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A systematic approach based on ‘package-peeling’ together with time-domain reflectometry (TDR) for package characterization using an EM-tool is presented. The said methodology is applied to investigate and address the possible causes of transmission losses for a measured 60 GHz flip-chipped package, embedding a power amplifier (PA) and a balanced-fed-aperture-coupled-patch (BFACP) antenna with an anisotropic conductive adhesive (ACA) flip-chip interconnection scheme. The proposed technique caters for TDR measurement system limitations and aids in investigation and improving the performance of the millimeter-wave flip-chipped packages.

This paper analyzes the frequency selectivity, which is caused by multipath effects, of indoor line-of-sight (LOS) and non-LOS (NLOS) channels based on channel measurements in the frequency band of 60 GHz. The coherence bandwidth is determined to characterize frequency selectivity figures of the channels employing the combination of omnidirectional, fan-beam and pencil-beam antennas at transmitter (TX) and receiver (RX) sides. The results quantitatively show how far directional configurations are more effective for combating multipath effect than the omnidirectional ones for LOS channels. The frequency selectivity of the fan-beam-to-fan-beam configuration is less sensitive to misaligned TX-RX beams than the fan-beam-to-pencil-beam one. In addition, when omnidirectional antennas are used at both TX and RX side, the frequency selectivity of a NLOS channel is less sensitive to the TX-RX height difference than that of a LOS channel. Moreover, coherence bandwidth is empirically related to root-mean-squared delay spread. Lastly, the results presented in this paper lead to some useful insights into antenna configurations and beamformer designs for a 60-GHz radio system.

In this paper the scan properties of integrated lens antennas with a quarter-wavelength matching layer are analyzed. For beam scanning on and within a cone, optimum feed positions are determined. It appears that for beam scanning on a cone the elliptical lens is the best choice if a small scan angle is required while the extended hemispherical lens should be used in case of a large scan angle. For beam scanning within a cone it is recommended to select an elliptical lens if a large average directivity is required while the extended hemispherical lens appears to be the best choice if a small variation in the directivity is important.

A comparison is made between wideband angle-of-arrival measurements obtained in two urban microcell environments in Switzerland and predictions generated by a two-dimensional ray-tracing based propagation prediction model. In general, theoretical and experimental results show a reasonable agreement. It is demonstrated however that in some particular situations transmission through buildings and scattering by vegetation can be the dominant propagation mechanism.

An algorithm is proposed to combine microwave radiometer and radar for the retrieval of cloud liquid water. The algorithm is based on a radiometer profile algorithm, but modifications are made to allow for the use of radar data. Because liquid water absorption is strongly dependent on temperature, it is important to know the heights of the clouds. The radar provides the algorithm with cloud heights and a liquid water model profile, resulting in an improved retrieval of cloud liquid water. In addition, our modifications enlarge the convergence area of the algorithm.

A theoretical investigation of the defocused Schwarzschild antenna system is described. Scan properties have been compared with those of the Cassegrain antenna system. It is shown that both the focused and defocused radiation patterns of the two systems are almost identical.