Overcoming MIMO Wi-Fi Front End Thermal Design Challenges

In the Wi-Fi world, one of the most critical design challenges that engineers need to address is product temperature.

Wi-Fi components within routers and access points are typically subjected to average temperatures of 60°C (140°F) or greater, even when the room temperature is a moderate 25°C (77°F). It’s important to consider this fact early on in Wi-Fi product design, to help minimize redesign issues and additional costs. Let’s examine some of the biggest impacts of temperature on component performance, as well as strategies and specific RF products for overcoming thermal challenges in Wi-Fi front-end designs.

An evolving Wi‑Fi ecosystem

Heat is always an issue in Wi-Fi access points and routers, and the challenges are increasing as the wireless ecosystem becomes more complex (Figure 1). Several trends contribute to the thermal challenges:

• More users on more Wi-Fi channels: Today’s access points and nodes support up to eight 2.4 GHz and eight 5 GHz paths, and they have to support more devices and users than ever before.
• Shrinking size and expanded functionality: Wi-Fi hardware continues to pack more capabilities into a smaller product footprint, especially in many distributed Wi-Fi/mesh products.
• Wi-Fi 6, the next Wi-Fi generation: With Wi-Fi 6 (802.11ax), the processor has to work harder to support more complex modulation schemes, higher data rates and greater throughput. This produces more heat and increases the risk of poor RF front-end (RFFE) performance.
• Support for the Internet of Things (IoT): Some Wi-Fi units now include even more wireless radios to enable support for IoT devices that communicate via Zigbee, Bluetooth, Bluetooth Low Energy (BLE) and Thread.