  Full-wave 3D electromagnetic simulations of complex planar devices,
multilayer interconnects, and chip packages are presented for wide-band
frequency-domain analysis using the finite difference integration technique
developed in the PETSc software package. Initial reordering of the index
assignment to the unknowns makes the resulting system matrix diagonally
dominant. The rearrangement also facilitates the decomposition of large domain
into slices for passing the mesh information to different machines. Matrix-free
methods are then exploited to minimize the number of element-wise
multiplications and memory requirements in the construction of the system of
linear equations. Besides, the recipes provide extreme ease of modifications in
the kernel of the code. The applicability of different Krylov subspace solvers
is investigated. The accuracy is checked through comparisons with CST MICROWAVE
STUDIO transient solver results. The parallel execution of the compiled code on
specific number of processors in multi-core distributed-memory architectures
demonstrate high scalability of the computational algorithm.
