All RF Cafe quizzes would make perfect fodder for employment interviews for technicians or engineers
- particularly those who are fresh out of school or are relatively new to the work world. Come to
think of it, they would make equally excellent study material for the same persons who are going to
be interviewed for a job.
Some of these books used in quizzes are available as prizes
in the monthly RF Cafe Giveaway.
Note: Many answers contain passages quoted in whole or in part from the text.
This quiz is based on the information presented in
Handbook of RF and Microwave Power Amplifiers, by John L. B. Walker.
University Press graciously provided the book.
Whether you are an RF transistor designer, an amplifier designer or a system designer, this
is your one-stop guide to RF and microwave transistor power amplifiers. A team of expert authors
brings you up to speed on every topic, including: devices (Si LDMOS and VDMOS, GaAs FETs, GaN
HEMTs), circuit and amplifier design (discrete, hybrid and monolithic), CAD, thermal design, reliability,
and system applications/requirements for RF and microwave transistor amplifiers. Covering state-of-the-art
developments and emphasizing practical communications applications, this is the complete professional
reference on the subject.
1. What are the two primary parasitic components of a ceramic package for
an RF power amplifier?
a) Thermal resistance and lead inductance
resistance and lead capacitance
c) Lead frame capacitance and wire bond inductance
d) Lead frame inductance and wire bond capacitance
What change to coaxial connectors is necessary to accommodate higher frequencies?
Physical size decreases
b) Physical size increases
c) Metallurgical compositions
changes are needed
d) No change is required
What are the ramifications of the results of Question 2?
a) Costs increase
c) Power handling decreases
d) There are none
4. What is(are) the broad class(es) of RF power transistor(s)?
a) Bipolar junction transistors (BJTs)
b) Metal oxide semiconductor field effect
c) Gallium devices (GaAs and GaN)
d) All the above
5. How is the average efficiency of a Class B amplifier
affected by power back-off?
a) Degrades as the square root of the power back-off
b) Increases as the square root of the power back-off level
linearly with the power back-off level
d) Increases linearly with the power back-off
6. What breakdown condition(s) is(are) typically
specified for FETs?
a) Gate-source (BVgs)
b) Gate-drain (BVgd)
c) Drain-source (BVds)
d) All the above
How is the crest factor (CF) related to peak signal-power-to-average-signal-power (PAPR)?
a) CF = √(PAPR)
b) CF = PAPR
c) CF = PAPR2
CF is not related to PAPR
8. What is the primary limitation
of RF power transistor applications?
a) Physical size
b) Parasitic elements
c) Heat dissipation
9. What is
a fundamental problem with using Newton's Method in a harmonic-balance simulation?
Newton's Method relies on the classical model
b) Newton's Method is useful only in linear
c) Newton's Method is not guaranteed to converge on a solution
There is no issue with using Newton's Method
is a limitation on RF power amplifier (RFPA) design margin requirements?
equipment precision and accuracy
b) Schedule constraints
c) Power handling
d) Bias voltage variation
Need some help? Click here for the
answers and explanations.
Posted August 3, 2013