On the Radiation Characteristics of Full-Loop, Half-Loop, and Quasi-Half-Loop Bond Wire Antennas

The theory, modeling, measurement, and analysis of the radiation characteristics of bond wire antennas (BWAs) is presented in this paper. We commence with rigorous formulations and derivations of analytical models for calculating the vector potential, radiated electromagnetic fields, and directivity of full-loop BWAs (FL-BWAs), considering nonconstant current distribution along the BWAs. Based on the image theory, we derive an analytical model for calculating the directivity of half-loop BWAs (HL-BWAs) from that of FL-BWAs. Very good correlation is obtained between the directivities calculated analytically using the derived models, and numerically using commercial full-wave solvers, thus validating our analytical approach. We apply the verified models to thoroughly analyze the radiation characteristics of FL-BWAs and HL-BWAs. The radiation characteristics of an HL-BWA are based on the assumption that its reference plane is infinitely large and perfectly conducting. However, for the development of wireless systems, reference planes of finite sizes are required. Therefore, we investigate the impact of realistic planes sizes. Our results reveal that the radiation characteristics of BWAs referred to as "HL-BWAs" in published literature differ significantly from those of true HL-BWAs. Therefore, we introduce the term "quasi-half-loop BWA (QHL-BWA)" to describe BWAs with small reference planes. For experimental verification, QHL-BWAs which operate in the 60 GHz band were fabricated using the wedge-wedge bonding process. Both S-parameter and radiation pattern measurements were performed. Very good correlation was obtained between measurement and simulation results.