Three‐port cascade de‐embedding methodology with the dangling leg effect considered for pHEMT electron trapping characterization at microwave frequency

Micro & Optical Tech Letters

2015

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In this article, temperature dependence on radio‐frequency (RF) avalanche effects of metal–oxide–semiconductor field‐effect transistors (MOSFETs) in the impact ionization region is investigated using RF measurements for the first time. Equivalent circuit parameters of MOSFETs including the inductive breakdown network are extracted from low to high temperatures to characterize device performance and its temperature dependency in the breakdown regime. At elevated temperatures, inductive behavior resulting from a RF avalanche mechanism becomes evident due to the pronounced inductive network with increasing temperature. When the RF avalanche mechanism is not considered, a deviation of the extracted channel resistance increases with raising temperature. The effect of inductive breakdown on output voltage standing wave ratio performance when designing an output matching network for the MOSFETs is also analyzed at different temperatures. The presented analysis of temperature dependence on device performance can be beneficial to RF power amplifier design in the breakdown region for high‐altitude applications at different temperatures. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:817–820, 2015

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Section: Introductionmentioning

confidence: 99%

Temperature dependence on RF avalanche breakdown of RF mosfets in the impact ionization region

Micro & Optical Tech Letters

2015

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“…Our previous research was devoted to III‐V device characterization with a three‐port de‐embedding method . Other works about silicon devices focused on p–n junction mixed breakdown characterization and MOSFET breakdown modeling .…”

Section: Introductionmentioning

confidence: 99%

Direct conversion Doppler radar vital sign detection system using power management technique

Micro & Optical Tech Letters

Chen

et al. 2014

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Furthermore, the tunable operation frequency range of the proposed impulse generator is experimentally studied. This impulse generator can work well at any input frequency around 1-15 MHz. Figure 4 displays the experimental results of the final output impulses at operation frequencies of 1, 5, 10, and 15 MHz. It can be recognized that the lower frequency, the slightly higher amplitude. This is attributed to the recovery time of the RC-circuit of the collector resistance and the output coupling capacitor. When frequency is higher the period is shorter so that the output coupling capacitor has shorter time for recovery. Consequently, the output amplitude is lower. Therefore, by adjusting the values of the collector resistance and the output coupling capacitor, we can broaden the working frequency range. In addition, the fabricated impulse generator was checked by HP 8593E RF spectrum analyzer with generated high-order harmonic up to 10 GHz.With such output UWB short impulses, the impulse generator can be used for many practical applications in electronics and optics. By utilizing the fast leading edge characteristic of the generated short impulses for driving actively mode-locked fiber lasers, we may anticipate a possible generation of shorter optical pulses than reported in [6]. This issue is currently under investigation and will be reported elsewhere. CONCLUSIONIn this article, we have described a method for generating UWB picosecond impulses with fast fall-time based on the fast switchon characteristic of a broadband bipolar transistor and the edge compression characteristic of a NLTL comb generator. The experimental results showed that the generated short impulses had a pulse-width of about 725 ps, a fall-time of 180 ps, and a peak power of 1 W at 50 X. ABSTRACT: This article is the first to present a low power consumption direct conversion Doppler radar vital sign detection system using a power management technique to detect biomedical signals. The optimal pulse bias with simultaneous switching noise considered was designed to decrease power consumption of the sensor. A noncontact vital sign detection measurement using the optimal pulse bias was performed on a human subject. Based on experimental results, the presented simple and low power system can accurately detect human cardiopulmonary activity, including respiration and heartbeat. Calculated physiological signal amplitudes based on a spectral analysis validates the detection result from presented work. When compared with the sensor using a power amplifier, the proposed sensor can achieve low power dissipation for biomedical monitoring and green energy applications.

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A simple and fast de-embedding procedure of X-parameter measurement for RF transistor characterization in the large-signal operating region

2016 IEEE International Symposium on Radio-Frequency Integration Technology (RFIT)

2016