A new white paper from AWR,
"RF/Microwave EDA Software Design Flow Considerations for PA MMIC Design," examines a gallium arsenide
high electron mobility transistor (pHEMT) power amplifier (PA) design approach from a systems perspective. The design
flow and its essential features for most PA design projects is illustrated through the design of a simple, Class
A GaAs pHEMT monolithic microwave integrated circuit (MMIC) PA using AWR’s Microwave Office® high-frequency design
USA also sends out their "today's engineer" newsletter on Fridays. Here are some items that strike my fancy.
- An Easy
Secret for Better
What Keeps Engineers
from Advancing in Their
Engineering Hall of Fame:
Isaac Newton famously said,
"If I have seen farther it is from standing on the shoulders of giants." His statement
was figurative, of course, but I can now say literally that I have stood on the shoulders of a giant. Somewhere
recently, I don't recall where, I read that although American Radio Relay League (ARRL) founder
Hiram Percy Maxim was born in New
York and spent most of his adult life in Connecticut, he was buried in
Rose Hill Cemetery located in Hagerstown,
Maryland. That just happens to be where Melanie and I stop a couple times each year to visit her mother. We lived
there ourselves for about three years in the early 1990s. That day, I surely stood if not exactly atop Mr. Maxim's
shoulders, then very nearly so as I maneuvered to take this picture of his grave marker. Why is he buried in
Maryland, you might ask? That is where his...
few new headlines for you from LinkedIn, in case you don't receive their weekly update. They usually have some
pretty good stuff. I'm not big into the social media scene, but LinkedIn is kind of like Facebook with a brain
required for participation.
- Upskilling for
How 'Bout Wi-Fi?
5 Things You Have to
Unlearn to Succeed at Work
Every Step You Take,
Every Move You Make
You've Got the Degree,
Now Get out the Passport
Electro-Photonics LLC is a global supplier of
Microwave components. Their products include SMT hybrid couplers, wire bondable passive components, coaxial
products, test fixtures and very useful test boards for evaluating components. The Electro-Photonics team
can support your small R&D design requirements with RF & Microwave test fixtures and save you
valuable design and characterization time.
extraterrestrial threat to existence, be it an impending asteroid strike or an intelligent being's announced intention
to do harm to the earth, would probably be required these days to invoke the sort of voluntary personal sacrifices
of today's average citizen that was exhibited in the enthusiastic, patriotic response by Americans to the
during World War II. You no doubt have seen pictures of kids pulling wagons filled with metal scrap, rubber
tires, and glass milk and pop bottles collected for the war effort, and pickup trucks piled high with sections of
pipe, car parts, and retired furnaces. Resources were relatively scarce at the time, and material was being consumed
very quickly in the effort beat back the aggressive advances of Axis forces throughout Europe, northern Africa,
and the South Pacific. This article from a 1942 edition of Radio Retailing Today encouraged radio
repairmen to check with customers during service calls...
is a well-know name amongst electronics technicians and engineers who have been in the business for any length
Triplett meter movements (aka panel meters) were considered to be
top-of-the-line product in the days before digital meters and displays. They were used in industrial
instrumentation, in military equipment, and in amateur radio gear. Triplett is still in business today but it
appears they no longer sell just meter movements, although there is a large supply (new
and used) available on eBay and Ham radio websites and swap meets. This advertisement for Triplett
Thin-Line Instruments appeared in the September 1942 edition of Radio Retailing Today magazine.
Solutions, Inc. unveils a new device for cellular infrastructure, VHF/UHF military and public safety radios. The
SKY12408-321LF is a 50-600 MHz, 6 dB
differential attenuator that
is pin-for-pin compatible with its 12 dB SKY12407-321LF attenuator, but ideal for IF radio applications requiring
lower overall attenuation and gain control. The new solution also offers a novel differential I/O design and fast
settling time for applications that down convert to a low Intermediate frequency.
was one of those, "Well, huh!," moments for me when I read in a story from the IEEE that claims the first recorded
use of the term 'bug' in reference to a problem in hardware was not by U.S. Navy Admiral Grace Hopper and her
colleagues, as popular belief (including mine) goes. Their finding of a dead moth
- a 'bug' - in a Harvard University computer is legend, but evidently was not the first known instance. Instead,
it was none other than Thomas Edison who may have originally used the term. Before you go accusing the respected
Institution of waging a War on Women (a popular indictment of convenience these
days) for denying credit where credit is due, nobody is implying that she purloined Mr. Edison's term.
