Interesting career change!

A few books that come to mind are

- RF Microelectronics, Behzad Razavi, Prentice Hall. There is a new 2nd edition which I assume is better or more comprehensive than the first edition.

- RF Circuit Design, Chris Bowick, Newnes/Elsevier 2008. This is a good primer introduction to RF concepts including matching networks, Smith chart and LC filters.

- RF System Design of Transceivers for Wireless Communications,  Qizheng Gu, Springer. Decent RF transceiver system design walk through for superhet and direct conversion WCDMA FDD systems.

I'm sure there are some references for Zigbee, but I don't know what they are off hand.

PCB design is mostly about signal integrity, controlled impedance lines, EM coupling, and supply decoupling. I don't know of a good reference that addresses all the issues. The amount of design and modeling effort depends a lot on the system specs. Tight RF or HF I/O performance specs or high isolation requirements can demand a lot of detailed EM modeling and verification.

Modeling/measurement of external components used for matching and decoupling networks can demand a lot of attention too.

RFICDUDE wrote on Dec 30^th, 2012, 6:28pm:

Modelling and simulation at the board level?

Not so much as at the chip level in my opinion.

When I am designing a chip I live on a simulator.
When I design a PCB I will do hand calculation estimates of critical things and then go build it.
If its not perfect, PCB respin is small money and more cost-time effective.