Dielectric spectroscopy is a label-free, non-contact, real-time, multi-layer sensing technology, and has been used for identification and quantification of many biological materials. A combination of such sensing features is in demand for monitoring of organ-on-chip systems; however available sensing technologies have yet to address this need. In this work, we explore the possibility of leveraging the inherent features of dielectric spectroscopy for the application in organ-on-chip systems, by investigating three key technological developments using open-ended coaxial probes. Firstly, biocompatible non-contact sensing capabilities are proved by showing similar sensing performance of Parylene C-coated probes and uncoated probes. Secondly, a setup and methodology are developed for highly accurate and non-destructive height positioning of the probe to allow for precise extraction of intermediate sample layers. Finally, non-contact multi-layer sensing performance of the presented technology is successfully demonstrated by means of a biological phantom in a three-layered system. With further integration, dielectric spectroscopy can potentially become a cornerstone sensing technique for organ-on-chip by enabling real-time non-contact tracking of various tissue contents and properties.

This contribution presents a silicon-integrated focal plane array (FPA) THz camera that achieves passive-level sensitivity and a densely sampled field-of-view. The FPA chip is designed in a 130nm SiGe BiCMOS technology from IHP and consists of a previously presented chessboard array topology with integrated direct detectors. The detectors are realized using a differential pair of heterojunction bipolar transistors in a common-base configuration biased in deep saturation. A silicon, hyper-hemispherical lens is mounted on the chip as a primary focusing element. The maximum responsivity of the camera is simulated to be 680 V/W at 350GHz, and above half this value between 260GHz and 600GHz. Simulations show that the minimum NEP is on the order of $2{\text{pW}}/\sqrt {Hz} $, yielding an NETD of 1K for a 150ms integration time. For characterization and future imaging demonstrations, the camera is mounted in a quasi-optical setup, which refocuses the beams from the silicon lens onto an imaging plane. Measurements performed in this setup demonstrate that the camera achieves a responsivity on the order of 550/W, while also realizing a dense focal plane sampling.

In this work, we present the development of a low-power and high-sensitivity electromagnetic field (EMF) sensor operating in the n258 FR2 band. The design of the sensor architecture and its sub-systems are discussed, and the sensor performance is characterised using over-the-air measurements. For the front end, a dual-polarised leaky-wave antenna feed is coupled to a dielectric lens and implemented in a multilayer PCB stack. The elliptical lens is 3D-printed using commercially available ABS. The back-end RF electronics are integrated on the same PCB to realise low-power direct down conversion sensing. The components include low noise amplifiers (LNA), digital step attenuators (DSA) and root-mean-square (RMS) detectors. An onboard 12-bit digitiser provides signal quantisation. The measured radiation patterns of the lens antenna agree well with the simulations with 17.18 dBi directivity. The responsivity is −57.7 dBm and the power consumption is about 0.6 W for a single polarisation.

A novel over-the-air (OTA) measurement setup for simultaneous and near-real-time characterization and mapping of the phased array radiation patterns to the error-vector-magnitude (EVM) is introduced. A cost-effective software-defined radio (SDR) system, including a Pluto SDR for both transmission and reception, is employed. For setup demonstration, the performance of a $4 \times 4$ active phased array antenna (APAA) is studied at 26.5 GHz. Calibration of the transmitter results in an EVM of 0.5%, proving the accuracy of the measurement system. The over-the-air measured EVM of the APAA is 1.2%. The proposed setup and approach provide deep insights into how array radiation characteristics affect signal quality, advancing the evaluation and development of APAAs for next-generation wireless communication systems.

This contribution presents the assessment of RDL technology at sub-terahertz frequencies based on polybenzoxazole (PBO) polymers. A stack of two PBO layers of 10 thickness with 3 metallization of 5 copper is being under development. Vias as small as 10 and a separation of 60 are being explored. To assess the materials and capabilities of this technology, GCPW, stripline transmission line structures are being assessed, expecting losses in the order of 1.3dB/mm and 2.1dB/mm respectively. Moreover, two resonators have been designed to enhance the accuracy of the characterization.

