High-gain Amplifier Research Articles

Covering 1280-1495 nm (215 nm) wideband high-gain bismuth-doped fiber amplifier with only 1240 nm pumping

Covering 1280-1495 nm (215 nm) wideband high-gain bismuth-doped fiber amplifier with only 1240 nm pumping

RFSoC Softwarisation of a 2.45 GHz Doppler Microwave Radar Motion Sensor

Microwave Doppler sensors are used extensively in motion detection as they are energy-efficient, small-size and relatively low-cost sensors. Common applications of microwave Doppler sensors are for detecting intrusion behind a car roof liner inside an automotive vehicle and to detect moving objects. These applications require a millisecond response from the target for effective detection. A Doppler microwave sensor is ideally suited to the task, as we are only interested in movement of a large water-based mass (i.e., a person) (FMCW Radar also detect static objects). Although microwave components at 2.45 GHz are now relatively cheap due to mass production of other Industrial Scientific and Medical application (ISM) devices, they do require tuning for temperature compensation, dielectric, and manufacturing variability. A digital solution would be ideal, as chip solutions are known to be more repeatable, but Application-Specific Integrated Circuits (ASICs) are expensive to initially prototype. This paper presents the first completely digital Doppler motion sensor solution at 2.45 GHz, implemented on the new RFSoC from Xilinx without the need to up/downconvert the frequency externally. Our proposed system uses a completely digital approach bringing the benefits of product repeatability, better overtemperature performance and softwarisation, without compromising any performance metric associated with a comparable analogue motion sensor. The RFSoC shows to give superior distance versus false detection, as the Signal-to-Noise Ratio (SNR) is better than a typical analogue system. This is mainly due to the high gain amplification requirement of an analogue system, making it susceptible to electrical noise appearing in the intermediate-frequency (IF) baseband. The proposed RFSoC-based Doppler sensor shows how digital technology can replace traditional analogue radio frequency (RF). A case study is presented showing how we can use a novel method of using multiple Doppler channels to provide range discrimination, which can be performed in both analogue and in a digital implementation (RFSoC).

A high gain and low noise instrument amplifier

A high gain and low noise instrument amplifier

Moving Real-Target Imaging of a Beam-Broaden ISAL Based on Orthogonal Polarization Receiver and Along-Track Interferometry

In response to the application requirement of wide-range high-resolution imaging of non-cooperative moving real targets by inverse synthetic-aperture ladar (ISAL), experiments were conducted on the depolarization effect of target materials, and the polarization selection of ISAL receiving and transmitting channels was discussed. Considering the impact of target depolarization and the demand for along-track interferometry, combined with beam-broaden and high-gain amplifiers, an ISAL system design method that can stably image multiple non-cooperative real targets has been proposed. Under the condition of broadening the transmitting and receiving beams to 3° in the elevation direction for non-cooperative moving vehicles, echo data with a duration of 1 s is obtained. The spatial correlation algorithm combined with along-track interferometry is used to estimate the vibration phase error. The sub-aperture Range-Doppler algorithm is used for imaging. The ISAL imaging results of the moving vehicle validated the high-resolution imaging ability of ISAL and its potential for stable imaging of non-cooperative moving real targets.

High-Resolution Drift Tube Ion Mobility Spectrometer with Ultra-Fast Polarity Switching.

Besides safety and security applications, ion mobility spectrometry (IMS) is increasingly used in other fields such as medicine, environmental monitoring and food quality analysis. However, some applications require gas chromatographic separation before analysis by IMS. Furthermore, different compounds in the sample may form positive or negative ions during ionization and therefore simultaneous detection of both ion polarities is highly beneficial to avoid two chromatographic runs of the same sample. This can be achieved by ultra-fast polarity switching of a single drift tube IMS, allowing for quasi-simultaneous detection of both ion polarities. By using a ramped aperture voltage during the switching process, we overcome the issue of excessive displacement currents at the detector during polarity switching, which usually lead to overdriving the output signal of the high-gain transimpedance amplifier. Furthermore, mechanical aperture grid oscillations caused by polarity switching were also reduced through the ramped aperture voltage. This enables a polarity switching time of only 7 ms at a drift voltage of 8 kV and a drift length of 103 mm, leading to a high resolving power of RP = 117. Requiring 50 ms to acquire a pair of positive and negative spectrum, the IMS achieves an acquisition rate of 20 Hz. It reaches limits of detection of 20 pptv for dimethyl methylphosphonate and 40 pptv for methyl salicylate. For demonstration, different hop varieties were investigated and could be clearly differentiated by considering both, the positive and negative spectra.

A V-Band Wideband Power Amplifier with High Gain in a 130 nm SiGe BiCMOS Process.

