Frequency adaptive temperature variable attenuator

1. A temperature-dependent 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 positive temperature coefficient of resistance;

a first inductive element shunting said first temperature dependent resistor;

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 negative temperature coefficient of resistance, said first and second temperature coefficients configured such that said attenuator changes attenuation at a desired rate with changes in temperature; and

a second inductive element shunting said second temperature dependent resistor.

2. The temperature-dependent attenuator of claim 1 , further comprising 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.

3. The temperature dependent attenuator of claim 2 further comprising a third inductive element shunting said third temperature-dependent resistor.