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archives. 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 (of course a gratuity will be graciously
accepted). 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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