High-bandwidth Design Research Articles

Application Of High Bandwidth Two-Stage Amplifier in Communication System

With the rapid development of communication technology, the application of high-bandwidth amplifiers in communication systems becomes more and more important. Currently researchers have applied high bandwidth two-stage amplifier technology in many fields such as cloud computing and data centers, video and audio transmission, virtual reality and augmented reality, Internet of Things, financial transactions, etc., and in this paper we will focus on its application in communication systems. In this paper, the basic principle and structure of two-stage amplifier are firstly described, and then the key theories of high-bandwidth technology including its concept, importance, principle and core technology of high-bandwidth design technology as well as stability analysis and design are elaborated, and the applications of high-bandwidth two-stage amplifiers in wireless communication system, fiber optic communication system, data center network, and satellite communication are enumerated. In summary, high-bandwidth two-stage amplifiers play a key role in a variety of communication systems, helping to provide stable, high-speed, long-range signal transmission. Through the research of this thesis, it is expected to provide new references and ideas for the research and development in the field of communication technology, and to promote the progress and innovation of communication system.

Enhanced Small-Signal Modeling for Charge-Controlled Resonant Converters

Charge control for resonant converters introduces an inner feedback loop that improves the system dynamic characteristics. However, small-signal modeling is not as straightforward with charge-controlled resonant converters as it is with current mode hard-switching topologies, due to the nature of resonant behavior. Conventional small-signal models for charge-controlled resonant converters are developed based on the converter input and output energy balance. This simplified approach overlooks the dynamics of the magnetizing inductor current and generates errors in small-signal frequency response. To improve the analytical model and enable high-bandwidth design, this article proposes a new methodology for modeling charge-controlled resonant converters. The energy stored in the resonant tank is analyzed using the theory of extended describing function, which accounts for the effect of the magnetizing current. This methodology applies to a wide range of charge control variants, such as bang-bang charge control and hybrid-hysteretic control. To demonstrate the modeling procedure, this article considers a high-order, five resonant-component half-bridge CLLC resonant converter as a case study. The proposed analytical model is applied to a 1 kW, 400-V/3.3-A power supply prototype for simulation and experimental validation. The proposed model successfully predicts the frequency response of the resonant converter across frequency and load conditions, providing rapid frequency-domain evaluation in the design process.

An Efficient High-Throughput LZ77-Based Decompressor in Reconfigurable Logic

To best leverage high-bandwidth storage and network technologies requires an improvement in the speed at which we can decompress data. We present a “refine and recycle” method applicable to LZ77-type decompressors that enables efficient high-bandwidth designs and present an implementation in reconfigurable logic. The method refines the write commands (for literal tokens) and read commands (for copy tokens) to a set of commands that target a single bank of block ram, and rather than performing all the dependency calculations saves logic by recycling (read) commands that return with an invalid result. A single “Snappy” decompressor implemented in reconfigurable logic leveraging this method is capable of processing multiple literal or copy tokens per cycle and achieves up to 7.2GB/s, which can keep pace with an NVMe device. The proposed method is about an order of magnitude faster and an order of magnitude more power efficient than a state-of-the-art single-core software implementation. The logic and block ram resources required by the decompressor are sufficiently low so that a set of these decompressors can be implemented on a single FPGA of reasonable size to keep up with the bandwidth provided by the most recent interface technologies.

State-Trajectory Control With Single-Cycle Response for Point-of-Load Converters

A popular variable-frequency control used for point-of-load (POL) converter application is the constant on-time (COT) control. COT control is able to improve light-load efficiency and reduce the amount of output capacitors with high-bandwidth designs, but the transient response of COT control is limited by the fixed on-time nature of the control. In this paper, a state-trajectory-based control with single-cycle transient response is proposed for POL converters. With the proposed control, the converter will follow the natural state trajectory of the converter for the duration of the detected load step-up transient, which can ensure a very fast transient response. Experimental results are presented to not only demonstrate the proposed idea but also the control's ability to further reduce the amount of output capacitors and save board footprint.

