The prediction of wall losses is a fundamental aspect in the planning of cellular systems. The broad variety of building materials and construction codes makes accurate attenuation prediction very difficult without the support of specific construction data or measurements. In this paper, the attenuation and equivalent electric parameters and of brick and doubly reinforced concrete walls are estimated for the 900-MHz band by fitting simple ray tracing models to empirical transmission data. The measurement setup is described, and extensive experimental results justifying the quasioptical modeling are presented.

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A number of microwave and terahertz grooved-dielectric Fresnel zone plate (FZP) and ordinary lenses and antennas are studed and compared numerically. Although the microwave (38 GHz) eight-step FZP lens is certainly inferior, the corresponding terahertz (1.5 THz) FZP lens is comparable in focusing action to the ordinary one. By use of a new design approach to the terahertz FZP lens/antenna the typical unwanted focusing shift from the design frequency is removed and even better focusing performance is obtained within a limited frequency band. Thus, at terahertz frequencies the dielectric FZP lens or antenna is a lightweight and an effective option to the ordinary lens or antenna.

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