Broadband microwave polarizer device

Claim 1

A broadband microwave polarizer device for introducing a relatively constant phase shift between orthogonal components of signals over a predetermined bandwidth, comprising: a section of waveguide having an input end for receiving signals having orthogonal components between which a phase shift is to be introduced, and an output end; a pair of opposing rows of pins at inner surface regions of the waveguide, said rows of pins being in a common, first plane; and a pair of opposing ridges at other inner surface regions of the waveguide, said ridges being in a common, second plane at an angle to the first plane; said polarizer device being operative to introduce a phase shift between orthogonal components of signals applied to the input end of the section of waveguide, the phase shifted orthogonal components of the signals appearing at the output end of the section of waveguide, the phase shift introduced between the orthogonal components of the signals applied to the section of waveguide being approximated by φ.sub.R = A.sub.0 - B.sub.0 + (A.sub.1 - B.sub.1) (f - f.sub.0) + (A.sub.2 - B.sub.2) (f - f.sub.0).sup.2, where f is the frequency of the signals applied to the section of waveguide, f 0 is the center frequency of the bandwidth over which the polarizer device operates, A 0 , A 1 and A 2 are constants associated with the rows of pins, B 0 , B 1 and B 2 are constants associated with the pair of opposing ridges; the characteristics of the rows of pins and the pair of ridges being selected so that the constants A 1 and B 1 are negative with the value of the constant A 1 being equal to the value of the constant B 1 , and so that the constants A 2 and B 2 are positive and essentially equal in value, whereby the phase shift introduced between the orthogonal components of signals applied to the section of waveguide is nearly constant over the bandwidth of the polarizer device.