Increasing demand for cryogenic electronics aimed at quantum sensors and computing technologies asks for accurate and quantifiable calibration methods and techniques. In this work, we present a structured approach to generate the nominal RF responses of standard artifacts, enabling wideband vector network analyzer (VNA) calibration algorithms, i.e., short, open, load, and reciprocal (SOLR), at cryogenic temperatures. Moreover, we present an EM simulation strategy to generate the perturbations in the artifacts’ responses based on mechanical fabrication tolerances and calculate an equivalent RF response uncertainty. Both the nominal and perturbed standard responses are computed at (user defined) cryogenic temperatures, by combining thermo-mechanical responses with the electromagnetic solver. A circuit simulator-based measurement model (MM) is used to compute the uncertainties of the cryogenic setups used in this work. Error contributions arising from the propagation of VNA noise, switch nonidealities, calibration artifacts uncertainties, temperature fluctuations, and temperature gradient over the interconnects are included in the MM. For validation, measured results of a coaxial air transmission line at 77 K and 4.2 K are presented and compared with 3-D EM simulation predictions. Finally, the measurement uncertainties are detailed in a budget analysis describing the individual contributions.

The THz spectrum is being explored due to its inherent large bandwidth to fulfill the throughput requirements for future wireless systems. However, there are intrinsic challenges for the exploitation of this spectrum for wireless communications, particularly concerning current technological capabilities. Moreover, it remains a big question if THz systems can be made efficient. In this contribution, we present a system analysis to show the potential of overcoming these challenges using quasi-optical antennas integrated with wideband SiGe-BiCMOS electronics and a suitable baseband design that can lead to the Tbit/sec and energy-efficient wireless transmission.

In this work, we present a numerical testbench, realized in a circuit simulation environment, enabling a priori uncertainty evaluation of dielectric spectroscopy in the application field of organs-on-chip. This testbench evaluates the impact of noise, ambient temperature variation and impurity of liquid standards on the uncertainty of dielectric spectroscopy measurements. Moreover, the proposed approach allows to account for the impact on measurement sensitivity of system parameters such as probe dimensions and probe coatings. The estimated uncertainty contributions for the considered effects are compared and benchmarked experimentally. Finally, the testbench is employed to project the dielectric spectroscopy accuracy on a relevant biological application, namely monitoring the growth of a 7 μm-thick kidney cell monolayer.

This work presents a structured, CAD-assisted design flow to realize broadband on-wafer calibration structures, validated in the prefabrication phase, and extract the intrinsic device response up to (sub)mm-waves. The strict requirements imposed by the design rule checks (DRCs) of 22 nm CMOS technology are incorporated during the design phase of the fixture by using a scripted connectable tile elements approach. The minimum dimension of a critical feature of the fixture is then identified using a newly defined metric based on the correspondence between the EM field distribution in the fixture versus a non-perturbed case of the same standard (STD) artifact. A simulation test bench environment, augmented with experimental data, is then used to add the uncertainties arising from three main error contributors: vector network analyzer (VNA) receiver noise, probe placement error, and calibration residual errors. Including these errors allows for the generation of pre-silicon numerical uncertainty bounds, which are benchmarked with experimental data using calibration quality metrics and device-level parameters. Measurement results ranging from 1 to 325 GHz are presented to demonstrate the validity of the proposed approach to establish the quality of on-wafer calibration approaches integrated in the back-end of line of Si-based technologies and to validate the compact model of CMOS devices up to (sub)mm-waves.

In this paper, we present a low-noise, high-gain readout hardware to be used in conjunction with (sub)mm-wave zero bias detectors, to enable high sensitivity (i.e., ∼-50dBm) and fast (i.e., below a second at -50 dBm) power detection.

