Ultra-Wideband Dual-Line Multiprobe Reflectometer

A new type of dual-line multiprobe reflectometer, featuring an ultra-wideband operational bandwidth, is proposed. The presented reflectometer is composed of two parallel transmission lines along which weakly coupled probes are arranged. By utilization of two separate transmission lines, the minimum distance between two consecutive probes can be smaller than the length of a single probe, which allows for a highly nonuniform probes' arrangement required to ensure ultra-wideband operation. Moreover, an efficient algorithm for the probes' arrangement ensuring maximization of reflectometer's bandwidth is proposed. The proposed concept has been validated by the design of an ultra-wideband dual-line multiprobe reflectometer having six probes and operating frequency range over 0.1-12 GHz. The obtained results are in a very good agreement with the reference values measured using a commercial VNA.