This paper introduces a high-gain wideband power amplifier (PA) designed for V-band applications, operating across 52 to 65 GHz. The proposed PA design employs a combination of techniques, including pole-gain distribution, base-capacitive peaking, and the parallel configuration of multiple small-sized transistors. These strategies enable significant bandwidth extension while maintaining high gain, substantial output power, and a compact footprint. A two-stage PA using the combination technique was developed and fabricated in a 130 nm SiGe BiCMOS process. The PA prototype achieved a peak gain of 27.3 dB at 64 GHz, with a 3 dB bandwidth exceeding 13 GHz and a fractional bandwidth greater than 22.2%. It delivered a maximum saturated output power of 19.7 dBm and an output 1 dB compression point of 18 dBm. Moreover, the PA chip occupied a total silicon area of 0.57 mm2, including all testing pads with a compact core size of 0.198 mm2.

A Low Mismatch Current Charge Pump Applied to Phase-Locked Loops.

This paper presents a charge pump circuit with a wide output range and low current mismatch applied to phase-locked loops. In this designed structure, T-shaped analog switches are adopted to suppress the non-ideal effects of clock feedthrough, switching time mismatch, and charge injection. A source follower and current splitting circuits are proposed to improve the matching accuracy of the charging and discharging currents and reduce the current mismatch rate. A rail-to-rail high-gain amplifier with a negative feedback connection is introduced to suppress the charge-sharing effect of the charge pump. A cascode current mirror with a high output impedance is used to provide the charge and discharge currents for the charge pump, which not only improves the current accuracy of the charge pump but also increases the output voltage range. The proposed charge pump is designed and simulated based on a 65 nm CMOS process. The results show that when the power supply voltage is 1.2 V, the output current of the charge pump is 100 μA, the output voltage is in the range of 0.2~1 V, and the maximum current mismatch rate and current variation rate are only 0.21% and 1.4%, respectively.

Modeling optimization design and amplification characteristics of O-band irregular Bragg bismuth-doped fiber amplifier

In recent years, O-band bismuth-doped fiber amplifier (BDFA) have been rapidly developed due to the fluorescence properties of bismuth-doped glass in the near-infrared (NIR) band, while there are still few studies on bismuth-doped fibers (BDF) with large mode fields as of now. In addition, although the use of a double-pass structure on the amplifier can lead to gain improvement, this also deteriorates the noise figure (NF). Therefore, the study of bismuth-doped fibers with large mode-field areas is a promising path to develop high-performance BDFA. In this work, taking a commercial bismuth-doped fiber as an instance, we first measured the refractive index distribution of the BDF in the O-band using a self-developed fiber refractive index tester, and thereby obtained its actual mode-field area. Then, based on this we further propose an irregular Bragg bismuth-doped fiber with the refractive index growing layer by layer. The results suggests that the effective mode-field area of this fiber reaches 401 um2 at 1320 nm, which is nearly 5.8 times that of a common single-mode BDF. Finally, we performed numerical simulations of the amplification performance based on this fiber. Under the condition of total pumping power of 8 W, the signal with −20 dBm input power obtains a gain of more than 54 dB and an NF of less than 5 dB at 1320 nm wavelength. This work demonstrates the great potential of this Bragg bismuth-doped fiber as an O-band high-gain amplifier and high-power laser.

An offset calibration scheme for on-chip thermal profiling with differential temperature sensors

This paper introduces an on-chip analog calibration method tailored for differential temperature sensors in thermal monitoring applications. A three-step calibration process is proposed within a two-stage high-gain instrumentation amplifier to compensate for the output voltage offset due to device mismatches and on-chip temperature gradients. The calibration circuits were designed in a standard 65 nm CMOS process for simulation. Results indicate that an input-referred offset with a mean of 0.2 μV can be achieved after calibration, through which the standard deviation is greatly reduced from σ = 880.3 to σ = 5086 μV. Furthermore, the proposed analog offset calibration scheme has negligible impact on the sensitivity of the complete temperature sensor circuit, as shown by Monte Carlo and process-temperature corner simulation results.

Design of high gain MMIC amplifier for LEO satellite communication systems

In this paper, we present a novel design of S-band monolithic microwave integrated circuit (MMIC) amplifier based on GaAs Mesfet HFET-1102 transistor used in radiofrequency (RF) and microwave communications system. Basing on Chebyshev gain response an analytical method is used to design two stages lumped microwave amplifier. The matching networks constituted by lumped elements are transformed to T inductive networks and the resulting amplifier is optimized using RF simulator software. Thelumped optimized amplifier is then transformed to distributed amplifier and implemented on Rogers TMM3 substrate, largely used in microwave circuits. The proposed MMIC distributed amplifier is stable in the frequency band (2–4 GHz) and excellent performances are obtained in terms of very high gain reaching a peak of 34.23 dB, minimum input return loss (S11) of −8.85 dB at f=2.62 GHz, minimum output return loss (S22) of −12.21 dB at f=2.05 GHz and very good output/input isolation (S12) lower than −51.99 dB. For its excellent performances, the proposed MMIC distributed amplifier, is very suitable for use in space telecommunications as in Low Earth Orbit (LEO) satellites onboard receivers where the high gain amplifier is very important to assure the success of the space missions.

