Post on 02-Jun-2018
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Microwave Frequency Band (300MHz300GHz)
VLF 3K30K
Lf 30K300K
MF 300K3 M
HF 3M30M
VHF 30M300M
UHF 300M3G
SHF 3G30G
EHF 30G300G
(cm) = 30/f(GHz) 1m1mm
IR
Visible
UV
X
Cosmic
mm waves
Band Freq(GHz)
L 1-2
S 2-4C 4-8
X 8-12
Ku 12-18
K 18-27
Ka 27-40
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Relative Power
"B" is in honor of Alexander Graham Bell
dBm power relative to 1 milliwatt
dBW power relative to 1 watt
dBk power relative to 1 Kilowatt
dBi the forward gain of an antenna compared to an isotropic
antenna
dBd the forward gain of an antenna compared to a half-wavedipole
0dBd = 2.15 dBi = [ 10 log(1.643) ]
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Reflection Coefficient
VSWR 2:1
Refln Co-efft 1/3
Return Loss -10 dB
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Standing Waves
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http://en.wikipedia.org/wiki/File:Standing_wave_2.gif8/10/2019 3 Maxwells Equations.
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Maxwells Equations
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DivergenceDivergence Net Outward flow
Flower Fragrance
Fountain WaterAntenna EM Wave
100 ml
100 ml
Zero+ ve
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Curl
Rotational + Translational motion
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Why Maxwells Equations?
Electromagnetic wave effectsthat, until now, were
in the domain of the microwave engineer are
becoming a limiting factorin digital circuit operation
Maxwells Equations are literally valid from dc to
light
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Why Maxwells Equations?
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Dimensions of devices/components are wavelength
comparable
Significant change in phase of an electrical signal
(V/I) over the physical length of the device
At higher frequencies, Maxwells Equations replace
Basic Circuit Theory
Circuit Theory is a subset of Electromagnetic Field
Theory
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Why Maxwells Equations?
High speed digital signalscan spuriously
Distort as they propagate along the metal
circuit paths
Couple (cross-talk) from one circuit path to
another
Radiate and create interferences to other
circuits and systems
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High Speed Electronics
a conventional dual in-line integrated-circuit package
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High Speed Electronics
coupling and crosstalk of a high-speed logic pulse
entering and leaving a microchip
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Why not Maxwells Equations?
Numerical methods for electromagnetic modelling
attempt to solve fundamental field equations
directly, subject to boundary conditions posed by
the geometry
http://www.ece.northwestern.edu/ecefaculty/Al
len1.html
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