High speed stripline coils for magnetic bubble devices

In magnetic bubble technology, high speed operation in practical systems has been hampered by the lack of suitable coil designs for in-plane fields. These coils should produce 20-40 Oe per ampere, have uniform fields over a large area, have low inductances, and be practical to fabricate. A close-wrapped, large area multistrip line approach, with the large areas being separated by only tens of mils (≥30 mils), is proposed. The normalized data allow handbook-type designs of a large range of coil sizes. A model, design equations, field uniformity contours, and useful coil area plots are presented. Results calculated using probable fabrication tolerances show that uniform fields with a tolerance of ±5 percent can be provided over an area covering 70 percent of the coil and with field strengths up to 45 Oe per ampere. Inductances range from 200 nh to 10 μh for 1/4 to 2 1/4 inch wide coils.