The developed hardware employs a cascade of two (COTS) programmable gain amplifier (PGA), capable of reaching up to 90 dB gain (volt to volt), each providing an input referred noise level of 16 nV/√Hz. The signal is then digitized on the same board via a 500 kHz 12bit ADC, providing an SNR of 74 dB. The digitized signal is then readout via an ST microcontroller and transferred to the operator PC via a USB interface. The sensitive bias voltages for the PGAs are provided via the microcontroller, or alternatively can be fed by an external lab grade supply to further improve on the (already high) supply noise rejection from the first stage PGA. The proposed hardware is designed to interface with VDI zero bias detectors, high responsivity and low NEP diodes (around 2000 V/W and below 12 pW/√Hz, respectively) operating in monomodal waveguide bands up to 500 GHz. In this contribution we demonstrate the usage of the developed hardware with WR10, WR6.5, WR5 and WR 3 ZBD diodes.

This review offers a detailed examination of the current landscape of radio frequency (RF) electromagnetic field (EMF) assessment tools, ranging from spectrum analyzers and broadband field meters to area monitors and custom-built devices. The discussion encompasses both standardized and non-standardized measurement protocols, shedding light on the various methods employed in this domain. Furthermore, the review highlights the prevalent use of mobile apps for characterizing 5G NR radio network data. A growing need for low-cost measurement devices is observed, commonly referred to as “sensors” or “sensor nodes”, that are capable of enduring diverse environmental conditions. These sensors play a crucial role in both microenvironmental surveys and individual exposures, enabling stationary, mobile, and personal exposure assessments based on body-worn sensors, across wider geographical areas. This review revealed a notable need for cost-effective and long-lasting sensors, whether for individual exposure assessments, mobile (vehicle-integrated) measurements, or incorporation into distributed sensor networks. However, there is a lack of comprehensive information on existing custom-developed RF-EMF measurement tools, especially in terms of measuring uncertainty. Additionally, there is a need for real-time, fast-sampling solutions to understand the highly irregular temporal variations EMF distribution in next-generation networks. Given the diversity of tools and methods, a comprehensive comparison is crucial to determine the necessary statistical tools for aggregating the available measurement data.

This contribution presents the measurement strategy to accurately characterize probe-fed high-gain antennas operating in the sub-THz band. First, a near-field technique employing a quasi-optical system is introduced to enable characterization of backside radiating antennas (with respect to the landing pads). The proposed setup employs classical manipulators for probe landing (i.e., above the structure) and linear xyz CNC controlled translation stage. After, the calibration and modelling techniques to allow for an accurate input reflection-coefficient at the antenna input plane, and the estimation of the antenna gain, in a near field planar scanning system, are described in details. The experimental data of an high-gain backside-radiating lens antenna operating in D-band are presented to validate the proposed approach and characterization bench.

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This work describes accurate methods for the characterization of sub-terahertz (sub-THz) devices and pad de-embedding procedures. The extraction of the intrinsic DUT is enabled by generating a precise pad model using two-tier calibration approaches. Moreover, the proposed approaches offer a solution to the designers to preserve precious silicon area by presenting a simplified and potentially parameterizable pad model. Employing two different thru-reflect-line (TRL) calibration kits (calKits) together with the DUT on the same die, this research validates the proposed calibration strategies. This paper uses as DUT at J-band, i.e. a Marchand balun, fabricated using IHP SiGe BiCMOS technology with an aluminum back-end-of-line (BEOL), alongside the mentioned calKits. The goal of the paper is to assess the performance of the DUT and validate two de-embedding methods. Moreover, the pad model offers a way for accurate DUT characterization saving silicon area for future optimized designs.

In this contribution, we describe a reconfigurable surface, designed in 130um SiGe technology, to realize a fully-electronic, planar chopper aiming at passive terahertz imaging applications. This surface consists of subwavelength metallic patches that are interconnected using FET-based varactors. By switching the bias voltage of the varactors between 0V and 1.2V, the reconfigurable surface can switch between a transmissive and opaque state, respectively. The expected transmissivity is simulated to be between 0.2 and 0.9 over a wide frequency band, from 250 GHz to 550 GHz. This chopping solution would enable a high degree of system integration for future passive terahertz cameras.

