The rapid performance progress in processors and memory cores by technology scaling requires further improvement in interface bandwidth. However, interface bandwidth is not keeping up with the processing speed of the core and is becoming a bottleneck in system performance. To fill the performance gap, wideband low power low-cost interfaces are strongly demanded. A wireless proximity interface that uses inductive coupling is one such interface expected to be used for interchip links in high-performance 3D system integration. Inductive coupling interfaces use the magnetic near-field induced by micro-coils. The coils (channels) can be arranged in a dense array because magnetic near-field localizes in the proximity of each coil, and crosstalk between the channels is small. Therefore, inductive coupling interfaces are suitable for wideband low-cost proximity communication. An inductive coupling interface can also realize highly reliable communication with low power consumption. Evaluation systems developed to study the performance of inductive coupling interfaces have demonstrated the feasibility of the interfaces in a wide range of applications.