A wide band coaxial hybrid

A family of coaxial transmission line bridges exhibiting hybrid characteristics is described. These bridges differ from the conventional coaxial hybrid ring in that the balance is inherently independent of frequency. The impedances can readily be compensated within 1.4 VSWR over a one octave band. Printed circuit versions have been constructed. A precisely built hybrid for rigid coaxial line has found use in the laboratory measurement of very small impedance mismatches. Reflection coefficients of the order of 0.01 in 3 1/8 inch diameter transmission line are measured with a precision of about plus or minus 0.001 in magnitude and plus or minus 5° in phase angle at 200 megacycles. Direct oscillographic display of impedance is obtained with a network incorporating several hybrids.