On the embedded vector RF measurements in frequency agile and reconfigurable front-ends

Emerging intelligent and reconfigurable radiofrequency front-ends require the use of embedded vector measurements to ensure their proper tuning and operation at the frequency of choice. Alternative solutions for embedded vector measurements are briefly reviewed and a new wideband, non directional four-port reflectometer for vector reflection coefficient measurement is proposed. The four-port is based on two nondirectional low coupling RF samplers judiciously placed on a transmission line. The principle and the basic theory governing the 4-port operation are presented. Experimental measurements using the proposed reflectometer are compared to simulations as well as measurements using commercial vector network analyzers for a wide range of loads. Good agreement is obtained with an error not exceeding 0.8 dB6∠6°.