AN78010 - NXP.com

Philips Semiconductors Rev. 1.0 November 200213.56 MHz RFID Proximity Antennas mifare ® (14443A)Optimisation of the coupling coefficient:V20 =ω⋅M⋅I1M = k⋅L ⋅L1 2V20M =ω ⋅ I1)N2⋅ B⋅AM=I12V)20 =N2⋅ω⋅⋅A2Bˆ2N1⋅r⋅I1⋅22⋅(r+x)B =μo232=2k222rN1⋅N2=μ0 ⋅⋅⋅A32222L1⋅L22(r+x)L221 =L01⋅N1L2=L02⋅N2L 01 , L 02 : single turn inductanceL01≈2 ⋅10−7[ m]2π⋅r⋅ 2π⋅ r⋅ln( )dCoupling coefficient k = f(r, x):k= μ ⋅0rA22⋅32 2 22(r + x ) L01⋅ L0223 PUBLIC