Lumped power loss

The power losses P z, t) and T (z, t) by elastic collisions and by the /th excitation or dissociation process, the lumped power loss P z, t) in inelastic collisions, and the total power loss P z, t) in collisions have the representation... 

Principles in Processing Materials. In most practical apphcations of microwave power, the material to be processed is adequately specified in terms of its dielectric permittivity and conductivity. The permittivity is generally taken as complex to reflect loss mechanisms of the dielectric polarization process the conductivity may be specified separately to designate free carriers. Eor simplicity, it is common to lump ah. loss or absorption processes under one constitutive parameter (20) which can be alternatively labeled a conductivity, <7, or an imaginary part of the complex dielectric constant, S, as expressed in the foUowing equations for complex permittivity ... 

Consideration of Fig. 11 immediately shows that at the low field (left), after an initial relaxation phase, the mean power loss by elastic collisions P /n becomes the dominant energy loss channel. This means as was already seen from Fig. 9 (left), that the final establishment and compensation of the power balance occur only by elastic collisions in the region of low electron energies. However, as can be seen from Fig. 8, for neon, the lumped frequency v U) for energy dissipation in collisions has very small values at lower energies, which makes the large relaxation time in neon at this field strength immediately understandable. 

ASTM D150 Standard Test Methods for AC Loss Characteristics and Permittivity (Dielectric Constant) of Solid Electrical Insulation includes the determination of relative permittivity, dissipation factor, loss index, power factor, phase angle, and loss angle through specimens of solid electrical insulating materials when the standards used are lumped impedances. The frequency range that can be covered extends from less than 1 Hz to several hundred megahertz. 

The two basic types of circulators, shown in Fig. 13.91(b) and Fig. 13.91(c), consist ofY-shaped conductors sandwiched between magnetized ferrite discs. The final shape, dimensions, and type of material varies according to frequency of operation, power handling requirements, and the method of coupHng. The distributed constant circulator is the older design it is a broadband device, not quite as efficient in terms of insertion loss and leg-to-leg isolation, and considerably more expensive to produce, but useful in applications where broadband isolation is needed. More common is the lump constant circulator, a less expensive and more efficient but narrow-band design. 

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