RF feed network for modular active aperture electronically steered arrays

A feed network for an antenna subarray comprising;

• a plurality of couplers, each one of the plurality of couplers having an antenna port, a sum port, a delta port and a termination port;
• a first feed arrangement connected to each one of the sum ports of the plurality of couplers, the first feed arrangement having a sum forming signal output;
• a second feed arrangement connected to each one of the delta ports of the plurality of couplers, the second feed arrangement having a delta forming signal output;
• a fixed attenuator having a first port and a second port, the first port of the fixed attenuator connected to the delta forming signal output of the second feed arrangement;
• a first power divider/combiner having a first and second port and a third port;
• the first port of the first power divider/combiner connected to the second port of the fixed attenuator;
• a variable phase shifter having a first port and a second port, the first port of the variable phase shifter connected to the second port of the first power divider/combiner;
• a variable attenuator having a first port and a second port, the first port of the variable attenuator connected to the second port of the variable phase shifter;
• a second power divider/combiner having a first and second port and a third port;
• the first port of the second power divider/combiner connected to the second port of the fixed attenuator;
• a first circulator having a first port, a second port and a third port, the first port of the first circulator connected to the sum forming signal output of the first feed arrangement and the second port of the first circulator connected to the third port of the second power divider/combiner;
• and
• a second circulator having a first port, a second port and a third port;
• the first port of the second circulator connected to the second port of the second power divider/combiner and the second port of the second circulator connected to the third port of the first circulator.

An antenna subarray comprising:

• a plurality of radiators;
• a plurality of transmit-receive modules, each one of the transmit-receive modules coupled to a respective one of the plurality of radiators;
• a plurality of RF couplers, each one connected to a respective one of said plurality of transmit-receive modules;
• a first feed arrangement of uniform power dividers coupled to said plurality of RF couplers;
• a second feed arrangement of uniform power dividers coupled to said plurality of RF couplers;
• a first circulator having a feed port, a transmit port and a sum port, the feed port of the first circulator connected to said first feed arrangement;
• a second circulator having a feed port, a transmit port and a sum port, the transmit port of the second circulator connected to the transmit port of the first circulator;
• a first power divider/combiner having a first and second port and a third port;
• a second power divider/combiner having a first and a second port and a third port, the third port of the second power divider/combiner connected to the sum port of the first circulator and the second port of the second power divider/combiner connected to the sum port of the second circulator;
• a variable attenuator having a first and a second port, the second port of the variable attenuator connected to the first port of the second power divider/combiner;
• a variable phase shifter having a first and a second port, the second port of the variable phase shifter connected to the first port of the variable attenuator and the first port of the variable phase shifter connected to the second port of the first power divider/combiner;
• a fixed attenuator having a first and a second port, the first port of the fixed attenuator connected to the second feed arrangement and the second port of the fixed attenuator connected to the first port of the first power divider/combiner.