Large time-bandwidth (TB) product Surface Acoustic Wave (SAW) Pulse Compression Filters are routinely designed and fabricated using Reflective Array Compressors (RAC). The reflection mechanism on these RACs is well understood though it is numerically cumbersome. Analytical methods are also fraught with difficulties. A simple semianalytical method is described herein that seeks to explain reflection mechanism with simple formulas for both reflections from grooves and as well as from strips. The method seeks to model the grooves and strips as an interior perturbation to the medium rather than surface perturbation. The resulting formula yields values of reflection coefficients that match well with those in literature. © 2004 IEEE.