 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!
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Note: Some material based on books have quoted passages.
Return to RF Cafe Quiz #58
This quiz is based on the information presented in Microwave and Millimeter-Wave Electronic Packaging,
by Rick Sturdivant.
Note: Some of these books are available as prizes in the
monthly RF Cafe Giveaway.
1. Match the following frequency band ranges with their proper letter
designations.
| VHF UHF L S C X Ku K Ka V W |
30 kHz - 300 MHz 300 MHz - 1 GHz 1 GHz - 2 GHz 2 GHz - 4 GHz 4 GHz - 8 GHz
8 GHz - 12 GHz 12 GHz - 18 GHz 18 GHz - 27 GHz 27 GHz - 40 GHz 40 GHz - 75 GHz
75 GHz - 110 GHz |
(see page 2)
2. What is the main additional issue concerning high versus low frequency
design?
d) All the above
At higher frequencies a set of additional issues arise compared to lower frequencies. Among
them are distributed effects, undesired resonances in packaging elements or modules, circuit traces
that must be treated as transmission lines, dispersion effects, coupling and cross-talk between
circuits, very high heat density in circuits, parasitic effects and proper RF grounding, and hermiticity
or otherwise protection of circuits. (see page 3)
3. What is the difference between loss tangent and dissipation factor?
b) Dissipation factor does not account for permittivity being complex at high frequencies
Dissipation factor ignores the fact that permittivity is complex at high frequencies due to
atonic resonances within the dielectric material. (see page 18)
4. What is a first-level interconnect in reference to RFIC design?
a) Electrical connection between the semiconductor device and the package
First-level interconnects (FLI) are the electrical connections between semiconductor devices
such as integrated circuits or transistors and the first level of packaging. (see page 31)
5. Match the following terms with their proper definitions.
| Atomic polarization |
Occurs when the center of an electron cloud of an atom is displaced relative to the center
of the nucleus in the presence of an electric field. |
| Ionic polarization |
Occurs when molecules with ionic bonds have a displacement of the positive ions relative
to negative ions in the presence of an electric field. |
| Orientation polarization |
Occurs when molecules that have a permanent dipole moment, but are naturally randomly
oriented, orient themselves in the presence of an electric field. |
(see page 42)
6. What makes metals good electrical conductors?
b) Free electrons
Metallic materials have free electrons, which giver rise to an electric current in the presence
of an electric field. (see page 56)
7. What are properties of ceramics that make them good as microwave
circuitry substrates?
g) All the above
Ceramics are useful in RF products for several reasons: inherently stable due to high Young's
modulus, easy to wire bond to, tight line resolution for impedance control, narrow line widths
for high impedance, easy brazing facilitated hermiticity, high thermal conductivity, high circuit
density with blind and buried vias, high reliability in extreme temperature environments. (see
page 67)
8. What type of thick film pastes are available for use on ceramic substrates?
g) All the above
The paste used to pattern thick-film ceramics can be metal, resistor material, or dielectrics
(see page 79)
 9.
What are the names of the two ends of the depicted type of wire
bond?
d) Ball and stitch
(see page 109)
10. What is one of the main advantages of flip chip mounting for high
frequency ICs?
c) Lower wire bond inductance
Flip chip interconnects are particularly useful at microwave an millimeterwave frequencies
because of the lower inductance and tight manufacturing tolerances. (see page 127)
|
