Antenna design guidelines for NRF52832 based board

[Sai teja]

Hello,
 I am designing a 2 layer board with NRF52832 IC. I am following all design considerations and reference design mentioned in IC's datasheet provided by Nordic. I have a query regarding antenna. "Application Note AN043 pdf contains reference meandered f-antenna antenna for 2.4gHz. As my requirement is also for 2.4gHz, I am using the same antenna as mentioned in pdf
link: http://www.tij.co.jp/jp/lit/an/swra117d/swra117d.pdf
I have attached the reference antenna image from this pdf.
A/c to the pdf, antenna distance from board edges(D1, D2 and D3) is mentioned. But my board dimensions would be 100X50.
Plese clarify my following doubts
1) Is it mandatory to follow those dimensions(D1, D2 and D3)?
2)Is board size affect antenna performance?
3)Is it required to use any passive component to tune the antenna?
4)Unfortunately, I don't have network analyzer with me. Can you suggest any online simulation tools to validate my design?