Claims
- 1. A power limiter for generating an output RF signal of substantially constant power level in response to an input RF signal of varying power level, comprising:
- a field effect type transistor having gate, drain and source electrodes;
- means for biasing said transistor such that said transistor operates in a gain region characterized by a power curve having a slope whose change in output power is substantially equal to or greater than the change in input power, and a saturation region characterized by a power curve having a compression slope whose change in output power is substantially less than the change in input power, such that the final output power variation is small compared to the input power variations; and
- feedback circuit means connected between said drain and gate electrodes to provide a predetermined voltage to said gate electrode to reduce said final output variation;
- said substantially constant output RF signal being generated over said saturation region.
- 2. A power limiter for generating an output RF signal of substantially constant power level in response to an input RF signal of varying power level, comprising:
- a first multistage amplifier responsive to said input RF signal for generating a first output RF signal;
- a second multistage amplifier responsive to said first output RF signal for generating a second output RF signal;
- each of said first and second amplifiers including one or more field effect type transistors each having gate, drain and source electrodes, said transistors of each amplifier being connected in cascaded arrangement;
- means for biasing said transistors of said first amplifier to produce a predetermined gain level of said first output RF signal;
- means for biasing said transistors of said second amplifier such that said second amplifier is operated in a saturated condition at the gain level of said first output RF signal, such that said second output RF signal is substantially constant with said varying input RF power and the final output power variation is small compared to the input power variation; and
- feedback circuit means between the gate and drain electrodes of each transistor of said second amplifier to provide a predetermined voltage to each transistor to reduce said final output power variation.
- 3. A power limiter for generating an output RF signal of substantially constant power level in response to an input RF signal of varying power level, comprising:
- a first multistage amplifier responsive to said input RF signal for generating a first output RF signal;
- a second multistage amplifier responsive to said first output RF signal for generating a second output RF signal;
- each of said first and second amplifiers including one or more field effect type transistors each having gate, drain and source electrodes, said transistors of each amplifier being connected in cascaded arrangement;
- means for biasing said transistors of said first amplifier to produce a predetermined gain level of said first output RF signal;
- means for biasing said transistors of said second amplifier such that said second amplifier is operated in a saturated condition at the gain level of said first output RF signal, such that said second output RF signal is substantially constant with said varying input RF power and the final output power variation is small compared to the input power variation; and
- feedback circuit means between the gate electrode of a preceeding transistor and the drain electrode of a succeeding transistor of said second amplifier to provide a predetermined voltage to said preceeding transistor to reduce said final output power variation.
Government Interests
The Government has rights in this invention pursuant to Contract No. N00039-74-C-0227 awarded by the Department of the Navy.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
4079325 |
Mawhinney et al. |
Mar 1978 |
|
Non-Patent Literature Citations (2)
Entry |
Fukuda et al., "A New Microwave Amplitude Limiter Using GaAs Field Effect Transistor"; IEEE Microwave Theory and Techniques Conf.; Jun. 1977. |
Int'l Microwave Symposium; 6/1977, in Microwaves (pub.), pp. 9-10. |