Source code for kqcircuits.elements.circular_capacitor

# This code is part of KQCircuits
# Copyright (C) 2021 IQM Finland Oy
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import math
from kqcircuits.pya_resolver import pya
from kqcircuits.util.parameters import Param, pdt, add_parameters_from
from kqcircuits.util.geometry_helper import circle_polygon, arc_points
from kqcircuits.elements.element import Element
from kqcircuits.elements.finger_capacitor_square import FingerCapacitorSquare

[docs]@add_parameters_from(FingerCapacitorSquare, "fixed_length", "a2", "b2") class CircularCapacitor(Element): """The PCell declaration for a circular capacitor. An outer semi-circular island with an inside circular island. Fixed-length capacitor is supported and different line impedance on each side can be used. Two ports with reference points. The feedline has the same length as the width of the ground gap around the coupler. .. MARKERS_FOR_PNG 30,0 -56,0 86,0 """ r_inner = Param(pdt.TypeDouble, "Internal island radius", 20, unit="μm", docstring="Radius of the outer edge of the center island (μm)") r_outer = Param(pdt.TypeDouble, "External island radius, measured at the outer edge", 80, unit="μm", docstring="Radius of the external coupler island (μm)") swept_angle = Param(pdt.TypeDouble, "Angle covered by the external island in degrees", 180) outer_island_width = Param(pdt.TypeDouble, "External island width", 40, unit="μm", docstring="Width of the external island (μm)") ground_gap = Param(pdt.TypeDouble, "Ground plane padding", 20, unit="μm")
[docs] def build(self): self.a2 = self.a if self.a2 < 0 else self.a2 self.b2 = self.b if self.b2 < 0 else self.b2 y_left = self.a / 2 y_right = self.a2 / 2 x_end = self.r_outer + self.ground_gap capacitor_region = [] # generate the inner island inner_island = circle_polygon(self.r_inner, self.n) capacitor_region.append(inner_island) # generate the outer island outer_island = self._get_outer_island(self.r_outer, self.outer_island_width, self.swept_angle) capacitor_region.append(outer_island) capacitor_neg = pya.Region([poly.to_itype(self.layout.dbu) for poly in capacitor_region]) # add the waveguides inside the ground padding capacitor_neg += pya.Region([pya.DPolygon([ pya.DPoint(-x_end, -y_left), pya.DPoint(-0, -y_left), pya.DPoint(-0, y_left), pya.DPoint(-x_end, y_left), ]).to_itype(self.layout.dbu)]) + pya.Region([pya.DPolygon([ pya.DPoint(x_end, y_right), pya.DPoint(self.r_outer - self.outer_island_width / 2, y_right), pya.DPoint(self.r_outer - self.outer_island_width / 2, -y_right), pya.DPoint(x_end, -y_right), ]).to_itype(self.layout.dbu)]) capacitor_neg.round_corners(5 / self.layout.dbu, 5 / self.layout.dbu, self.n) self._add_waveguides(capacitor_neg, x_end, y_left, y_right) # define the capacitor in the ground ground_region = self._add_ground_region(x_end) capacitor_region = ground_region - capacitor_neg self.cell.shapes(self.get_layer("base_metal_gap_wo_grid")).insert(capacitor_region) # protection region region_protection = self._get_protection_region(ground_region) self.add_protection(region_protection) # ports x_port = max(x_end, self.fixed_length / 2) self.add_port("a", pya.DPoint(-x_port, 0), pya.DVector(-1, 0)) self.add_port("b", pya.DPoint(x_port, 0), pya.DVector(1, 0))
# adds annotation based on refpoints calculated above def _get_outer_island(self, r_outer, outer_island_width, swept_angle): angle_rad = math.radians(swept_angle) points_outside = arc_points(r_outer, -angle_rad / 2, angle_rad / 2, self.n) points_inside = arc_points(r_outer - outer_island_width, angle_rad / 2, -angle_rad / 2, self.n) points = points_outside + points_inside outer_island = pya.DPolygon(points) return outer_island def _add_ground_region(self, x_end): # generate the ground region ground_region = [] island_ground = circle_polygon(self.r_outer + self.ground_gap, self.n) ground_region.append(island_ground) ground_region = pya.Region([poly.to_itype(self.layout.dbu) for poly in ground_region]) self._add_waveguides(ground_region, x_end, self.a / 2 + self.b, self.a2 / 2 + self.b2) return ground_region def _get_protection_region(self, region): protection_region = region.sized(self.margin / self.layout.dbu, self.margin / self.layout.dbu, 2) return protection_region def _add_waveguides(self, region, x_end, y_left, y_right): x_guide = self.fixed_length / 2 if (self.fixed_length > 0) else x_end if x_guide < x_end: raise ValueError(f"Circular capacitor parameters not compatible with fixed_length={self.fixed_length}") region += pya.Region([pya.DPolygon([ pya.DPoint(-x_end + self.margin, -y_left), pya.DPoint(-x_guide, -y_left), pya.DPoint(-x_guide, y_left), pya.DPoint(-x_end + self.margin, y_left), ]).to_itype(self.layout.dbu)]) + pya.Region([pya.DPolygon([ pya.DPoint(x_end - self.margin, y_right), pya.DPoint(x_guide, y_right), pya.DPoint(x_guide, -y_right), pya.DPoint(x_end - self.margin, -y_right), ]).to_itype(self.layout.dbu)])