in example 1 the dried mixture is calcined at 1200 u00b0 c for 4 h ground and again calcined in the temperature range 1300 1450 u00b0 c and cooled to the room temperature the sintering temperatures of the samples are optimized by sintering at different temperatures between 1550 and 1650 u00b0 c the initial firing of the mixed oxide powders has to be done at sufficiently high temperatures for sufficient duration in order to get a single phase polycrystalline ceramic of srla 4 ti 4 o 15 the sintered pellets showed density gt 98 except for calcination at 1500 u00b0 c where the sintered density droped to u02dc 93 the processing shaping and characterization techniques are as explained in example 1 the microwave dielectric properties of the ceramics at different calcination temperatures are given in table 2 the cao u2014 la 2 o 3 u2014 tio 2 ceramics including the single phase polycrystalline cala 4 ti 5 o 17 and cala 8 ti 9 o 31 are prepared by reacting high purity caco 3 la 2 o 3 tio 2 in the molar ratios 1 2 5 and 1 4 9 respectively through the solid state ceramic route the preparation and characterization follows the steps given in the example 1 the firing involves initial calcination at 1200 u00b0 c for 4 h grinding well and again calcining at 1350 1450 u00b0 c for different durations optimizing sintering in the range 1600 to 1675 u00b0 c for 2 8 hours the highly dense single phase ceramics gt 93 of theoretical density are used for microwave measurements.