Elliptical Rings

Full script

from fnpcell import all as fp
from gpdk.technology import get_technology


@fp.pcell_class()

class EllipticalRings(fp.PCell):
    def build(self):
        insts, elems, ports = super().build()
        # fmt: off
        TECH = get_technology()

        # elems += fp.el.EllipticalRing(outer_radius=(8, 10), inner_radius=(4, 5), initial_degrees=(0, 0), final_degrees=(180, 180), layer=TECH.LAYER.M1_DRW, origin=(0, 0))
        elems += fp.el.Ring(outer_radius=4, inner_radius=2, initial_degrees=(60, 30), final_degrees=(120, 150), layer=TECH.LAYER.M2_DRW, origin=(30, 0))
        # fmt: on
        return insts, elems, ports


if __name__ == "__main__":
    from pathlib import Path

    gds_file = Path(__file__).parent / "local" / Path(__file__).with_suffix(".gds").name
    library = fp.Library()

    TECH = get_technology()
    # =============================================================
    # fmt: off

    library += EllipticalRings()

    # fmt: on
    # =============================================================
    fp.export_gds(library, file=gds_file)
    fp.plot(library)

fp.el.Ring Description

elems += fp.el.Ring(outer_radius=4, inner_radius=2, initial_degrees=(0, 0), final_degrees=(180, 180), layer=TECH.LAYER.M2_DRW, origin=(30, 0))

As shown in the figure, initial_degrees is the angle between the starting end and the x-axis, final_degrees is the angle between the ending end and the x-axis, the left parameter in the parentheses is the angle parameter of the external circle, the right is the angle parameter of the internal circle; origin defines the location of the center of the whole ring.

In the following, we set the initial and end angles to (0, 30) and (150, 120), respectively. The following figure is obtained after running the script.

fp.el.EllipticalRing Description

elems += fp.el.EllipticalRing(outer_radius=(8, 10), inner_radius=(4, 5), initial_degrees=(0, 0), final_degrees=(180, 180), layer=TECH.LAYER.M1_DRW, origin=(0, 0))

We can get an elliptical ring after running the above script. The first parameter of outer_radius and inner_radius represents the semi-short axis of the ellipse, and the second parameter represents the semi-long axis of the ellipse. initial_degrees and final_degrees are used in the same way as in the Ring function, so we will not repeat them here.