What's new for May 2008?

As is always the case, we've been busy this month adding plenty of new features to Microwaves101. We ain't been slack, Cap'n Walker!

• Last month we ran a contest on determining the reason why a certain Plextek MMIC switch has "bond pads" at the interior of the chip. Let's begin the discussion by extending our thanks to everyone who responded! The reason for them according to Plextek's Liam Devlin is that the design called for tight amplitude and phase tracking between all four possible paths, and whatever phase/amplitude disturbance that bond pads create on the paths that need them, the designer attempted to instill onto paths that didn't need them. There were two correct answers submitted, Matt's was first (he's our winner) and Don came in just a little later. We'll send the $50 prize off to Matt, and of course we already asked them both for resumes... For the record, we're not convinced that this approach is 100% valid, loading due to bondpads will be different depending on the presence or absence of a wire bond, how long the wirebond is, and what the wirebond is connected to...
• After a message board post on the Klopfenstein taper looking for help, we now have an Excel spreadsheet that can provide correct impedance taper thanks to Chip from NAU! The spreadsheet is available in our download area, we have a page on this topic that explains why the taper is useful and how the spreadsheet works. Trust us, the page doesn't do Chip's spreadsheet justice!
• Thanks to the Unknown Editor there's a free alternative to AutoCAD for you to use when planning a layout of an amplifier or your company's next office recubing initiative. FraudoCAD is the the name of this great new design tool! We have an accompanying page where we'll attempt to describe the powerful features of this AutoCAD clone that runs in Microsoft Excel. OK, maybe we've raised your expectations just a little too high, but you can plot up to 50 polylines and 50 arcs by entering their characteristic coordinates (start point, width, angle, etc.) What do you want for free? If we get some requests we'll try to add more features one of these days, and by all means if anyone actually uses it for something productive send us some screen shots and we'll post them!
• A new Lim-Eom 3-way power combiner example has been posted. We could use some expert help here... it turns out when using this three-way splitter to combine three amplifiers, one of the combined ports is trapped inside the network. Take a look at the schematic and offer your assistance!
• Freespace rule of thumb page was added thanks to
• Here's a new page on calculating airbridge inductance.
• Thanks to several Microwaves101 readers the Navy Electronic Warfare and Radar Systems Engineering Handbook has been posted on its own page. Now we won't have to worry about the Navy's flaky web postings of this public domain document. Our page offers the information as a zipped file, an unzipped file and chapter-by-chapter. No need to download the thing it will always appear on Microwaves101 until the Unknown Editor's future "estate sale" discards the site along with all of the broken stuff in his garage... Now someone be a sport and tell RFCafe their link to this document is broken and maybe they want to fix it by pointing to our new page...
• There's three new sets of pictures in the Microwave Mortuary. We've got a radio that was hit by a bus, a space-qualified sense resistor that caused a small fire, and a lightening arrestor that suffered an untimely demise due to a poorly tuned antenna!
• Last month the Unknown Editor some controversial material on America's best recognized 7000 pound SUV. As we predicted we got some "negative feedback" from readers that confused Microwaves101 with that scholarly web site that charges money for their nerdly publications or a microwave trade journal that can't afford to be controversial. Like Britney,said, oops we did it again!

• We've got some new questions--and answers--on our Microwave Message Board. We've have hundreds of topics posted on various microwave engineering subjects, with many more replies; our message board is an industry resource. Post your own questions, or help us answer some of the ones that are already posted. Some of the posted material may eventually get captured in our encyclopedia, so do your part for posterity! We'll remove any postings that we consider inappropriate.
  

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