With the advent of new technologies introduced with each cellular generation, there is need to characterize a variety of different communications links. Areas, such as software defined radios, have been explored to fill flexibility needs for dynamic sounding. Also of heavy interest is exploring the terahertz frequency band for communication potential in 6G. However, numerous channel sounding measurements must be collected to properly support channel models for this region. The work detailed in this thesis aims to address this current research areas, with three main contributions: (1) detailing a flexible software define radio channel sounding architecture for easy, configurable channel sounding, (2) a comparison of sounding waveforms within a software defined radio framework, and (3) a detailed D-Band channel sounding framework and short-range path loss measurements. In the first contribution, a low cost radio (Ettus B210) is used as the channel sounding transmitter with a frequency retuning software to overcome the small instantaneous bandwidth of the low cost transmitter. In the second contribution, an upgraded version of the SDR channel sounder transmitter from the first contribution is used to compare different sounding waveforms. Each of the waveforms were tested within the same channel sounder architecture and the results were compared to make recommendations about which waveform to use in a variety of circumstance. In the third contribution, a new channel sounder, with sub-THz up and down conversion, was used to collect path loss measurements at D-Band. In these contributions, we target addressing two prominent areas of channel sounding research: use of low-cost radios for channel sounding and (sub-)terahetz frequency channel characterization. / Master of Science / In communications, sending information is done by modulating information bits in a signal that can be sent from the sender to the receiver. The environment, or channel, in between the sender and receiver plays a significant role in whether the information is successfully received. Thus, in developing of communications links, it is important to have an understanding of how the channel behaves and affects the information signal. Channel sounding is a process of collecting measurements that characterize the behavior of the channel. In recent years, more devices are being connected, creating new environments to be characterized, which require flexibility in channel sounder design. Additionally, with new devices, there is interest in leveraging higher portions of the RF spectrum. Moving up in frequency introduces new challenges in successfully communicating, but higher frequencies offer the reward of accessing greater bandwidth and thereby data throughput. In this work, we (1) detail the design of a channel sounder using low-cost hardware, (2) analyze the performance achieved using different waveforms for sounding on low-cost hardware, and (3) collect measurements using a live hardware system capable of measuring at high frequencies, 120-130 GHz.

The complexity of vehicular communication and radar sensing becomes increasingly complex with the growing demand for advanced driver-assistant systems in the automotive industry. Researchers are currently looking into combining communication and sensing by utilizing traditional communication waveforms in the mmWave radar bands to mitigate congestion and inter-radar interference. This thesis investigates a local-oscillator (LO) phase-shifting architecture to simplify the implementation of D-band (110–170 GHz) phased arrays for such applications. The constructed signal chain includes four 8–12-GHz voltage-controlled analog phase shifters, each mounted on the LO feed of a quadrature subharmonic upconverter, and a four-channel slot antenna. Through careful calibration of the analog control voltages, the 100-MHz baseband feed, and the LO distribution, antenna measurements in an anechoic chamber resulted in a beambook with antenna diagrams at seven angles from −30° to +30°. The gain was between 10.78 dB and 12.80 dB relative to the gain of one element, and the sidelobe levels were less than 8.9 dB. / Fordononsindustrins ökade efterfrågan på avancerade assistansystem gör framtidens kommunikation och radaravkänning allt mer komplex. Forskare undersöker just nu möjligheten att integrera kommunikation och radar genom att använda traditionella vågformer på millimetervågsfrekvenser för att förhindra nätverksträngsel och interferens mellan närliggande sensorer. Detta examensarbete undersöker möjligheten att fasstyra en radarantenn genom att skifta fasen på sändarens lokaloscillator (LO) och på så sätt förenkla konstruktionen av fasade gruppantenner på D-bandet (110–170 GHz). Signalkedjan bestod av fyra spänningsstyrda 8–12 GHz-fasskiftare, var och en monterade på LO-matningen till en subharmonisk mixer, samt en fyrkanals slitsantenn. Genom noggrann kalibrering av kontrollspänningar, 100 MHz-basbandsmatning och LO-distribution kunde antennmätningar i en ekofri kammare påvisa de önskade antenndiagramen för sju vinklar mellan −30° och +30°. Förstärkningen i förhållande till ett antennelement var mellan 10.78 dB och 12.80 dB och sidlobsnivåerna var lägre än 8.9 dB.

Novel polymer-enhanced photodefined through-silicon via (TSV) and passive technologies have been demonstrated for silicon interposers to obtain compact heterogeneous computing and mixed-signal systems. These technologies include: (1) Polymer-clad TSVs with thick (~20 µm) liners to help reduce TSV losses and stress, and obtain optical TSVs in parallel for interposer-to-interposer long-distance communication; (2) Polymer-embedded vias with copper vias embedded in polymer wells to significantly reduce the TSV losses; (3) Coaxial vias in polymer wells to reduce the TSV losses with controlled impedance; (4) Antennas over polymer wells to attain a high radiation efficiency; and (5) High-Q inductors over polymer wells. Cleanroom fabrication and characterization of the technologies have been demonstrated. For the fabricated polymer-clad TSVs, resistance and synchrotron x-ray diffraction (XRD) measurements have been demonstrated. High-frequency measurements up to 170 GHz and time-domain measurements up to 10 Gbps have been demonstrated for the fabricated polymer-embedded vias. For the fabricated coaxial vias and inductors, high-frequency measurements up to 50 GHz have been demonstrated. Lastly, for the fabricated antennas, measurements in the W-band have been demonstrated.