A new SOLT calibration method for leaky on-wafer measurements using a 10-term error model

We present a new Short-Open-Load-Thru (SOLT) calibration method for on-wafer S-parameter measurements. The new calibration method is based on a 10-term error model which is a simplified version of the 16-term error model. Compared with the latter, the former ignores all signal leakages except the ones between the probes. Experimental results show that this is valid for modern vector network analyzers (VNA). The advantage of using this 10-term error model is that the exact values of all error terms can be obtained by using the same calibration standards as the conventional SOLT method. This avoids not only the singularity problem with approximate methods, such as least squares, but also the usage of additional calibration standards. In this paper, we first demonstrate how the 10-term error model is developed and then the experimental verification of the theory is given. Finally, a practical application of the error model using a 10 dB attenuator from 140 GHz to 220 GHz is presented. Compared with the conventional SOLT calibration method without crosstalk corrections, the new method shows approximately 1 dB improvement in the transmission coefficients of the attenuator at 220 GHz

Benchmarking Electrical Loss in Rectangular Metallic Waveguide at Submillimeter Wavelengths

A series of documentary standards has recently been published (the IEEE 1785 series) that provides specification details for rectangular metallic waveguides used at frequencies from 110 GHz to at least 3.3 THz. This includes values of electrical loss (both reflection and transmission) for these waveguides. However, the values specified in these standards are based on calculated (i.e. modelled) performance and not measured values for real waveguide devices. This paper presents measured values of loss for commercially available waveguides in this frequency range. A comparison is given between the standardized values and values obtained from measurements made under precision laboratory conditions

An active interferometric method for extreme impedance on-wafer device measurements

Nano-scale devices and high-power transistors present extreme impedances, which are far removed from the 50-Ω reference impedance of conventional test equipment, resulting in a reduction in the measurement sensitivity as compared with impedances close to the reference impedance. This letter describes a novel method based on active interferometry to increase the measurement sensitivity of a vector network analyzer for measuring such extreme impedances, using only a single coupler. The theory of the method is explained with supporting simulation. An interferometry-based method is demonstrated for the first time with on-wafer measurements, resulting in an improved measurement sensitivity for extreme impedance device characterization of up to 9%

Uncertainty Analysis of Calibration Standards for On-wafer Measurements over 110 GHz

We present uncertainty analysis of calibration standards on a commercial calibration substrate for on-wafer S-parameter measurements over 110 GHz. At these frequencies, manufacturing tolerance is comparable to the sizes of calibration standards. Thus accurate knowledge about the actual dimensions of calibration standards becomes critical for system calibration and establishment of uncertainty budget. In this work, three different tools namely surfaceprofiler, optical interferometer, and Scanning Electron Microscope (SEM) have been used to measure calibration standards and investigate the effect of manufacturing tolerance on electrical parameters by using numerical software. Finally uncertainty of calibration standards will be given. In this work, we use three different techniques to characterise calibration standards and obtain manufacturing tolerance. And then numerical software is used to simulate how the electrical parameters are affected by the manufacturing imperfections. Finally uncertainty of the calibration is analysed

Development of a very light rail vehicle

The collaborative very light rail project involves the development of a novel railcar designed to revolutionise the rail industry: a self-powered, Very Light Rail (VLR) vehicle. Each of the two bogies contains a complete diesel-electric series-hybrid drive system, whilst the whole vehicle has undergone significant lightweighting activity to realise a target weight of less than 18 tonnes, or 1 tonne per linear meter. The target cost is £500,000, which is to be achieved through the use of standardised, modular components, and appropriate materials and structural design methodologies. The research covers several aspects of the GB Rail Technical Strategy (RTS) chapter relating to Rolling Stock. Lightweighting leads to a reduction in the propulsion requirements and reduces the infrastructure installation and maintenance costs. The use of higher efficiency drive systems achieved through on-board energy systems enables a reduction in carbon emissions. These hybridisation activities improve the passenger experience through quieter operation, decreased vibration and the possible elimination of exhaust emissions in stations. Combining new drive systems with modular lightweight structures will lead to lower life-cycle costs and thus could enable the economical reopening of lines

Fabricación aditiva de atenuadores variables de veleta rotatoria en guía de onda

Rotary Vane Attenuator is considered an industry standard in precision waveguide attenuators. These attenuators exhibit high accuracy, repeatability and reliability. In this paper, the design and fabrication of a rotary vane attenuator using additive manufacturing techniques is presented. The use of several materials to fabricate the lossy septum is discussed. ABS has been used to design all mechanical and waveguide parts. Waveguide parts has been metallised using a dual component spraying technology. Measurements has assessed the validity of the manufacturing process.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech