February 2021
15
station is surrounded by six equidis-
tant stations [1].”
So what is Bell Labs up to now?
Owned currently by the Finnish
company Nokia, it recently received
a US$14.1 million contract from
NASA to design and develop a 4G
network on the moon [2]. According
to Bell Labs, “Astronauts will use
its wireless network for data trans-
mission, controlling of lunar rov-
ers, real-time navigation over lunar
geography (think Google Maps for
the moon), and streaming of high-
definition video” [2]. It is all a part of
the long-term NASA plan [3], “which
entails 37 launches of private and
NASA rockets, as well as a mix of
robotic and human landers . . . with
a ‘Lunar Surface Asset Deployment’
in 2028, likely the beginning of a
surface outpost for long-duration
crew stays.”
At least in principle, the proposed
4G network should “work better on the
moon than it does here—it won’t have
any trees, buildings or TV signals to
interfere with the 4G signal” [2]. On the
other hand, it will have to be “specially
designed to withstand the particulari-
ties of the lunar surface: extreme tem-
perature, radiation and space’s vacuum.
It will also stay functional during lunar
landings and launches, even though
rockets significantly vibrate the moon’s
surface” [2]. Like the 5G networks
being developed currently on Earth,
the lunar mobile network will make
use of the so-called small cells [2], [4]. I
can’t wait to see images of an astronaut
traipsing around on the moon asking,
“Can you hear me now?”
References
[1] A. Madrigal. “The 1947 paper that first de-
scribed a cell-phone network.” The Atlantic.
Accessed: Nov. 3, 2020. [Online]. Available:
https://www.theatlantic.com/technology/
archive/2011/09/the-1947-paper-that-first
-described-a-cell-phone-network/245222/
[2] D. Goldman. “ NASA and Nokia are putting
a 4G network on the moon.” CNN. Accessed:
Nov. 3, 2020. [Online]. Available: https://www
.cnn.com/2020/10/18/tech/4g-network-moon
-trnd/index.html
[3] E. Berger. “ NASA’s full Artemis plan revealed:
37 launches and a lunar outpost.” Ars Techni-
ca. Accessed: Nov. 3, 2020. [Online]. Available:
https://arstechnica.com/science/2019/05/
nasas-full-artemis-plan-revealed-37-launches
-and-a-lunar-outpost/
[4] A. Nordrum et al. “ Everything you need to
know about 5G.” IEEE Spectrum. Accessed:
Sept. 5, 2020. [Online]. Available: h t t p s ://
spectrum.ieee.org/video/telecom/wireless/
everything-you-need-to-know-about-5g
for these nonidealities, negative group
delay circuits are often employed.
This article covers a number of circuit
topologies for group delay compensa-
tion, along with numerous references,
allowing you to delve deeper into the
operation of these circuits.
In the second article, “Waveguide
Components Based on Multiple-
Mode Resonators,” Wong et al. look
at the use of multimode resonators in
waveguides as a method to improve
the frequency selectivity of the reso-
nator while reducing the overall foot-
print. The article provides a tutorial
on multimode waveguide resonators
and shows numerous examples of
these structures in applications such
as diplexers, filters, and baluns.
The third feature, “Tunable Balanced
Power Dividers” by Lin et al., provides
an overview of balanced power divid-
ers. Balanced power dividers (and
their combining counterparts) are
particularly useful because the bal-
anced nature of their circuit operation
provides some immunity to common
mode issues as well as noise. A num-
ber of circuits are shown with expla-
nations of their operation; an extensive
reference list is also provided for those
wishing to learn more.
We also have an “Application
Notes” column in this issue by Zubair
Ahmed, “Revisiting the Binomial
Multisection Transformer.” This im -
pedance matching structure is com-
monly studied in various microwave
engineering textbooks, but the author
takes a different approach in explain-
ing its operation. If any of your stu-
dents have difficulty understanding
common textbook approaches, this
alternative explanation may be useful.
Also in this issue is the MTT-S pres-
ident’s column, where Dr. Gregory
Lyons introduces you to the new
MTT-S president-elect for 2021 as
well as returning Administrative
Committee (AdCom) members for
new three-year terms. As you have
read about in the previous Society
news “Spotlight” columns on the
various AdCom committees, the MTT-S
AdCom is a group of volunteers
engaged in promoting the direction
and growth of the Society.
One area t hat the AdCom is i n volved
with is the organization, promotion,
and presentation of our MTT-S webi-
nar series, and this month we have a
short column on the planned webinars
through the middle of the year. We also
have a review of the recently published
book Millimeter-Wave Circuits for 5G and
Radar that you may wish to read or add
to your library. Our “MicroBusiness”
column speaks to all members about
the pandemic restrictions on travel and
how they affect the way we work as
well as our lives. In addition, we have
a “Microwave Surfing” column focus-
ing on the origins of the concept of cel-
lular mobile communication. Finally,
Dr. Takashi Ohira continues his
“Enigmas, etc.” series with another
waveform engineering problem for you
to solve. The solution to last month’s
enigma is also included. I hope you
enjoy the issue.
From the Editor’s Desk (continued from page 6)