 Sunday the 28th
 This
Engineering Theme Crossword Puzzle for February 28th contains only words
and clues related to engineering, mathematics, chemistry, physics, and other
technical words. As always, this crossword contains no names of politicians,
mountain ranges, exotic foods or plants, movie stars, or anything of the sort
unless it/he/she is related to this puzzle's technology theme (e.g., Hedy
Lamarr or the Bikini Atoll). The technically inclined cruciverbalists amongst
us will appreciate the effort. Enjoy!
Friday the 26th
 "Two's company, but three's a crowd
- unless you're trying to make graphene superconduct at higher temperatures.
That is the finding of researchers at Harvard University in the U.S., who
discovered that the superconducting state in three stacked and twisted layers
of graphene is more robust to temperature increase than the equivalent state
in two-layer graphene. The researchers also found evidence that superconductivity
in the trilayer system comes from strong interactions between electrons, rather
than weak ones as in most conventional superconductors - corroborating a result
reported a few days earlier by a separate team at the Massachusetts Institute
of Technology (MIT). A sheet of graphene consists of a simple repetition of
carbon atoms arranged in a two-dimensional hexagonal lattice..."
 RF Cafe's raison d'être is and always
has been to provide useful, quality content for engineers, technicians, engineering
managers, students, and hobbyists. Part of that mission is offering to post
applicable job openings.
HR department employees and/or managers of hiring companies are welcome to
submit opportunities for posting at no charge. 3rd party recruiters and temp
agencies are not included so as to assure a high quality of listings. Please
read through the easy procedure to benefit from RF Cafe's high quality visitors...
 "Princeton University has found a way
to determine the direction to an object in three dimensions using only
on-chip THz antennas with ~2°accuracy. It exploits frequency-dispersive
leaky-wave antennas - end-fed strips, 1.7mm long, with transverse slots spaced
at 43 μm intervals. The crucial property of these, is that injecting
a frequency between 360 and 400 GHz into one end results in fan of energy
leaving the antenna at right angles to its long axis (see diagram). The higher
the frequency, the further tilted away from the feed end is the fan: 360 GHz
leaves at right angles and 400 GHz tilts the fan at 40° to the normal,
so scanning from 360 to 400 GHz sweeps the fan from 0° (normal) to +40°..."
 "My husband wants a selenimum rectalfire,
a silicode capasitator, and a 16 bome appleflyer." That is the caption of
one of the "Hobnobbing
with Harbaugh," comics that appeared in the June 1962 edition of Popular
Electronics magazine. Dave Harbaugh's "Hobnobbing with Harbaugh"
was a monthly feature for a couple years that dealt with stereotypical (pun
intended) behavior of technophiles and their often unwilling, often unwitting
wives, girlfriends, kids, parents, workmates, and neighbors.
 It was a lot of work, but I finally
finished a version of the "RF &
Electronics Schematic & Block Diagram Symbols" that works well with
Microsoft Office™ programs Word™, Excel™, and Power Point™. This is
an equivalent of the extensive set of amplifier, mixer, filter, switch, connector,
waveguide, digital, analog, antenna, and other commonly used symbols for system
block diagrams and schematics created for Visio™. Each of the 1,000 or so
symbols was exported individually from Visio in the EMF file format, then
imported into Word on a Drawing Canvas. The EMF format allows an image to
be scaled up or down without becoming pixelated, so all the shapes can be
resized in a document and still look good. The imported symbols can also be
UnGrouped into their original constituent parts for editing. Check them out!
 Exodus Advanced Communications has
introduced a broadband amplifier, model
AMP1074−9, which covers 1.0 to 18.0 GHz and produces >10 Watts
minimum power (15 W nominal). The AMP1074−9 has a minimum gain of 40
dB with -20 dBc harmonics. The unit is a compact Linear Class A/AB design
for optimum reliability & ruggedness for all applications. Nominal dimensions
of 140W x 160L x 27H mm with SMA female connectors. Features: Class AB
GaN design, instantaneous ultra-wide bandwidth, broadband coverage of C, X
and Ku Bands...
 Triad RF Systems designs and manufactures
RF power amplifiers and systems.
