A package substrate may include a circuit and a leaky surface wave launcher. The circuit may perform engineering tests and end-user operations using sideband signals. The leaky surface wave launcher may perform near field wireless communication. The leaky surface wave launcher may include a via and a strip line. The via may be electrically coupled to the circuit. The via may provide the sideband signals to and receive the sideband signals from the circuit. The strip line may be electrically coupled to the via. The strip line may be excited by the sideband signals to wirelessly couple the leaky surface wave launcher with an external device. The strip line and the via may be unbalanced such that the strip line generates a leaky wave that propagates at least a portion of the package substrate and an environment proximate the package substrate.