"This
is the first useful device that exploits charge-density wave modulation of current through a 2D material,
claims the University of California Riverside, which worked with the University of Georgia. Graphene
can conducts electrons rapidly, but has no usable bandgap from which to forge switching behaviour.
Instead of switching with graphene, a 2D crystal form material tantalum sulphide (TaS2) was
..."
Although
single capacitor, single inductor resonant tank circuits are not widely used, one place you do find
them is in transistor amplifier stages in order to peak gain in a particular frequency band. Author
Jack Najork offers here a few pointers regarding preforming quick mental calculations for how ranges
of capacitance values affect the resonant frequency. For instance the
ratio of capacitance
values needed to cover a certain range of resonant frequencies is equal (ideally)
to the square root of the frequency ratio. This comes into play both when determining values during
the design phase and the selecting a variable capacitor for providing tuning
...
Each
month I randomly select 1 or 2 people from my
software purchaser list and offer
to award a free book in the monthly RF Cafe Book Drawing.
Also each month most people never respond to my notice of being a winner (probably
thinking my e-mail notice is spam). Most of the books sell for >$100 on Amazon. This month,
fortunately, Robert E., of Carlisle, Massachusetts, did respond. He wisely selected
Highly Integrated Low-Power Radars, by Sergio Saponara, Maria Greco, Egidio Ragonese
(graciously provided by Artech House).
In
this issue: Wolfspeed, a Cree company that stands alone as the premier provider of the most field-tested
SiC and GaN Power and RF solutions in the world, is currently sponsoring free access to Dr. Francesco
Fornetti's "Conquer Radio Frequency:
a Multimedia Conceptual Guide to RF & Microwave Engineering using AWR Microwave Office." This
resource contains more than twelve hours of video tutorials supplemented by a reference textbook. The
tutorials cover: Transmission lines, Smith Chart, S-parameters, Impedance matching with both discrete
and distributed elements, Basics of amplifier design
...
Following a four-year development program, Aaronia launched the
Drone Detector,
a product that exploits the RF radiation emitted by the UAV's onboard systems and by the operator's
control unit. Two types of 3D direction-finding antenna are offered by the Drone Detector—the IsoLOG
3D 80-UWB and IsoLOG 3D 160-UWB. Both cover from 9 kHz to 6 GHz, and extenders are available should
VLF (below 9 kHz) and 6-20 GHz coverage be required. The Drone Detector
has a real-time bandwidth of 80 MHz. Optionally this can be extended to 175 MHz
...
Take
a break and work this week's RF Engineering-themed crossword puzzle. All the words are pulled from a hand-built
list of terms, names, and abbreviations that have only to do with science, mathematics, and engineering.
Clues for words having to do with types of engineers are marked with an asterisk (*). If you want a
crossword with names of movie stars and obscure countries, try the local newspaper
...
Electronic
warfare (EW) is a familiar term today, but in 1947 its use was a relatively new concept. As you
know, great advancements in electronics occurred during the War years - from all the major Allied and
Axis countries involved. Transmitters and receivers, modulation techniques, antenna designs, transmission
lines, component introductions and improvements, ruggedness and portability features, reliability, serviceability,
operational techniques, and other aspects of electronics benefitted from that oft-credited 'mother of
invention' named 'necessity.' Along with electronic communication improvements came the need to thwart
the enemy's ...
Withwave's
Compact Calibration Kits offers
excellent performance characteristics that is specially designed for the fine-tuning in production environments
and quality testing facilities using 50 ohm N-type & 3.5 mm connectors up to 6 GHz and
9 GHz, respectively. This Cal Kit includes all needed calibration standard (Open, Short, Load) in one
unit that is best solution available for ease of use in VNA calibration, especially in the field
...
Thanks once again to the folks at everythingRF for advertising
on RF 
Cafe! It is their support that helps deliver this website to you.
everything RF is a product discovery platform for RF & Microwave Products/Services.
We currently have 211,299 Products from more 
than
1,027 Companies across 222 Categories in our database and enable engineers to search for them using
our customized parametric search tool.