Triad RF Systems comprises three partners (hence 'Triad')
with over 40 years of accumulated knowledge of what is required to design,
manufacture, market, sell and service RF/Microwave amplifiers and amplifier
systems. PA, LNA, bi-directional, and frequency translating amplifiers are
available, in formats including tower mount, benchtop, rack mount, and chassis
mount. "We view Triad more as a technology partner than a vendor for our line-of-sight
communications product line." Please check to see how they can help your project.
Thursday the 25th
 This
Electronic Puzzle Square, compliments of Lt. C.K. Johnson, appeared in
the January 1945 issue of Radio-Craft magazine. It consists of electronics-related
numerical questions whose answers, if correct, create a 4x4 matrix whose columns,
rows, and long diagonals all add up to 45. Non-integer answers need to be
rounded according to standard rules (do not just truncate). In case you left
your slide rule at the office, a link is provided to assist with Q2. The biggest
head scratcher question is Q4, since it requires the conversion from polar
to rectangular coordinates, but hey, you're an engineer (or a crack technician).
Having Euclid on-hand for Q5 might be helpful. A link is provided to a copper
wire parameter table for Q9. Have fun.
 Withwave's W701 Series are complete
line of high performance flexible microwave cable assemblies. Specially,
Flexible Armored W701 Series have low density PTFE structure to achieve
velocity propagation of 76% and good phase and amplitude stability performance.
They have excellent RF performance up to 26.5 GHz, and DC to 40 GHz with SMA
and 2.92 mm connectors, respectively. Features: center conductor: silver plated
copper, insulator: low density PTFE, outer conductor 1: silver plated copper
foil, outer conductor 2: silver plated copper wire, jacket: FEP...
 When doing some research for creating
a new quiz on inventors
and their inventions, I decided to look for people according to their
countries. I almost always do image searches since doing so does a good job
of filtering out pages that merely mention the topic of interest. My first
Google search was "american inventors." I expected to see the familiar faces
of Thomas Edison, Henry Ford, George Westinghouse, Marie Curie, Alexander
Graham Bell, George Washington Carver, Edwin Armstrong, Hedy Lamarr, Benjamin
Franklin, Robert Goddard, Albert Einstein, the Wright Brothers, Samuel Morse,
William Shockley, etc. Those are the names that first come to my mind, and
admittedly the list is dominated by White men. Imagine my surprise when the
Google search results belied my perception. Take a look at the first few pages
of results to see what I mean. Next, I moved on to an image search for "canadian
inventors..."
 "A team of researchers from Duke University,
in partnership with Facebook's Connectivity Lab, have announced a major advancement
towards the dream of ditching the fiber in fiber optics. Visible and infrared
light can carry more data than radio waves, but has always been confined to
a hard-wired, fiber-optic cable. While working to create a
free-space optical communication system for high-speed wireless internet,
the researchers showed that speed and efficiency properties previously demonstrated
on tiny, single-unit plasmonic antennas can also be achieved on larger, centimeter-scale
devices. The research appeared online in the journal Optica. In 2016, researchers
from Internet.org's Connectivity Lab..."
 Anatech Electronics offers the industry's
largest portfolio of high-performance standard and customized
RF and microwave filters and filter-related products for military, commercial,
aerospace and defense, and industrial applications up to 40 GHz. Two
new filters have been introduced: a 10.01 GHz cavity bandpass filter
with a 320 MHz bandwidth and 1 dB of insertion loss, and an LTE
Band 8 uplink / Band 3 downlink multiband duplexer filter with <50 dB isolation
between bands and 1 dB insertion loss. Custom RF power directional coupler
designs can be designed and produced when a standard cannot be found, or the
requirements are such that a custom approach is necessary...
 Audio crossover networks have the same
fundamental mission as RF multiplexer filters in radio systems, which is to
separate and steer specific bands of frequencies into two or more signal paths.
While simple in concept, implementation in hardware can be a major challenge
depending on requirements for channel separation, feedthrough, phase and group
delay, amplitude equalization, distortion, and other factors. This article
discusses some of the decisions used by crossover network designers when considering
where to make band breaks, while leaving actual circuit design rules to other
authors. I built a set of custom speakers many moons ago and went through
the frustrating process of deciding where to place the breaks and which speakers
to use...
