High-frequency Noise Analysis Research Articles

냉장고 기계실의 고주파 소음 특성 분석을 통한 음질 개선

냉장고 기계실의 고주파 소음 특성 분석을 통한 음질 개선

Apparent base resistance decomposition by means of small-signal and high-frequency noise analyses of submicron InP/InGaAs HBTs

We present an original and reliable technique to elucidate the different contributions to the apparent base resistance (RB = RBx + XRBi) of double heterojunction bipolar transistors (HBTs) designed by Alcatel-Thales III–V Lab. The extrinsic base resistance (RBx) is quantified using small-signal measurements. The base-collector junction distribution factor (X) and the intrinsic base resistance (RBi) are extracted from high-frequency noise (HFN) measurements. This method was applied to three InP/InGaAs HBTs having different emitter surfaces (SE). The correct determination of RBx, X and RBi may be a useful tool for compact and/or linear electrical modelling and may give some guidelines to designers to improve operation frequencies. Moreover, this strategy can be applied to any layout and technological variation of HBT; it can be also applied to homojunction bipolar transistors. Our results show that HFN analysis should be included to fully characterize bipolar transistors.

RFCMOS Unit Width Optimization Technique

In this paper, we demonstrate a unit width ( W <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> ) optimization technique based on their unity short-circuit current gain frequency (f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> ) unilateral power gain frequency (f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">MAX</sub> )? and high-frequency (HF) noise for RFCMOS transistors. Our results show that the trend for the above figures-of-merit (FOMs) with respect to the W <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> change is different; hence, some tradeoff is required to obtain the optimum W <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> value. During the HF noise analysis, a new FOM is proposed to study the W <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> effect on the HF noise performance. In our experiment, the flicker noise of the transistor is also measured and the result shows that the change in W <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> does not affect the noise spectral density at the low-frequency range. This technique enables RF engineers to optimize the transistor's layout and helps to select the optimum Wf for transistors used in specific circuit design such as the low-noise amplifier, voltage-controlled oscillator, and mixer. Furthermore, by using layout optimized transistors in the RF circuit, the optimal circuit's performance can be easily achieved and, thus, greatly reduced the circuit development time. In the aspect of RF device modeling, by knowing the optimum W <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> for a particular process or technology, the number of transistors to model is reduced and, hence, greatly shortens the RF modeling development time for existing and future technologies.

Understanding of the excess channel noise in InAlAs∕InGaAs∕InP high electron mobility transistors in impact ionization regime

The characterization and analysis of high frequency noise of InP-based high electron mobility transistors in the impact ionization regime reveal that different physical mechanisms are responsible for the excess channel noise at different frequency ranges. The excess noise at frequencies below 10GHz is mainly due to the hole recombination in the channel. However, excess channel noise at higher frequencies could be dominated by the fluctuation of impact ionization which has a much smaller time constant and therefore a much higher cutoff frequency.

Advanced structure methodologies for next-generation ground vehicles. Part 2: Case study

In the first paper of this two-part study, basic theories were introduced for several new methodologies developed in the Automotive Research Center (a US Army TACOM Center of Excellence for Modelling and Simulation of Ground Vehicles at the University of Michigan) for the simulation and design of advanced structures and materials for next-generation ground vehicles. These new methodologies include: (1) an advanced topology optimisation technique for innovative conceptual design of vehicle structures and materials; (2) a systematic design optimisation process with efficient analysis and sensitivity analysis capabilities for detailed design modifications to improve the vibration and noise characteristics of a complex vehicle structure; (3) a reduced-order modelling technique that can be used to systematically generate low-order models for the prediction of vehicle vibration, power flow, and the effects of parameter uncertainties; and (4) an efficient and accurate energy boundary element analysis method for high-frequency noise analysis outside the vehicle. In this second paper, an extensive case study is presented to demonstrate how the methodologies presented in the first paper can be applied to a vehicle system. A pick-up truck equipped with an advanced hybrid propulsion system is considered in this paper, and various example design and prediction problems are discussed, which provide proof-of-concept for the methodologies developed.

Analysis of high frequency noise in engine timing belt

The purpose of this study is to investigate the generating mechanism and the reduction method of high frequency noise for the timing belt. It was identified that this noise is generated by the discontinuous slips and the flow of holding air between the belt and pulley of trial belts. Good correlation between the tooth load and the noise was obtained, which proves the validity of the tooth load measurement for estimating the belt noise. Improving the meshing smoothness and releasing the air with the grooved pulley are shown to be effective for reducing the noise.

Analysis of high frequency noise in engine timing belt Hiroharu Tokoro, Mayu Nakamura, Noboru Sugiura, Hirofumi Tani (Toyota Central R &amp; D Labs., Inc.), Ken-ichi Yamamoto, Tatsuo Shuku (Toyota Motor Corp.)

Analysis of high frequency noise in engine timing belt Hiroharu Tokoro, Mayu Nakamura, Noboru Sugiura, Hirofumi Tani (Toyota Central R &amp; D Labs., Inc.), Ken-ichi Yamamoto, Tatsuo Shuku (Toyota Motor Corp.)

Noise modeling and measurement techniques (HEMTs)

The high electron mobility transistor's (HEMT's) noise behavior is presented from theoretical and experimental points of view. The general method used in the high-frequency noise analysis is described and the different approximations commonly used in the derivation of the noise parameter expressions are discussed. A comparison between the noise performance of both MESFETs and HEMTs is carried out. The measurement techniques providing the noise figure and the other noise parameters are then described and compared.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>