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An experimental approach to verify the forward scattering sum rule for periodic structures is presented. This approach allows an upper bound on the total cross section integrated over a bandwidth from a simple static problem to be found. Based on energy conservation, the optical theorem is used to construct a relation between the total cross section and the forward scattering of periodic structures as well as single scatterers inside a parallel plate waveguide. Dynamic measurements are performed using a parallel plate waveguide and a parallel plate capacitor is utilized to nd the static polarizability. Convex optimization is introduced to identify the total scattering in the dynamic measurements. The results show that the all spectrum interaction between the electromagnetic eld and an object are proportional to the static polarizability of the object.

Time-domain material characterization using a leaky lens antenna and an in-house fabricated millimeter-wave wavelet generator using III-V technology is investigated. The wavelet generator produces short high-frequency pulses and is connected to a wideband and nondispersive leaky lens antenna. A purely timedomain methodology is used to extract the complex permittivity of nondispersive and nonmagnetic materials. The permittivity is found from the phase delay and the amplitude mismatch introduced by the object at the carrier frequency of the pulse. The wide bandwidth of the wavelet is used to investigate frequency-dependent material properties. Measurement results from two dielectric slabs are illustrated. The time-domain methodology is verified by frequency-domain measurements and analysis.Index Terms-Leaky lens antenna, material characterizations, millimeter-wave (mm-wave), time domain, wavelet generator.