QN9080-001-M17(SIP) Antenna design for no ground plane

tpgurtpgur2 — Tue, 09 Nov 2021 02:28:24 GMT

I am trying to make a very small BLE device using a QN9080 SIP. Since there should be no ground plane on the PCB because i am designing in a special situation, i connected all ground pins of the circuit with traces.

The datasheet has guidelines only if a ground plane is present. If there is no ground plane like mine, how do I connect the antenna function pins (Pin 48, 49, 50) and do I need an additional antenna trace or small ground plane or chip antenna?

I tested both with and without a ground plane, and there was a difference in RF performance, and the performance decreased when there was no ground plane.
(Please check the attached photos of both test layouts.)

I would appreciate it if you could provide a guideline for maintaining the same high RF performance even in the absence of a ground plane.

Thank you.

Best regards.
Oh.

Re: QN9080-001-M17(SIP) Antenna design for no ground plane

ryan_xu — Thu, 11 Nov 2021 07:18:00 GMT

HI Oh

can you share the your test result that test done on both of boards?

in fact, we don't recommend that layout the no ground plane on the PCB, you know a complete GND is important to ensure RF performance and power performance,

Anyway, what mode of antenna in your application? I guessing that internal antenna is used, right? if so please see my suggestion in below,

1. increase the line wide for those GND trace connection,

2. layout a few of gnd shape on RF GND(48,49,50) pin and connect it as following,

Best regards

Ryan

topic Re: QN9080-001-M17(SIP) Antenna design for no ground plane in Wireless MCU

QN9080-001-M17(SIP) Antenna design for no ground plane

Re: QN9080-001-M17(SIP) Antenna design for no ground plane