 Please take a few moments to visit
the
everythingRF website to see how they can assist you with
your project. everythingRF is a product discovery platform for RF and microwave
products and services. They currently have 267,269 products from more than
1397 companies across 314 categories in their database and enable engineers
to search for them using their customized parametric search tool. Amplifiers,
test equipment, power couplers and dividers, coaxial connectors, waveguide,
antennas, filters, mixers, power supplies, and everything else. Please visit
everythingRF today to see how they can help you.
Wednesday the 24th
 Constant K filters are not seen much
in modern designs, but were some of the earliest types of controlled impedance
frequency selective networks. George Campbell is credited with inventing constant
K filters in the early days of the last century. He referred to the circuits
as "electric wave filters." Campbell's filters consisted of identical cascaded
sections of "T" and "pi" inductor and capacitor combinations, yielding arbitrarily
high (theoretically) out-of-band cutoff and band edge steepness. Less than
ideal quality factor of the components causes realizable filters to exhibit
increasing insertion loss and reduction in band edge corner sharpness as sections
are added. Within a couple decades as improved filters became necessary...
 "Characterizing the fundamental mechanisms
and charge transport phenomena governing the interactions between ionizing
and non-ionizing radiation with carbon-based (nanotube and graphene) field-effect
transistors (FETs) devices and integrated circuits (ICs). The main objective
of the
RadCNT program was the characterization of fundamental mechanisms and
charge transport phenomena governing the interactions between ionizing and
non-ionizing radiation with carbon-based (nanotube and graphene) field-effect
transistors (FETs) devices and integrated circuits (ICs). This effort was
supported through the fabrication of aligned single-walled carbon nanotubes
(SWCNT) FETs at the University of Southern California's (USC) Nanotechnology
Research Laboratory and through a collaboration with the Naval Research Laboratories
(NRL) for radiation testing and expertise..."
 Even though my fingers stop working
when exposed to temperatures below freezing, I love the northern climate -
four full seasons, snow, iced-over lakes, migrating birds, fiery autumns,
cool summers, the whole experience. Having the option of not participating
in the cold outdoor environs is what makes it good. However, the
U.S. Army Signal Corps guys pulling duty in Alaska during World War II
did not have that luxury. As told by radio engineer Major Colvin in this story
from a 1945 edition of ARRL's QST magazine, winter life in Alaska at -40°
was a real challenge. It was a world where Prestone antifreeze froze, the
sun shone only a few hours a day, vehicles had to be left running 24/7 or
risk not being able to be re-started, and mile-long treks between buildings
was common. There were no snowmobiles. The success of the communications station...
 For the past few months, this full-page
BridgeCom advertisement has been running in the American Radio Relay League
(ARRL) magazine QST. When I first saw it I though it might be one
of those research laboratory hydraulic apparatuses for generating the kind
of pressure found at the center of the Earth. Scientists use such devices
to synthesize diamonds by compacting coal. In actuality, the four cylinders
are part of the
BridgeCom BCD-144250 Rack Mount VHF Duplexer. Per their website: BridgeCom
Systems' BCD-144250 Duplexer for amateur and commercial applications. The
BCD-144250 utilizes four high-quality cavities that results in uncompromising
duplex isolation. It will handle up to 250W continuously for the most demanding
applications...
 ConductRF announces availability of
professional high frequency
TSA89 series of RF test cables with performance to 40 GHz. Precision
connector choices include; SMA, Type-N, 3.5mm, 2.92mm, & 2.4mm. Key features:
High-frequency point to point cable, light weight rugged double-shielded,
flexible cable, low loss <0.68 dB/ft @ 40 GHz, low VSWR <
1.35:1 (Typical < 1.25:1), RF leakage >−100 dB to 18 GHz,
temperature rated from -55ºC to 125ºC. 100% factory VSWR and insertion loss
tested. Wide selection of configurations & lengths. Cables are in stock
and available immediately from Digi−Key...