Recently,
a company based in China contacted me about advertising on RF Cafe. After doing a lot of up-front work
for them creating advertising materials, the representative informed me that he cannot access the RFCafe.com
domain from his location. It is really difficult to conduct business when the customer cannot review
your work, so at least for now, I am going to pass on the opportunity. The obvious question that arises
from the experience is whether RFCafe.com is being blocked by China, and how do I find out? Fortunately,
a few options exist with websites that will perform the check for you by pinging your URL from servers
within multiple countries. Some, such as GreatFirewallOfChina.org,
tests from inside China using servers in Beijing
...
"Europe's
largest particle accelerator, the
Large Hadron Collider, is back in action. According to two newly published studies,
its latest round of experiments yielded three new 'exotic' particles and confirmed the existence of
a fourth. The newly identified particles are considered 'exotic' because they contain four quarks, the
building blocks of all matter. Particle physicists used to believe all particles were composed of mesons,
a quark-antiquark pair, or baryons, three
..."
Mr. John Higgins, of the
Ace Wire Spring & Form Company, wrote
to ask that his firm be added to the Hardware Vendors
page on RF Cafe. Located in McKees Rock, PA, Ace is an industry leading precision manufacturer of compression
springs, extension springs, torsion springs, specialty springs, and wire forms. Free engineering design
services available. Please contact them to see whether you have a need they can fill. 412-458-4830
...
Whenever I think of
springs, the goofy short film "A Case of Spring Fever" comes to mind. 'Coilie the Spring Sprite' teaches Gilbert
an important life lesson after wishing for 'no more springs!'
Anatech Electronics, a manufacturer of
RF and microwave filters, has published its July 2016 newsletter. As always, it includes both company
news and some tidbits about relevant industry happenings. This month, Sam Benzacar continues his previous
discussion regarding the increasing challenge that interference is to mission-critical systems. He also
reports on news about cancers risks that come with extensive cellphone use, LTE-U deployment schedules,
E-Band data system advances, and using radar-based sensors to monitor and characterize patient behavior
and health status. Anatech's business is to make certain that system
...
June 1931 was a year and a half into the Great Depression, which
began with the Wall Street crash of October 1929. It followed on the heels of the very prosperous decade
known as the "Roaring Twenties," when significant, rapid advances in technology had taken place in electronics,
medicine, physics, chemistry, and other fields. A huge number of radios were sold to the military, businesses,
and private consumers both before stock market crash and after. A quick look at my list of Radio Service
Data Sheets from the era show that to be so. In fact, it wasn't until World War II that production
of new radio sets began to decrease, as all available
...
"Amateur Electronic Supply (AES) will close its doors at the end of July after 59 years in business. No reason
has been given for the decision to close the business. AES has been a premier player among Amateur Radio
equipment retailers for decades, as well as a major presence at Dayton Hamvention® and other events.
Various media outlets were informed of the closing in a brief e-mail message on July 6, but word of
the closing has not yet appeared
..."
We have recently
updated the Antenna Search
tool on everything RF. There are 4,000 Antennas from 48 manufacturers listed on the site. Use the
search tools to find antennas by Type (Dipole, Yagi, Whip, etc.), Frequency, Gain, Industry Type (IoT,
Military, SATCOM, etc.), Communications Standard (WLAN, Bluetooth, GPS, etc.), Frequency Band (UHF,
L, S, C, Ka, etc.), Mounting (Pole, Magnetic, etc.) and a number of other parameters. Please let us
know what you think. We are still adding more products and manufacturers
...
The mission of
the Graphene
Flagship is to translate graphene out of the academic laboratory, through industry and into society.
This broad and ambitious aim has been at the forefront of the choices made to direct the Flagship; it
focuses on real problem areas where it can make a real difference such as in Optical Communications.
Optical Communications are increasingly important because they have the potential to solve one of the
biggest problems of our information age: energy consumption. Almost everything we do in everyday life
consumes information and all of this information is powered by energy
...