Peripheral circuits for ideal performance of a traveling-wave parametric amplifier

We investigate the peripheral circuits required to enable ideal performance for a high-gain traveling-wave parametric amplifier (TWPA) based on three-wave mixing . By embedding the TWPA in a network of superconducting diplexers, hybrid couplers, and impedance matching networks, the amplifier can deliver a high stable gain with near-quantum-limited noise performance, with suppressed gain ripples, while eliminating the reflections of the signal, the idler and the pump as well as the transmission of all unwanted tones. We also demonstrate a configuration where the amplifier can isolate. We call this technique (WIF). The theory is supported by simulations that predict over 20 dB gain in the 4–8 GHz band with 10 dB isolation for a single amplifier and 30 dB isolation for two cascaded amplifiers. We demonstrate how the WIF-TWPAs can be used to construct controllable isolators with over 40 dB isolation over the full 4–8 GHz band. Finally, we look at nonidealities and show how certain nonidealities can be devastating for both the gain and the idler filtering, especially a cutoff imbalance or a flux imbalance, and discuss how to compensate for them. Published by the American Physical Society 2024

A Fast and Cost-Effective Calibration Strategy of Inter-Stage Residual Amplification Errors for Cyclic-Pipelined ADCs

Due to nonideal residue amplification, the limited resolution of pipelined analog-to-digital converters (ADCs) has become a popular research topic for ADC designers. High-gain and high-speed amplifiers usually consume too much power for a decent ADC. Hence, this paper proposes a fast and cost-effective foreground calibration strategy for cyclic-pipelined ADCs. The calibration strategy compensates for the gain error due to inter-stage residual amplification, which alleviates the DC gain requirement for internal amplifiers. Unlike other digital calibrations, the proposed scheme is implemented with a cyclic-pipelined structure, and only one parameter needs to be calibrated, whose value can be feasibly calculated by the Fix-Point Iteration algorithm. The proposed calibration scheme is implemented in an area-efficient 16-bit, 2 MS/s cyclic-pipelined ADC, fabricated in 180 nm CMOS technology. The ADC is designed and realized by cycling a 6-bit sub-ADC four times with 1-bit redundancy each time. The calibration algorithm manages to recover the sampled data to 93.85 dB spurious free dynamic range (SFDR) even with a 57.8 dB-DC-gain amplifier. The total power consumption of ADC is 17.92 mW and it occupies an active area of 1.8 mm2.

High-gain ultra-wideband bismuth-doped fiber amplifier operating in the O + E + S band.

We present a double-pass bismuth (Bi)-doped fiber amplifier (BDFA) providing high-gain wideband amplification from 1330 to 1480 nm. A peak gain of 38 dB with 4.7 dB noise figure (NF) was obtained at 1420 nm for a -23 dBm input signal, with >20 dB gain from 1335 to 1475 nm. We achieved 30 and 21.5 dB peak gains with 122 nm (1341-1463 nm) and 140 nm (1333-1473 nm) 6 dB-gain bandwidth for -10 and 0 dBm input signal, respectively. For a 0 dBm signal, the power conversion efficiency (PCE) reached 23.7%, and the in-band optical-signal-to-noise ratio (OSNR) across the wideband BDFA was >44 dB. Also, the absorption and luminescence characteristics have been studied for different Bi-doped phosphosilicate fibers (BPSFs) fabricated in-house.

A high-gain high-drive operational amplifier

Abstract This paper presents a high-gain, high-drive operational amplifier based on the 0.18 μm technology. The first stage employs a current-reuse common-source common-gate structure to enhance gain, while the second stage utilizes a transconductance-enhanced push-pull output stage. This design achieves high-drive performance while retaining a high gain. Simulation using Cadence software demonstrates that, under a 5 V power supply voltage, the amplifier exhibits a low-frequency gain of 120 dB, with output sink and source current capabilities reaching 17.7 mA and 2.53 mA, respectively.

Design of a Compact 2-6 GHz High-Efficiency and High-Gain GaN Power Amplifier.

