基于RF-BJT的超宽带极窄脉冲发生器的设计

本文简要介绍了超宽带(UWB)技术,讨论并分析了几种UWB中几种常用窄脉冲方法的特点及其局限性。基于RF-BJT雪崩特性,设计并制作了高重复速率的UWB脉冲电路发生器,获得亚纳秒级的超短、快速前沿的单极性UWB脉冲,幅度为-13.1 V,宽度为816.3 ps。     

超宽带脉冲产生电路的研究与设计

在UWB脉冲信号发生器的研制中,通过分析UWB脉冲波形的特征,以一阶高斯脉冲为设计目标,提出了一种以振荡源、储能元件和高速开关为主体的UWB脉冲产生电路系统模型,并且在实际电路中设计了不同的实现方式。利用复杂可编程器件(CPLD)为UWB脉冲发生模块设计了脉冲时序触发电路。针对脉冲的产生方案,设计了一种利用雪崩晶体管产生UWB脉冲的电路,实际测试得到了1 ns以内的窄脉冲;与此同时设计了一种基于阶跃恢复二极管的UWB脉冲发生电路,在PSpice中仿真得到了宽度约400 ps的UWB脉冲信号。仿真结果表明,PSpice建立的SRD模型符合理论分析,设计的UWB脉冲信号发生电路也完全满足在超宽带引信上使用的需求。     

一种用于UWB-TWSR的窄脉冲产生电路的设计

实现TWSR(穿墙探测雷达)技术的关键之一是如何设计并产生可以控制的UWB窄脉冲.为此,文中介绍了TWSR的基本概念及工作原理,讨论了几种UWB中常用的窄脉冲产生方法和特点;给出了一种基于RF-BJT雪崩特性的UWB窄脉冲产生电路,同时进行了仿真调试.通过该电路可获得峰值电压为-10.1 V、宽度为654.8 ps的单极性UWB窄脉冲.     

一种简易的超宽带纳秒级脉冲发生器设计

为了得到超宽带纳秒级窄脉冲信号,在对UWB脉冲产生方法分析总结的基础上,提出了一种基于数字逻辑器件的简单脉冲产生电路。对实际制做的电路进行了测试,能够得到重复频率为10 MHz,脉冲宽度约为4ns,幅度约为500mV的窄脉冲。该电路成本低,结构简单,易于制作,工程实用性较强。     

应用于超宽带穿墙雷达的极窄脉冲发生器设计

介绍了一种可用于超宽带(UWB)穿墙雷达的脉冲发生电路,讨论并分析了UWB中几种常用窄脉冲产生方法的特点及其局限性。基于雪崩三极管和射频双极性晶体管的雪崩特性,设计并制作了UWB脉冲电路发生器,指出电路中需要注意的事项及改进脉冲性能的方法,并获得亚纳秒级的超短、快速前沿的单极性UWB脉冲,幅度为28 V,宽度为0.95 ns。     

一种基于SRD和NLTL的皮秒级脉冲产生电路

提出了一种利用SRD产生窄脉冲信号的方法,对其产生窄脉冲的机理进行了分析和仿真,为了使得脉冲宽度变得更窄,电路采用了NLTL结构,拓展了SRD产生窄脉冲的应用,文中分析了NLTL的工作原理。设计了基于SRD和NLTL的皮秒级脉冲产生电路,给出了测试结果,脉冲宽度为110 ps,幅度为3 V。     

UWB over Fiber室内无线传输的实验研究

采用被动谐波锁模环形光纤激光器作为超宽带(UWB)光脉冲源,进行了UWB over Fiber室内无线传输的实验研究。利用啁啾脉冲补偿无线信道的色散效应的原理,减小脉冲的宽度,降低符号间干扰。基于被动谐波锁模、光脉冲展宽原理以及UWB光电转换、UWB脉冲放大和Bowtie孔径UWB天线技术,将光纤激光器的光脉冲转换为满足FCC(US federal communications commission)规定的UWB微波脉冲序列进行传输。使用光纤激光器、宽带光电转换器、宽带脉冲放大器和Bowtie孔径UWB天线搭建UWB无线通信系统,实现了约1.2m的UWB室内无线传输。并通过研究天线的间距,电磁干扰,光脉冲源以及衰减器和放大器对UWB室内无线传输的影响,得出了这种系统的最佳结构。对应无线传输发射端前加和不加电脉冲放大的两种情况,经过UWB室内无线传输后分别探测到高斯单周脉冲(FWHM约150ps)和高斯偶脉冲(FWHM约120ps)。     

用于激光脉冲整形的电脉冲产生技术

介绍了一种用于激光脉冲整形的超宽带脉冲产生方法.电路中利用阶跃恢复二极管(SRD)载流子可控、截止速度快的特点,采用对阶跃恢复二极管进行串并联相结合的方法设计了超宽带脉冲产生电路.给出了实际电路的测试结果,并且对实验结果在物理层面上进行了理论分析,实验结果与理论分析结果吻合.此脉冲产生电路可输出幅度约10V,脉冲宽度约...     

