Mitigation of interference among adjacent radio systems is a topic of growing interest as the spectrum occupation increases. Site-shielding techniques appear as a method of improving millimeter-wave wireless communication system design, allowing frequency reuse and reducing cochannel interference. The viability of applying such techniques to systems operating in frequency bands around 40 GHz is the aim of this paper. Several propagation mechanisms are experimentally studied, including transmission across building obstacles, depolarization, reflection, and diffraction. The performance of some theoretical models of the different scattering mechanisms has been compared with measurement results. The measuring and processing procedures have also been improved. Values of the dielectric parameters of the materials in this frequency band have been obtained and are given in this paper. The attenuation results indicate that various materials, such as mortar, brick, and concrete walls, that present large values of attenuation in decibels per centimeter, can be used to shield base stations, reducing the frequency reuse distance in radio cellular networks. It can also be concluded that there is a significant diffracted field in the shadow region of brick corners.

In this contribution we present two practical implementation cases of single patch antennas at 28GHz and 60GHz. We describe the design challenge of conciliating the antenna performance specifications and fabrication restrictions. Over this basic element of an array antenna we discuss the influence of three different categories of design issues.

The results of a wideband channel measurement campaign carried at Ku-band and X-band are presented and discussed in this paper. The propagation effects in the satellite-to-mobile radio link due to the environment surrounding the terrestrial terminal have been characterized using a sweep time delay cross-correlation (STDCC) sounder. The campaign was carried out in four different environments: wooded, rural, suburb and urban. From these results, we obtained the root-mean-square delay spread and coherence bandwidth of the radio channel. The low coherence bandwidth values found for urban and suburb environments suggest that channel equalization would be needed for high-data-rate services. The delay spread values for these two environments are also larger than for wooded and rural environments. A detailed analysis of the results shows that three-state semi-Markov narrow-band channel models for satellite communications could be easily extended to wideband.

Our society has become fully submersed in fourth generation (4G) technologies, setting constant connectivity as the norm. Together with self-driving cars, augmented reality, and upcoming technologies, the new generation of Internet of Things (IoT) devices is pushing the development of fifth generation (5G) communication systems. In 5G architecture, increased capacity, improved data rate, and decreased latency are the objectives. In this paper, a measurement campaign is proposed; we focused on studying the propagation properties of microwaves at a center frequency of 3.5 GHz, commonly used in 5G cellular networks. Wideband measurement data were gathered at various indoor environments with different dimensions and characteristics. A ray-tracing analysis showed that the power spectrum is dominated by the line of sight component together with reflections on two sidewalls, indicating the practical applicability of our results. Two wideband parameters, root mean square delay spread and coherence bandwidth, were estimated for the considered scenarios, and we found that they are highly dependent on the physical dimension of the environment rather than on furniture present in the room. The relationship between both parameters was also investigated to provide support to network planners when obtaining the bandwidth from the delay spread, easily computed by a ray-tracing tool.