Why have smart antennas not yet gained traction with wireless network operators?

Many research and development activities have been poured into developing smart antennas for wireless communications systems. Yet despite the promise of increased network capacity and enhanced spectrum utilization, smart antenna systems have largely failed to break into the mainstream cellular networks, as operators have balked at adopting these technologies. This article examines some of the reasons why smart antennas have historically been met with resistance, and suggests that provided some identified obstacles are overcome, the proliferation of certain types of smart antennas is imminent.