Anton
That is quite a wide freq range. What kind if common mode Z are you looking for? You must maintain the characteristic Z of the RF path so coax wrapped around a core is the way to go. Bifilar is tough to maintain a characteristic Z. A device like this will go thru self resonance like an inductor as frequency is increased. Above self resonance the common mode Z is capacitve and drops with increasing freq. Is the CMC for HF or really for 50k to 300 MHz?
