Patent ID: 8461938

Claim:
A directional coupler comprising: a set of coupled lines that includes: a first conductive structure having a first port, a second port, and a substantially linear, first conductive central portion between the first port and the second port, and second conductive structure having a third port, a fourth port, a first conductive arm coupled to the first port, a second conductive arm coupled to the fourth port, a substantially linear, second conductive central portion having a principal axis that is perpendicular to principal axes of the first and second conductive arms, a first capacitive coupling structure coupled between the first conductive arm and a first end of the second conductive central portion, a second capacitive coupling structure coupled between the second conductive arm and a second end of the second conductive central portion, wherein the first and second capacitive coupling structures each include a continuously curving edge oriented toward the first conductive structure, wherein a principal axis of the first conductive central portion is substantially parallel to the principal axis of the second conductive central portion, and a first edge of the first conductive central portion is spatially separated from a second edge of the second conductive central portion across a gap; and a reflection coefficient manipulator integrated with the set of coupled lines and disposed in proximity to the gap, wherein the reflection coefficient manipulator is configured to substantially equate a first reflection coefficient of the first conductive structure and a second reflection coefficient of the second conductive structure.