EE 3113
INTRODUCTION INTO RF
CIRCUIT DESIGN
Lecture Notes for A-term 1999
LECTURE 1
Prof. R. Ludwig
Department of Electrical and Computer Engineering
Worcester Polytechnic Institute
Worcester, MA
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Copyright, 1998 © R. Ludwig
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EE 3113: Lecture 1
• Importance of RF circuit design
– wireless communications (explosive growth of
cell phones)
– global positioning systems (GPS)
– computer engineering (bus systems, CPU,
peripherals exceeding 600 MHz)
• Why this course???
– lumped circuit representation no longer applies!
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What do we mean by going from lumped to distributed theory?
• Example: INDUCTOR
High-frequency
Low-frequency
(lumped)
Z = R + jω L
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Z=?
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Current and voltage vary spatially over the component size
E (or V) and H (or I) fields
Upper MHz to GHz range
6
4
z
1
2
0.5
0
y
0
-0.5
-1
-0.5
0
0.5
x
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-1
1
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Frequency spectrum
• RadioFrequency (RF)
– TV, wireless phones, GPS
– 300 MHz … 3 GHz operational frequency
– 1 m … 10 cm wavelength in air
• MicroWave (MW)
– RADAR, remote sensing
– 8 GHz … 40 GHz operational frequency
– 3.75 cm …7.5 mm wavelength in air
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Design Focus
Cell phone transceiver circuit
Typical frequency
range:
• 950 MHz
• 1.9 GHz
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Implementation
• matching networks
• BJT/FET active devices
• biasing circuits
• printed circuit board
• mircostripline realization
• surface mount technology
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