Curved wire analysis and axial surface current model of a normal mode helical antenna driven by a single turn loop

Computer modelling of parasitically-excited Normal-Mode Helical Antenna (NMHA) is reported and compared with the measurements. This structure is particularly suitable for realisation with high temperature superconductors (HTS) but attempts to model it using standard method of moments (MOM) techniques are very prone to instability. A new MOM program was written using polynomial basis functions over a curved wire structure. The results are in excellent agreement with the measurements.