Just
as the paperless office, predicted to quickly become a reality when personal computers were beginning
to dominate the workplace and home in the 1980s, has yet to occur, neither has desktop software for
high-end applications totally replaced online equivalents. Microsoft has made good progress in the last
few years in moving part of their Office suite online, you still need a local copy of Visio, Project,
and even their Visual Studio software development tools if you want to use them. Graphics and video
editing software cannot be used efficiently online. The problem is mostly due to time latency between
user input and software display response. Speed on the host server end is addressable with pumped up
computing power and extra
...
"The
Five-hundred-meter Aperture Spherical radio Telescope (FAST) is a mega-project designed
to search the cosmos for clues about our creation and whether there are any other civilizations out
there. The project began development back in March of 2011. Five and a half years later, it is finally
functional. The telescope, as the name would suggest, is a monstrous 500 meters in diameter, able to
achieve a zenith angle of 40 degrees. The telescope
..."
You just never know when your
number is going to be called. People who engage in a dangerous activity they love often claim that if
they are going to die in an accident, it would preferably be while engaging in that activity. It really
sucks to die like Army-Air Force Lt.
Henry B Harris who was an accomplished instrument flight research pilot (and noted Ham radio
operator). Rather than expiring in an airplane, he met his end as a passenger in a car that was towing
some other pilot in a glider ...
"Mimicking
nature is not easy, but new insights by researchers at the Department of Energy's Lawrence Berkeley
National Laboratory could help create a viable artificial system of photosynthesis. One of the major
challenges for scientists working to create systems that efficiently convert sunlight, water and carbon
dioxide into fuel is finding materials that can do the work while also surviving the corrosive conditions
that are part of the process
..."
Skyworks Solutions,
an innovator of high performance analog semiconductors connecting people, places and things, today expanded
its best-in-class antenna tuning product portfolio with the addition of several new high performance
solutions. Skyworks' latest antenna tuning offerings address the design challenges mobile device manufacturers
face as smartphones become thinner, leverage revolutionary case materials and integrate more cellular
bands. By optimizing radiated efficiency, Skyworks' antenna aperture tuners enable higher data throughput
and smaller footprints, minimizing dropped calls and improving the consumer experience. 'Cellular band
proliferation in smartphones
..."
"Conventional
USB flash drives are electronic data storage devices. They store information by using millions of small
gates that process information into 'words' consisting of various combinations of the numbers 0 and
1. A team of scientists at Hokkaido University's Research Institute for Electronic Science investigated
the possibility of using a
magnetic signal along with the electronic signal to allow double the storage capacity
in these 'multiplex writing / reading' devices. In addition to the binary
..."
Even
if you have no use for building a "twin lamp" standing wave indicator for a
twin lead transmission line (solid
or open ladder type), this article makes an interesting read for its theoretical description of how
the device works based on current phases in the circuit. A pair of flashlight bulbs and couple feet
of wire is all that is needed. When operating properly, the "twin lamp" indicator indicates by virtue
of whether one or both bulbs are illuminated whether there is a significant standing wave present on
the line. Author Charles Wright warns that the VSWR level cannot be reliably determined based on relative
brightnesses of the two bulbs; it is meant for use as a best case
...
"Rensselaer
Polytechnic Institute and General Electric Global Research Center in the USA 'experimentally demonstrate,
for the first time, bi-directional 4H-silicon carbide planar gate, insulated-gate bipolar transistors
(IGBTs) fabricated on 250μm-thick, lightly doped free-standing substrates.' The researchers see potential
for their bi-directional (BD) IGBTs as switches that can control current in both directions with application
in matrix or neutral point piloted multi-level converters. Compared with multi-component implementations
..."
"Just because it's futuristic
doesn't mean it's practical." - Crow T. Robot, MST3K, 'Design for Dreaming,' Mystery Science Theater 3000 (MST3K). MST3K was a TV series
in the 1980s-1990s where a human was forced by evil scentists to watch B movies, with automatons
Crow T. Robot and Mike Servo provided for comfort. Their silhouettes
are seen in the theater's front row as they make wise cracks about and gestures toward the movie as
it plays. One of my favorite clips is from the "Space Mutiny" film, where Crow,
Mike, and Servo roll out a long string of insulting names for the 'hero' character. You'll definitely
get a laugh out of it.
