Differential temperature sensors: Review of applications in the test and characterization of circuits, usage and design methodology

Differential temperature sensors can be placed in integrated circuits to extract a signature ofthe power dissipated by the adjacent circuit blocks built in the same silicon die. This review paper firstdiscusses the singularity that differential temperature sensors provide with respect to other sensortopologies, with circuit monitoring being their main application. The paper focuses on the monitoringof radio-frequency analog circuits. The strategies to extract the power signature of the monitoredcircuit are reviewed, and a list of application examples in the domain of test and characterizationis provided. As a practical example, we elaborate the design methodology to conceive, step bystep, a differential temperature sensor to monitor the aging degradation in a class-A linear poweramplifier working in the 2.4 GHz Industrial Scientific Medical—ISM—band. It is discussed how,for this particular application, a sensor with a temperature resolution of 0.02 K and a high dynamicrange is required. A circuit solution for this objective is proposed, as well as recommendations for thedimensions and location of the devices that form the temperature sensor. The paper concludes with adescription of a simple procedure to monitor time variability.Postprint (published version

An Experiment and Detection Scheme for Cavity-based Cold Dark Matter Searches

A resonance detection scheme and some useful ideas for cavity-based searches of light cold dark matter particles (such as axions) are presented, as an effort to aid in the on-going endeavors in this direction as well as for future experiments, especially in possibly developing a table-top experiment. The scheme is based on our idea of a resonant detector, incorporating an integrated Tunnel Diode (TD) and a GaAs HEMT/HFET (High Electron Mobility Transistor/Heterogenous FET) transistor amplifier, weakly coupled to a cavity in a strong transverse magnetic field. The TD-amplifier combination is suggested as a sensitive and simple technique to facilitate resonance detection within the cavity while maintaining excellent noise performance, whereas our proposed Halbach magnet array could serve as a low-noise and permanent solution replacing the conventional electromagnets scheme. We present some preliminary test results which demonstrate resonance detection from simulated test signals in a small optimal axion mass range with superior Signal-to-Noise Ratios (SNR). Our suggested design also contains an overview of a simpler on-resonance dc signal read-out scheme replacing the complicated heterodyne readout. We believe that all these factors and our propositions could possibly improve or at least simplify the resonance detection and read-out in cavity-based DM particle detection searches (and other spectroscopy applications) and reduce the complications (and associated costs), in addition to reducing the electromagnetic interference and background.Comment: 22 pages, 7 figure

Trick or Heat? Manipulating Critical Temperature-Based Control Systems Using Rectification Attacks

Temperature sensing and control systems are widely used in the closed-loop control of critical processes such as maintaining the thermal stability of patients, or in alarm systems for detecting temperature-related hazards. However, the security of these systems has yet to be completely explored, leaving potential attack surfaces that can be exploited to take control over critical systems. In this paper we investigate the reliability of temperature-based control systems from a security and safety perspective. We show how unexpected consequences and safety risks can be induced by physical-level attacks on analog temperature sensing components. For instance, we demonstrate that an adversary could remotely manipulate the temperature sensor measurements of an infant incubator to cause potential safety issues, without tampering with the victim system or triggering automatic temperature alarms. This attack exploits the unintended rectification effect that can be induced in operational and instrumentation amplifiers to control the sensor output, tricking the internal control loop of the victim system to heat up or cool down. Furthermore, we show how the exploit of this hardware-level vulnerability could affect different classes of analog sensors that share similar signal conditioning processes. Our experimental results indicate that conventional defenses commonly deployed in these systems are not sufficient to mitigate the threat, so we propose a prototype design of a low-cost anomaly detector for critical applications to ensure the integrity of temperature sensor signals.Comment: Accepted at the ACM Conference on Computer and Communications Security (CCS), 201

