Tunable Reconfigurable Compact Antennas

Hi people, I need some information on 'Tunable Reconfigurable Compact Antennas for Mobile Communications'. Any papers/websites/relevant ebooks would be highly appreciated.

After some further research I made, the information I need is on Planar Inverted F Antennas.

Specifically I'm trying to find the following 2 papers,
Zidong Liu "Multi-Frequency Antennas for Personal Mobile Communications" University of Birmingham, UK, February 1998.

Kevin Boyle "Antennas for Multi-band RF Front-end Modules" Delft University Press, 2004. ISBN 90-407-2549-7.