Smart antenna array technology has been shown to greatly improve the performance of wireless communication systems. In this article, we describe the impact of smart antenna array processing at the mobile terminal for Wideband Code Division Multiple Access (WCDMA) cellular networks. Using system simulations we demonstrate the quality of service, network coverage, and network capacity improvement provided by a WCDMA dual antenna receiver and we establish a relationship between this improvement and the link level performance. We then describe a receiver architecture for a dual antenna WCDMA mobile receiver. The proposed receiver was implemented, as part of a complete mobile terminal solution, in an ASIC using a 0.18 μm, 1.8 V CMOS technology. The ASIC was integrated with RF, analog and digital components in a PCMCIA card form factor. The PCMCIA is a 3GPP compliant user equipment and has been submitted to standardized performance and conformance tests. Experimental measurements gathered with the PCMCIA card illustrate the impact of a diversity enabled mobile data terminal on the link level performance. For various propagation environments and transmission data rates, improvements in the range of 2.7 - 10 dB in the required DPCH I c/I or for a 1% Block Error Rate (BLER) were observed. These measurements are within 1.4 dB of the ideal link level simulations which indicates that the predicted improvement at the network level should also materialize. The results presented in this paper show the tremendous potential of smart antenna arrays in 3G WCDMA cellular networks and establish diversity as a viable solution for high-speed cellular communications. © 2007 Springer Science+Business Media, LLC.