Johannes Nehring

Single- and Dual-Port 50-100-GHz Integrated Vector Network Analyzers With On-Chip Dielectric Sensors

This work presents a single- and dual-port fully integrated millimeter-wave ultra-broadband vector network analyzer. Both circuits, realized in a commercial 0.35-μm SiGe:C technology with an ft/fmax of 170/250 GHz, cover an octave frequency bandwidth between 50-100 GHz. The presented chips can be configured to measure complex scattering parameters of external devices or determine the permittivity of different materials using an integrated millimeter-wave dielectric sensor. Both devices are based on a heterodyne architecture that achieves a receiver dynamic range of 57-72.5 dB over the complete design frequency range. Two integrated frequency synthesizer modules are included in each chip that enable the generation of the required test and local-oscillator millimeter-wave signals. A measurement 3σ statistical phase error lower than 0.3 ° is achieved. Automated measurement of changes in the dielectric properties of different materials is demonstrated using the proposed systems. The single- and dual-port network analyzer chips have a current consumption of 600 and 700 mA, respectively, drawn from a single 3.3-V supply.

Miniature Microwave Biosensors: Noninvasive Applications

Demographic shifts are part of the process of social and economic change that has been taking place worldwide over the last century. Europe is the first large subcontinent to encounter the effects of an aging society [1]. The same pattern is repeating in Latin America and Japan but with a quicker pace of transition compared with that which took place in the countries that are now industrialized [2]. This situation impacts the productivity and economic growth of the countries due to the reduction of the working age population [3]. Additionally, the increase in the number of elderly people who make use of service in the social security systems has a tremendous fiscal impact, which is represented in the expenses for pensions, health care, and longterm care. In addition, the increase of chronic diseases correlated with the lifestyle and the behavior in industrial countries (e.g., tobacco consumption, obesity, and the fact that the need for the primary care increases while the number of primary care providers diminishes) represent the challenges to be solved for the health systems of modern society [4].

A 4–32-GHz Chipset for a Highly Integrated Heterodyne Two-Port Vector Network Analyzer

This work presents a chipset for a highly integrated heterodyne vector network analyzer (VNA) with two ports and a multi-octave bandwidth from 4 to 32 GHz. The chipset is comprised of a stimulus integrated circuit (IC) with two selectable single-ended output channels and a four-channel receiver IC. Both chips contain a frequency synthesizer with an average output power of 2.5 dBm and a single-sideband phase noise between -96.3 and -115.3 dBc/Hz at 1-MHz offset. The synthesizer consists of an array of three voltage-controlled oscillators with tuning ranges between 24.8% and 28.2% and a bandwidth extension stage. Wideband design techniques based on cascaded emitter followers are applied to a variable gain amplifier with a peak gain of 15.1 dB and to a wideband source switch with a minimum isolation of 23.6 dB. Single-ended receiver components such as a wideband low-noise amplifier with an average gain of 10 dB and a micromixer are used to compose the four-channel receiver with an average conversion gain of 14.4 dB. A hybrid microwave integrated circuit was fabricated in order to prove the functionality of a VNA utilizing the proposed chipset and wideband directional couplers. The measured scattering parameters of an arbitrary device-under-test showed an average deviation of 0.18 dB in magnitude and 1.8 ° in phase from the measurements obtained with a commercial VNA.

A silicon integrated microwave vector network analyzer for biomedical sensor read-out applications

This paper proposes an integrated reflectometer for biomedical sensor read-out applications using a low-cost silicon-germanium technology. The heterodyne reflectometer consists of two integrated cross-coupled oscillators, a set of two directional couplers as well as Gilbert-Cell downconversion mixers. A dual phase-locked-loop architecture guarantees the phase lock of both on-chip signal sources to an external reference oscillator. An OSM-calibration was applied to the reflectometer and measurements of the complex reflection coefficient of an arbitrary device under test (DUT) showed excellent agreement with the results of a commercial vector network analyzer. As a proof of concept for sensor read-out, five solutions with different mixture ratios were characterized with a dielectric probe connected to the reflectometer.

Highly Integrated 4-32-GHz Two-Port Vector Network Analyzers for Instrumentation and Biomedical Applications

This paper addresses the miniaturization of microwave vector network analyzers (VNAs) and the future vision of the VNA on a chip. Therefore, a highly integrated two-port VNA with a multioctave bandwidth from 4 to 32 GHz is presented. The proposed system is based on a fully integrated radio-frequency frontend consisting of a two-port stimulus, a four-channel heterodyne receiver, and a wideband testset. The testset is comprised of on-chip multisection directional couplers. The chip is operated inside a hardware demonstrator using a 16-term calibration procedure. The measurement of arbitrary devices under test is in excellent agreement with commercial measurement equipment and showed a mean deviation from the reference measurement of 0.17 dB and 1.29° regarding the forward transmission of a coaxial 30-dB attenuator. The system and receiver dynamic ranges are 44–77 and 82–101 dB at a resolution bandwidth of 100 kHz over the full system bandwidth. The measurements are highly repeatable and are robust against drift over time. As a proof of concept, the developed integrated network analyzers are utilized in a biomedical sensing scenario with an external and an on-chip sensor. Both approaches showed good sensitivity regarding the mixture ratio of binary solutions of ethanol and methanol.

A wideband scalar network analyzer for biomedical dehydration measurements

This paper presents a wideband microwave approach towards biomedical dehydration monitoring. The introduced concept is verified via invasive measurements on several blood samples. A microwave measurement circuit, based of a two-port scalar vector network analyzer is presented. The circuit operates between 5GHz and 20GHz using a planar permittivity sensor. Measurements of all subcomponents are shown together with measurements of a Water-NaCl-Glycerol solution.

A 10 Gb/s highly-integrated adaptive pseudo-noise transmitter for biomedical applications

A highly-integrated 211 −1 pseudo-random bit sequence (PRBS) transmitter for biomedical applications is presented. The chip consists of an ultra-wideband synthesizer with an integrated divider to drive a PLL, a linear feedback shift register (LFSR) to generate an M-sequence and a programmable binary divider to enable adaptive subsampling technique in the signal processing path. The circuit is created to be used in a miniaturized portable PRBS based sensor system for biomedical applications. A conceivable application is the measurement of dehydration in a human body. The PRBS generator is capable of generating a bit-rate up to 10Gb/s, correlating to a maximum bandwidth of the generated sequence of 5GHz, which is sufficient for the designated applications. The circuit is manufactured in an 0.35 μm SiGe-Bipolar technology with an ft of 200GHz using 12mm2 chip area.

Integrated test concepts for in-situ millimeter-wave device characterization

This paper presents our recent work towards state-of-the-art integrated test concepts for the in-situ characterization of silicon-integrated millimeter-wave devices and transceiver components for radar and communication applications. Narrowband as well as ultra-broadband integrated network analysis solutions for a variety of frequency bands ranging from 50 to 120 GHz are outlined. In this context, direct-conversion and heterodyne architectures and their respective implementations in silicon-germanium technologies are discussed.