Do you want a fixed phase shift or a variable one? Do you want a mechanical version, such as a double stub tuner or an electronic solution using something like microstrips and PIN diodes? Whats the application?
The classical methods are branch line couplers and parallel line couplers. To get these wide bandwidths, you will have to use many elements and usually an analysis program with an optimizer. In each type the elements are a quarter wave long at the center frequency. In the branch line method they are of different impedances. In the parallel line method they are different distances. In both methods the system is symetrical from end to end.
the lange coupler lately is always used in broadband shifter,and using cascaded coupler reflective phase shfter was reported reaching the 1-19GHz wideband.
could you give us more information about lange couplers as a phase shifter device? You say 1-19 GHz bandwidth reported, but where? Could you give us paper name and year?