Bandwidth Of Amplifier Research Articles

Measurements on wireless transmission of ECG signals

The scope of this research is to design an electronic prototype, an operative system as a proof of concept, to transmit and receive biological parameters, in particular electrocardiogram signals, through dedicated wireless circuits. The apparatus features microelectronics chips that were developed for more general biomedical applications, here adapted to deal with cardiac signals. The paper mainly focuses on the electronic aspects, as in this study we do not face medical or clinical aspects of the system. The transmitter circuit uses a commercial instrumentation amplifier and the receiver has been equipped with wide-band amplifiers along with made-in-the-lab band-pass filters centered at the carrier. We have been able to mount the entire system prototype into a preliminary data acquisition chain that reads out the electrocardiogram signal. The prototype allows acquiring the waveform, converting it to a digital pattern and open the transmission through a series of high-frequency packets exploiting the Ultra Wide Band protocol. The sensor value is embedded in the transmission through the rate of the digital packets. In fact, these are sent wireless at a specific packet-frequency that depends on the sensor amplitude and are detected into a receiver circuit that recovers the information.

PA Thermal Management and Packaging: Wideband PA and Packaging, History, and Recent Advances: Part 2

Wide-band power amplifiers (PAs) are considered the most expensive and critical component for RF and microwave applications. New power systems, including those for radars, transmitters, electronic warfare (EW) jammers, and electromagnetic compatibility (EMC) testers, require the latest, state-of-the-art semiconductor technologies for power, linearity, and bandwidth [1], [2]. In addition, wide bandwidth is essential for high-speed communication and high resolution in radar, imagers, and sensors [2], [3]. In modern electronic vehicles, complexity is rapidly increasing and imposing strict EMC regulations, which often require very high 1-dB compression point (P1dB) power [to kilowatt, continuous wave (CW)] across an ultrawide bandwidth (decade) with high linearity, good reliability, and long life [4], [5].

Achievable Rate and Energy Efficiency of Hybrid and Digital Beamforming Receivers with Low Resolution ADC

For 5G it will be important to leverage the available millimeter wave spectrum. To achieve an approximately omni- directional coverage with a similar effective antenna aperture compared to state of the art cellular systems, an antenna array is required at both the mobile and basestation. Due to the large bandwidth and inefficient amplifiers available in CMOS for mmWave, the analog front-end of the receiver with a large number of antennas becomes especially power hungry. Two main solutions exist to reduce the power consumption: Hybrid BeamForming (HBF) and Digital BeamForming (DBF) with low resolution ADC. Hybrid beamforming can also be combined with low resolution ADCs. This paper compares the spectral and energy efficiency based on the chosen RF-frontend configuration. A channel with multipath propagation is used. In contrast to previous publication, we take the spatial correlation of the quantization noise into account. We show that the low resolution ADC are robust to small Automatic Gain Control (AGC) imperfections. We showed that in the low SNR regime the performance of DBF even with 1-2 bit resolution outperforms HBF. If we consider the relationship of spectral and energy efficiency then DBF with 3-5 bits resolution achieves the best ratio of spectral efficiency per power consumption of the RF receiver frontend over a very wide SNR region. The power consumption model is based on components reported in literature.

Non-degenerate optical parametric amplification analysis of surface plasmon polariton wave in a silver coated PPLN planar waveguide

Propagation length enhancement of surface plasmon polariton (SPP) wave in telecom c-band through nonlinear χ(2)-based nondegenerate difference frequency generation (ndDFG) process is investigated theoretically. The SPP wave is excited in a silver coated planar periodically poled lithium niobate (PPLN) waveguide. Quasi phase matching is used to compensate the phase mismatch between the interacting excited SPP and guided modes. Domain inversion with proper domain wavelength of Λ = 101.9 μm leads to nonlinear efficient mode interaction of guided↔SPP. With 31 MW/cm coupled pump intensity a SPP amplification of about 16 dB is achievable which results in enhancement of the propagation length about 11 mm. The acceptance SPP amplification bandwidth is pump power dependent. In a low pump depletion regime, a 3-dB bandwidth is about 75 nm whereas in more depletion the bandwidth becomes narrower but not less than 25 nm.

