KA-Band Solid State Power Combining Amplifier

Solid state combining amplifier power levels in the multiwatt range have been achieved at frequencies in excess of 35 GHz. Both GaAs lo-hi-lo profile diodes, and Si double drift diodes are utilized in an amplifier which has an output power in excess of 5 watts at 37 GHz. The total amplifier gain is 33 dB and the 1 dB bandwidth exceeds 700 MHz. The amplifier features 5 stages, 3 of which operate in the negative resistance mode with 2 GHz of bandwidth, while the final two stages operate in the injection locked mode. These final stages represent the power stages and utilize TM010 resonant cavity combining structures. Computer aided design has been used extensively for circuit modeling and performance optimization. This solid state amplifier is small in size and lightweight, and is a first step towards replacement of the traveling wave tube amplifier for space applications.