Modelling the shape, length and radiation characteristics of bond wire antennas

Novel analytical models for accurately modelling the shape and length of bond wires in dependence on the loop height (Lh_max), distance between the bonding positions (d_bp) and the thickness of the metallisation (t_met.) on which the wires are bonded, are derived in this work. These analytical models, which are based on the Gaussian distribution function, are applied to (i) develop realistic three-dimensional electromagnetic models of bond wire antennas and study their radiation characteristics and (ii) study the impact of process tolerances of bond wire parameters on the performance of the antennas. For these studies, a 42 GHz half-loop bond wire antenna is considered as an example. It is designed, fabricated and measured. Our results reveal that d_bp has the most significant impact on the antenna performance. For example, -10% fluctuations in d_bp causes ~2.5 GHz shift in the resonance frequency and 24% reduction in the maximum realised gain. Since this may completely detune the antenna, it is recommended that fluctuations in d_bp should be kept below 10% during the manufacturing process. Good correlation is obtained between measurement and simulation results.