According to researcher Dr. Paul Israel, editor of the The Papers of Thomas A. Edison,
and the IEEE History Center, Edison regularly referred to technical problems as bugs. "In 1873 Edison first
confronted what he later called a bug when he began developing a quadruplex telegraph...
LLC announces the availability of Y2D-900R, a high
power 2-way SMD power divider / combiner. Our new Y2D-900R power divider/combiner operates
from 700-1000 MHz and can dissipate up to 350 W in a small 480 mil x 650 mil package. This
power divider offers excellent isolation, low insertion loss, and good phase balance for most critical applications. The
Y2D-900R requires an external 100 ohm resistor for operation. Power will only be limited by the size
and power ratings of the chosen resistor.
Instruments designs and manufactures the world's finest high-precision
Programmable Delay Line (PDL)
instruments and modules. All instruments are fully programmable via GPIB interface, and are suitable for use in
high frequency RF signal applications as phase shifters or where an extremely high precision and accurate amount
of delay is required. Colby Instruments has been helping deliver RF Cafe since 2009.
radar technician Elbert Cook just sent some photos of the
TPN-19 radar units that were based with
him at the 3rd Combat Communications Group (aka 3rd MOB, aka 3CCG) at Tinker AFB,
Oklahoma. He also sent the first couple pictures of a scale model of the
MPN-13 radar unit that he has begun. Stay tuned for
has introduced a high power 30 dB coupler with a 2-4 GHz
frequency range (other coupling values available). Average power is 500 W, with
a Peak of 8 kW. Loss is 0.25 dB (excluding coupled power), directivity
is 18 dB, and VSWR is 1.30:1. Connector type is "N" Female on all ports. Custom designs available upon
request. VidaRF offers a wide selection of Directional Couplers, Dual Directional Couplers and Hybrid Couplers,
designed to cover 0.1 GHz to 20 GHz.
fair number of people who visit RF Cafe have at some point been involved as an Expert Witness for a court case
involving product liability and/or IP ownership or infringement. They quickly learn how important it is to
competent and renowned legal representation.
IMS ExpertServices is a law firm specializing in expert
witness cases. Every month or so they send me an article about specific court cases that could be of interest
to RF Cafe visitors. This particular article is titled "Fortune Telling & Reliability? An Expert Testimony
Enigma." It illustrates how dicey the process of selecting appropriate Expert Witnesses can be for legal teams
- especially given the subjective nature of judges who decide on admissibility of evidence.
Technology Innovation announces the immediate availability of very affordable
composite DIN 7/16 connectors. The body material is a
composite plastic black with silver-plated bronze contacts, as opposed to a standard brass body and beryllium-copper
(Be-Cu) contacts. This newly developed 7/16 connector is seeing a steep increase
in use in leading countries like Japan, Germany, and the USA.
former comrade contacted me recently to say he, too, had moved on from where we used to work. He is a very capable
RF engineer and is now retired from his 20+-year stint as a communications
officer in the Air National Guard. Parsec Technologies is now the beneficiary of his know-how. He recommended
that they try advertising on RF Cafe and the result is this announcement. Thanks Conrad! Parsec's LNAs have been
designed to optimize GaAs for the ultimate combination of noise figure, gain, and IP3. We are redefining what
high performance amplifiers are in today's market for low voltage,
low power amplifiers with low noise, high gain and high IP3 normally found on amplifiers that consume much more
texts must have been a real challenge on this early portable phone. Aside from having to type out your message
on a standard telephone keypad (oh, the humanity), the baud rate must have been snail-like.
