A new white paper from AWR, "RF/Microwave
EDA Software Design Flow Considerations for PA MMIC Design," examines a gallium arsenide (GaAs)
pseudomorphic 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 software.
IEEE 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...
Here a 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 Career
Who's Your New Mobile
Carrier? 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
LLC is a global supplier of RF & 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.
An 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
'V' for Victory
campaign 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...
Triplett is a well-know name amongst electronics technicians and engineers who have
been in the business for any length of time.
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
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.
It 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...
Electro-Photonics 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.
Colby 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.
USAF 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 project updates.
VidaRF 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.
A 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
have 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.
DongJin 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.
A 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 power.
Sending 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.
Troubleshooting 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.
There 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...
The 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.
Anatech 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.
Davis 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 projects.
Innovative 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
Uncertainties, Sook H. Wong
Conducting Noise Figure
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
Something 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 relics...
"If 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.
Take 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.
PMI Model No.
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
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...
I 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...
AWR 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
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.
Here is the latest bunch of engineering career and employment
news headlines from IEEE's JobSite.
- Slideshow: Special
Silicon Valley's Dirty Secret
- Age Bias
(it ain't just in SV)
Layoff Taboo: Japan's
- 5 Global Recruiting Trends
to Help You Land Your
Your Entry-Level Job
Here are a couple more I found while looking around:
- Engineers' Career
Confidence on the Rise
Five Ways Job Seekers
Can be Proactive While
Engineering Grads Enjoy
Greater Job Prospects
The Myth of America's
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.
This 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...
After 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
VidaRF 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.
Once 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
low voltage tube design and methods employed to overcome them.
Waveform 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.
OK, 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
I've 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...
Have 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...
The 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
Analyzer 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.
"An acquisition is the end of a dream."
- Jake Lodwick, co-founder of Vimeo. This quote appeared in the July/August 2013
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."
Take 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 you.
What 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...
Both 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.
play a big role in most of the court cases that get reported here.
IMS 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.