function [phy, cfg] = case_config()
%CASE_CONFIG  3D 一阶 + 单周期 Bloch 边界（main_singlePBC.m）。

phy.eps = [1 1.2];
phy.mur = [1 1];
phy.f0 = 6e9;
phy.lda0 = 0.049965;
phy.out = [3 9];
phy.inc = [8];
phy.Einc = [0.5; -0.5*1i; 0];
phy.src = [1 4];
phy.dst = [2 5];

cfg.FemType = 4;
cfg.EletricType = 2;
% BoundaryFlag(i) = type of mesh face domain i (DomainOfTri 1..9)
% 0=PMC, 2=SBC, 4=PBC; order matches phy.src/dst/out/inc
cfg.NbrBoundary = 9;
cfg.BoundaryFlag = [4, 4, 2, 4, 4, 0, 0, 2, 2];
cfg.MeshFile = 'PBCmesh.dat';
cfg.OutFile = './OutFile';
cfg.jsonFile = 'PBCmesh.json';
cfg.meshMatFile = 'c6.mat';
cfg.pbcAngle = pi / 3;
cfg.pbcPhi = exp(1i * 2 * pi / 6);

end