MMIC tunable biphase modulator

An apparatus for providing electronically tunable biphase modulation, said apparatus comprising:

• an input;
• a first switch having a first input coupled to said input, a first output and a second output, said first switch coupling said first input to either said first output or to said second output in response to a modulating signal;
• a first signal path having a first phase shift, said first signal path coupled to said first output;
• a second signal path having a second phase shift different than said first phase shift, said second signal path coupled to said second output;
• a second switch having a first input coupled to said first signal path, a second input coupled to said second signal path and a terminal output, said second switch coupling said first signal path to said terminal output when said first switch couples said input to said first signal path and coupling said second signal path to said terminal output when said first switch couples said input to said second signal path;
• wherein said first signal path comprises a first coupler having first, second, third and fourth ports, said first port coupled to said first output of said first switch, said second port coupled to a first reactance element, said third port coupled to said first input of said second switch and said fourth port coupled to a second reactance element;
• and
• wherein said second signal comprises a second coupler having first, second, third and fourth ports, said first port of said second coupler coupled to said second output of said first switch, said second port of said second coupler coupled to a third reactance element, said third port of said second coupler coupled to said second input of said second switch and said fourth port of said second coupler coupled to a fourth reactance element.