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When I was a postgraduate at Edinburgh University, my office was in the James Clerk Maxwell Building, the JCMB. Maxwell was most famous for Maxwell's Equations, which give the rules for how electrical and magnetic forces interact, and how electromagnetic waves such as light and RF work. These equations also laid the groundwork for relativity (a charge becomes a current when you look at it from a frame of reference that is moving, for example). When Einstein was told that he stood on the shoulders of Newton, he demurred and said "No I don't. I stand on the shoulders of Maxwell."
Maxwell studied at Edinburgh University and later unsuccessfully applied to be a professor there. But he got a building named after him as a consolation prize (as did Darwin, who never graduated, but got the biology building named after him anyway). In later life, he set up the Cavendish Laboratory at University of Cambridge, which would go on to discover the electron, the neutron, the Josephson Junction (critical in quantum computing), and other major research that resulted (so far) in 29 Nobel prizes, mostly in physics, but some in chemistry, and some in what is often called biology but is actually called "physiology or medicine". He died, having done all that, at the age of just 48.
I'm not going to attempt to explain Maxwell's Equations in a blog post like this, not least because I don't remember that much of my Electrodynamics course from undergraduate mathematics. But I will tell you that the second equation:
tells you that you can't have a magnetic monopole, like the south pole of a magnet, without a north pole to go along with it. The same is not true of charge, you can have an isolated charge like an electron or a proton. Or a hole, for that matter, which is a sort of virtual charge.
But this post is not really about Maxwell, but rather about a series of blog posts that have the series title Virtuoso Meets Maxwell. These cover various aspects of doing RF design in Virtuoso.
Virtuoso Meets Maxwell: Virtuoso RF Solution – Revolution Begins with a Common Goal for One Flow
Virtuoso Meets Maxwell: TILP! What’s a TILP?
Virtuoso Meets Maxwell: Learn Your Moves – We’re Doing an Edit-in-Concert
Virtuoso Meets Maxwell: Export the Die? What Am I Exporting? To Where?
And there is more to come...Virtuoso Meets Maxwell publishes a new blog post every other Monday.
If you are doing a low-performance design, then you can get away with handling chips, packages, and boards separately, writing out files to do the limited analysis required. But who does low-performance designs any more? Designs for data centers, what we usually call HPC for high-performance computing, rely on high-speed serial interfaces for a lot of communication. Almost any IoT device involves wireless communication of some sort, and thus RF.
That's before even thinking about all the "More than Moore" approaches to design, which are increasingly common. 2.5D interposers. Memory on logic. 3D stacked chips. Chiplets. Wafer-on-wafer.
The most demanding of all are high-performance RF designs, with both high-frequency radios and high-speed data. You can't go a day without hearing something about 5G. The low bands of 5G, so-called sub-6GHz bands, are demanding enough. The very high-frequency bands, known as mmWave, are even more demanding and are breaking new ground in many ways. (For a 5G primer, see my posts What Is 5G? and Why Is 5G Such a Big Deal?) In an RF design, everything is important. The chip, obviously. The package. The board. The antenna. Everything affects everything else, so even the traces on the board that are not carrying the RF signals are important since they can affect the traces that are. This means that the chip, the various elements that make up the package, the traces on the board, connectors, antennas...everything...need to be designed together in a single design system that has a holistic view on everything.
For example, "edit in concert" allows one part of the design to be edited while showing other parts of the design for context, as in the diagram below.
It can also keep some parts of the design aligned—if you move a bump on a package, then the bump on the die moves, too, as in the diagram below.
If you are doing a high-performance design (is there any other kind any more?) then you should take a look at the Virtuoso Meets Maxwell series of blog posts, with a new one every fortnight.
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