who can give me some advice about RF studies?

I have studied antennas for a long time, but I am an newbie in RF, who can give me some suggestions about RF studies, what books, what simulation software?
Thanks a lot!

which type of RF ,
if it is discrete "board level" the best simulation tools @DS and MWO
if in integrated "chip level" u have @DS and Spectre

thanks very much for your reply!
I m interested in integrated system, what books should I study?

I think this post maybe og help

https://www.edaboard.com/ftopic89166.html

read lots of papers.
read lots of books.
learn to use ADS and HFSS.
it is ok!

Microwave office is a user freindly software for rf engineers
pozar's book microwave engineering is a good start.

@DS is a very good software for rf designer.
Thomas H.Lee's book,the design of CMOS Radio-frequency Integrated circuits is good too.

Fundamental of Microwace Engineering by Collins

and read many books , i think it need a great efforts to study RF

I suggest you to read this book:
RF Microelectronic by: Behzad Razavi
It's available in this site.

yes, the book written by Razavi is quite useful and it can be understand easily!I promote it!