The article doesn't mention whether dropped calls were a big issue and whether there was a massive marketing plan
with a bespectacled "Can You Hear Me now?" guy. I'm just kidding, of course. This news item appeared in a 1955
edition of Air Trails: Hobbies for Young Men. Before you laugh at the
Portaphone's dipole antenna and carrying case,
consider that it was only a little over two decades ago that Motorola debuted its famous M800 'Bag Phone.' From
the magazine: "Portable two-way radio phone...
is a world leader in the design and development of surface mount VCO
modules & PLL frequency synthesizers for the commercial microwave/RF wireless market. RoHS compliant signal
source products currently range from 40 MHz to 13.5 GHz bands. PLLs available in integer, fractional-N
and single frequency models. VCOs feature coaxial resonator based and high-Q distributed resonator construction.
and Repairing Commercial Electrical Equipment, by David Herres, is another in a series where he has leveraged
his many years working as a Master Electrician. It is his first work that offers a practical approach to diagnosing
and repairing commercial / industrial electrical equipment – covering everything from motors, computers, elevators,
and fire alarm systems to heavy-duty ovens and audio equipment. This one-of-a-kind guide can help you become more
competent in your profession. Inside you'll find ways to become faster, more efficient, and able to achieve a
much higher success rate in restoring large electrical equipment without damaging it, introducing an additional
defect, or creating a hazard.
don't seem to be many electronic products these days without some form of software in them
(EEPROMs, ASICs, μProcessors, FPGAs, etc.); indeed, many electrical engineers
also wear a software engineer's hat. Two consultants that advertise on RF Cafe, Lance Lascari
(RF Dude) and Joe
Cahak (Sunshine Design)
come to mind, along with many others known during my career. I've even done a bit of software and FPGA programming
myself. This installment of EDN's "Tales from the Cube" series involves an engineer who needed to live
in both worlds in order to solve his problem with a meter designed by someone long gone from the company. Mihaela
Costin applied a bit of ingenuity to make the best of a bad situation...
New Cable Assembly Builder tool
on everything RF lets you specify your cable assembly requirements in a form and on submission directs it to over
20 companies that can manufacturer it. Your query will be directed to the leading cable assembly manufacturers
– Aeroflex, Emerson, Amphenol, San-tron, RF Industries, VidaRF, Pasternack, SV Microwave and many others. You
no longer need to send out individual request to each manufacturer - everything RF does that for you. The tool
has been optimized for Desktops, Tablets and Mobiles so you can use it from anywhere on any device.
Electronics has released new designs for a 710-716 MHz / 740-746 MHz bandpass combiner , 779 MHz
/ 749 MHz ceramic duplexer , and a 1710-1755 MHz / 2110-2155 MHz cavity duplexer. All can be ordered
directly through their AMCrf web store.
sent me a link to Mike Yancey's (KM5Z) website where there is a scanned version of
the 1948 National Radio Institute (NRI) home study course for radio technicians.
It is a very extensive collection of 55 volumes (PDF format) covering topics like
Simple Radio Circuits and Meters, Radio Coils and How They Work, How Detectors Work in Radio and Television Receivers,
Current, Voltage and Resistance Measurements, and How to Eliminate Man-Made Interference. KM5Z also has some other
good content that you might be interested in while you're there like a 1958 edition the RCA Radio & TV Course,
online calculators for toroids, inductor Q, voltage dividers, and antenna field strength, and radio restoration
Power Products, Inc. has more than 25 years of experience designing and manufacturing
RF Passive Components. Our couplers, combiners, resistors,
and terminations incorporate the latest technology in materials available, which equates to unrivaled product
performance. IPP has been with RF Cafe since early 2008.
Product Digest just posted articles from their August edition. Lots of good stuff there, as usual.
- How to Calculate Peak
Sook H. Wong
Measurements, Sean Flavin
EMC Test Equipment and
Services Market – Another
Opportunity in China,
USB Brings Portability and
Flexibility to MW Test Bench
– Wherever it May Be,
Building Low PIM Coax
Assemblies with Consistent
old, something new, something borrowed, something... brown. My paraphrasing (lamely)
of the old saying for bringing good luck to a bride aptly describes Adam Vaughan's effort in building his 'Twittertape
Machine.' Adam's machine prints out Twitter messages on a paper tape in the manner of early stock market tickers.
