This article presents a method for designing and fabricating a surface acoustic wave (SAW) delay line for chemical-agent sensors. To improve the frequency stability and detection sensitivity, the authors designed and fabricated a SAW dual delay line with electrode-width control/single-phase unidirectional transducer and single-mode selection capability. Electron-beam direct writing lithography, x-ray lithography, and metal lift-off are applied to the fabrication of a SAW delay line with a submicron feature size. The experimental results are approximately in agreement with the design goals.