Design of High Gain, Bandwidth and Efficient Double Split Ring Slotted Antenna with Swastika Shape EBG Structures at 21.29GHz for High Data Rate Communications

Design of High Gain, Bandwidth and Efficient Double Split Ring Slotted Antenna with Swastika Shape EBG Structures at 21.29GHz for High Data Rate Communications

Multiple Gateway Transmit Diversity in Q/V Band Feeder Links

Design of high bandwidth and reliable feeder links are central toward provisioning new services on the user link of a multibeam satellite communication system. Toward this, utilization of the Q/V band and an exploitation of multiple gateways (GWs) as a transmit diversity measure for overcoming severe propagation effects are being considered. In this context, this contribution deals with the design of a feeder link comprising <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$N+P$</tex-math></inline-formula> GWs ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$N$</tex-math></inline-formula> active and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$P$</tex-math></inline-formula> redundant GWs). Toward provisioning the desired availability, a novel switching scheme is analyzed and practical aspects such as prediction-based switching and switching rate are discussed. Unlike most relevant works, a dynamic rain attenuation model is used to analytically derive average outage probability in the fundamental <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$1+1$</tex-math></inline-formula> GW case. Building on this result, an analysis for the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$N+P$</tex-math></inline-formula> scenario leading to a quantification of the end-to-end performance is provided. This analysis aids system sizing by illustrating the interplay between the number of active and redundant GWs on the chosen metrics: average outage and average switching rate.

Design and analysis of superstrate embedded dielectric resonator antenna

Antenna high gain, wide bandwidth, reconfigurability and compact design has been long requirements in the field of mobile communications and aeronautics. This paper experimentally investigates superstrate layer of arrays placed above the dielectric resonator antenna (DRA), which can largely enhance the gain of antenna. Experimental and simulated results of gain with and without superstrate have been investigated. The superstrate arrays placed on DRA has improved the antenna gain, i.e., 8.7 dBi to 12.27 dBi. The effect of high permittivity material has been studied for gain and bandwidth improvement. Barium strontium titanate (BaSrTio3) mixed with silicon oil was used in DRA. Superstrate array have resulted into gain improvement to the extent of 28%. The design frequency was kept at 6.59 Ghz and verified theoretically using MATLAB. Height of substrate and dielectric constant affected the gain and bandwidth. Theoretical, simulated and experimental results have been compared and found in good agreement.

High‐bandwidth design of hard disk control system using H∞ control with feedback‐type uncertainty

AbstractIn hard disk drives, it is important to enlarge the control bandwidth in order to shorten the track pitch for larger data capacity. However, it is difficult for the H∞ control method to increase the control bandwidth if the mechanical resonance modes have uncertainty. This is because the robustness of the H∞ control method is assured by the small‐gain theorem for additive or multiplicative perturbation and the control bandwidth is limited by the uncertainty. In this study, we propose an H∞ control method for high‐bandwidth design by introducing a new uncertainty model with a feedforward and a feedback path in order to reduce the conservatism of robust design. The effectiveness is shown by numerical simulations. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 173(4): 54–62, 2010; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21025

Performance Enhancement of Track-Following Control of HDD by Using Inter-Sampling Information

The sampling rate of the position error signal is limited in most hard disk drives (HDDs) by the number of sectors and the spinning speed of the disks. If inter-sampling position can be obtained, the control performance may be improved even if the quality is very low. In this paper, we discuss about high bandwidth design of feedback control system by using inter-sampling position signal with large measurement noise. The effectiveness of the proposed method is evaluated by simulations.

Elimination of Sampling-Induced Dead Bands in Multiple-Sampled Pulsewidth Modulators for DC–DC Converters

This letter presents a linearization technique for multisampled pulsewidth modulators (MSPWMs) employed in digitally controlled dc-dc converters. MSPWMs, i.e., PWMs operated at a sampling rate strictly higher than the switching frequency, greatly reduce the significant small-signal phase lag exhibited by conventional single-sampled PWMs, thus enabling for high-bandwidth design. On the other hand, the increased sampling frequency generates nonlinear phenomena known as sampling-induced dead bands, which represent zero differential gain regions in the modulator transcharacteristic that degrade the system closed-loop operation. This letter proposes a correction algorithm that allows for dead band removal, thus linearizing the PWM behavior, while still retaining the multisampling benefits. This result is achieved by a simple solution that can be easily implemented with simple hardware requirements. Simulation and experimental results on a dc-dc synchronous buck converter are provided to show the effectiveness and overall simplicity of the proposed solution.

