Gain Tuning Research Articles

A Sub-GHz Low-Power Receiver Employing Resistive-Feedback-Tuned LNA With 2.1-dB NF and 106-dB Gain Tuning Range

This letter presents a configurable sub-GHz low-power receiver achieving a low noise figure (NF) and a large gain tuning range. An inverter-based low-noise amplifier (LNA) with a resistive-feedback-tuning technique is realized to achieve low power and optimize NF while tuning the gain level. Implemented in 130-nm CMOS technology, this receiver occupies an active area of 2.3 mm2. It achieves a low power of 3.63 mW over a large gain tuning range of 106 dB in 6 dB steps. It also achieves a low NF of 2.1 dB and an image rejection ratio (IRR) of over 37.1 dB.

A New Robust Integral Reinforcement Learning Based Control Algorithm for Interleaved DC/DC Boost Converter

This article proposes a novel online integral reinforcement learning (IRL) based data-driven control algorithm for interleaved dc/dc boost converter. The proposed algorithm is independent of system model due to the usage of a three-layer neural network (NN). Furthermore, its controller gains are autonomously adjusted online through the value function based NN weights updating mechanism, which simplifies the controller gain tuning process. Compared to the conventional model-dependent control approaches, it provides superior control performance. Additionally, the proposed method contributes to significantly reduce the computational burden of classical IRL algorithm by removing the disturbance updating process. Experimental results are presented to verify the efficacy of the proposed algorithm.

Kinetics of Metastable Argon Optical Excitation and Gain in Ar/He Microplasmas.

The optically pumped rare-gas metastable laser is capable of high-intensity lasing on a broad range of near-infrared transitions for excited-state rare gas atoms (Ar*, Kr*, Ne*, Xe*) diluted in flowing He. The lasing action is generated by photoexcitation of the metastable atom to an upper state, followed by collisional energy transfer with He to a neighboring state and lasing back to the metastable state. The metastables are generated in a high-efficiency electric discharge at pressures of ∼0.4 to 1 atm. The diode-pumped rare-gas laser (DPRGL) is a chemically inert analogue to diode-pumped alkali laser (DPAL) systems, with similar optical and power scaling characteristics for high-energy laser applications. We used a continuous-wave linear microplasma array in Ar/He mixtures to produce Ar(1s5) (Paschen notation) metastables at number densities exceeding 1013 cm-3. The gain medium was optically pumped by both a narrow-line 1 W titanium-sapphire laser and a 30 W diode laser. Tunable diode laser absorption and gain spectroscopy determined Ar(1s5) number densities and small-signal gains up to ∼2.5 cm-1. Continuous-wave lasing was observed using the diode pump laser. The results were analyzed with a steady-state kinetics model relating the gain and the Ar(1s5) number density.

Controller Design in <i>αβ</i> domain for Grid-Forming Inverters by Complex Vector Theory

Grid-forming inverter control plays an important role in ensuring frequency and voltage stability in a microgrid (MG). This paper proposes a novel power and voltage control in the αβ domain. The proposed method includes two control loops; an outer loop for power droop control and an inner loop for output voltage control. With the proposed controller, active and reactive powers can be controlled according to simple complex power control principles described only in the αβ-domain. Controller gain tuning for both the outer droop and the inner voltage regulator is also proposed; the droop control gains are tuned based on transfer functions around an operating point and the voltage regulator is tuned by a linear quadratic regulator (LQR). The proposed control method is investigated and validated by simulations with a C control program and by experiments with a DSP-based digital control system.

Novel tunable current feedback instrumentation amplifier based on BBFC OP-AMP for biomedical applications with low power and high CMRR

The paper presents a novel low power, low noise and high CMRR current feedback instrumentation amplifier (CFIA) design for biomedical signal acquisition i.e. EEG/ECG applications is presented. The proposed instrumentation amplifier performance is evaluated using 0.18μm, CMOS technology with 1.8 V supply and results are obtained in Cadence EDA tool. The proposed CFIA is implemented using a dual output bandwidth boosted folded cascode operational amplifier (BBFC OP-AMP) active block. In this paper the proposed CFIA performance parameters has been considered for optimization to get better results by using the idea of signal to noise ratio (SNR) with Taguchi design of experiments (Taguchi DoE) and analysis of variance (ANOVA) to estimate the most important independent variable which control the performance of the design. The bias voltage, channel length and width of input MOS transistors have been selected to optimize the proposed circuit performance. The proposed CFIA structure have 50.33 to 69.67 dB tunable differential gain, common mode rejection ratio (CMRR) of 143.19 dB, tunable bandwidth of 148.24 kHz to 1.31 MHz, dynamic range (DR) of 74.31 dB and 297.73 dB of figure of merit (FoM). The CFIA shows an equivalent input referred noise (IRN) of 0.586 μV at 0.1 Hz to 148.24 kHz frequency range, with total power dissipation of 102.73 μW and occupies 8194μm2 of core area. The simulation results of the proposed CFIA are close to the predicted solution obtained from ANOVA. The PVT analysis and post layout simulation has been performed to check the robustness of the proposed design. The proposed design has been compared with the other existing literature which shows the competence of the design.

