A novel reflectometer using a wideband monolithic active unilateral 4-port junction

The concept of using an active unilateral circuit to separate incident and reflected signals for the measurement of reflection coefficient has been demonstrated. The monolithic active unilateral circuit uses distributed amplification techniques, and operates over 1 to 20 GHz. The circuit can be used to replace conventional directional couplers and bridges in a wideband reflectometer, and this has been successfully achieved with good performance over the 1 to 10 GHz range. The circuit has been integrated with an HP8410 network analyser using full errorcorrection. The active technique has the advantage of very small size and is intended for fully active wafer probe heads. The technique promises extremely wide bandwidth and high directivity