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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,
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Return to RF Cafe Quiz #40
This quiz is based on the information presented
Introduction to Antenna Analysis Using EM Simulation, by Hiroaki Kogure,
Yoshie Kogure, and James C. Rautio, published by Artech House. It is written for
novice engineers and engineering students. This easy-to-comprehend resource offers
readers thorough introductory-level treatment of antenna analysis using electromagnetic
(EM) simulators. This richly-illustrated book shows how to use EM software to analyze
and tune wireless antennas to meet specific requirements. Readers learn important
wireless antenna design terminology and gain a detailed understanding of how antennas
work. Moreover, the book offers guidance in troubleshooting problems with wireless
Note: Sonnet Lite is a free download provided by the Sonnet company,
of Syracuse, NY.
1. What was the James C. Ratio's first antenna design
"The programs I wrote for those QST articles, called "Annie," is what got my
company started. (see page xiii)
2. Just exactly what is an antenna?
c) Any structure that performs the function of transmitting and receiving
An antenna is usually made from metal pipe, conducting
wire, or metal traces on a PCB. (see page 3)
3. Where is the approximate location
of the near field / far field transition?
c) 1λ from the antenna
Up to about one wavelength around the antenna is called the near field.
(see page 29)
4. What does a time-varying magnetic field generate?
a) An electric field
Faraday's law of induction, described in Chapter 1, states that "a time varying
magnetic field generates an electric field." (see page 53)
5. What is the impedance of a minimum-loss coaxial cable
with an air dielectric?
c) 75 Ω
When coax uses an air dielectric, we see minimum loss in the cable when we choose
its dimensions so that the characteristic impedance (Z0) is about 75
ohms. When the coax is filled with a dielectric of relative permittivity of 2.55
(say, polyethylene), the minimum loss dimensions give a Z0 of about 50
ohms. (see page 88)
6. How is dielectric material modeled in an EM simulator?
b) Parallel RC
Dielectric material can be represented as an equivalent parallel RC circuit.
The capacitor represents a lossless dielectric and the resistor represents dielectric
loss. (see page 131)
7. What happens to magnetic flux if current through the
loop is doubled?
a) It also doubles
Φ (flux) = L (inductance) * I (current). (see page 165)
8. For an input power of 1 W, what is the output power
of a lossless passive antenna with a specified gain of 3 dB or 6 dB?
b) 1 W for both gains
An antenna with gain outputs more power in one direction and less power in another.
If we look at the total power radiated in all directions, no extra power is created.
(see page 200)
9. Where does a log-periodic antenna get its name?
d) From the logarithmic spacing and length ratios of its dipoles
A log-periodic antenna has different length dipoles whose spacings and lengths
are determined by means of the logarithmic function. (see page 229)
10. Proper test environments are crucial to reliable EM
field measurements as evidenced by what factor in Heinrich Hertz's early experiments?
d) A nearby pot-bellied stove
Hertz initially measured a wildly incorrect value for the speed of light in one
of his early experiments. It turns out that the problem was a large cast iron stove
located nearby in his laboratory. Effects of objects of any kind, including walls,
earth, concrete, people, and so forth, can seriously disrupt measurements.
(see page 203)
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