Incorporating an RF module into a design is straightforward, but there are some design guidelines that should be followed. Even though the RF design is done in the module, the product’s construction will have a significant impact on the module’s performance. The PCB layout and the product’s overall construction are critical to the overall performance of the module. Even though the complicated RF design is done, care must be used in the implementation of the module. Proper grounding is crucial with the best performance achieved using full planes instead of traces. Perf board is great for prototyping low frequency designs, but should be avoided at all costs with RF modules. If the module does not have an integrated antenna or antenna connector, then proper layout for impedance controlled traces between the module and the antenna is important. Providing a clean power supply is a priority. A noisy supply will cause a degradation of a receiver’s sensitivity and could cause excessive EMI radiation on a transmitter that could prevent regulatory compliance. This noise can come from switching power supplies, oscillators, and high speed digital lines. The antenna is a critical and often overlooked design consideration. The placement and attachment of the antenna as well as the antenna type is often the last consideration in a design when it should be one of the first. Throwing an antenna on the product without consideration of the impact of the product’s construction will not lead to optimal performance. Linx Application Notes AN-0500 and AN-0501 discuss antenna performance and design considerations. Interfacing to the module depends on the module, but generally follows a couple of techniques. The most basic is a simple asynchronous serial interface. This type of interface is a single wire where whatever logic level is present on the line determines what is sent over the air. Some modules have standard UART interfaces. Modules with built-in protocols or radio standards (like WiFi or ZigBee) have UART, IIC, or SPI interfaces.