"Researchers at the Oak Ridge National Laboratory in the U.S.
and Uppsala University in Sweden have developed a new electron-microscopy technique that can detect
magnetism at the atomic scale. The technique exploits distortions - or "aberrations"
- in how the microscope's electron beam is focused, and could be used could be used to study magnetic
domains in devices such as computer hard-disk drives. Electron microscopes focus beams of electrons
in much the same way that optical microscopes
..."
Summer
has traditionally not been the best time to be
job hunting in industries where project
budgets begin and end on the calendar year, but I these days there probably are no discernable rules.
A lot of advice has been written regarding what to do and what not to do during job hunting and during
the first months of employment. As with technology, the list of do's and don'ts regarding all aspects
of a career change over time. Workers today need to know about how to exploit and/or avoid social media,
how to handle interviews within the constraints
...
"Researchers at Cornell University have fabricated
graphene membranes into micrometer-scale drums that can be stimulated by a voltage
to transfer one type of mechanical vibration into another. The researchers believe this capability can
lead to new applications in telecommunications where graphene-based mechanical resonators could be used
as frequency mixers, which are often used, for example, to modulate carrier waves with signals
..."
This might
be my oldest copy of QST, being Vol. XIII, Number 6 (December 1915 was the first
issue). Up until a few decades ago, authors commonly appropriated themes and characters from
familiar fairy tales and fables for use in articles of instructional nature. Some publications even
used comic book style formats for teaching to beginners. The term 'wabbulation'
(aka 'wobbulation') is spoken to Uncle Jimmy by the fabled Piper, and
I have to admit not being familiar with the term. According to W2PA's story, 1920s era QST
technical editor Robert Kruse coined the word to describe inadvertent modulation
...
The following announcement was posted in the September 1930 edition
of Radio-Craft
magazine regarding Radio Data Service Sheets:
"We are pleased to announce that RADIO-CRAFT has taken over the subscription list of "RADIO SERVICE,"
formerly published in Dallas, Texas. All subscribers of record to RADIO SERVICE will receive RADIOCRAFT
until the expiration of their subscriptions."
A few days ago, Mr.
Tim O. sent me photos of the
Crosley model 03CB console
(floor) radio that his mother owns and which he remembers listening to as a kid. Tim says as far
as he knows the radio still works. As can be seen in the images below, it is still in pretty good condition
for a 75-year-old radio! I noticed that both the volume and tuning knobs appear to be a bit melted,
which must have been a common occurrence in this model because the Crosley 03CB radio that I recently
bought and restored also had melted volume and tuning knobs. The metal chassis
...
For
the sake of avid cruciverbalists amongst us, each week I create a new
crossword puzzle that has a theme
related to engineering, mathematics, chemistry, physics, and other technical words. This one has extra
words pertaining to radar and radio. You will never be asked the name of a movie star unless he/she
was involved in a technical endeavor (e.g., Hedy Lamar). Enjoy!
The free whitepapers,
pamphlets, books, magazines, and chapter examples listed here are a small sample of a lot of new items
that are offered for FREE through TradePub. The publishers make them available to qualifying people as a promotional
campaign for their full line of offerings. Note: I earn a few pennies (literally)
when you download one of these or the many other pubs available, so please help yourself.
"The Wi-Fi Alliance this week announced its expanded
Wi-Fi Certified ac to include new features that provide a better experience. The
new features in 802.11ac Wave 2 should provide operators and their end users with big improvements in
the user experience. One of the most talked about features – multi-user multiple input multiple output
(MU-MIMO) - allows more devices to operate simultaneously on the same
network. The ability for a single access
..."
The VOLSCAN (Volume Scanning) radar
system was a paradigm changer for air traffic controllers charges with guiding aircraft while assuring
safe separation. Busy terminal areas were a particularly difficult challenge due to the large variation
in aircraft speeds and types.
VOLSCAN was a computer that tracked the position, direction, and speed of each target and even made
recommendations to controllers for course assignments. It also warned of impending dangerous scenarios.
Another VOLSCAN article in the July 1954 issue of Radio-Electronics went
...