A 27–43 GHz CMOS Body-Biased Digital Current-Steering VGA With 4 Bit and Low Phase Shift

This letter presents a broadband digital-controlled variable gain amplifier (VGA) on 65-nm CMOS process. A body-biased digital current-steering topology is proposed to enlarge the gain control range (GCR) of the VGA under low supply voltage. For phased-array applications, a phase compensation network is added to minimize the phase shift during the gain tuning. The proposed VGA achieves a small-signal gain of 16.3/16.1 dB at 28/38 GHz with a 3-dB gain bandwidth from 25.5 to 46 GHz. The measured phase variation is 2.32°/4.8° with a GCR of 8.7/8.4 dB at 28/38 GHz. The phase variation of the VGA is less than 5° and the rms phase error is less than 1.46° over a wide frequency band of 27–43 GHz covering multiple 5G bands.

A 120 MHz fast automatic tuning CMOS active-RC lowpass filter

In this paper, a fast automatic cutoff frequency calibrating, CMOS lowpass filter with linear-in-dB tunable gain and constant in-band group delay is presented. The automatic frequency tuning (AFT) circuit can successfully tune the cutoff frequency to 120 MHz with less than 4.7% error. In-band group delay variation is handled using a capacitor process variation detection circuit (CPVD), and the overall tuning time is less than 700 ns. The design is done using STM PD-SOI 130 nm CMOS process, and the supply voltage is 1.2 V with a total power consumption of 21.7 mW. The overall filter provides a programmable linear-in-dB gain of 0.5 dB to 17.6 dB range with a cutoff tuning range of 80 to 180 MHz. The in-band group delay variation is below 500 ps with an adjacent channel ratio (ACR) of 85 dB. The spurious free dynamic range (SFDR) is over 66.6 dBc. The active area of the filter with tuning is 0.171 mm2.

Efficient diffraction control using a tunable active-Raman gain medium

We present a scheme to create an all-optical tunable and lossless waveguide using a controllable coherent Raman process in an atomic rubidium vapor in an $\mathcal{N}$-type configuration. We employ a Gaussian Raman field and a Laguerre-Gaussian control field to imprint a high-contrast tunable waveguidelike feature inside the atomic medium. We numerically demonstrate that such a waveguide is able to guide arbitrary modes of a weak probe beam to several Rayleigh lengths without diffraction and absorption. Our results on an all-optical waveguide-based scheme may have potential applications in lossless image processing, high-contrast biomedical imaging, and image metrology.

In-Line Vector Modulator Integration in Dielectric-Filled Waveguide

This paper proposes a scalable substrate-integrated waveguide (SIW) module accommodating an in-line vector modulator monolithic millimeter integrated circuit (MMIC). The SIW module is realized with low-temperature co-fired ceramic (LTCC) technology, and it can be inserted in a dielectric-filled waveguide (DFWG). The module combines λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>g</i></sub> /4-transformer-based E-plane tapering and SIWs on LTCC with the wire-bonded vector modulator. The proposed active LTCC module and two passive test structures (i.e., a constant-height-SIW module and a SIW module with E-plane taperings) are manufactured and tested as in-line modules in a DFWG. The passive test structures with the waveguide-to-DFWG and DFWG-to-SIW transitions measure 3.1 dB and 4.6 dB of insertion loss on average, respectively, at the 71–81 GHz frequency range. The active LTCC module measurements demonstrate a dielectric-filled waveguide with phase and amplitude tuning capability and gain up to 17.6 dB within the same frequency range. A four-channel mock-up module with λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> /2 channel spacing is designed and manufactured to demonstrate the scalability of the design.

