PCB DESIGN BEST PRACTICE

A/D/RF co-design

A/D/RF co-design enables the design and shielding of complex RF circuits in context with the rest of the PCB. Engineers can enter schematics, optimize layout, and prepare for manufacturing when designing with RF circuits. Integrations with RF design and analysis tools ensure RF circuit quality.

What is A/D/RF co-design?

A/D/RF co-design refers to the integrated design approach that simultaneously considers analog, digital, and radio frequency circuits in a single PCB. 

What are the benefits of A/D/RF co-design?

Seamless data exchange

Information can be exchanged Between RF circuit design tools and PCB design tools.

Built in intelligence

Identify parametric RF elements including ground plane cutouts so when a circuit is edited or resized the cutouts adapt automatically. 

Integrated verification

Once a PCB design is created, it can be brought back into the RF design tool for optimization and verification against industry safety radiation standards.  

Key features of A/D/RF co-design with Xpedition

Design RF, analog and digital circuits on the same PCB 

Xpedition RF PCB design eliminates the traditional “black box” approach to RF PCB design, facilitating concurrent design, optimization, and verification of RF circuits on a PCB. 

Streamline RF tool integration 

Eliminate manual data transfer with dynamic integration between Xpedition and industry RF tools, including ADS and HFSS. The library is synchronized with the circuit-simulation model counterpart in the RF simulation environment to ensure that their behavior is identical. 

Optimize RF circuits in context 

Modify parametric RF elements within PCB layout to optimize space efficiency. 

Accelerate design time 

The ability to edit RF elements within PCB layout, combined with efficient RF tool integration eliminates workarounds and increases engineering productivity. 

Reuse verified RF circuits in other designs 

Xpedition’s robust design reuse capability enables teams to manage and share known-good circuits, eliminating redundant design efforts. 

Frequently asked questions about RF PCB design

What is the difference between analog, RF and digital circuits?

Analog circuits: deal with continuous signals, focus on fidelity and linearity, used in audio and sensor applications. 

RF circuits: handle high-frequency signals for communication, require careful impedance matching and EMI management, used in wireless communication systems. 

Digital circuits: handle discrete binary signals, emphasize speed and power efficiency, used in computing and digital communication. 

Each type of circuit has its own set of challenges and design methodologies tailored to its specific application domain. 

Why are RF PCBs hard to design?

RF PCBs are hard to design because they must handle high-frequency signals where even small layout imperfections can cause significant performance issues. Challenges include maintaining signal integrity, minimizing noise and electromagnetic interference (EMI), and achieving precise impedance matching to ensure efficient power transfer and reduce reflections. Parasitic inductance and capacitance, which are negligible in low-frequency circuits, become critical at RF frequencies and can degrade performance. Additionally, specialized materials and careful consideration of trace geometries are required to manage signal loss and dispersion, making the design process more complex and demanding compared to analog or digital PCBs. 

What kind of material is commonly used for an RF PCB?

Commonly used materials for RF PCBs include high-frequency laminates that offer low dielectric loss and stable dielectric constant across a wide range of frequencies. These materials are preferred for their excellent signal integrity, low signal loss, and ability to handle the high-speed signals typical in RF applications. Other materials like PTFE (Polytetrafluoroethylene) are also popular due to their low dielectric constant and minimal signal dispersion. 

How do you start with a RF PCB design?

First you can create the RF schematic and physical structures, then place and modify them in the context of the PCB RF component. Information can be seamlessly imported using integration between your PCB design tool such as Xpedition, and any 3rd party RF tools like ADS and HFSS. When information is passed into the PCB domain from an RF design tool, there can be built in intelligence that identifies parametric RF elements. This includes information like ground plane cutouts so when a circuit is edited or resized the cutouts adapt automatically. 

How do you simulate an RF circuit?

Once a PCB design is created, it can be brought back into the RF design tool for optimization and verification against industry safety radiation standards. This bidirectional integration enables the quick and efficient exchange of data between the different design domains and eliminates the need for manually reentering RF design information in either domain.