ECE265C Fall 2013
Problem Set #2
half-wave rectified
v(t) that has
[:*i:I l rours" waveformhevoftIg;(tithe faorm of a cross a load resistor of
is pprieo a
r
sinusoid as shown nerow.
value RL.
v(t)
Vo
time
the power at the fundamental
1) Determine the dc p
Midterm Examination
ECE287A
Fall 2010
Name.
General Directions: This is a closed book, closed notes examination. Calculators may
not be used. A Smith chart is provided in case you would like to refer to it. The duration
of the examination is 1 hour 20 min
ECE265C Fall 2015
Problem Set #6
Handed Out: November 24
Due date: December 3
Problem 1
In this homework set, in problems 1 and 2, you are requested to design and simulate a
simple Doherty amplifier, and determine some features of its operation. For the f
ECE265C
Fall 2013
Problem Set #1 Solutions
Problem 1
Consider a simple power amplifier which is being fed with a signal that goes between
two states, spending half time in each of these states. ln the high output state, the
output powei is 20dBm, and the
Mid-Term Solutions
ECE 265C Fall2012
Problem 1 (50%)
consider a class B amplifier implemented with a GaAs FET, as shown below'
The load resistance RL seen at the transistor drain is 5 ohms for the fundamental
L2 and c2 below'
frequency; the impedance matc
Final Examination
ECE265C
Fall 2012
Name.
General Directions: Answer all 6 questions. This is a closed book, closed
notes examination.
Calculators may not be used. The duration of the
examination is 3 hours.
Problem 1 (10%)
1) Consider an ideal Class A am
ECE265C Fall 2013
Problem Set #5 Solutions
Problem 1
In this problem you are asked to design a balun for application to differential amplifiers.
The frequency of operation is 1GHz. The balun shoul d operate so that its differential
input impedance (seen f
Mid-Term Examination Solutions
ECE 265C Fall 2013
Problem 1 (50%)
Consider that you work for a well-known Southern California wireless communications
company, and one of your colleagues has just invented a new class of power amplifier
operation called Cla
ECE265C Fall 2013
Problem Set #4 Solutions
Problem 1
In this problem and the next, you are asked to design Class E power amplifiers. In this
problem 1, the amplifier is to be based on a nearly ideal switch, so that you can get a
feel for a very well-behav
ECE265C Fall 2013
Problem Set #6 Solutions
Problem 1
In this homework set, you are requested to design and simulate a simple Doherty
amplifier, and determine some features of its operation. For the first problem, an
idealized amplifier is considered, whic
ECE265C Fall 2015
Problem Set #2 Solutions
Problem 1
Imagine you are designing a power amplifier for a cellular handset operating at
1.9 GHz, and that the transistor used for the final stage has Id-Vds
characteristics such as given in the figure below (th
ECE265C Fall 2015
Problem Set #1
Handed Out: September 24
Due date: October 1
Problem 1
Consider the 2 stage amplifier shown below. The drain efficiency and gain for the driver
amplifier are 25% and 16dB, and for the power stage, they are 50% and 6dB,
res
ECE265C Fall 2015
Problem Set #3
Handed Out: October 13
Due date: October 22
Problem 1
Consider a power amplifier designed by a student, called here Class B minus, shown below.
The amplifier is identical to a Class B amplifier, except that the harmonic sh
ECE265C Fall 2015
Problem Set #2
Handed Out: October 1
Due date: October 13
Problem 1
Imagine you are designing a power amplifier for a cellular handset operating at
1.9 GHz, and that the transistor used for the final stage has Id-Vds
characteristics such
Power Amplifier
Linearity
Why Is Linearity Important?
1) To obtain a faithful reproduction of input signal
modulation
Measure with EVM Error Vector Magnitude
2) To avoid generation of spurious outputs particularly
in adjacent spectral bands
Measure with A
ECE265C Fall 2015
Problem Set #5
Handed Out: November 12
Due date: November 24
Problem 1
In this problem you are asked to design a balun for application to differential amplifiers.