A Broadband Multistage LNA With Bandwidth and Linearity Enhancement

Design techniques to enhance bandwidth and linearity of broadband multistage low-noise amplifiers (LNAs) are presented. A feedback amplifier circuit is proposed to compensate for transistor gain roll-off with frequency in other amplifier stages and extend overall bandwidth. Moreover, a transistor width tapering in a multistage LNA is applied to improve linearity. These techniques are adopted in a three-stage monolithic microwave integrated circuit (MMIC) LNA implemented in a 0.1- $\mu \text {m}$ GaAs pHEMT process. The LNA features 18–43 GHz bandwidth, 21.6 dB average gain, and 1.8–2.7 noise figure (NF). It exhibits output 1-dB compression point of 11.5 dBm at 30 GHz and consumes 70 mA bias current from a 2-V supply.

High-capacity transmission over multi-core fibers

The ultimate transmission capacity of standard single-mode fiber (SSMF) is limited by fiber nonlinearity which prevents increasing transmission power and finite amplifier bandwidth. In order to overcome such limitation, space-division multiplexing (SDM) has been proposed. Multi-core fiber (MCF) is a strong candidate to realize practical SDM transmission system because of high isolation of individual spatial modes sharing the same cladding, which enables ultra-high capacity transmission in cooperation with wide band WDM.

Material gain simulation of the GaInNAs/GaAs semiconductor optical amplifier (SOA)

In this paper, we present theoretical studies of the effect of nitrogen incorporation on the material gain in the Ga0.8In0.2NyAs1-y/GaAs semiconductor optical amplifier. For the calculation, we have used the semi-empirical band anti-crossing (BAC) model which has been most successful in explaining the band gap bowing effect in GaInAsN alloys. From this model, we have calculated the material gain in the active layer for this semiconductor quantum well derived from the energies transition as well as the densities of state of this (SOA) for different nitrogen concentrations (0.01, 0.02, 0.025 and 0.03).From the results, we find that the presence of N atoms in the active layer affects the value of the band gap which leads to the increase of the material gain peak. This latter has also been studied as a function of the wavelength for different transparency carrier densities. As a consequence, we state that the incorporation of nitrogen changes the bandwidth of this semiconductor optical amplifier.

High frequency oscillations for lateralizing suspected bitemporal epilepsy

ObjectiveIn some cases of single focus epilepsy, conventional video electroencephalography (EEG) cannot reveal the epileptogenic focus even when intracranial electrodes are used. Here, we tested whether analyzing high frequency oscillations (HFOs) can be used to determine the ictal onset zone in suspected bitemporal epilepsy and improve seizure outcome. MethodsWe prospectively studied 13 patients with refractory temporal seizures who were treated over a 4-year period and underwent bilateral placement of intracranial electrodes. Subdural strips were used in all cases, and depth electrodes were implanted into mesial temporal lobes in 10 patients. The mean patient age was 30.92 years, and 30.7% of patients were male. Patients were monitored by conventional and wide-band frequency amplifiers. ResultsConventional invasive EEG monitoring of interictal periods showed bilateral epileptiform abnormalities in 12 patients (92.3%) and unilateral epileptiform abnormalities in one (7.7%), and monitoring of ictal periods revealed unilateral seizure origins in nine patients (69.2%) and bilateral origins in four (30.8%). In contrast, high frequency invasive EEG monitoring of interictal periods showed bilateral HFOs in seven patients (53.8%) and unilateral HFOs in six (46.2%), and monitoring of ictal periods revealed unilateral HFOs in all 10 patients who were tested. Three patients were not monitored during ictal periods because of time limitations. All 13 patients subsequently underwent a standard unilateral temporal lobectomy and have been followed-up for a minimum of 12 months. Eleven (84%) had a Class I outcome, one (8%) a Class II outcome, and one a Class III outcome. SignificanceBilateral placement of subdural strip and depth electrodes for seizure monitoring in patients with suspected bitemporal epilepsy is both safe and effective. Monitoring high frequency oscillations can help determine the laterality of the onset zone when localization using conventional EEG or brain MRI fails.

20-nm enhancement-mode metamorphic GaAs HEMT with highly doped InGaAs source/drain regions for high-frequency applications

ABSTRACTIn this article, the DC and RF performance of a SiN passivated 20-nm gate length metamorphic high electron mobility transistor (MHEMT) on GaAs substrate with highly doped InGaAs source/drain (S/D) regions have investigated using the Synopsys TCAD tool. The 20-nm enhancement-mode (E-mode) MHEMT device also features δ-doped sheets on either side of the In0.53Ga0.47As/InAs/In0.53Ga0.47As channel which exhibits a transconductance of 3100 mS/mm, cut-off frequency (fT) of 740 GHz and a maximum oscillation frequency (fmax) of 1040 GHz. The threshold voltage of the device is found to be 0.07 V. The room temperature Hall mobilities of the 2-dimensional sheet charge density are measured to be over 12,600 cm2/Vs with a sheet charge density larger than 3.6 × 1012 cm−2. These high-performance E-mode MHEMTs are attractive candidates for sub-millimetre wave applications such as high-resolution radars for space research, remote atmospheric sensing, imaging systems and also for low noise wide bandwidth amplifier for future communication systems.