"This astounding device will print a permanent copy of all Tweets yet requires no ink or computer." So says a
proclamation in vintage serif font and decorative trimmings on the website's homepage. Indeed it does. The prototype
uses two wall wart AC/DC adapters, an Arduino-style microcontroller with an Ethernet interface, a Bell jar, a
thermal printer, and miscellaneous clock parts. Full details of the design and operation are provided, including
a video. It checks for and prints out available Tweets every 30 seconds. Before you get upset about altering historic
you think it's expensive to hire a professional for a job, wait until you hire an amateur." -
Red Adair, famous global firefighter. Red Adair is the
guy who put out all the Kuwait oil well fires after Hussein's troops ignited them while retreating from occupied
territory. Television 'experts' said those fires would burn for decades. They were out in months.
a break and work this week's wireless
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. If you want a crossword with names
of movie stars and obscure countries, try the local newspaper. If you want to exercise your nerd knowledge, this
is the one for you.
is a 30 MHz to 26.5 GHz Low Noise Amplifier that provides greater than 35 dB of gain while maintaining
a maximum gain flatness of ±3.5 dB maximum over the operating frequency. The noise figure is 6.0 dB
typical and offers an OP1dB of +12 dBm minimum. The operating voltage is +12 to 15 VDC and the
current draw is 700 mA maximum.
going to love this installment of Sherlock Ohms. Even if you have never had to deal directly with customers for
a product performance issue, you will easily empathize with engineer Jonathan Eckrich in "The
Case of the Confused Customer." The incident reminds me of a story I read years ago by an engineer who worked
on development of one of the early computer languages - I think it was FORTRAN. The user called to complain that
a section of code was failing and demanded assistance because in his opinion, the language kernel was faulty.
The caller's name was not disclosed, but the engineer said he was a notable figure. After listening to the problem,
the cause seemed obvious, so the engineer (wish I could remember his name) instructed
the guy to make sure he was using the "less than" symbol, to which the guy responded that he is no idiot and the
problem must be something else...
challenge you to find a calculus lesson in a modern-day electronics magazine. In 1932, not all that long after
Isaac Newton developed differential calculus (that's a joke), Radio News magazine ran a series of "Mathematics
in Radio" articles that included, among other topics, a few lessons in calculus. Anyone who has taken college-level
science or engineering courses knows how indispensible calculus is in working out many circuit, physics, and chemistry
problems. My appreciation for calculus came when I realized that it actually allowed me to derive the kinds of
standard equations that are commonly seen in lower level applications. For instance, if you needed to know the
volume of a sphere, you could look up the familiar Volume = 4/3 π r3
formula, or you could write the equation...
Corporation, the innovation leader in high-frequency EDA software, gifted its software to the winners of the High
Efficiency Power Amplifier (HEPA) and Software Defined Radio
(SDR) Student Design Contests offered at the 2013 IMS MTT-S conference. The gifts
are part of the
University Program, which sponsors student design contests throughout the world to encourage students to become
involved in the dynamic profession of microwave and RF engineering and to apply their knowledge to practical designs
using the highly efficient AWR design methodology.
is the latest bunch of engineering career and employment news headlines from IEEE's JobSite.
- Age Bias
(it ain't just in SV)
Layoff Taboo: Japan's
5 Global Recruiting
to Help You Land
Does Your Entry-Level Job
Have Growth Potential?
Here are a couple more I found while looking around:
Confidence on the Rise
Five Ways Job Seekers
Can be Proactive While
Engineering Grads Enjoy
Greater Job Prospects
Jin Technology Innovations helps to deliver RF Cafe through their advertising, which was just renewed for another
term. Dong Jin designs, manufactures, and assembles RF connectors,
cable assemblies and components. Competitive price, on-time delivery and best quality. No minimum order size.