基于脉冲耦合的超宽带高功率电脉冲源

以固态半导体器件为基础,基于超快电子学中的晶体管雪崩导通理论,利用脉冲耦合原理,在时域上将多路高压皮秒脉冲耦合输出,获得了超宽带高功率脉冲。通过四路脉冲耦合实验验证了该设计思路的可行性,提高了输出脉冲功率。实验中,单路高压皮秒脉冲的幅度为1.33kV,宽度为770ps,峰值抖动≤1%,脉宽抖动≤1%,四路脉冲耦合后,输出脉冲幅度为2.66 kV,宽度为875 ps,峰值抖动≤1%,脉宽抖动≤1%。该方法可以推广至多路脉冲耦合,获得更高的功率。     

超宽带雷达系统中皮秒级脉冲源的研制

提出一种新型超宽带雷达高斯脉冲信号产生电路的设计方法,该电路利用微波三极管的开关特性和阶跃恢复二极管的阶跃特性,以及电容的充放电过程产生高斯脉冲信号,利用ADS软件对脉冲产生电路进行了仿真与分析。测量结果表明,该电路可以产生脉冲宽度400ps,重复频率1MHz,幅度4.1V的窄脉冲信号,且脉冲振铃很小,与仿真结果基本吻合,从而验证了该方法的合理性。该电路通过调节充放电电容的值实现脉冲幅度可调,当重复频率提高至10 MHz时,可得到3V～8V的幅度可调皮秒级高斯脉冲。该脉冲源能够满足超宽带雷达系统不同的应用要求。     

A CMOS UWB Pulse Generator for 6–10 GHz Applications

A CMOS ultra wideband (UWB) pulse generator with low energy dissipation and high peak amplitude is presented for 6–10 GHz applications. The pulse generator complies with the FCC spectral mask for indoor UWB systems. It consists of a glitch generator, a pulsed oscillator, and a pulse shaping filter. The pulsed oscillator is switched on by the glitch signal only for a short duration, so as to make a UWB pulse. For sub-nanosecond pulse generation, a pulsed oscillator with fast transient response is proposed. A pulse shaping filter makes the oscillator output fall into the FCC spectral mask. The pulse generator is fabricated using a 0.18 $mu$ m CMOS process. The core chip has a size of 0.11 mm $^{2}$. It shows pulse duration of about 500 ps with ${-}10$ dB bandwidth of 4.5 GHz from 5.9 to 10.4 GHz. The energy consumption is 27.6 pJ per pulse with a peak-to-peak amplitude of 673 mV on a 50 $Omega$ output load. The generated pulses are very coherent with 1.8 ps RMS jitter.      

High-Voltage High-Efficiency Ultrawideband Pulse Synthesizer

A novel ultrawideband pulse synthesizer based on distributed amplifier topology is presented. The basic concept is to combine different delayed Gaussian pulses with both positive and negative polarities to form an UWB pulse. Compared to other ultrawideband pulse-formation methods, this method can have both high-efficiency and high-voltage output. The prototype circuit based on 0.25-$mu$m pHEMT transistors is fabricated, and the fabricated pulse synthesizer consumes only 1-mA current under 5-V power supply with high energy efficiency of 10.1% at 10-MHz pulse repetition frequency (PRF). Measurement results show that with 1.5 -V amplitude and 240-ps Gaussian input pulse, the output pulse of the designed UWB pulse synthesizer is centered at 4 GHz with 4.5-V peak to peak amplitude (into 50-ohms load) and 1.0-ns duration at 50% of the peak pulse envelope.      

20 GHz Wavelet Generator Using a Gated Tunnel Diode

We demonstrate the use of a GaAs-AlGaAs gated tunnel diode (GTD) in an ultra-wideband (UWB) wavelet generator. An inductor is integrated to form an oscillator circuit, which is driven by the negative differential conductance property of a GTD. It is demonstrated that as the gate tunes the magnitude of the output conductance, the oscillator may be switched on and off, creating short RF pulses. The shortest pulses generated are 500 ps long, the highest output power for the free running oscillator is $-$4.1 dBm, and the highest oscillation frequency is 22 GHz. Analytical expressions based on the van der Pol equation describing the pulse length and amplitude are presented. This technique is applicable for high frequency impulse radio UWB implementations.      

