Wireless Network-on-Chip (WNoC) appears as a promising alternative to conventional interconnect fabrics for chip-scale communications. WNoC takes advantage of an overlaid network composed by a set of millimeter-wave antennas to reduce latency and increase throughput in the communication between cores. Similarly, wireless inter-chip communication has been also proposed to improve the information transfer between processors, memory, and accelerators in multi-chip settings. However, the wireless channel remains largely unknown in both scenarios, especially in the presence of realistic chip packages. This work addresses the issue by accurately modeling flip-chip packages and investigating the propagation both its interior and its surroundings. Through parametric studies, package configurations that minimize path loss are obtained and the trade-offs observed when applying such optimizations are discussed. Single-chip and multi-chip architectures are compared in terms of the path loss exponent, confirming that the amount of bulk silicon found in the pathway between transmitter and receiver is the main determinant of losses.
Designing and implementing wireless networks on chips (WiNoCs) presents numerous engineering challenges, in the areas of computer architecture, multiple access, wireless propagation, physical layer communications processing, and device design and fabrication. In this article we provide a survey on WiNoC propagation and the issues involved with WiNoC channel modeling. We address both attenuation and dispersion, and illustrate the dramatic differences between the miniature WiNoC case and more familiar terrestrial wireless channels. Remaining channel modeling research is outlined.  Tunable metasurfaces are ultra-thin, artificial electromagnetic components that provide engineered and externally adjustable functionalities. The programmable metasurface, the HyperSurFace, concept consists in integrating controllers within the metasurface that interact locally and communicate globally to obtain a given electromagnetic behaviour. Here, we address the design constraints introduced by both functions accommodated by the programmable metasurface, i.e., the desired metasurface operation and the unit cells wireless communication enabling such programmable functionality. The design process for meeting both sets of specifications is thoroughly discussed. Two scenarios for wireless intercell communication are proposed. The first exploits the metasurface layer itself, while the second employs a dedicated communication layer beneath the metasurface backplane. Complexity and performance trade-offs are highlighted. Wireless chip area network (WCAN) that realizes wireless interconnects within a chip (intra-chip) or among chips (inter-chip) represents a new development in wireless communications. WCAN features unique intra- and inter-chip wireless channels. This paper focuses on understanding of inter-chip wireless communication channels in computer cases. Inter-chip wireless communication channel is characterized for the first time based on measurements conducted in frequency domain inside a computer case on a laboratory workbench. A novel technique for doubling the time-domain resolution is proposed for converting the frequency-domain data to time-domain using inverse discrete Fourier transform (IDFT). It is found that path loss factor is 1.607 for case closed and energy follows lognormal distribution in small scale. Based on analysis in practical situations, channel models are developed and simulated. Comparison between model-generated and empirical data shows that simulated channel responses closely match experimental data. Further more, sampled data in different computer cases give consistent results, making the work presented a representative channel model for wireless inter-chip communication  The wireless harness is a new emerging short-range communication to replace wire harness implemented in devices with wireless communications between internal components. In such an in-device wireless harness, the communication distance is up to a couple of meters at most. Through the challenge to apply this wireless communication technology to information and communication technology (ICT) equipment, we found that the radio channel inside the ICT equipment deeply depends on its internal structure more than we expected. In order to understand the radio propagation characteristics inside such equipment, we propose a new modeling technique with using a frequency- dependent path loss exponent expressing the near- and far-field propagation, which enables us to successfully extract attenuation factors for the frequency and the propagation distance from the measured data. The results shows the path loss characteristics can be divided into three regions; line-of-sight (LOS), non-line-of-sight (NLOS), and a transition range. The transition range, which appears between the LOS and the NLOS, is caused by a blocking due to the densely-packaged internal components. These findings and equations can be criteria to design a wireless harness communication link. This paper presents the channel measurements performed within a closed met al cabinet at 60 GHz covering the frequency range 57–62 GHz. Two different volumes of an empty met al cupboard are considered to emulate the environment of interest (an industrial machine). Furthermore, we have considered a number of scenarios such as line of sight, non line of sight, and placing absorbers. A statistical channel model is provided to aid short-range wireless link design within such a reflective and confined environment. Based on the measurements, the large- and small-scale parameters are extracted and fitted using the standard log-normal and Saleh–Valenzuela models, respectively. The obtained results are characterized by a very small path loss exponent, a single cluster phenomenon, and a significantly large root-mean-square (RMS) delay spread. The results show that covering a wall with absorber material dramatically reduces the RMS delay spread. Finally, the proposed channel model is validated by comparing the measured channel with a simulated channel, where the simulated channel is generated from the extracted parameters. 