In this paper, a novel wideband power amplifier (PA) operating in the 2-6 GHz frequency range is presented. The proposed PA design utilizes a combination technique consisting of a distributed equalization technique, multiplexing the power supply network and matching network technique, an LR dissipative structure, and an RC stability network technique to achieve significant bandwidth while maintaining superior gain flatness, high efficiency, high gain, and compact size. For verification, a three-stage PA using the combination technique is designed and implemented in a 0.25 μm GaN high-electron-mobility transistor (HEMT) process. The fabricated prototype demonstrates a saturated output power of 4 W, a power gain of 21 dB, a gain flatness of ±0.6 dB, a power-added efficiency of 39-46%, and a fractional bandwidth of 100% under the operating conditions of drain voltage 28 V (continuous wave) and gate voltage -2.6 V. Moreover, the chip occupies a compact size of only 2.51 mm × 1.97 mm.

A 2–20-GHz Ultrawideband High-Gain Low-Noise Amplifier With Enhanced Stability

A 2–20-GHz Ultrawideband High-Gain Low-Noise Amplifier With Enhanced Stability

A 26-28 GHz, Two-Stage, Low-Noise Amplifier for Fifth-Generation Radio Frequency and Millimeter-Wave Applications.

This paper presents a high-gain low-noise amplifier (LNA) operating at the 5G mm-wave band. The full design combines two conventional cascode stages: common base (CB) and common emitter (CS). The design technique reduces the miller effect and uses low-voltage supply and low-current-density transistors to simultaneously achieve high gain and low noise figures (NFs). The two-stage LNA topology is analyzed and designed using 0.25 µm SiGe BiCMOS process technology from NXP semiconductors. The measured circuit shows a small signal gain at 26 GHz of 26 dB with a gain error below 1 dB on the entire frequency band (26-28 GHz). The measured average NF is 3.84 dB, demonstrated over the full frequency band under 15 mA current consumption per stage, supplied with a voltage of 3.3 V.

Total net-rate of 27.88 Tb/s full C-band transmission over 4,550 km using 150 km span length and high-gain EDFA amplification

We experimentally demonstrate a total net-rate of 27.88 Tb/s for C-band wavelength-division multiplexing (WDM) transmission over an ultralong span-length of 150 km. It is the largest net capacity × span-length product of 4182 Tb/s·km for C-band, single-core, standard single-mode optical fiber transmission over a length of more than 3,000 km. A total of 99 channels, spaced at 50 GHz intervals, are employed for transmitting 32 GBaud probabilistically constellation-shaped (PCS) 64QAM signals with an information entropy of 5.5. High gain amplifiers can achieve wavelength-division multiplexing (WDM) transmission with a bandwidth of 6.25 THz, at a noise figure below 4.3 dB, without the assistance of distributed Raman amplification.

Investigating the effects of sum-frequency conversions and surface impedance uniformity in traveling wave superconducting parametric amplifiers

Traveling wave parametric amplifiers (TWPAs) offer the most promising solution for high gain, broadband, and quantum noise limited amplification at microwave frequencies. Experimental realization of TWPAs has proved challenging with often major discrepancies between the theoretically predicted and the measured gain performance of the devices. Here, we extend the conventional modeling techniques to account for spatial variation in the surface impedance of the thin film and the parametric sum-frequency conversions effect, which subsequently results in accurate reproduction of experimental device behavior. We further show that such an analysis may be critical to ensure fabricated TWPAs can operate as designed.

Design, Simulation and Comparative Analysis of Two Stage Operational Amplifier Based on CNTFETs Using Indirect Feedback Frequency Compensation

In the course of this study, an efficient implementation of a high gain and low power two-stage operational amplifier using indirect feedback frequency compensation based on CNTFETs. HSPICE software was used to develop and simulate CNTFETs. The op-amps were designed using 0.9[Formula: see text]V input supply voltage. The proposed structures were formed either using CNTFETs only known as pure CNTFET-IFFC-2SOA or hybrid structures consisting a mix of both CNTFETs and conventional CMOS named as PCNTFET-NMOS-IFFC-2SOA and NCNTFET-PMOS-2SOA. The comparative investigation revealed that CNT-based structures performed significantly better than the traditional CMOS-based devices. In the instance of CNTFET-IFFC-2SOA, there was a considerable improvement in DC gain, power dissipation, phase margin, and CMRR. The DC Gain increased by 140.92%, the CMRR increased by 32.94%, and the phase margin increased by 4.9%. Furthermore, at the 32[Formula: see text]nm technology node, a GNRFET-based structure was designed and compared to conventional CMOS and pure CNTFET-based IFFC-2SOA. It was discovered that the DC gain, phase margin, and power dissipation obtained by the CNTFET-based structure were superior to both. The DC Gain of CNTFET-IFFC-2SOA was 156.79% more than that of GNRFET-IFFC-2SOA. To confirm the workability of the proposed circuits, an integrator was designed and simulated as its application. The CNTFET-based IFFC-2SOA integrators showed better integration action than the traditional CMOS-IFFC-2SOA.