Tunable virtual gain in resonantly absorbing media

Virtual gain refers to the simulation of real light amplification using radiation with exponentially decaying amplitude, so that its complex frequency corresponds to the scattering pole. We theoretically study virtual gain in a two-level resonant medium for different regimes of light-matter interaction depending on the radiation intensity. We show that virtual gain at the pole can be most clearly observed for low intensities, when the medium is absorbing, in contrast to the saturated medium at high intensities. The efficiency of virtual gain can be tuned with the light intensity and can be controlled dynamically through the population inversion of the medium. Our results show that resonantly absorbing media paradoxically mimics gain-like response, which admit a number of related phenomena and methods to mold both optical signals and material properties without relying on instability-prone gain media.

On adaptive attitude tracking control of spacecraft: A reinforcement learning based gain tuning way with guaranteed performance

This paper investigates the attitude tracking control problem of a rigid spacecraft subject to inertial uncertainties, uncertain space perturbations and actuator saturation. Firstly, a static inertial-matrix free attitude controller is designed to guarantee the appointed-time convergence and tracking accuracy indicators of the spacecraft. Then, two-layer critic-action NNs are used to tune and optimize the control gains adaptively to improve the robustness and tracking performance of the devised static attitude controller via exploring the reinforcement learning (RL) technique. Compared with the existing attitude control methods, the prominent advantage of our work is that the devised controller is inertial-matrix free with a simple RL-based adaptive parameter tuning scheme, which reduces the conservativeness of the traditional attitude controllers with fixed control gains and is also easy to be achieved. Finally, two groups of illustrative examples are organized to validate the effectiveness of the proposed attitude control method.

Improving gain of real time PI controller using particle swarm optimization in active power filter

This paper incorporates the PSO based PI control for systematic switching function of APF topology. The proportional and integral (PI) gain tuning of active power filter (APF) using the particle swam optimization (PSO) method for reactive power compensation and harmonics mitigation. A conventional PI controller required more computation time and has less accuracy. The harmonic load currents are extracted using an instantaneous real and reactive power scheme. The performance indices including total harmonic distortion, reactive power, power factor and capacitor voltage regulation using PSO trained PI controller is compared with convention PI controller. PSO has quick convergence, minimal adjusting parameters and fast execution to solve non-linear problems. The traditional PI controller is substituted by an online PSO trained PI controller for the objectives of enhancing the dc voltage tracking in APF under non-linear load conditions. The proposed work is developed in sim-power system tool box which is a software package in Matlab/ Simulink.

Multiagent LQR-based Control Design and Gain tuning for Quadcopters Fleet

An LQR-based Control design and gain tuning strategies proposals for a multi-agent system are presented in this article, the agents are connected in an undirected graph. Controller gains tuning are adjusted by selecting the Q and R weighting matrices of the Linear Quadratic Regulator. Agreement (consensus) is one of the fundamental problems in multi-agent control, where a set of agents must agree on a joint state value. In the proposed design, first considering that the behavior of the agreement protocol is undirected and static, the main objective is to highlight the complexity of the relationship between the convergence properties of this protocol and the structure of adjacent interconnections. The effects on the formation due to static geometry are analyzed from the resulting data according to the proximity between the agents, where behavior and stability are analyzed based on the desired formation geometry through the construction of the Laplacian matrix.

Optimization Reinforced PID-Sliding Mode Controller for Rotary Inverted Pendulum

The control of a rotary inverted pendulum (RIP) is challenging because it is an underactuated, highly sensitive, and unsteady system. Sliding mode control (SMC) is a nonlinear control method with high-frequency switching control. Designing a proportional integral derivative (PID) controller for a RIP is challenging due to its nonlinearity and instability in open-loop characteristics. The primacy of the SMC over the PID is the stability of the closed-loop. Hybrid control of a PID-SMC controller can provide better performance because this technique demonstrates less chatter, higher precision, no oscillation, and adequate gain tuning. To achieve gain tuning, the PID and SMC parameters must be optimized. Thus, this paper proposed a congruently tuned control strategy (CTCS) to fine-tune the controller parameters. The proposed strategy uses an improved whale optimization algorithm (WOA), i.e., the modified Manhattan distance updated WOA (MMD-WOA) to identify effective coefficient values for the sliding surface to reduce tracking errors while reaching the desired position. The proposed CTCS for a RIP with the MMD-WOA was implemented, and the results are very promising.

Output feedback finite-time stabilization of a class of large-scale high-order nonlinear stochastic feedforward systems

This paper considers the output feedback finite-time stabilization in probability for a class of large-scale high-order stochastic nonlinear feedforward systems. The output feedback finite-time stabilized controller in probability is firstly designed for the nominal systems by the adding one power integrator. Then with the homogeneous domination method, by introducing an appropriate coordination, an equivalent system of the original system with tunable gain is obtained. After that, by constructing a observer and determining the tunable gains, the output feedback stabilized controller in probability of the original systems is finally given and analysed.

