This paper presents two new structures for six-port reflectometers with very large operating bandwidths of more than three decades, using a combination of lumped reflectors and transmission lines. Circuits working over a range of 2 MHz to 1300 MHz and 2 MHz to 2200 MHz have been built using inexpensive passive surface mount elements and Schottky detector diodes. Comparing results obtained from the new proposed structures with those obtained from a commercial network analyzer showed a worst case absolute value of 0.020 for the complex difference between the measured reflection coefficients. A convenient calibration procedure, for the entire band, is proposed using three standards and four approximately known loads.
Jan Hesselbarth, Frank Wiedmann, Bernard Huyart, "Two new six-port reflectometers covering very large bandwidths," IEEE Transactions on Instrumentation and Measurement, vol. 46, no. 4, pp. 966-969, August 1997.
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