Low-terahertz (Low-THz, 100 GHz-1.0 THz) technology is expected to provide unprecedented data rates in future generations of wireless system such as the 6th generation (6G) mobile communication system. Increasing the carrier frequencies from millimeter wave to THz is a potential solution to guarantee the transmission rate and channel capacity. Due to the large transmission loss of Low-THz wave in free space, it is particularly urgent to design high-gain antennas to compensate the additional path loss, and to overcome the power limitation of Low-THz source. Recently, with the continuous updating and progress of additive manufacturing (AM) and 3D printing (3DP) technology, antennas with complicated structures can now be easily manufactured with high precision and low cost. In the first part, this paper demonstrates different approaches of recent development on wideband and high gain sub-millimeter-wave and Low-THz antennas as well as their fabrication technologies. In addition, the performances of the state-of-the-art wideband and high-gain antennas are presented. A comparison among these reported antennas is summarized and discussed. In the second part, one case study of a broadband high-gain antenna at 300 GHz is introduced, which is an all-metal model based on the Fabry–Perot cavity (FPC) theory. The proposed FPC antenna is very suitable for manufacturing using AM technology, which provides a low-cost, reliable solution for emerging THz applications.

This article reports the design and fabrication of a novel all-metal antenna operating in the millimeter-wave band. Based on the resonant cavity antenna (RCA) concept, the principle of antenna operation is explained, and parametric studies of several key design parameters are provided. A novel impedance matching technique is introduced to broaden the antenna return loss bandwidth. Two gain enhancement methods have been employed to achieve a more directive beam with reduced side lobes and back lobes. The D-band antenna prototypes are produced using i) all-metal printing without any postprocessing; ii) dielectric printing with copper metallization applied later. Comparisons of the simulated and measured results amongst the antennas fabricated using the two additive manufacturing techniques are made. Measurement results of the two antenna prototypes show that the proposed design can achieve a 14.2% bandwidth with a maximum gain of 15.5 dBi at 135 GHz. The present work is the first D-band resonant cavity antenna fabricated using two different 3D printing methods.

This study proposes a linear approach for propagating uncertainties in the multiline thru-reflect-line (TRL) calibration method for vector network analyzers. The multiline TRL formulation we are proposing applies the law of uncertainty propagation as outlined in the ISO Guide to the Expression of Uncertainty in Measurement (GUM) to both measurement and model uncertainties. In addition, we conducted a Monte Carlo analysis using a combination of measured and synthetic data to model various uncertainties, such as measurement noise, reflect asymmetry, line mismatch, and line length offset. The results of our linear uncertainty formulation demonstrate agreement with the Monte Carlo analysis and provide a more efficient means of assessing the uncertainty budget of the multiline TRL calibration.

Automated driving is seen as one of the key technologies that influences and shapes our future mobility. Modern advanced driver assistance systems (ADAS) play a vital role towards achieving this goal of automated driving. Depending on the level of automation, the ADAS takes over the complete or partial control of the movement of the car. Hence, it is mandatory that the system reacts reproducibly and safely in a wide range of possible situations. Especially in complex and potentially dangerous traffic scenarios a test system with the ability to simulate realistic scenarios is required. The authors present an implementation of a vehicle‐in‐the‐loop (ViL) test system which accomplishes these goals in a defined environment. Of the great plenty of sensors stimulated in this context, the radar sensor takes a special position due to its robust and comprehensive information perceiving capability. Stimulating the automotive radar sensor in a ViL environment requires supporting the complex movements of the considered traffic scenarios. For this task, a modular and highly scalable radar target stimulator is necessary, which is capable of stimulating multiple independent moving targets with realistic parameters. The authors are discussing the underlying concepts of the suggested solution and are presenting its performance.

Car manufacturers spend quite a lot on the development of driver assistance systems and subsequently on autonomous driving functionality. To ensure the safety and reliability of these functions meet industrial standards it is necessary to verify and validate their functionality. While tests on the road are still the ultimate evidence of correct operation they are associated with huge efforts and risks. Therefore, they have to be complemented by other means like simulations and tests on specialised testbeds. For the latter the car's sensors have to be stimulated in a way that they perceive a desired - but only virtual - environment. An important type of sensor in cars is the radar due to its various advantages. This article describes the development of a stimulator generating virtual radar targets in order to enable the testing of autonomous driving functions.