Here's an Amazon list of candidates. These are not cheap, so I'd like to get things other people have read and like. NB I'm a paper book guy.
Introduction to RF Power Amplifier Design and Simulation
Abdullah Eroglu
Advanced Techniques in RF Power Amplifier Design
Steve C. Cripps
Load-Pull Techniques with Applications to Power Amplifier Design
Fadhel M. Ghannouchi & Mohammad S. Hashmi
RF and Microwave Power Amplifier Design
Andrei Grebennikov
Linear and Switch-Mode RF Power Amplifiers: Design and Implementation Methods
Abdullah Eroglu
Modeling and Design Techniques for RF Power Amplifiers
Arvind Raghavan
The Load-pull Method of RF and Microwave Power Amplifier Design
John F. Sevic
Practical RF Amplifier Design and Performance Optimization with SPICE and Load- and Source-pull Techniques
Amal Banerjee
Advanced Design Techniques for RF Power Amplifiers
Anna N. Rudiakova & Vladimir Krizhanovski
Switchmode RF and Microwave Power Amplifiers
Andrei Grebennikov, Nathan O. Sokal & Marc J. Franco
Have Fun!
Reg