Integrated phase shifter of differential signals in quadrature
A distributed phase shifter including: a first planar winding having its ends defining accesses in phase opposition; a second planar winding coupled with the first one and grounded by a first capacitive element; a third planar winding in a conductive level different from that receiving the first winding and electrically in series with the second winding; and a fourth planar winding, coupled with the third one in a conductive level different from that receiving the second winding, first ends of the third and fourth windings being connected by a capacitive element and their second ends being connected by another capacitive element, their first and second respective ends defining accesses in phase quadrature.
1. A distributed phase shifter comprising:
a first planar winding having its ends defining accesses in phase opposition;
a second planar winding coupled with the first one and grounded by a first capacitive element;
a third planar winding in a conductive level different from that receiving the first winding and electrically in series with the second winding; and
a fourth planar winding, coupled with the third one in a conductive level different from that receiving the second winding, first ends of the third and fourth windings being connected by a capacitive element and their second ends being connected by another capacitive element, their first and second respective ends defining accesses in phase quadrature.
2. The phase shifter of claim 1 , wherein the second and third windings are formed side by side in a first conductive level, the first and fourth windings being formed side by side in a second conductive level, the second and third windings being respectively superposed to the first and fourth ones and a third conductive level being used to form contact tracks of the internal ends of the windings.
3. The phase shifter of claim 2 , wherein all windings wind in the same direction.
4. The phase shifter of claim 1 , wherein the first and second windings are interleaved with each other in a first conductive level, the third and fourth windings being interleaved with each other in a second conductive level superposed to the first one.
5. The phase shifter of claim 4 , wherein the windings formed in different levels wind in reverse directions.
6. The phase shifter of claim 1 , wherein a resistive element grounds the first end of the fourth winding.
7. The phase shifter of claim 1 , wherein capacitive elements have values selected from a range from 0.5 to 10 picofarads.
8. The phase shifter of claim 1 , wherein the capacitive elements are lumped elements.
9. A radio-frequency transceiver circuit comprising at least one phase shifter according to claim 1 .