In this contribution we present an approach to reduce the error arising from the variations of the lumped load, due to process spread, in probe level calibrations. First, full-wave electromagnetic (EM) simulations are employed to generate the nominal standard responses, then a parametric EM simulation of the load structure is used to generate a parametrized model of the standard. The approach is tested using a Short-Open-Load-Reciprocal calibration algorithm and an impedance standard calibration substrates developed on a 150 mm Quartz wafer (400 pm thick). In this process the high fidelity of the lateral dimension of the fabricated structures, realized using IC Photolithography, allows to confine the variations of the load response to only the thin-film resistor thickness spread. The DC response of the load, measured during the calibration step, is used to identify the specific RF response of the probed load from the parametric model. A complete analysis using full-wave EM simulations accounting for process variation is presented together with a set of experimental data up to 67GHz.

The evolution of emerging technologies that use Radio Frequency Electromagnetic Field (RF-EMF ) has increased the interest of the scientific community and society regarding the possible adverse effects on human health and the environment. This article provides NextGEM’s vision to
assure safety for EU citizens when employing existing and future EMF-based telecommunication technologies. This is accomplished by generating relevant knowledge that ascertains appropriate prevention and control/actuation actions regarding RF-EMF exposure in residential, public, and occupational settings. Fulfilling this vision, NextGEM commits to the need for a healthy living
and working environment under safe RF-EMF exposure conditions that can be trusted by people and be in line with the regulations and laws developed by public authorities. NextGEM provides a framework for generating health-relevant scientific knowledge and data on new scenarios of exposure to RF-EMF in multiple frequency bands and developing and validating tools for evidence-based risk assessment. Finally, NextGEM’s Innovation and Knowledge Hub (NIKH) will offer a standardized way for European regulatory authorities and the scientific community to store and assess project outcomes and provide access to findable, accessible, interoperable, and reusable (FAIR) data.

In this contribution, we describe the modeling approaches and the characterization procedures used to develop accurate standard models for cryogenic, probe-level, calibrations substrates.The key electrical and mechanical parameters of the impedance terminations and the lines used in commercially available impedance standard substrates are first characterized versus temperature. After, these component are simulated using 2.5D EM solvers including their mechanical variation when exposed to cryogenic temperatures, to extract their nominal response at 7 Kelvin. The quality of the resulting calibrations at cryogenic is evaluated first using independent CPW lines on the calibration substrates and then by measuring the response of a transformer-based resonator realized on a Si-based technology.Ambient temperature models are used as a comparison, to highlight the accuracy improvement that can be achieved employing optimized Cryo-EM based models.

This article presents the development of a focal plane array (FPA) for terahertz imaging applications with a near diffraction-limited resolution achieved through a very tight sampling of the focal plane. The antenna array is integrated with direct detectors in a 22-nm CMOS technology and operates from 200 to 600 GHz. The tight sampling of the focal plane is realized by using a combination of leaky-wave radiation and a dual-polarized connected array configuration that closely resembles a chessboard. By utilizing both the polarizations in the chessboard design, the number of array elements per unit area is effectively doubled. The geometry of the chessboard array was co-optimized together with that of a silicon elliptical lens to achieve both high aperture efficiency and beam overlap. Measurements in the WR2.2 band of a fabricated demonstrator showed that an aperture efficiency of −4.1 dB was realized at 400 GHz. The average gain roll-off between two diagonally adjacent array elements was measured to be −1.5 dB at 400 GHz. Compared to the reference configuration of an idealized, equivalently sampled hexagonal FPA, the improvement in gain at the edge of coverage yields 1.2 dB, which includes 1.9 dB of ohmic losses in the chessboard array. The agreement between measurements and simulations proved to be within 1 dB from 325 to 475 GHz.