Adaptive Modulation Control for Multiple-Phase Voltage Regulators

This letter presents an adaptive modulation control (AMC) method which has proven to be effective in achieving high bandwidth designs as well as stabilizing the control loop during large load transients. The AMC adaptively adjusts control bandwidth by changing the modulation gain, depending on different load conditions. With the AMC, a multiphase voltage regulator can be designed with an aggressively high bandwidth, while in heavy load transients where the loop could be potentially unstable, the bandwidth is lowered. Therefore, the AMC provides an optimal means for robust high-bandwidth design with excellent transient performance. It is a type of non-linear control designed for, but not limited to, multiphase voltage regulators with droop control. Detailed analysis of the operational mechanism is presented. Experiment results are included to verify the analysis.

フィードバック型誤差モデルを用いた&lt;i&gt;H&lt;/i&gt;&lt;sub&gt;&amp;infin;&lt;/sub&gt;制御によるハードディスク制御系の高帯域化

In hard disk drives, it is important to enlarge the control bandwidth in order to shorten the track pitch for larger data capacity. However, it is difficult for the H∞ control method to increase the control bandwidth if the mechanical resonance modes have uncertainty. This is because the robustness of the H∞ control method is assured by the small-gain theorem for additive or multiplicative perturbation and the control bandwidth is limited by the uncertainty. In this study, we propose an H∞ control method for high-bandwidth design by introducing a new uncertainty model with a feedforward and a feedback path in order to reduce the conservatism of robust design. The effectiveness is shown by numerical simulations. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 173(4): 54–62, 2010; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21025

Bandwidth Improvements for Peak-Current Controlled Voltage Regulators

To ensure the current sharing among the interleaved phases, the peak-current control is widely used in the voltage regulator (VR) applications. Meanwhile, to save the cost and footprint by reducing the output capacitance, high control bandwidths are mandatory. Because of the sample-hold effect in the peak-current loop, there exist stringent challenges to the high-bandwidth designs for VRs. In this paper, the influence from the sample-hold effect is investigated to clarify the difference between the VR and conventional applications. After that, two approaches for higher bandwidth are introduced. To decrease the phase delay due to the sample-hold related double poles, excessive external ramps are inserted to the modulators. To increase the effective sampling frequency, the phase inductor currents are coupled, either by the coupled-inductor structure or through the feedback control. In addition, a small-signal model including the sample-hold effect is derived for the coupled-inductor buck to explain the improvement. High-bandwidth designs are verified by the simulation and experimental results. A bandwidth of one-third switching frequency is demonstrated with a coupled-inductor VR.

Investigations into Hybrid Magneto-hydrodynamic (MHD) Antenna

Dielectric Resonator Antennas (DRAs) have received lots of attention in the last two decades due to several attractive characteristics such as high radiation efficiency, light weight, and low profile. There is also increasing challenges for the design of high bandwidth and multi-bands antennas which can be achieved using MHD Antennas for high speed and reconfigurable applications in wireless communication. In this work the objective is to design and develop a cylindrical MHD antenna with circular patch and two annular rings. Magneto-hydrodynamics (MHD) Antenna is a Fluid based Antenna in which the fluid resonator provides excellent coupling of RF energy into fluid. Fluid resonator volume, chemical properties, electric field and magnetic fields are the factors of resonant frequency, gain and return loss. The proposed antenna shall be tuned in the wide band of frequency range between 7.9 – 27 GHz. Simulations using HFSS and measurements have been carried out in respect of design prototype for ‘Air’ and BSTO (Barium Strontium Titanate Oxide) microwave fluid. The findings in this work that the Fluid Resonator based hybrid approach for antenna enhances the bandwidth by a large factor and annular rings with circular patch in proper geometry provides multiband operation. Variation in the volume of the fluid shifts the resonant frequency of the solid structure in the wideband. When magnetic field is applied, significant improvement has been noticed in return loss of the proposed antenna.

1133 共振特性を考慮した磁気ディスク装置の高帯域化サーボ技術

1133 共振特性を考慮した磁気ディスク装置の高帯域化サーボ技術

A high-bandwidth induction sensor coil

A description is given of an induction sensor coil, the main application of which is in low-level transient electromagnetic detection. The coil is a compact air-cored spiral design of high bandwidth with low distributed winding capacitance. The optimum signal-to-noise ratio is determined by the size of the coil and the noise voltage source of the field effect transistor (FET) used in the input preamplifier.