This document provides an introduction to using millimeter wave technology for 5G cellular networks. It discusses the limitations of current cellular spectrum and the need for higher bandwidth. Millimeter wave spectrum from 30-300GHz is proposed as a solution due to the large amounts of unused spectrum available. However, propagation characteristics and device technologies present challenges at these frequencies that must be addressed. The document outlines some of these challenges and argues that millimeter wave mobile broadband could enable gigabit-per-second data rates at distances up to 1 km in urban mobile environments.