New design of 3.2–4.8 GHz generator for multi-bands architecture of UWB communication

In this paper a new design of Ultra-Wide Band (UWB) generator is presented. This circuit is the most important block in multi-bands transmitter architecture of UWB communication system. The proposed UWB generator is composed of multi-bands voltage controlled oscillator (VCO), mixer and rectangular pulse generator which consist of ring oscillator, time delay and AND gate function. The UWB generator is based on multiplying the rectangular pulse envelope to a continuous sinusoidal wave in order to generate the UWB signal. This UWB generator circuit produces an output signal which is characterized by the bandwidth of 1600 MHz divided into three sub-bands of 528 MHz, centered at frequencies of 3.432, 3.96, 4.488 GHz and the limited Power Spectral Density (PSD) is −41.44 dBm/MHz. The maximum amplitude of UWB signal is 214 mV, the pulse is during of 3 ns and the pulse repetition period (PRP) is 32 ns. The power consumption is approximately equal to 26 mW at a voltage supply of 2.5 V. This topology is designed in CMOS 0.35 μm AMS process technology.     

Truly balanced pulse generator using microwave transistor and SRD

A novel efficient circuit for Ultra-WideBand (UWB) balanced sub-nanosecond monocycle pulse generation is presented. The pulse generator employs wideband bipolar transistor, step recovery diodes, Schottky diodes, and simple charging and discharging circuitry. Simple transient analysis and design of the circuit are presented along with their operating principle. The pulse generator produces truly balanced monocycle pulse with 500 ps pulse-width and 800 mV peak voltage. The generated monocycle pulse also has very symmetrical positive and negative portions and low ringing level. The presented pulse generator can be used as both a transmitter feeding UWB balanced antennas without broadband baluns and a balanced switching pulse generator that used in UWB receiver.     

Subnanosecond-pulse generator employing 2-stage pulse step sharpener

A 24 V pulse step of less than 70 ps risetime is obtained from a pulse-sharpening circuit using step-recovery diodes. The initial pulse is generated by an avalanche transistor. Super-position of two opposite steps, appropriately delayed, yields a pulse of variable duration between 150 ps and 20 ns at constant amplitude.     

简易的超宽带亚周期微波脉冲产生方法

提出了一种简易的超宽带亚周期微波脉冲电路设计方案,该方案利用阶跃恢复二极管的阶跃特性和肖特基二极管正向压降小且恢复时间短的特性,产生单极性、亚周期的微波脉冲,其电路结构简单、体积小巧、设计制造成本低廉、调试方便。实验结果表明,采用该方案设计的微波脉冲发生器可以产生半高宽为150 ps 的超宽带亚周期微波脉冲,且脉冲拖尾现象很小。在脉冲的重复率为85 MHz 时,产生的脉冲幅值最大,约为3.7 V,且波形拖尾现象最小。提出的设计适用于各类超宽带系统中的窄脉冲发生电路。     

一种有载频超宽带脉冲源设计

针对无载频脉冲低频分量大、辐射效率低、频带可调性差等问题,设计了一种以阶跃恢复二极管、D触发器及超宽带调制器为主的宽频带、高重复频率、低振铃水平的有载频超宽带脉冲源。该脉冲源电路由驱动电路、高速开关电路、整形电路、超宽带调制器及振荡器电路组成。实测结果表明,脉冲源输出脉冲信号重复频率可达125 MHz,脉冲宽度600 ps（底宽）,脉冲振铃水平低于10%,峰-峰值为5.4 V,-10 dB带宽可达4.2 GHz。脉冲信号中心频率与载频相同,可在6.6~8.5 GHz之间灵活设置。利用所设计的脉冲源进行时域测量,其结果与矢量网络分析仪频域测量结果相比幅频特性均方根误差小于0.21 dB。该脉冲源可应用于超宽带时域测量、短距离高速无线通信、高精度室内定位等应用。     

Sub-nanosecond pulse-forming network on SiGe BiCMOS for UWB communications

A pulse-forming network (PFN) has been developed for ultra-wideband (UWB) communication systems. This PFN generates sub-nanosecond pulses at a pulse repetition frequency (PRF) of >500 MHz for high data-rate applications like wireless video streaming. To generate the pulses, the PFN performs two operations on an input data signal: it decreases the signal rise time, then it differentiates the signal. The differentiation circuit is a frequency-dependent negative-feedback system. The PFN is fabricated in SiGe BiCMOS with an active die size of less than 0.25 mm/sup 2/, and it requires 3.3-V 20-mA dc during operation. Measured performance is validated at 500-MHz PRF, achieving pulsewidth of 175 ps and pulse amplitude of 0.17 V. The PFN is also validated within a transmitter system that transmits Manchester coded pseudorandom bit sequence. Measured effective isotropic radiated power of the transmitter shows that the PFN output power is sufficient to meet the Federal Communications Commission's emission limits, thus eliminating the need of amplification before transmission.