# Microwave Circulator DesignRF Cafe Quiz #59

All RF Cafe quizzes would make perfect fodder in 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.

Note: Some material based on books have quoted passages.

This quiz is based on the information presented in Microwave Circulator Design, 2nd Edition, by Douglas K. Linkhart.

Graciously provided by Artech House

Circulator design has advanced significantly since the first edition of this book was published 25 years ago. The objective of this second edition is to present theory, information, and design procedures that will enable microwave engineers and technicians to design and build circulators successfully. This resource contains a discussion of the various units used in the circulator design computations, as well as covers the theory of operation. This book presents numerous applications, giving microwave engineers new ideas about how to solve problems using circulators.

1.  What is the primary characteristic of a circulator?

a)  It is round in shape
b)  It must be free to rotate
c)  Energy is evenly distributed among all ports
d)  Energy entering one port is coupled to an adjacent port, but to no other ports

2.  What is a common mechanical analog of ferrimagnetic resonance?

a)  A level
b)  An inclined plane
c)  A gyroscope
d)  A massive body

3.  What explains nonreciprocal action in ferrites?

a)  Coupling of microwave energy with electron spins
b)  Coupling of microwave energy with electron orbital motion
c)  Diode action
d)  Rectifier action

4.  What explains nonreciprocal action in semiconductors?

a)  Coupling of microwave energy with electron spins
b)  Coupling of microwave energy with electron orbital motion
c)  Diode action
d)  Rectifier action

5.  What are ferrites?

a)  Natural magnets
b)  Toroidal magnets
c)  Artificial ferrimagnetic materials
d)  Fuzzy pets

6.  In which resonance region do most waveguide circulators operate?

a)  Above resonance
b)  Below resonance
c)  Both above and below resonance
d)  Neither above nor below resonance

7.  Which type of circulator typically has the highest power handling capability?

a)  Differential phase shift
b)  Lumped constant
d)  Field displacement

8.  What is the primary difference between a circulator and an isolator?

a)  Circulators are round, whereas isolators are not
b)  The isolator has an internally terminated, inaccessible port
c)  Isolators have higher power handling than circulators
d)  Circulators have higher power handling than isolators

9.  How important is the microwave transmission medium (waveguide, stripline, coaxial line) in ferrite selection?

a)  Each transmission medium type has specific needs
b)  Transmission medium type is not important
c)  Waveguide requires a different ferrite type than stripline and coaxial line
d)  Waveguide and stripline require a different ferrite type than coaxial line

10.  What can be the result of imperfect contact between the ferrite and the ground plane?

a)  Undesired resonances
b)  Generally poor electrical performance
c)  Both a) and b)
d)  Neither a) nor b)