One-day delivery. ISO9001, ISO14001, RoHS certified.
is another great RF troubleshooting saga; in fact, it would make a good short action film. Designing and
implementing proper lightning protection can be a real challenge - and quite expensive. Lightning has a nasty
habit of seeking out and exploiting weaknesses. Author Rod Hine doesn't cite improper protection as the culprit
for causing his woes in his telling of, The Case of the "Earth
Station Stopped by Lightning." A couple decades ago I worked with a team that designed a prototype weather
radar system with cobbled-together parts that included a surplus military phased array antenna. After doing all
the initial design, build and test at our facility, everything was moved to an open air site that sat at the top
of a ridge which was known to attract lightning like trailer parks attract tornadoes. A fair amount of effort
went into lightning mitigation over the years, so we felt comfortable hooking into the existing system. All went
fine for the remaining time I was there. About a year later...
being contacted by a friend of mine who works for Parsec Technologies
about adding their company to my categorical Manufacturers and Services
pages, I realized that I blinked and missed the need to add resources for the relatively new fields of
Software Defined Radio,
White Space, and
Mobile HDTV. Having just awoken,
there are now the beginnings of pages for them. In searching for companies to include it quickly became apparent
that most of what is available to fill the need is re-purposed ICs and hardware, but as the technologies mature
and standards are established there will be more specialty products. Parsec Technologies is one of those companies
working now to fill the need.
has introduced a low loss Waveguide Isolator,
model VDWR42-2021-A, with a frequency range from 20.2-21.2 GHz. The isolator offers 0.1 dB loss, isolation
28 dB, VSWR of 1.11:1. Forward power handling is 3 watts with operating temperature -40 to +80 C. Pressure
sealed to 10 psi.
radios in the family car became a standard accessory, a push ensued to make them cheaper, more reliable, and service-free.
A major Achilles' Heel was the high voltage power supply required to energize vacuum tubes. Known as vibrator
power supplies due to using an oscillator to convert the battery's 12 DC supply (some autos
still used 6 V systems) into AC that could be transformed up to the 300 volts used by most tubes of
the day, most early failures were attributed to the circuits. They also caused annoying noise in the audio output
if careful filtering and installation was not performed. Having been invented only a couple years earlier, transistors
were being designed into the power supplies, but low-voltage tubes were still needed for the electronics. In response
to the demand, low-voltage tubes were created to fill the gap until acceptable transistors became available for
a fully solid-state radio. This article discusses some of the problems with
voltage tube design and methods employed to overcome them.
Design for Active Sensing Systems: A Computational Approach, by Hao He Hao He, Jian Li, and Petre Stoica,
is my Featured Book for this week. With a focus on developing computational algorithms for examining waveform
design in diverse active sensing applications, this guide is ideal for researchers and practitioners in the field.
The three parts conveniently correspond to the three categories of desirable waveform properties: good aperiodic
correlations, good periodic correlations and beam pattern matching. In addition to numerical results, the authors
present theoretical analyses describing lower bounds or limitations of performance.
Cambridge University Press.
so now I have read about someone who credits social media - LinkedIn specifically - for success.
Judy Warner, of Transline Technology, responded
to the "Fake Twitter Follower Factory" commentary that I posted
on LinkedIn to say she has had an overwhelmingly good response from reaching out to and engaging the LinkedIn
community of engineers. In fact, Judy's experience was so spectacular that in a few short years she went from
being a connectionless marketing exec re-entering the PCB marketing realm after a decade-long hiatus, to being
a sought-after expert in her field. Read her short article "Does
Marketing Matter?" in the April 2013 edition of the pcb magazine (page 62). Maybe Judy's feedback
to my LinkedIn post means I, too, can now claim social media success!
always been a bit dubious about the whole social media thing. Yes, it can be a great medium for connecting with
old friends and maybe getting some breaking news, but otherwise services like
Twitter seem to mostly be a time-wasting enabler for people with
too little meaningful purpose in their lives. Achieving the largest number of 'Followers' is now a lifetime goal
in order to assert and prove popularity and dominance in society. Catering to vanity is big business so as you
might expect, there is a plethora of opportunists who offer to inflate the Followership of gullible Twits. A recent
story in Inc magazine, one of many such stories in many news reports, illustrated just how easy it is given even
a modest cash outlay to buy Followers - some charge as little as a penny apiece. If you are thinking of starting
a Twitter Follower business of your own, businesses will also sell you 'verified' e-mails address batches, Captcha
defeaters, and HideMyAss.com will...