Cryogenic probe station for on-wafer characterization of electrical devices

A probe station, suitable for the electrical characterization of integrated circuits at cryogenic temperatures is presented. The unique design incorporates all moving components inside the cryostat at room temperature, greatly simplifying the design and allowing automated step and repeat testing. The system can characterize wafers up to 100 mm in diameter, at temperatures <20 K. It is capable of highly repeatable measurements at millimeter-wave frequencies, even though it utilizes a Gifford McMahon cryocooler which typically imposes limits due to vibration. Its capabilities are illustrated by noise temperature and S-parameter measurements on low noise amplifiers for radio astronomy, operating at 75–116 GHz

Design, development and verification of the 30 and 44 GHz front-end modules for the Planck Low Frequency Instrument

We give a description of the design, construction and testing of the 30 and 44 GHz Front End Modules (FEMs) for the Low Frequency Instrument (LFI) of the Planck mission to be launched in 2009. The scientific requirements of the mission determine the performance parameters to be met by the FEMs, including their linear polarization characteristics. The FEM design is that of a differential pseudo-correlation radiometer in which the signal from the sky is compared with a 4-K blackbody load. The Low Noise Amplifier (LNA) at the heart of the FEM is based on indium phosphide High Electron Mobility Transistors (HEMTs). The radiometer incorporates a novel phase-switch design which gives excellent amplitude and phase match across the band. The noise temperature requirements are met within the measurement errors at the two frequencies. For the most sensitive LNAs, the noise temperature at the band centre is 3 and 5 times the quantum limit at 30 and 44 GHz respectively. For some of the FEMs, the noise temperature is still falling as the ambient temperature is reduced to 20 K. Stability tests of the FEMs, including a measurement of the 1/f knee frequency, also meet mission requirements. The 30 and 44 GHz FEMs have met or bettered the mission requirements in all critical aspects. The most sensitive LNAs have reached new limits of noise temperature for HEMTs at their band centres. The FEMs have well-defined linear polarization characteristcs.Comment: 39 pages, 33 figures (33 EPS files), 12 tables. Planck LFI technical papers published by JINST: http://www.iop.org/EJ/journal/-page=extra.proc5/1748-022

Millimeter wave experiment for ATS-F

A detailed description of spaceborne equipment is provided. The equipment consists of two transmitters radiating signals at 20 and 30 GHz from either U.S. coverage horn antennas or a narrow beam parabolic antenna. Three modes of operation are provided: a continuous wave mode, a multitone mode in which nine spectral lines having 180 MHz separation and spaced symmetrically about each carrier, and a communications mode in which communications signals from the main spacecraft transponder are modulated on the two carriers. Detailed performance attained in the flight/prototype model of the equipment is presented both under laboratory conditions and under environmental extremes. Provisions made for ensuring reliability in space operation are described. Also described the bench test equipment developed for use with the experiment, and a summary of the new technology is included

Noise Parameters of CW Radar Sensors Used in Active Defense Systems

Active defense represents an innovative way of protecting military vehicles. It is based on the employment of a set of radar sensors which detect an approaching threat missile and activate a suitable counter-measure. Since the radar sensors are supposed to detect flying missiles very fast and, at the same time, distinguish them from stationary or slow-moving objects, CW Doppler radar sensors can be employed with a benefit. The submitted article deals with a complex noise analysis of this type of sensors. The analysis considers the noise of linear and quasi-linear RF components, phase-noise of the local oscillator as well as the noise of low-frequency circuits. Since the incidence of the phase-noise depends strongly upon the time delay between the reference and the cross-talked signals, a new method of measuring noise parameters utilizing a reflecting wall has been developed and verified. The achieved results confirm potentially high influence of the phase-noise on the noise parameters of the mentioned type of radar sensors. Obtained results can be used for the analysis of noise parameters of the similar but even more complex sensors

The evaluation of a HgCdTe photomixer with a Tunable Diode Laser (TDL) and the evaluation of TDL's as a local oscillator in a heterodyne detection system

Heterodyne systems would be much more versatile if a broadly tunable laser, such as a semiconductor diode laser (TDL), could be used as the local oscillator (LO). Previous studies have shown that while a TDL can be used as an LO, the TDL lack sufficient power to cause the signal-to-noise ratio to be shot noise limited. The heterodyne system with a HgCdTe photodiode as the LO was characterized and the beat frequency response of the heterodyne systems was mapped out