A low temperature dependent microstrip substrate

An X band resonant ring temperature coefficient and the coefficient of effective dielectric constant for a modified zirconate substrate have been measured as -1.58 × 10
^-6
per °C and 3.0 × 10
^-6
per °C over the temperature range -40°C to +120°C at X band. The effective dielectric constant at room temperature varies from 19.82 at 5.98 GHz to 21.24 at 11.61.