Electrical characterization of some materials in the X-band

Some properties of dielectric, semiconducting, and conducting materials in the X-band (8 to 12 GHz) are presented. The measurements reported cover the insertion loss (IL), return loss (RL), the equivalent input impedance (Z), and the shielding effectiveness (SE). The RL and the IL for the dielectric materials are roughly constant over the X-band, where RL is always larger than IL, except for the quartz specimen. The calculated SE is relatively small for these specimens. The IL and RL for silicon specimens depend weakly on frequency. IL, however, is always greater than RL, resulting in an average SE better than 9 dB for a 0.5 mm thick specimen. The GaAs specimen produces low RL (approximately 0.5 dB), while the IL depends strongly on frequency and reaches its maximum value at 10 GHz (approximately 34 dB), so the calculated SR is around 34 dB. The carbon specimens show IL greater than RL, and both depend on frequency. The SE yields an average value of about 19 dB. Z is found to be roughly constant for the dielectric and conducting materials while exhibiting a high frequency dependence for the semiconducting materials oscillating between inductive and capacitive.