Design of Broadband Power Amplifiers Based on Resistive-Reactive Series of Continuous Modes

In this letter, the bandwidth of the series of continuous modes (SCMs) power amplifiers (PAs) is extended. The SCMs are composed of a series of continuous working modes between Class-B/J and Class-F continuums. The second harmonic load of the series of continuums is purely reactive. By introducing resistive part to the purely reactive second harmonic load of the series of continuous modes, the operation bandwidth of power amplifiers is expanded. A broadband PA working across 0.8–3.05 GHz (117% bandwidth) is simulated and fabricated. Experimental results show that the drain efficiencies in interesting band are 57.4%–79%. The fabricated PA can deliver output power of 10.1–20.7 W.

Wideband Amplifiers and Their Applications [Book\/Software Reviews

This textbook aims to present all relevant information and comprehensive design methodologies for wideband amplifiers and their applications—from theoretical approaches and circuit simulations to practical implementation techniques for RF and microwave distributed amplifiers.

New topology of wide band EDFA using split band double pass amplification

ABSTRACTA novel design of high and broad gain that covers C and L bands is demonstrated experimentally. The techniques, used in this paper, combine two double pass with split band structure. The signals travel in separate paths after being splitted using a coupler band splitter. The topology of this new configuration uses this technique to broaden the gain at its maximum range of amplification. The presented paper is to study the performance of the augmented gain of the EDFA configuration using what it can be called double pass wide band amplification. The results show a broadening range of 80 nm between 1520 nm and 1600 nm in the C and L band and high gain of 45 dB for the range 1525 nm and 1580 nm and lower gain for the range 1580 nm and 1600 nm. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2093–2096, 2016

A magnetoelectric composite based signal generator

Self-oscillations in an active loop consisting of a wide-band amplifier and a magnetoelectric composite in the feedback circuit have been observed. The composite with a ferroelectric lead zirconate titanate bimorph and ferromagnetic Metglas serves as a resonator that determines the frequency of oscillations and provides the feedback voltage. Under amplitude balance and phase matching conditions, the device generated signals at 2.3 kHz, at the bending resonance frequency of the composite. The oscillations were observed over a specific range of magnetic bias H. The shape of the signal generated is dependent on electrical circuit parameters and magnitude and orientation of H.

Improving the bandwidth of the transimpedance amplifier based on CS stages in cascode configuration using impedance matching techniques

This paper describes a matching technique to improve the bandwidth of multi-GHz frequency ranges for the transimpedance amplifier. It is shown that by simultaneously using of series input matching ...

Wavelength dimensioning for wavelength-routed WDM satellite network

Internet and broadband applications driven by data traffic demand have become key drivers for satellite constellations. The key technology to satisfy the high capacity requirements between satellites is optical satellite networks by means of wavelength division multiplexing inter-satellite links (ISLs) with wavelength routing (WDM-OSN). Due to the limited optical amplifier bandwidth onboard the satellite, it is important to minimize the wavelength requirements to provision requests. However, ISLs should be dynamically established and deleted for each satellite according to its visible satellites. Furthermore, different link assignments will result in different topologies, hence yielding different routings and wavelength assignments. Thus, a perfect match model-based link assignment scheme (LAS-PMM) is proposed to design an appropriate topology such that shorter path could be routed and less wavelengths could be assigned for each ISL along the path. Finally, simulation results show that in comparison to the regular Manhattan street network (MSN) topology, wavelength requirements and average end-to-end delay based on the topology generated by LAS-PMM could be reduced by 24.8% and 12.4%, respectively.

