Dual RF generator design oriented towards the development of a VNA

Abstract

This paper presents the design and fabrication of
a dual radio frequency generator with an operating range
between 40 MHz and 4.4 GHz, intended for the development of
vector network analyzers (VNAs). The system is based on two
ADF4351 synthesizers that share a 10 MHz external reference,
allowing the generation of independent or frequency-coherent
signals depending on the required architecture. This feature
enables its use in homodyne and heterodyne configurations
without the need for additional synchronization hardware. The
main electronic design and high-frequency layout
considerations are described, including the implementation of
coplanar lines, confinement techniques using via fencing, and
decoupling and mass distribution criteria. The developed
module constitutes a modular, low-cost, and replicable solution
suitable for academic and research applications in
instrumentation.