Investigations of the Temperature Sensitivity of Dual-Band Dual-Mode Inwate Filters for Satellite Converters

Investigations of temperature sensitivity of INWATE-circuits are presented. INWATE-circuits are in principle dielectric filled waveguides and adhesion problems may occur due to the different thermal expansion coefficients of the dielectric material and the metal wall layer. It has been shown that thermal cycling from -35 °C to + 70 °C has no influence on transmission properties of Ka-band-resonators. Due to the negative temperature coefficient of polystyrene dielectric filling, the temperature coefficient of resonant frequency is nearly compensated. Furthermore a polarization independent dual-band dual-mode INWATE-filter for satellite converters has been investigated in a temperature range of -35 °C to 70 °C and there is no significant change in filter characteristic.