All RF traces are routed on Layer 1 (primary side), and all other remaining layers are ground planes that provide a solid ground for RF transmission lines. The top dielectric material is Rogers 4350, offering low loss performance. The prepreg material in the middle sticks core layers together, which includes an Isola 370HR layer with copper traces above and below. Both the prepreg material and the Isola 370HR core layer are used to achieve required board finish thickness.
The circuit board used in the application uses radio frequency (RF) circuit design techniques. Signal lines must have 50 Ω impedance while the package ground leads and exposed paddle must be connected directly to the ground plane. Use a sufficient number of via holes to connect the top and bottom ground planes. The EV1HMC890ALP5 evaluation board is available from Analog Devices, Inc. upon request.