IBM Release 1.93 OBJECT Group, xhi1,yhi1,zhi1 and xlo2,ylo2,zlo2, xhi2,yhi2,zhi2. These must be

Type PEC Type black

Perfect conductor. All fields inside a PEC are zero. Sometimes useful for saving CPU cycles in regions where the fields are known to be zero, e.g. deep inside metal objects.

Parameters: none

3.1.5. OBJECT Group

Like all dimensions in POEMS, object dimensions are measured from edge to edge, as you would measure with calipers. All dimensions are correctly rounded to the nearest multiple of basicstep in the subdomain in which they occur. A cell is included if its centre lies inside the specified region. This can lead to steps at boundaries between subdomains with different basicstep values, due to differences in rounding.

When an object’s midline is specified in terms of a curve, e.g. FAN, GRATING, CURVE, and 3DCURVE, the end points of the curve are taken to lie at the centre of the outermost plane of blocks on each end. This makes sure that if the local object axis is highly inclined, the outermost blocks don’t disappear due to their centres falling outside the region, as they would if the endpoint were taken to lie in the outer face. Sufficiently inclined objects may still become discontinuous.

BLOCK	Adds a rectangular prism (like a shoe box) of material matname,
	covering the region xlo ≤ x ≤ xhi, ylo ≤ y ≤ yhi, zlo ≤ z ≤ zhi. Like
	everything else in POEMS, these dimensions will be rounded to the
	nearest cell boundaries.
	Parameters: matname xlo xhi ylo yhi zlo zhi
	Example:
	block matname = AirPML xlo=0 xhi=8*dx ylo = 0 yhi=ymax ,
	zlo=0 zhi=zmax
FAN	Adds a fan shaped object such as a dielectric waveguide horn or
	taper. A fan is specified by a choice of curve and rectangular end
	faces 1 and 2, defined by their diagonal points ((xlo1,ylo1,zlo1),
	(xhi1,yhi1,zhi1)) and ((xlo2,ylo2,zlo2), (xhi2,yhi2,zhi2)). These must be
	parallel and lie in a coordinate plane. Intervening planes are
	defined by the choice of taper and the taper parameter, which is a
	scale factor for the domain of the curve—increasing the parameter
	causes the taper to be sharper, and decreasing it makes the taper
	more gradual. Allowed tapers are LINEAR, EXPONENTIAL, and
	ERF. Exponential tapers are useful for converting guided waves to
	free space, and ERF tapers are useful for converting between
	different-sized waveguides without strong back reflections from
	either end.

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