“…Starting from the outer dimensions of the concentrator l, w, t, the width of its gap, w g , and its relative magnetic permeability r , all one has to do is to 1. determine its aspect ratiosw = w/l andt = t/l; 2. evaluate D, eff , and eff,max using Eqs. (4), (8) and (9), respectively; 3. determine z = eff / eff,max and decide whether the concentrator is limited by geometry or by permeability; 4. depending on the answer, compute A m or A m,max at the desired relative gap width w g /l, using Eqs. (15) or (16), respectively; 5. depending on the value of z, using Fig.…”