A dual-band antenna includes a first antenna and a second antenna. The metal plates are electrically connected together. A retractable sealing element surrounding a hollow fluid delivery needle may be used to seal a port of the fluid reservoir. The two shallow diffraction gratings are harmonically-related and can be recorded on a single substrate for compact interferometric based schemes. Also provided is a system including a rate controller controlling the transmission rate of data between two stations over a network and a rate reporter in communication with the rate controller. Collectively, adjacent or near neighboring nozzles are also controlled by time-sequencing through different modes of operation or physical configurations on each spray nozzle.