The frequency of operation is 1GHz. The balun should operate so that its o
ECE265C Fall 2013
Problem Set #4
Handed Out: November 5 Due date: November 17
Problem 1
In this problem and the next, you are asked to design Class E power amplifiers. In this
problem 1, the amplifier is to be based on a nearly ideal switch, so that you c
Mid-Term Examination Solutions
ECE 265C Fall 2013
Problem 1 (50%)
Consider that you work for a well-known Southern California wireless communications
company, and one of your colleagues has just invented a new class of power amplifier
operation called Cla
ECE265C Fall 2015
Solution to Practice Problem
In class, the Current-Mode Class D amplifier has been discussed. Another possible amplifier
configuration closely related to the CMCD is shown below. Here there is an extra pair of
switches at the power suppl
Mid-Term Examination Solutions
ECE 265C Fall 2015
Problem 1 (50%)
Consider that you work for a well-known Southern California wireless communications
company, and you are designing a power amplifier for basestations at 2 GHz, using a
high voltage transist
Mid-Term Examination Solutions
ECE 265C Fall 2014
Problem 1 (15%)
1) Consider an ideal Class A amplifier, used to amplify signals for an EDGE system,
with a peak-to-average power ratio of 3 dB. Estimate the best drain efficiency that
will be attainable fo
Final Examination
ECE265C
Fall 2014
Name.
General Directions: Answer all 6 questions. The duration of the examination is 3
hours. This is a closed book, closed notes examination. Calculators may not be used.
Numerical answers do not have to be evaluated,
Final Examination
ECE265C
Fall2013
Name
General Directions: Answer all 6 questions. This is a closed book, closed notes
examination. Calculators may not be used. The duration of the examination is 3 hours.
Problem 1 (10o/ol
lmagine that you are employed b
ECE265C Fall 2015
Problem Set #1 Solutions
Problem 1
Consider the 2 stage amplifier shown below. The drain efficiency and gain for the driver
amplifier are 25% and 16dB, and for the power stage, they are 50% and 6dB,
respectively.
1) Compute the power-add
Mid-Term Examination
ECE 265C Fall 2012
Name
General: This is a closed book, closed notes exam. Duration 1 hour 20 minutes.
Calculators are not permitted. Numerical answers do not have to be evaluated, you can
leave things in terms of expressions to be ca
Microwave Power Combiners
Applications of Power Combining
More Power Combiners
Coax Baluns
Free-space
Power Combining
Power Combiners are Frustrating
+
Simple summer for powers from 2 sources
which is lossless and has fixed input
impedance for both channe
Characteristics of
Classical Transistor Amplifiers
"Load Line" in Microwave Circuits
For microwave circuits, load line
definitions are a little different
An ideal choke and ideal dc block
are generally assumed
Id
Vmax/RL
Iddc
Vdd
Vdd
Vout
RL
Vmax
Vds
DC q
Switching-Mode Power Amplifiers
VMCD, CMCD, F, F-1, E
Switching-Mode Amplifiers
Switching-mode minimizes power dissipation in transistor:
when voltage is high, current is zero
when current is high, voltage is minimum
No overlap
Vo
Iout
Vsw
Pdiss
driver
Vh
Transistor Technologies
for Power Amplifiers
HEMT
GaAs, InGaAs or GaN
Requirements for Transistors
in Power Amplifiers
High microwave gain
Iout
Low on-resistance & low knee voltage
FET
High power density
High voltage capability
Vout
Linearity
Ease of matc
ECE 265C
Power Amplifiers
for Wireless Communications
Instructor:
Peter Asbeck
Office EBU1-3607
Phone 534-6713
Fax 534-0556
[email protected]
TA:
Bentao Zhang
[email protected]
Objectives
1) Provide foundation in fundamentals of solid-state power ampl