Microwave circular polarizer

A circular polarization means for changing polarization of a microwave signal between circular and linear including:

• a first dual mode transducer for coupling power between a circular waveguide and two rectangular waveguides so that the power in each of the rectangular waveguides is one-half the power in the circular waveguide;
• a second dual mode transducer for coupling power between two rectangular waveguides and a circular waveguide so that the power in the circular waveguide is twice the power in each of the rectangular waveguides;
• compensation means for causing a phase shift between two signals, said compensation means including a first rectangular waveguide path and a second rectangular waveguide path extending from said first dual mode transducer to said second dual mode transducer, said first and second paths having a different length between said first and second dual mode transducer, said first path having a wide dimension which decreases then increases in magnitude, the decrease and the increase being symmetrically equal in magnitude so that there is a first central portion of decreased width relative to the remainder of said first path, said second path having a wide dimension which increases then decreases in magnitude, the increase and decrease being symmetric and equal in magnitude so that there is a second central portion of increased width relative to the remainder of said second path, said compensation means having dimensions so that there is a phase difference of 90.degree. at two different frequencies of signals being conducted by said compensation means;
• and
• a third dual mode transducer having a circular waveguide portion coupled to the circular waveguide portion of said second dual mode transducer and two rectangular waveguide ports rotated 45.degree. with respect to the rectangular waveguide ports of said dual mode transducer, said rectangular waveguide ports of said third dual mode transducer being adapted for passing signals uniquely associated with polarizations of the opposing sense.

A circular polarizer for converting a linearly polarized microwave signal to a circularly polarized signal and vice versa, said circular polarizer comprising:

• a first transducer means having a first, second and third ports, said first transducer means being adapted to permit passage through said first port of first and second signals in a first frequency band which are orthogonally polarized with respect to each other, said first transducer means being adapted to permit passage through said second port of said first signal and to block passage through said second port of said second signal, said first transducer means being adapted to permit passage through said third port of said second signal and to block passage through said third port of said first signal;
• a first polarization adjusting means having fourth, fifth, sixth and seventh ports, said fourth and fifth ports being coupled to said second and third ports, respectively, and being adapted to pass said first and second signals respectively, said sixth and seventh ports being adapted to pass two signals of said first frequency band which are orthogonally polarized with respect to each other, one of the signals passing through each of the ports, said first polarization adjusting means being operable to adjust the polarization of signals passing therethrough with a relatively high degree of isolation between polarizations over a relatively broad frequency band, said polarization adjusting means having a first compensation guide coupled between said fourth and sixth ports and a second compensation guide coupled between said fifth and seventh ports, said first and second compensation guides having a width and length suitable for adjusting the polarization of signals passing therethrough, by changing the relative phase with respect to time between the two signals;
• a second transducer means having eighth, ninth, tenth and eleventh ports, said eighth and ninth ports being coupled to said sixth and seventh ports, respectively, said eighth and ninth signals being adapted to pass two signals which are orthogonally polarized with respect to each other, said second transducer means being adapted to adjust the relative spatial phase of the signals passing therethrough;
• an electromagnetic wave conducting means having twelfth, thirteenth, fourteenth and fifthteenth ports, said electromagnetic wave conducting means being adapted to permit passage through said twelfth port of said first and second signals of said first frequency band and third and fourth signals in a second frequency band which are orthogonally polarized with respect to each other, being adapted to permit passage through said thirteenth port of said first and second signals and to block passage through said thirteenth port of said third and fourth signals, said conducting means being adapted to permit passage through said fourteenth port of said third signal and to block passage through said fourteenth port of said first, second and fourth signals, and being adapted to permit passage through said fifteenth port of said fourth signal and to block passage through said fifteenth port of said first, second and third signals, said thirteenth port being in communication with said first port;
• a third transducer means having sixteenth, seventeenth, eighteenth and nineteenth ports, said sixteenth and seventeenth ports being adapted to pass signals of said second frequency band, said eighteenth and nineteenth ports being adapted to pass two signals of said second frequency band which are orthogonally polarized with respect to each other, one of the signals passing through each of the ports;
• and
• a second polarization adjusting means having a third compensation guide coupled between said fourteenth andd seventeenth ports and a fourth compensation guide coupled between said fifteenth and seventeenth ports, said third and fourth compensation guides having a width and length suitable for adjusting the polarization of signals passing therethrough with a relatively high degree of isolation between polarizations over a relatively broad frequency by changing the relative phase with respect to time between the two signals so that said third and fourth signals are received to produce two signals of said second frequency band which are orthogonally polarized with respect to each other.