High-frequency temperature-variable attenuator
AssigneeSmiths Interconnect Microwave Components, Inc.
InventorsRobert J. Blacka, David A. Raymond
Life of this patent
Estimating the term…
Abstract
An absorptive temperature-variable microwave attenuator is produced using at least two temperature-variable (or fixed) resistors in series with a transmission line. 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 resistors. Furthermore, attenuators can be created having either a negative temperature coefficient of attenuation or a positive temperature coefficient of attenuation.
Claims18
A temperature-dependent radio-frequency attenuator, comprising:
- a first temperature-dependent resistor disposed in series with a transmission line, said first temperature-dependent resistor changing resistance with temperature according to a first temperature coefficient;
- and
- a second temperature-dependent resistor disposed in series with said transmission line approximately one-quarter wavelength from said first temperature-dependent resistor at a desired frequency, said second temperature-dependent resistor changing resistance with temperature according to a second temperature coefficient, said first and second temperature coefficients configured such that said attenuator changes attenuation at a desired rate with changes in temperature
- wherein said first temperature coefficient comprises a positive temperature coefficient of resistance and said second temperature coefficient comprises a negative temperature coefficient of resistance.
A temperature-dependent radio-frequency attenuator, comprising:
- a first temperature-dependent resistor disposed in series with a transmission line, said first temperature-dependent resistor changing resistance with temperature according to a first temperature coefficient;
- a second temperature-dependent resistor disposed in series with said transmission line approximately one-quarter wavelength from said first temperature-dependent resistor at a desired frequency, said second temperature-dependent resistor changing resistance with temperature according to a second temperature coefficient, said first and second temperature coefficients configured such that said attenuator changes attenuation at a desired rate with changes in temperature;
- and
- a third temperature-dependent resistor disposed in series with said transmission line approximately one-quarter wavelength from said second temperature-dependent resistor such that said second temperature-dependent resistor lies electrically between said first temperature-dependent resistor and said third temperature-dependent resistor, said third temperature-dependent resistor changing resistance with temperature according to a third temperature coefficient,
- wherein a resistance of said first temperature-dependent resistor is approximately equal to a resistance of said third temperature-dependent resistor, and a resistance of said second temperature-dependent resistor is approximately equal to twice said resistance of said third temperature-dependent resistor.
A temperature-dependent radio-frequency attenuator, comprising:
- a first temperature-dependent resistor disposed in series with a transmission line, said first temperature-dependent resistor changing resistance with temperature according to a first temperature coefficient;
- a second temperature-dependent resistor disposed in series with said transmission line approximately one-quarter wavelength from said first temperature-dependent resistor at a desired frequency, said second temperature-dependent resistor changing resistance with temperature according to a second temperature coefficient, said first and second temperature coefficients configured such that said attenuator changes attenuation at a desired rate with changes in temperature;
- and
- a third temperature-dependent resistor disposed in series with said transmission line approximately one-quarter wavelength from said second temperature-dependent resistor such that said second temperature-dependent resistor lies electrically between said first temperature-dependent resistor and said third temperature-dependent resistor, said third temperature-dependent resistor changing resistance with temperature according to a third temperature coefficient,
- wherein a resistance of said second temperature-dependent resistor is approximately equal to twice a resistance of said first temperature-dependent resistor and said third temperature-dependent resistor.
Dependencies are inferred from the claim text.