Antenna PCB and components parameters nrf54

[MAndris]

Subject: Questions About RF Circuit Differences in a Test Board

I have designed a test PCB using 0603 components while keeping the same nominal values as in the reference design. However, there are several concerns related to the RF section:

1. Component Size & RF Performance:

   • I understand that not only electrical parameters but also geometric factors influence the RF performance.
   • Since I used larger components (0603) compared to the original design, I am uncertain if this might degrade the RF performance.

2. Antenna Differences:

   • The reference schematic does not explicitly show the antenna, which adds uncertainty.
   • On the development board, the antenna makes a 90-degree turn, has an unknown length, and is 2 mm wide.
   • In my design, I made the antenna completely straight, 23 mm long, and 1 mm wide.
   • I am unsure if this deviation will significantly impact performance.

3. Capacitor Tolerance Concern:

   • One capacitor in the design (C11, 0.3 pF, C0G, ±0.01 pF, 50 V) is not available in retail with the specified tolerance.
   • The closest available component has a tolerance of ±0.02 pF.
   • Will this tolerance difference be critical for RF performance?

4. Additional Component After the Spectrum Analyzer Connector:

   • I included a connector for spectrum analyzer testing in my design.
   • However, I noticed that the development board has an additional component after this connector, which is not listed in the official documentation.
   • I suspect this might be another capacitor, similar to the one before the connector.
   • Should I include this component in my design as well?

Key Question:

Are these deviations (component size, antenna geometry, capacitor tolerance, and missing component after the test connector) critical for proper RF performance?
Do you have recommendations for adjusting my schematic and component selection before finalizing my first test batch?

I have attached:

• Mouser component list (prepared for ordering)
• Schematic
• PCB layout

I am developing a zigbee switch based on nrf54l15.
I took the basic diagram from the documentation:
https://docs.nordicsemi.com/bundle/ps_nrf54L15/page/chapters/ref_circuitry.html

Files link:

https://drive.google.com/drive/folders/1zhuwbWaI4HWGG0Gb3hgsDK38rfpMWAzH?usp=sharing

Thanks in advance for your feedback!