# Practical Microwave CircuitsRF Cafe Quiz #61

All RF Cafe Quizzes make great 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. Bonne chance, Viel Glück, がんばろう, buena suerte, удачи, in bocca al lupo, 행운을 빕니다, ádh mór, בהצלחה, lykke til, 祝你好運. Well, you know what I mean: Good luck!

Note: Some material based on books have quoted passages.

This quiz is based on the information presented in Practical Microwave Circuits, by Stephen A. Maas.

Note: Some of these books are available as prizes in the monthly RF Cafe Giveaway.

"This book is a collection of things I learned. largely on my own, over forty years in microwave circuit design. While almost all of the material in this book existed somewhere in some form, no single source was comprehensive and accessible. I learned most of it by experience, talking to people and digging through technical papers and books. In some cases, I just had to figure it out..."

1.  Where are coupled transmission lines likely to be found?

a)  Filters.

b)  Directional couplers.

c)  Baluns.

d)  All the above.

2.  What is a homogeneous transmission line?

a)  A transmission line with a constant cross-section.

b)  A transmission line with a single conductor.

c)  A transmission line which can only be mated to a similar transmission line.

d)  A transmission line in which all of the field lines are contained within a single dielectric medium.

3.  Which transmission line is an example of a non-homogeneous transmission line?

b)  Stripline.

c)  Coaxial line.

d)  Waveguide.

4.  Which problem did the Lange coupler solve for two-strip planar couplers?

a)  The inability to achieve sufficient coupling between two edge-coupled strips to realize a 3-dB coupler.

b)  The inability to prevent excessive coupling between two edge-coupled strips to realize a 3-dB coupler

c)  High frequency operation became possible.

d)  Low frequency operation became possible.

5.  Which of the following describes a balanced transmission line?

a)  Two lines equally distributed on the substrate.

b)  Even and odd mode waves are equal on both conductors.

c)  The ground is used as a conductor.

d)  Two conductors of identical cross-section surrounded by free space (isolated from ground).

6.  Which of the following describes an unbalanced transmission line?

a)  Two lines unequally distributed on the substrate.

b)  Fringing fields "leak" from the edges of the conductor.

c)  Uses the ground surface as one conductor.

d)  Unequal currents in the conductors.

7.  When did S parameters first come into common use?

a)  1990s.

b)  1960s.

c)  1930s.

d)  1900s.

8.  What is the main difference between microwave and lower frequency analog circuit design?

a)  Microwave design focuses more on maximum power transfer whereas lower frequency circuit

design focuses more on voltage gain.

b)  Microwaves are at a higher frequency.

c)  Microwave circuits require more curent.

d)  Analog circuits are available in integrated form.

9.  What is another name for a normalized lowpass filter design?

a)  A Butterworth filter.

b)  A Chebyshev filter.

c)  A complimentary network.

d)  A prototype network.

10.  What is meant by "de-embedding" S parameters?

a)  Removing embedded losses from the measurement.

b)  Removing all effects test fixture elements from the measurement of a discrete component being measured.

c)  Removing capacitive influences.

d)  Removing even and odd mode waves from the equation.