0 pins are on the high power RF circuit board.Input RF type Mixer of the Evaluation board.Using the HMC819 search parameter, you can discover variants of the RF Board.
EV1HMC8191LC4 Features
0 pins Mixer Type
EV1HMC8191LC4 Applications
There are a lot of Analog Devices Inc. EV1HMC8191LC4 RF Boards applications.