I see magnetic materials for use as directional couplers, isolators, gyrators, circulators, etc. but they never give the kind of spec.s like I need to see, for like an inductor core. I need to see spec.s with a chart of 2 separate curves, 1 for real permeability and 1 for imaginary permeability versus frequency in the GHz range. I need to find magnetic materials that have significant real permeability levels with low loss in the GHz range. I guess that means the imaginary permeability needs to not kick in until an even higher GHz range than the real permeability GHz range. Does anyone make and market such animals? Are there any trade magazines where I can find advertisers for such magnetic materials? Years ago I talked to the president of a materials company and he said his company had developed magnetic material with real permeability of 40 at 1GHz but today I still see no products like that on the market, not even from the guy who once told me they had created it . With all the advancements in nanomagnetic materials and molecular magnets I'd expect to see GHz range inductor cores more available. Any leads others can give me would be appreciated.