Microwave dielectric properties of(Y/sub 2-x/R/sub x/)BaCuO/sub 5/ (R=rare-earth) solid solutions

(Y/sub 2-x/R/sub x/)BaCuO/sub 5/ (R=rare-earth) solid solutions, in which Yb, Tm, Er, Ho, Dy and Gd ions are substituted for Y ions, were studied concerning the microwave dielectric properties. Each rare-earth series form solid solutions with the same crystal structure of the Y/sub 2/BaCuO/sub 5/-type. The dielectric constants of all the solid solutions are low, around 14, which is very good for high microwave frequency applications. The quality factors (Q/spl middot/f) show high values with no systematic change: 62741 GHz for Yb-system with x=2 and 42602 GHz for Dy-system with x=1. Moreover, the temperature coefficients decrease according to the composition x and the value of Dy-system especially decrease to -6.4 ppm//spl deg/C. The solid solutions in Dy-system with x=2 have good properties: Q/spl middot/f=31617 GHz, /spl epsiv//sub r/=14.9 and /spl tau//sub f/=-6.4 ppm//spl deg/C.