Analysis of thermal effects in integrated radio transmitters

The combination of compact size and low efficiency at mm-waves has turned heat dissipation into a fundamental constraint for design of multi-antenna radios. This paper describes methods for analysis of thermal effects at both at the circuit, system and component level. The first part describes how thermal analysis can be combined with advanced RF modeling techniques to predict self-heating and thermal coupling in multi-antenna transmitter systems. Experimental methods are then used to determine thermal coupling effects occurring at chip level. Various experimental and theoretical results, using MIMO amplifiers and GaN HEMTs, are used to demonstrate the methods in realistic application scenarios.