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How is a RF trace isolated from other components?
An RF trace must be properly isolated from other high speed signals (such as clock traces for crystals, USB differential pairs, HDMI, ethernet, etc). This is often done by “via stitching”, i.e. stitching vias around the RF trace to prevent it from interfering with other components on board.
What should the impedance be on a RF PCB?
If you have never tried out RF PCB layout before and you do not have access to proper tools for simulating your design in 3D, the best you can do is pick components that have a characteristic impedance of 50 ohms on RF ports. The trace impedance on your PCB that carries RF signals can also be made 50 ohms by adjusting its width appropriately.
How is the trace width of a PCB determined?
The trace impedance on your PCB that carries RF signals can also be made 50 ohms by adjusting its width appropriately. You can calculate the trace width using online trace impedance calculators or microstrip impedance calculators.
How can I calculate the trace width of a filter?
You can calculate the trace width using online trace impedance calculators or microstrip impedance calculators. It is also easy to find parts (such as filters, amplifiers, antennas, etc) with 50 ohms characteristic input/output impedance.
What do you need to know about trace length matching?
In simple words, PCB trace length matching is the process of ensuring two or more signal traces are of the same length. The question that begs an answer is: what types of traces need to be matched?
Why are RF traces so difficult to layout?
Remember, RF traces are EXTREMELY high frequency signal carrying structures. If you lay them out last, or if you try to lay them out when the board has already gotten rather clumsy, you will make compromises with the trace layout that can make your design fail.
How are vias stitched around a RF trace?
This is often done by “via stitching”, i.e. stitching vias around the RF trace to prevent it from interfering with other components on board. Note that improper isolation will not render your design defunct, but it deteriorates the receiver performance and average data throughtput in most cases.