Originally published at: https://www.protoexpress.com/blog/antenna-integration-rf-design-guidelines-for-5g-pcbs/
Designing an RF PCB for 5G devices requires a deep understanding of antenna integration, high-frequency signal handling, precise impedance matching, and effective noise mitigation. Selecting the right antenna is crucial, as it significantly influences the device’s overall performance. In this article, you will learn essential RF PCB design guidelines for 5G boards and strategies for effective antenna integration in radio-frequency circuit boards. Highlights: To design RF boards for 5G and IoT applications: Place the antennas at a distance from each other, pointing in opposite directions. Prefer ceramic substrates for compact designs, which are ideal for high-frequency precision. Route high-speed RF…
Download the RF & Microwave Design Guide_Sierra Circuits.pdf (1.6 MB)
How can the same antenna be designed to function effectively for both transmitting and receiving signals?
What strategies do you use to create a low-impedance ground plane in RF boards?
An antenna is designed to be resonant at specific frequencies, which means it can efficiently transmit and receive electromagnetic waves at those frequencies. The key to using the same antenna for both purposes lies in a device called a T/R (transmit/receive) switch.
When the system is in transmit mode, the T/R switch ensures that the transmitter is connected to the antenna, allowing it to send out signals. When in receive mode, the switch connects the antenna to the receiver, enabling it to pick up incoming signals. This switching mechanism prevents the transmitter and receiver from being active simultaneously, which could otherwise lead to damage.
Lower-power systems typically use PIN diodes in their T/R switches due to their fast switching speeds and reliability. Higher-power systems, on the other hand, use relays because they can handle greater power levels without damage.
By incorporating a T/R switch, the system ensures that the same antenna can be effectively and safely used for both transmitting and receiving.
Extensive use of copper in planes and pours is a fundamental approach, although it’s important to note that due to the skin effect, simply adding more copper isn’t always sufficient.
Utilizing highly conductive materials such as gold and silver for surface finishes can significantly enhance performance, with common finishes including electroless nickel immersion gold (ENIG), which offers excellent conductivity and corrosion resistance.
Implementing coplanar waveguide and microstrip lines is preferred, with CPW used inside the board and microstrip lines on the surface, ensuring optimal signal integrity. Additionally, ensuring precise dimensions and accuracy in the design and manufacturing process is crucial to maintaining a low-impedance ground plane.