QUESTION

Question

Dear experts,

I use the antenna in a design with a 85 mm GND plane and of course considerung all design rules.

Here is the link to the antenna: https://www.antenova.com/wp-content/uploads/2022/04/Inversa-SR4L034-PS-2.04.pdf

I observe quite sharp resonance in Sub-GHz area. I can optimize the matching for e.g. 800 MHz and 1800 MHz, but the resonance is still quite sharp and I cant optimze for both, 800 MHz and 900 MHz. Probably I can achieve the behaviour like in the datasheet, when I change L4 (T1/Return). Currently I use the value from the datasheet.

Does anyone have a hint how to tune T1? Is there any strategy or how-to-guide?

Thank you for your help!
Johannes

Answer 1

Hi Johannes,

Which frequencies do you need to match?

Normally we would recommend starting with the matching specified in the datasheet then change 1 component at a time.

Best regards,

Yu Kai Yeung

Comments

Hi Yu Kai Yeung,

thank you for the fast reply. I want to match to around 800, 900, 1800 and 2100 MHz. I startet with the matching from the datasheet and did an Optimization. I do net get good results for 800 and 900 MHz at the same time as the resonance is quite sharp in my measurement and simulation. My next step would be to change the L4 (see datasheet), the inductance which is connected to T1/Return. Shall I just do try and error with measurement or is there any smarter way to change this inductance?

Thank you!
Best Regards

Johanes