0 pins are on the high power RF circuit board.Input RF type Amplifier of the Evaluation board.Using the HMC698 search parameter, you can discover variants of the RF Board.
EVAL01-HMC6981LS6 Features
0 pins Amplifier Type
EVAL01-HMC6981LS6 Applications
There are a lot of Analog Devices Inc. EVAL01-HMC6981LS6 RF Boards applications.