TRANSMISSION MODE UHF MAGNETO-ACOUSTIC DELAY LINE

摘要

Results are presented on the investigation of an experimental magneto acoustic transmission delay line using a single crystal rod of yttrium iron garnet (YIG), over the frequency range of 200 to 1000 megacycles. Data is given on delay time and insertion loss as a function of magnetic bias field. Both a /slow and a fast variation of insertion loss with bias field are noted. The slow variation of insertion loss is quite flat and insertion loss is at a minimum, over the range of 900 to 1050 oersteds, for all frequencies from 200 to 1000 mc. Measurements of VSWR of an unturned line show that the losses due to impedance mismatch account for a relatively small portion of the overall insertion loss. A study of the fast variation, of insertion loss shows that this variation occurs only over a portion of the pulse. Therefore, if-the pulse is short enough the fast variation is absent. The separation (in biasing field) of adjacent insertion loss peaks, of this fast variation, appears to be in reasonable agreement with theoretical calculations recently presented. Also small permanent magnets are used to supply a biasing field orthogonal to the primary biasing field that is parallel to the rod axis. The effects of the orthogonal field on the slow and fast variations of insertion loss are described. In addition, two YIG rods were bonded together to provide longer delays than possible with available single rods. Data is presented on the variation of delay time and insertion loss with field of the bonded line.