Circuit arrangement for summing the powers of two isofrequential microwave signals

A circuit arrangement for summing the powers of two isofrequential microwave signals, comprising:

• a first and a second signal path carrying respective microwave signals of identical frequency to be combined;
• a directional coupler with a pair of first input ports respectively connected to said signal paths and with a pair of first output ports emitting composite signals each including an in-phase signal component from an associated first input port and a quadrature signal component from the respectively opposite first input port;
• a hybrid junction with a pair of second input ports respectively connected to said first output ports and with a pair of second output ports, said hybrid junction combining said composite signals cophasally into a sum signal on one second output port and with relative phase inversion into a difference signal on the other second output port, said sum signal being available for the energization of a load;
• a first adjustable phase shifter upstream of said directional coupler in series with one of said first input ports;
• a second adjustable phase shifter inserted between one of said first output ports and one of said second input ports;
• a first coherent detector with a reference input connected to said one second output port and with a monitoring input connected to said other second output port for emitting a first error signal to a corrective input of said first adjustable phase shifters in response to a difference signal in phase with said sum signal;
• and
• a second coherent detector with a reference input connected to said one second output port and with a monitoring input connected to said other second output port for emitting a second error signal to a corrective input of said second adjustable phase shifters in response to a difference signal in quadrature with said sum signal.