A uhf Delay Line Using Single-Crystal Yttrium Iron Garnet

An investigation has been made to determine the properties of yttrium iron garnet at room temperature as a delay-line transducer material. Preliminary results show a specific delay of 2.5 μ sec/cm and an attenuation of 0.4 dB/cm in the frequency range 0.5 to 1.0 Gc/sec. At low input power the insertion loss is constant whereas at high input power the output power is approximately constant; the high-power behavior appears suitable for sonic limiting devices. A method has been found for suppression of unwanted echoes. Evidence from low power level insertion loss measurements indicates that it may be possible to construct a YIG delay line with a 3-dB bandwidth greater than 100 Mc/sec and at the same time an insertion loss less than 60 dB.