High temperature characterization of alumina substrates and folded slot antenna

The characterization of 99.6% poly crystalline alumina substrates and folded slot antennas has been presented. TRL calibrations were performed at temperatures of 25 to 400 degC over a frequency range from 0.5 to 50 GHz. The effective dielectric constant of the CPW on alumina substrates was determined to be relatively constant at 5.4 from 25 to 200 degC and then increased steadily to approximately 6 at 400 degC. The loss of the CPW lines increased as temperature and frequency increased as well noting that the increase in loss is even more profound as both the temperature and frequency increased simultaneously.