Coplanar differential bi-strip delay line, higher-order differential filter and filtering antenna furnished with such a line

A coplanar differential bi-strip delay line, comprising:

• two meandering conducting strips disposed on one and a same face of a dielectric substrate and each comprising a first and a second end, the two first ends of the two meandering conducting strips forming two distinct conductors of a first bi-strip port for connection to a first external differential device, the two second ends of the two meandering conducting strips forming two distinct conductors of a second bi-strip port for connection to a second external differential device,
• wherein the bi-strip delay line is in a form of a printed circuit so as to exhibit structural discontinuities which generate at least one impedance jump and at least one capacitive coupling with interdigitated capacitance between the two meandering conducting strips so as to reproduce a predetermined phase shift, and
• the interdigitated capacitance is formed by at least one pair of overlapping conducting fingers, different from the two meandering conducting strips, joined respectively by one end of the overlapping conducting fingers, respectively, to the two conducting strips.