Things to Note on RF Design

This topic describes the things to note on radio frequency (RF) design after you select Tuya’s module for product development. This helps you improve development efficiency and achieve optimal module and product performance.

Module layout

Module with PCB antenna

The module is provided with a printed circuit board (PCB) antenna, as shown in the following figure.

Module with external antenna

The module is provided with an IPEX interface, as shown in the following figure.

Product layout

Horizontal placement

Recommend layout: Place the module at the edge of the backplane with the antenna facing outward with an exposed length of over 6 mm. Flush the module GND with the backplane GND that are fully connected with each other.
The area below the antenna (including the module and antenna) is kept clean, without any PCB substrate, wires, or structure that might interfere with the antenna.

Embedded placement

The module can be embedded in the backplane, as shown in the following figure.

However, in this layout, the module is blocked by the motherboard GND. The antenna performance might be affected. You can cut slots on the motherboard to reduce interference with the antenna, as shown in the following figure.

Enclosure design

• A plastic enclosure is recommended, such as acrylonitrile butadiene styrene (ABS), polycarbonates (PC), or other materials with similar dielectric constants.

• A certain distance is kept between the enclosure and the antenna.

• Do not use metal shells and shells with metallic paint or coating in the direction of the antenna radiation.

• Do not use metal objects such as screws and rivets near the antenna. Otherwise, the antenna efficiency might be affected.

  

• The distance from the top cover to the antenna affects the antenna performance. A longer distance decreases the impact on the antenna performance.

  

• Try to increase the distance from the upper and bottom shells to the antenna to minimize the impact on antenna performance.

  

Backplane GND shape

If GND is removed from one side of the backplane or the backplane GND is partially divided, the return loss waveform of the antenna shows a frequency deviation and a shallow depth.

Arrangement of module and antenna

• Keep a distance of 30 mm or more between the module (particularly the antenna) and speakers, batteries, power switches, cameras, liquid crystal displays (LCDs), Ethernet ports, High-Definition Multimedia Interface (HDMI) connectors, USB connectors, and other high-speed signals to avoid interference.
• Reserve a sufficient clearance area below the antenna. No wiring or other medium layer is allowed in this clearance area to avoid interference from structural parts.
• Avoid signals of the same or similar frequency within a distance of 30 mm from the antenna to minimize interference.
• The antenna radiation directions cannot be blocked by metal.
• A PCB antenna provides limited performance for a module. We recommend that you use an external antenna if conditions permit.