Developement an InGaAs Detecto-Amplfier Applied to Atmospheric Remote Sensing

The InGaAs PIN photodiodes are widely used in spectrometric and medical equipment. However, it is not widespread its use for atmospheric remote sensing phenomena studies. In the present work we shows the development and construction of a detector-amplifier based on an InGaAs PIN photodiode, with high gain (110dB), low bandwidth (10MHz) and low distortion. Such device is the detection unit used for a backscatter LIDAR (Light Detection And Ranging) operating in 1064 nm. The PIN photodiode responsivity was characterized for the specific wavelength (1064 nm), as well as its juncture capacitance for the bandwidth of device. The independently characterization of amplifier (gain and bandwidth) without sensor, let us improve its performances. These characterizations allowed obtain a detector-amplifier system with a remarkable performance for remote sensing applications. Finally, we present the preliminary results obtained with a backscatter LIDAR, where we shows the measurements of cirrus clouds observations with altitude between 8 and 12 kilometers.

Note: Expanding the bandwidth of the ultra-low current amplifier using an artificial negative capacitor.

The bandwidth and low noise characteristics are often contradictory in ultra-low current amplifier, because an inevitable parasitic capacitance is paralleled with the high value feedback resistor. In order to expand the amplifier's bandwidth, a novel approach was proposed by introducing an artificial negative capacitor to cancel the parasitic capacitance. The theory of the negative capacitance and the performance of the improved amplifier circuit with the negative capacitor are presented in this manuscript. The test was conducted by modifying an ultra-low current amplifier with a trans-impedance gain of 50 GΩ. The results show that the maximum bandwidth was expanded from 18.7 Hz to 3.3 kHz with more than 150 times of increase when the parasitic capacitance (∼0.17 pF) was cancelled. Meanwhile, the rise time decreased from 18.7 ms to 0.26 ms with no overshot. Any desired bandwidth or rise time within these ranges can be obtained by adjusting the ratio of cancellation of the parasitic and negative capacitance. This approach is especially suitable for the demand of rapid response to weak current, such as transient ion-beam detector, mass spectrometry analysis, and fast scanning microscope.

High-efficiency optical parametric chirped-pulse amplifier in BiB_3O_6 for generation of 3 mJ, two-cycle, carrier-envelope-phase-stable pulses at 17 μm

We produce a 3 mJ, two-cycle (11.4 fs), 1 kHz, carrier-envelope phase (CEP)-stable laser source at 1.7 μm via a three-stage Ti:sapphire-pumped optical parametric chirped-pulse amplifier in BiB3O6. We achieve a pump-to-signal conversion efficiency of 18% in the last stage, which is, to the best of our knowledge, the highest yet achieved for near-octave bandwidth amplification. A f-to-2f measurement shows a CEP instability of 165 mrad over 1 h. This is an ideal light source for generating isolated attosecond pulses in the soft x-ray region.

Theoretical Analysis of the Optical Filtering Effect on a Directly Modulated Reflective Semiconductor Optical Amplifier

The modulation bandwidth of a reflective semiconductor optical amplifier (RSOA) is limited by carrier lifetime. Therefore, it is hard to directly modulate an RSOA with high-speed electrical signals. We theorize that an optical filter can act as an optical equalizer, compensating for the narrow bandwidth limitation imposed by the RSOA. By modeling a time-varying RSOA with a modified transfer matrix method (TMM), we simulated 25 Gbps operation of an RSOA with optical filtering effects. We investigated the impact of detuning the center wavelength of the optical filter on the modulation of an RSOA. The numerical results show that it is possible to modulate an RSOA with an optical filtering effect at 25 Gbps without electronic equalization or digital signal processing.

Two-path inverter-based low noise amplifier for 10–12 GHz applications

This paper presents a two-path inverter-based low-noise-amplifier (LNA) in TSMC 0.18µm CMOS technology for 10–12GHz frequency band applications. The primary path provides a flat and high enough gain within the interested frequency band. The secondary path ensures the input impedance matching for the proposed LNA. A peaking inductor is applied to the gate of inverters NMOS transistor. With this technique, the parasitic capacitance of MOS transistors will be appropriately compensated at high frequencies. Furthermore, resistive shunt feedback is applied to CMOS inverters in order to extend the amplifier bandwidth. The feedback resistor makes the LNA to be a self-biased structure. The proposed LNA consumes 10.3mW from a 1.8V supply. The amplifier gain is high enough and S21=12.8dB while the gain flatness is 0.55dB in the whole frequency band. The structure is optimized for minimum noise figure (NF) and the NF is 2.1–2.3dB within the bandwidth. The input impedance is matched and S11 is less than −10dB. The linearity of the LNA is sufficient and IIP3 is equal to −11dBm.