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28 The PCB Design Magazine • June 2017 A DEEP LOOK INTO EMBEDDED TECHNOLOGY on a board that has buried vias. Then you panel plate because you have to metalize the holes, then pattern plate and etch through more cop- per for the second etch to define the resistor ele- ments. Not only is it difficult, but it adds cost. Before we thought surface mount resistors are inexpensive and all we're doing is putting solder mask over them; in terms of fine-line etching they can be just as much of a challenge as anything else. But that's old news. The new news is the buried vias and sequential build type PCB constructions where the resistors are in the subassembly of the sequential build and are es- sentially buried surface resistors; so there isn't solder mask over them, but prepreg or whatever they're using to build it up with. The challenge, again, is using direct imaging to etch through not only the copper cladding or the OhmegaPly copper, but etch through the plating as well. There may be a 25-micron mini- mum on the wall of the hole that turns out to be what you're adding to the traces and then etching becomes more difficult. People do it all the time, but you're adding cost to it. Holden: The Japanese are still working on this. What are the Japanese doing on embedded com- ponents? I firmly believe their big focus is min- iaturization of everything; they certainly have more examples of miniaturization than we do. Their mobile phones are smaller than ours are, and they always try to make the lightest ones they can get by with or the thinnest ones they can get by with. Brandler: I agree with you on that 100%. We are working with some Japanese companies that have, since manufacturing is expensive, also offloaded some of theirs to Taiwan or Ma- laysia. We're working with Japanese companies Figure 9: RF power divider application in Globalstar satellite antenna.