Abstract: A programmable microwave network test device is capable of establishing a multitude of reflection and transmission coefficients determined by a set of digital inputs. The programmable network enables the collection of groups of measurements which are used to characterize a non-linear or linear device. The microwave structure of the network is comprised of a series of PIN diodes interconnected through microstrip transmission lines. The lengths of the transmission lines between the PIN divide are proportioned so as to allow use of the network over a broad frequency range, with a minimization of repeated reflection coefficients in a use of the network, the device to be characterized would be placed at the input port of the network with the output port of the network terminated in its characteristic impedance.