Superluminal behavior in the near field of crossing micorwave beams

Superluminal processes in wave propagation have been demonstrated in several cases, but whether this behavior can be extended to the signal velocity is still a debatable question. In this Letter, we present new experimental results on microwave propagation in open space, which show anomalous behavior in the near field range. We discuss their interpretation by considering a variety of mechanisms, including standard theories, as well as less canonical ones. This new experiment provides further opportunities to discuss this intriguing and debated topic.