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This article presents a low power triple-mode parallel-processing CMOS receiver for BD-II/GPS/Galileo joint navigation applications. An innovative image rejecting parallel-processing architecture is proposed, which utilizes a single frequency synthesizer, shares the front-end, and adopts two complex band-pass filters in two channels separately, aiming for the receiving of BD-II B1/GPS L1/GALILEO L1 multistandard navigation signals simultaneously. The proposed triple-mode parallel-processing receiver is fabricated in a 0.18 μm CMOS process with 22.2 mA power consumption under the triple-mode parallel-processing navigation. Measured results show that it has a maximum conversion gain of 101.5 dB and a double-side-band noise figure of 3.3 dB with the fixed IF of 7*f0 (f0 = 1.023 MHz), tunable IF bandwidth of 2*f0/4*f0, and more than 34 dB image rejection. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2616–2620, 2013

Ionization gas sensors need to combine with chromatograph and mass spectrograph to separate gas mixture; this results in huge, bulky architecture, high power consumption and risky high-voltage operation. Here we proposed using two-sensor array composed of two carbon-nanotube film cathode gas sensors with different gaps and using multi-information fusion technology to directly and precisely identify the gas mixture at atmospheric pressure without separating the mixture. Two-sensor array with different gaps were used, and experiments were conducted to obtain the original patterns (OPs) of the two sensors, viz. the relationship between the breakdown voltages and the gas concentrations of the two-gas mixture. The interpolation technology was used to improve OPs, and the neural network technology was used to precisely identify the two components without separating the mixture. This novel method greatly improved the performance of the gas sensor, and can be used to identify n-gas mixture (n > 2) with n-sensor array.

A novel temperature-compensating structure for micromechanical bridge resonators has been developed in this paper. The temperature drift of resonance frequency is compensated by the output voltage of a Si/SiO2 bilayer cantilever temperature sensor, which is integrated in the same chip with the bridge resonator. The mechanism of this kind of temperature sensor resembles that of commercial bimetallic temperature sensors. The deformation of the cantilever measured by a Wheatstone bridge located at the clamped end changes with temperature due to the different thermal expansion coefficients of silicon and silicon dioxide. Both the bridge and the cantilever are of the same thickness and are fabricated simultaneously with the same materials and by an identical process flow. So there are few errors caused by the temperature difference between the temperature sensor and the resonator itself, which occurs during fast temperature changes.

A novel micromechanical bridge shape voltage-controlled oscillator with high Q value was fabricated. The core of this class of oscillators is an electrothermally excited and piezoresistively detected micromechanical bridge resonator. Its resonance frequency can be adjusted by changing the DC bias voltage applied on the excitation resistor. Theoretical analysis and experiment data show that its resonance frequency is linear with the square of the DC bias voltage. The kind of VCO has the advantages of good linearity, wide adjustable frequency range and high quality factor Q.

This paper mainly deals with the sensor drift in the application of gas concentration measurement, but little has been done in previous works. The algorithm of detecting the drift of sensors presented in this paper is based on the combination of the principal component analysis (PCA) with the wavelet analysis. By this algorithm the sensor drift can be detected online sensitively. For compensating the drift of sensors, an adaptive dynamic drift compensation algorithm (ADDC) based on a drift model is also provided in this paper. From the drift model, the drift compensation factors used to compensate the drifting sensor’s data are calculated. When the drift feature changed, the drift model will be updated online adaptively. In this way, a lifelong efficient drift compensation is made possible for every sensor. The superior performance of this drift counteraction strategy is illustrated with the examples using real semiconductor sensor array data.

The dependence of the resonance frequency of thermally excited microcantilever resonators on temperature has been reported by several papers. All these papers ignored the film grown or deposited on the surface of a cantilever and regarded the beam as a single layer one. As a result, there was difference between the theoretical model and experimental results. The paper proposes a bilayer beam model to calculate the dependence of resonance frequency on temperature. This novel model regard the film as another mechanical layer and takes the induced mass by the surrounding gas into account. The calculated results are in good agreement with experimental results.

In the study of electrostatic forces of semiconductor microstructures, especially in submicrometer or nanometer orders, it is valuable to analyse the influence of the space-charge layer at the surface of the microstructures. When the distance between microstructures is larger than 1 µm, the influence of space charge is a negligible factor and the metal approximation formula can be used. When the distance is reduced to the order of submicrometers or tens of nanometers, the error introduced by the metal approximation formula increases rapidly, dominated by the distance and the doping concentration. For the commonly used material n-type silicon, whose doping concentration is 1015 cm-3, when the distance is less than 450 nm, the error caused by the metal approximation formula is more than 10%. At this time, the metal approximation formula cannot be used and the influence of the space-charge layer must be taken into account.

Based on the optically-induced capacitance change (OICC) effect of the metal-P/N-semiconductor-isolator-metal (MPNIM), a new type of photosensitive capacitor (PCS) has been developed. The dependence of the capacitance on the intensity and wavelength of light and on the temperature and the measuring have been studied. The C - V characteristics of the device have been studied as well.