CC1121: CC1121 & DN038 PCB antenna

Trevor Hunt

Part Number: CC1121
Other Parts Discussed in Thread: CC-ANTENNA-DK2

Hi there,

Our company is considering bringing out a product for multiple regions and thus multiple frequency bands must be supported..

We will be using the CC1121 & the DN038 PCB helical antenna..

The frequency bands required are 868Mhz, 915Mhz, 920Mhz & 866Mhz

1. I have read the DS for the cc1121 and its appears that 866Mhz is not supported, is this correct?

2. Do we have to re-tune the antenna for each band or would 1 single tune suffice for all?

Regards

Trevor

+1 RGW over 2 years ago

Hi Trevor,

The DN038 antenna can be tuned to 866-920 MHz. The main question is the bandwidth of the antenna and this will depend on the size of your GND plane.

The CC-Antenna-DK2 kit uses this antenna and the GND plane is 63 (length) x 43 mm (width) and the BW is 37 MHz.

From CC-Antenna-DK2 report:

Pros: Compact antenna design with a good efficiency average of 63% at 868 MHz and a good bandwidth of 37 MHz. This is the second general recommended antenna for 868 MHz or 915 MHz or 920 MHz. The kit antenna has similar efficiency performance (see Section A.15.3).
Cons: The match is dependent of the external discrete components and the PCB thickness. Tight tolerances are recommended for the antenna match network. The bandwidth (VSWR: 2) is not sufficient to cover both 868 MHz and 915/920 MHz with one match. If space is available for the antenna design then use board # 9 instead (see Section 2.1.9), since this has a greater efficiency (average of 80%) and even better bandwidth (122 MHz).

Size of your GND plane ?

Can you use DN024 antenna to achieve a greater BW ?

Multiple BOMs allowed to cover 866-868 MHz and 915-920 MHz ?