Frequency selective distributed amplifier

A distributed amplifier, comprising:

• a plurality of amplifier stages having input nodes and output nodes;
• an output phase shift circuit connecting the output nodes of the plurality of amplifier stages in a manner that causes output signals from the plurality of output nodes to add together for delivery to a load, the output phase shift circuit having a first phase shift at a frequency F0 and a second phase shift at a frequency F1;
• and
• an input phase shift circuit, coupled to the plurality of input nodes and providing input signals thereto, the input phase shift circuit having a phase shift at F0 equal to the first phase shift, and having a phase shift at F1 that is not equal to the second phase shift;
• whereby, output signals from the plurality of amplifier stages are added in phase at F0 and are added with a phase difference at F1 so that the distributed amplifier has greater gain at F0 than at F1.

An N stage distributed amplifier, comprising:

• a plurality of N amplifier stages having input nodes and output nodes;
• a plurality of N−1 output phase shift circuits connecting the output nodes of the plurality of amplifier stages in a manner that causes output signals from the plurality of output nodes to add together for delivery to a load, the plurality of output phase shift circuits having a plurality of phase shifts of θ(f)={θ(f)1,2;
• θ(f)2,3;
• . . . ;
• θ(f)N−2,N−1}, where θ(f0)a,b represents a phase shift between output nodes of amplifiers a and b at frequency F0;
• a plurality of N−1 input phase shift circuits, coupled to the plurality of input nodes and providing input signals thereto, the plurality of input phase shift circuits having a plurality of phase shifts of Φ(f)={Φ(f)1,2;
• Φ(f)2,3;
• . . . ;
• Φ(f)N−2,N−1}, where Φ(f0)a,b represents a phase shift between input nodes of amplifier stages a and b at frequency F0;
• and
• wherein, θ(f) is not equal to Φ(f), so that output signals from the plurality of N amplifier stages are added with a frequency dependent phase relationship.