mode.
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No metal boundaries ==> hybrid modes beam waveguide
y Waveguides x z
modes • Ez = 0 and Hz = 0 ==> TEM mode - plane wave - ideal coax or strip line • Ez = 0 and Hz 0 ==> TE mode • Ez 0 and Hz = 0 ==> TM mode • Ez 0 and Hz 0 ==> hybrid mode
Can we find a radial field distribution that will repeat itself? How about the phase? z – zo z z + zo
r j Cylindrical Waves
Assume no j dependence Jm is mth-order Bessel function
Due to no boundaries, g is not discrete. Continuous spectrum of g values. Propagation mainly along z axis.
z – zo z z + zo Periodic means field distribution at z = -zo is the same as at z = + zo.
z – zo z z + zo Identify this as the Hankel transform of.
z – zo z z + zo inverse Hankel transform leads to Loss can be calculated by integrating from R to
z – zo z z + zo Periodic means field distribution at z = -zo is the same as at z = + zo.
z – zo z z + zo Integral over g can be done.
z – zo z z + zo
Phase shift - lens or mirror z – zo z z + zo Normal wave propagation
z – zo z z + zo Is there a function that is a Hankel transform of itself? Is there a function that is a Fourier transform of itself?
Is there a function that is a Hankel transform of itself? a Gaussian x Laguerre polynomial Is there a function that is a Fourier transform of itself? a Gaussian x Hermite polynomial Weber function
z Surface wave guided by a dielectric above a conductorTM mode Dielectric -- thickness d Metal conductor
Dielectric -- thickness d Metal conductor z Surface wave guided by a dielectric above a conductorTM mode • Obtain Ez in the dielectric and in the vacuum • Assume Ez goes to 0 as y
Dielectric -- thickness d Metal conductor z Surface wave guided by a dielectric above a conductorTM mode
Dielectric -- thickness d Metal conductor z Surface wave guided by a dielectric above a conductorTM mode
Dielectric -- thickness d Metal conductor z Surface wave guided by a dielectric above a conductorTM mode