The measurement of the equivalent admittance of 3-port circulators via an automated measurement system
Abstract
A derivation of the equivalent admittance of symmetrical 3-port circulators is given which is based on the requirement that the S-matrix eigenvalues be separated by 120 deg on the unit circle for perfect circulation. This quantity has the property that if a 2-port matching network is found which matches into this admittance, then the same matching network connected in each circulator arm will match the circulator. It was used in conjunction with a computerized measurement system to determine the optimal single-step transformer matching of a stripline 3.7-4.2-GHz circulator and resulted in a device with performance better than 30 dB over this band.
- Publication:
-
IEEE Transactions on Microwave Theory Techniques
- Pub Date:
- May 1977
- DOI:
- 10.1109/TMTT.1977.1129110
- Bibcode:
- 1977ITMTT..25..401R
- Keywords:
-
- Circulators (Phase Shift Circuits);
- Electrical Impedance;
- Impedance Matching;
- Impedance Measurement;
- Microwave Circuits;
- Strip Transmission Lines;
- Computer Techniques;
- Electric Terminals;
- Performance Prediction;
- S Matrix Theory;
- Superhigh Frequencies;
- Transformers;
- Electronics and Electrical Engineering