A 3D microwave sensor includes a cloud of particles, e.g., rubidium 87 atoms. A laser system produces: a first probe beam directed through the particle cloud along a first path; a second probe beam directed through the particle cloud along a second path that intersects the first path to define a Rydberg intersection; a first coupling beam that counterpropagates with respect to the first probe beam along the first path; and a second coupling beam that counterpropagates with respect to the second probe beam along the second path. A spectrum analyzer characterizes the microwave field strength at the Rydberg intersection. The laser beams can be steered to move the Rydberg intersection within the particle cloud to compile a microwave field strength distribution in the particle cloud.