A K-Band Hybrid-Packaged Temperature-Compensated Phased-Array Receiver and Integrated Antenna Array

This article presents an eight-channel 1.9-dB noise figure (NF) <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$K$ </tex-math></inline-formula> -band phased-array receiver (RX) for satellite communication (SATCOM). It employs the hybrid-packaged 65-nm CMOS beamformer and 0.1- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> GaAs low-noise amplifiers (LNAs) based on the fan-out wafer-level chip-scale packaging (WLCSP) technology. For the power-efficient RX implementation, the power consumption of gain and phase tuning blocks is discussed, and the fully passive phase shifter (PS) and attenuator (ATT) are employed in this work. A global biasing scheme is proposed to ensure performance uniformity across temperature variations. Across the SATCOM band of 17.7–20.2 GHz, the proposed hybrid-packaged phased-array RX IC only consumes 30.2-mW dc power per channel and achieves < 1.2-dB gain variation and < 0.9-dB NF variation from −40° to 85 °C. Based on the RX IC, a dual-polarized 1024-element RX antenna array is further introduced. The measured gain-to-noise temperature ratios (G/Ts) are 6.22 and 6.51 dB/K at 19.7 GHz for left- and right-hand circular polarizations, respectively.

Online Learning Based Mobile Robot Controller Adaptation for Slip Reduction

Slip is a very common phenomena present in wheeled mobile robotic systems. It has undesirable consequences such as wasting energy and impeding system stability. To tackle the challenge of mobile robot trajectory tracking under slippery conditions, we propose a hierarchical framework that learns and adapts gains of the tracking controllers simultaneously online. Concretely, a reinforcement learning (RL) module is used to auto-tune parameters in a lateral predictive controller and a longitudinal speed PID controller. Experiments show the necessity of simultaneous gain tuning, and have demonstrated that our online framework outperforms the best baseline controller using fixed gains. By utilizing online gain adaptation, our framework achieves robust tracking performance by rejecting slip and reducing tracking errors when the mobile robot travels through various terrains.

Improved Adaptive PSO-based Gain Tuning for PID Controllers in Utility Boilers

In this paper, the stabilization and set point tracking of the utility boiler is achieved via the Proportional-Integral-Derivative (PID) controller, tuned using the versions of metaheuristic Particle Swarm Optimization (PSO) algorithms. The utility boiler model dynamics are based on the Bell and Astrom boiler turbine system. Initially, the non-linear mathematical model is obtained using the first principles data from the plant model. Further, Taylor series approximation is applied to linearize the non-linear equations around the equilibrium point to implement a stable controller for the plant. Finally, the PID controller gains for the plant model are determined using the PSO algorithms to achieve the desired response. For tuning the PID controller, three PSO algorithms namely standard PSO, Adaptive PSO (APSO) and Improved Adaptive PSO (IAPSO) are proposed. The performance of the proposed PSO based PID control algorithms are evaluated using error metrics such as Integral Absolute Error (IAE), Integral Time Absolute Error (ITAE) and Integral Square Error (ISE). The simulation results show that the proposed APSO and IAPSO algorithms have improved performance when compared to regular PSO algorithms and are capable of optimizing the control parameters.

Towards Gain Tuning for Numerical KKL Observers

This paper presents a first step towards tuning observers for general nonlinear systems. Relying on recent results around Kazantzis-Kravaris/Luenberger (KKL) observers, we propose an empirical criterion to guide the calibration off the observer, by trading of transient performance and sensitivity to measurement noise. We parametrize the gain matrix and evaluate this criterion over a family of observers for different parameter values. We then use neural networks to learn the mapping between the observer and the nonlinear system, and present a novel method to sample the state-space efficiently for nonlinear regression. We illustrate the merits of this approach in numerical simulations.

A 60-MHz Silicon Carbide Voltage-Controlled Oscillator for Extreme Temperature Applications

In this brief, a custom-built silicon carbide (SiC) junction field-effect transistor (JFET) is characterized from room temperature to 52°C, and a 60 MHz voltage-controlled oscillator (VCO) based on this SiC JFET is designed and fabricated through low temperature co-fired ceramic (LTCC) process. The test results of the VCO prototype demonstrate that the proposed SiC JFET VCO is capable of operating from 25 °C to 500 °C. RF signal of 50dB above the noise floor is generated, and the tuning gain of 9.22 kHz/V is achieved at 500 °C. The proposed SiC JFET VCO can serve as the fundamental building block for wireless sensing or data communication in extreme temperature industrial and space applications.