Introduction to Developing a New Wireless Product

https://blog.hackster.io/introduction-to-developing-a-new-wireless-product-bf0a6c5b51a4#.esxyeyiei

There are two routes to incorporating wireless functionality into a custom PCB design: a self-contained module, or a chip design. In almost all cases, it’s best to start off with a module solution. Wireless functions can be one of the trickiest types of circuits to design so modules are very commonly used.