Abstract: A temperature and frequency variable gain attenuator comprises a temperature variable attenuator and a temperature variable filter network whose resistances changed to c generate different responses that vary over temperature and frequency. At least three different thick film thermistors are used, with two of these used on the attenuator and a third one used on the filter network. The temperature coefficients of the thermistors are different and are selected so that the attenuator and filter network attenuation change at a controlled rate with changes in temperature while the impedance of the gain equalizer remains within acceptable levels. Substantially any temperature coefficient of resistance can be created for each resistor by properly selecting and mixing different inks when forming the thick film thermistors. Furthermore, the attenuator can have either a negative temperature coefficient of attenuation or a positive temperature coefficient of attenuation.

Abstract: The present invention is an absorptive-type cable temperature and frequency equalizer that offsets changes in the gain of the other circuit components cables with increases in temperature and/or frequency. The equalizer comprises a temperature variable filter network having component values and a temperature coefficient of resistance that vary over temperature and frequency to produce a desired response. The temperature and frequency equalizer has at least one thick film thermistor connected in series with a quarter wavelength transmission line. The thermistor absorbs forward and reflected signals at lower frequencies.

Abstract: An absorptive temperature-variable microwave attenuator is produced using a first plurality of shunt resistors separated by quarter-wave transmission lines connected by a series resistor with a second plurality of shunt resistors separated by quarter-wave transmission lines. At least one or more of the resistors are temperature-variable resistors. The temperature coefficients of the temperature-variable resistors are selected so that the attenuator changes at a controlled rate with changes in temperature while attenuator remains relatively matched to the transmission line. In one embodiment, the resistors are thick-film resistors and a variety of temperature coefficients can be created for each resistor by properly selecting and mixing different inks when forming the thick film resistors. Furthermore, attenuators can be created having either a negative temperature coefficient of attenuation or a positive temperature coefficient of attenuation.