 KR Electronics designs and manufactures
high quality filters for both the commercial and military markets. KR Electronics'
line of filters includes
lowpass, highpass, bandpass, bandstop and individually synthesized filters
for special applications - both commercial and military. State of the art
computer synthesis, analysis and test methods are used to meet the most challenging
specifications. All common connector types and package form factors are available.
Please visit their website today to see how they might be of assistance. Products
are designed and manufactured in the USA.
Tuesday the 23rd
 "Zero Emissions" has got to be one
of most egregiously contrived, deceptive terms in the history of technology.
Likewise for "Green Dollars," which really means government subsidization
for something that citizens will not pay for. Per the story: "Despite accounting
for only 9% of the global vehicle stock, large diesel truck engines represent
39% of the transport sectors' greenhouse gas emissions, and about 5% of Co2
emissions from fossil fuels. But this may soon change. For those in the automotive
world trying to convince the boss that climate change is an important strategic
issue for business, something important is happening: Companies are going
after green dollars, money spent to reduce pollution and waste, and in doing
so, they're also demonstrating good corporate citizenship."
 Lotus Communication Systems began
in 2009, setting up CNC machine shop and RF/microwave assembling and testing
lab in Middlesex Country, Massachusetts. Lotus is committed to highest quality
and innovative products. Each RF/microwave
module meets exceedingly high standards of quality, performance and excellent
value, and are 100% MADE IN USA. Lotus' RF/microwave products cover frequency
band up to 67 GHz. Lotus also offers an COTS shield enclosures for RF/microwave
prototyping and production. All products are custom designed. We will find
a solution and save your time and cost. Lotus has multiple 4 axis CNC machines
and LPKF circuit plotters.
 Qorvo, a leading provider of innovative
RF solutions that connect the world, today announced that
Dr. Michael Roberg, a Qorvo Fellow, has received this year's prestigious
Outstanding Young Engineer Award from the Institute of Electronics Engineers
(IEEE) Microwave Theory and Techniques Society (MTT-S). This award recognizes
an outstanding young MTT-S member who has distinguished himself/herself through
a sequence of achievements which may be technical (within the MTT-S field
of interest), may constitute exemplary service to the MTT-S, or may be a combination
of both. Doug Bostrom, vice president of Engineering, Infrastructure and Defense
Products, said, 'We are proud of Dr. Roberg's accomplishments and important
contributions to Qorvo in advancing our RF leadership and innovation..."
 Yes, this is another article that will
probably appeal to a small percentage of RF Cafe visitors, but please countenance
my indulgence in things aeronautical as well as things electrical. The early
1930s was a time when both airplanes and electronics were a wonder and a mystery
to most of the public worldwide. Of course today both are still a mystery
to the public but the wonder is gone - it's merely taken for granted. Many
idiosyncrasies of
airborne electronic communications were encountered for the first time,
like the need for proper grounding and static electricity dissipation. Ruggedization
of chassis assemblies in terms of mechanical vibration and shock as well as
for temperature extremes was a real challenge to engineers, technicians, and
pilots...
 Spectra Labs' Sean Wallace has a nice
rundown of
the evolution of RF signal-observing tools in an article by that name,
posted on the Microwaves & RF website. H begins with swept-tuned spectrum
analyzers and progresses through FFT spectrum analyzer, the real-time spectrum
analyzer, and finally the RF recorder. Says Sean: "Tools used to visualize
RF signals have evolved over time from the spectrum analyzer to today's RF
recorders. However, each era's tools have had limitations. This article shows
how the modern approach builds on the best aspects of what's come before..."
 Since 1996, ISOTEC has designed,
developed and manufactured an extensive line of
RF/microwave connectors, between-series
adapters, RF components and filters for wireless service providers including
non-magnetic connectors for quantum computing and MRI equipments etc. ISOTEC's
product line includes low-PIM RF connectors components such as power dividers
and directional couplers. Off-the-shelf and customized products up to 40 GHz
and our low-PIM products can meet -160 dBc with 2 tones and 20 W
test. Quick prototyping, advanced in-house testing and high-performance. Designs
that are cost effective practical and repeatable.
