A compact CPW-fed aperture-coupled patch antenna is modeled using the moment method code IE3D. It is shown that improvements can be made by optimizing various parameters of the antenna, such as patch diameter, CPW slot width, etc. The improvements are an increase in the bandwidth of the antenna, in the return loss across the band, as well as in the design which yield a more practical antenna in terms of construction (i.e., typical manufacturing tolerances do not significantly affect the performance of the antenna). It is also shown that a CPW-fed aperture-coupled patch antenna can be made with a ground plane which will actually improve the performance of the antenna after careful consideration of the height above the ground plane and dielectric used. © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 19: 391–396, 1998.