I mentioned how much I appreciate good graphs and illustrations for conveying information? Yeah, I guess I have...
often. The adage about a picture being worth a thousand words certainly holds true - even if the thousand words
inadvertently describes the artist's crappy attempt to get his/her message across. This particular graphic presents
information on some of the vast resources of [mostly] free online educational sources for engineering and related
topics. Massive Open Online Courses (MOOC) was launched
in 2008 at the University of Winnipeg and is credited with birthing the idea (at least for being the first to
successfully implement it). There are, of course even more courses in other areas of interest. Flight vehicle
aerodynamics, astronomy, solar energy, physics, numerical statistics, even sci-fi and creative writing, all useful
in a well rounded engineering experience, are among the listed types...
writers at Test & Measurement magazine hit a high note this month with articles. Enjoy.
by Jeffrey Dierker
and Reliability Degradation
Issues, by T. Nishimura
Improve Wireless Testing
of Sensitive Devices,
by Per Nielsen
Repair is based in Cocoa, Florida, and focuses on servicing
spectrum analyzers and
network analyzers. "All
of our technicians are military PMEL graduates." After their tenure, they spent time in R&D labs, USAF
PMEL labs, and commercial calibration labs. Repair calibration services for new equipment & extend life of
obsolete high performance analyzers.
acquisition is the end of a dream." - Jake Lodwick, co-founder of Vimeo. This quote appeared in the July/August
Inc magazine, where Mr. Lodwick describes the Heck he went through with his company. He further states,
"If you truly believe in the potential of your company to change the world for the better, there's no excuse for
settling for an acquisition."
a break and work this week's 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. If you want a crossword with names of movie stars
and obscure countries, try the local newspaper. If you want to exercise your nerd knowledge, this is the one for
do you think of the USAF's plan to deploy a band of millions of tiny
dipole antennas into orbit around Earth for communications support? Because over-the-horizon
(OTH) radio communications rely on the upper atmosphere being conductive to reflect
radio waves, it is essential that there always be something for bending signals back to Earth rather than allowing
them to escape into space. The ionosphere has many identified regions that do a good job of reflecting signals
of certain wavelengths during particular times of day and under special atmospheric conditions cause by solar
activity. There are times when reliable OTH communications are not possible because of severe coronal mass ejections
(CMEs), high meteoric activity, and even terrestrial events like major volcanic eruptions.
Even predictable variation in ionosphere characteristics like the diurnal blending of the F1 and F2 layers into
a single F layer complicates emergency and strategic communications planning...
BRL Test and their Analyzer Repair division are helping
to deliver RF Cafe by advertising. BRL Test Analyzer Repair specializes in the repair of spectrum and network
analyzers. They are a leading dealer of new and reconditioned test and measurement equipment. They buy, sell,
rent, lease, repair and calibrate all types of general purpose test and measurement equipment.
witnesses play a big role in most of the court cases that get reported here.
ExpertServices is a law firm specializing in expert witnesses. Every month or so they send me an article about
specific court cases that could be of interest to RF Cafe visitors. This particular article is titled "Can
Expert Statements Inadvertently Waive Protection?" It the case, an expert witness used by Company A to compel
Company B to submit to claims was not intended to be used in court and so per Company A, he/she should not be
able to be deposed during the discovery phase of the lawsuit (it involved faulty materials
in a transmission). The expert witness' opinion was quoted but not declared as evidence. The laws pertaining
to testifying and non-testifying experts are, as you might imagine, complex and prone to the subjective whims
of courts even though most might consider the codified law to be quite clear. The lesson here is to be careful
how expert witnesses are handled, even if you have no intention of using their opinions in court.