Monday the 22nd
 Since there does not seem to be service-related
trade magazines - at least for electronics - anymore, most people have never
gotten first-hand experiences of the kinds of travails endured by servicemen
as imposed by customers. Radio News, Radio-Electronics,
Popular Electronics, Radio-Craft, and other such magazines
regularly carried articles and sometimes regular monthly columns with content
contributed by guys in the repair shop and in homes. Some were actual scenarios
and others were fictional based on typical experiences. The most entertaining
were told in story form, and were undoubtedly embellished a bit in order to
increase the drama factor. This Serviceman's Experiences feature ran in
Radio News for a few years. I have to admit to not quite getting
the "Leg Department" comment, unless it means he was treated as a gofer (i.e.,
go for this and go for that, using his legs). Optional theories are welcome...
 Qorvo®, a leading provider of innovative
RF solutions that connect the world, today introduced a family of
compact Quadrature IF Mixers, or IQ Mixers, that address the needs of
wideband and high frequency applications such as phased array radar, satellite
communications and electronic warfare (EW). These four new I/Q mixer products,
QPX0001, QPX0002, QPX0003D (die) and QPX0004D(die) help to extend and strengthen
Qorvo's existing mixer portfolio by delivering industry-leading broadband
performance while covering an impressive operating frequency range from 2.5 GHz
up to 40 GHz. They offer excellent image rejection (>20 dB) and
are a much smaller alternative to higher cost hybrid I/Q mixers and single
sideband...
 When civil engineers and mechanical
engineers take their introductory classes in hydraulics, are they taught that
the
functional equivalent of water pressure in a pipe is equivalent to voltage
in a battery, and that the rate of water flow is equivalent to current in
a circuit, and that the diameter and surface finish of pipes are equivalent
to resistance in electricity... in the same manner that electronics students
are taught from the opposite point of view? The answer is 'yes,' they are.
It's kind of funny how for some reason using an analogy from another familiar
physical process always seems to help make more sense of the subject at hand.
In fact, for macro level problems, the mathematical equations that govern
mechanical and electrical systems are identical, with only the objects and
units being different. Oscillating LC (inductor and capacitor) tank and damping
circuits have equations that look just like spring and dashpot systems...
 Bogdan Adamczyk has an interesting
a paper on the InCompliance website entitled "EMC
Resonance Part I: Non-Ideal Passive Components." "This article is
part of a two-article series devoted to the concept of resonance in EMC. In
Part I the fundamental circuit background is presented and illustrated by
the resonance phenomenon in the non-ideal models of passive circuit components:
capacitors, ferrite beads, resistors, and inductors. Part II (to appear in
the next issue) describes the resonance in the decoupling capacitor circuits.
Resonance in RLC Circuits In circuit courses, the study of resonance is usually
limited to the two classical 2nd-order circuits, series and parallel RLC configurations.
These circuits, shown in Figure 1, contain a single lumped capacitor and a
single lumped inductor connected either 'purely' in series or 'purely' in
parallel..."
 Triad is proud to announce we've been
awarded a contract from Sierra Nevada Corporation to provide turnkey
amplified radio systems for use on the U.S. Army's and National Guard's
latest fleet of Lakota helicopters. The integrated radio solution is a component
of the U.S. Army/National Guard (ARNG) Mission Equipment Package (MEP) program.
This MEP enables multi-role helicopter missions and operations that range
from homeland security and medical evacuation to drug interdiction, support,
and logistics. These versatile, high-powered radio kits are providing the
next-level position/location/navigation voice, data, and video communication
capabilities needed to improve efficacy of tactical maneuvers and increase
soldier safety...
 TotalTemp Technologies has more than
40 years of combined experience providing thermal platforms.
Thermal Platforms
are available to provide temperatures between −100°C and +200°C for cryogenic
cooling, recirculating circulating coolers, temperature chambers and temperature
controllers, thermal range safety controllers, space simulation chambers,
hybrid benchtop chambers, custom systems and platforms. Manual and automated
configurations for laboratory and production environments. Please contact
TotalTemp Technologies today to learn how they can help your project.
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