WUSB中新型带陷UWB天线

给出了一种紧凑的可用于WUSB的新型带陷超宽带印刷单极子天线．天线由内嵌条带的U形环组成并采用部分接地技术,从而使天线具有带陷超宽带特性．实测结果表明该天线输入端驻波比小于2的绝对阻抗带宽为7．88GHz,覆盖了3．12～11GHz的频率范围,其中5．06～5．89GHz范围内具有带阻特性．讨论了各几何参数对天线性能的影响,同时获得了该天线相对稳定的、近似全向且对称的测试方向图．由于此种天线无需额外的带阻滤波器来隔离天线与其他通信系统的干扰,从而大大简化了WUSB系统的设计．     

New band-notched UWB antenna

A simple and compact ultra wideband (UWB) printed monopole antenna with band-notched performance is proposed in this paper. The antenna is partially grounded so that the Q value is depressed and the impedance bandwidth is broadened. A small strip bar is loaded on each arm of the similar U-shaped radiator. The impedance bandwidth of the antenna overlap with IEEE 802.11a is rejected consequently. The geometry parameters of the antenna are investigated and optimized with HFSS. The measured bandwidth of the proposed antenna occupies about 7.89 GHz covering from 3.05 GHz to 10.94 GHz with expected notched band from 4.96 GHz to 5.98 GHz. A quasi-omnidirectional and quasi-symmetrical radiation pattern in the whole band is also obtained. As a result, a UWB wireless communication system can be simplified with the band-notched UWB antenna presented.     

用于通信的超宽带印刷天线

1IntroductionUltra-wideband(UWB)microwave antennas are ofinterest for a variety of applications such as electroniccountermeasure,transient radars,mine detection,andunexploded ordnance(UXO)location and identifica-tion.In the early2002,the release of the UWB forcommercial communications by the Federal Communi-cation Commission(FCC,USA)sparked renewed in-terest in the subject of UWB antennas.Conventional UWB antennas such as log-periodic orspiral antennas exhibit good UWB characteristi…     

用于人体中心无线网络的平面倒F天线仿真

仿真了用于构建人体中心无线网络的蓝牙通信系统平面倒F天线.依据天线理论和人体中心无线网络的特定需求,选择工作于蓝牙频段的平面倒F天线为仿真对象.通过对电磁场EDA仿真软件的整体了解,选择美国REMCOM公司的全波三维电磁仿真软件XFDTD作为仿真平台.仿真结果为,在2.45 GHz的中心频率下,电压驻波比1.31,输入阻抗50.4-j13.3Ω,频带宽度130 MHz,相对带宽5.3%,天线系统效率79.94%.该性能优良的窄带天线,可满足人体中心无线网络的通信需求.     

应急通信跨段中继套筒单极子天线设计

将套筒单极子天线用于应急通信的V/U频段,提出了一个无地板的套筒天线设计,用An-soft HFSS软件研究该天线的多频带特性和辐射特性,并从工程角度优化了该天线的参数,套筒和同轴电缆均为标准尺寸,便于批量生产。仿真结果表明其在V/U双段能够满足所需的驻波比带宽,并且具有很好的辐射特性。VSWR小于2的频率范围是V段：127MHz-149MHz,带宽22MHz;U段：417 MHz-450MHz,带宽33MHz。取消地板以后,该天线横向尺寸大为减小,便于车载和移动使用。     

Compact wideband microstrip array antenna with beam squint

A compact wideband microstrip array antenna with a squint beam is introduced without the matched load. Its measured beam is at 10° offset to the broadside with a measured gain of 12 dB at 10 GHz. The measured impedance bandwidth (voltage standing wave ratio (VSWR)⩽2) is over 16%, which agrees well with the simulated one. It is a low-cost wideband design with compact simple structure, suited for military and commercial application.     

超宽带平面天线研究进展

This paper introduces the advances of ultra-wideband(UWB)and super-wideband(SWB)planar antennas based on the printed monopole,microstrip slot and other planar antenna designs in the last decade.A brief history of the ultra- wideband antennas is first provided.Several types of planar antennas for UWB systems with band-notched designs are reviewed.Special SWB planar antenna designs with the bandwidth ratio greater than 10:1 including metal-plate and printed monopole antennas and tapered slot antennas are presented and compared.     

一种新的UWB成形脉冲设计方法

脉冲波形设计是关系到UWB系统性能的关键因素,基于Hermite矩阵特征向量和Chirp信号提出了一种产生UWB信号正交成形脉冲的新方法,并且得到了期望的成形脉冲.仿真结果表明,利用这种方法产生的UWB瞬时成形脉冲的功率谱密度分布符合FCC频谱规定的要求,有较高的频谱利用率,脉冲函数自相关性强,互相关为零,利于多址检测.     

双频超宽带微带天线的设计与仿真

提出了一种基于圆形缝隙结构的双频超宽带微带天线.通过在圆形缝隙内加载椭圆形贴片使得天线在获得双频超宽带特性的同时又保持了很小的物理尺寸.仿真结果表明,该天线的-10 dB阻抗带宽分别为2.1~4.0 GHz和5.2~8.8 GHz,天线的相对带宽分别达到了62.3%和51.4%,覆盖了无线局域网(WLAN)的2.45 GHz、5.20 GHz和5.80 GHz三个频段以及宽带互通微波接入(WiMAX)的2.50 GHz和5.25 GHz两个频段.在通带范围内,有良好的辐射特性,并且天线的尺寸为35 mm×35 mm×1 mm,便于集成在电路系统中.     

宽阻带小型化低通滤波器的设计

This paper presents a novel low-pass filter （LPF） with sharp rejection, wide stopband and compact size, which are realized by the defected ground structure （DGS） and the defected microstrip structure （DMS）. The equivalent circuit model is proposed and the circuit parameters are extracted by the circuit simulation software. The parameters measured are 3 dB cutoff frequency fc of 5.2 GHz, the insertion loss less than 0.5 dB from DC to 4.0 GHz and S21 less than -20 dB within the wide stopband from 6 GHz to 16 GHz. The results of the circuit optimization agree well with those of the full wave simulation and the measured ones, which validate the effectiveness of the equivalent circuit model. The size of the proposed LPF is decreased compared with normal LPF. This LPF can be applied in rectennas to eliminate high order harmonics.     

超宽带信号设计研究

超宽带技术被认为是无线电技术的革命性进展,在无线通信、雷达跟踪、精确定位等方面具有广阔的应用前景.信号设计是其中的关键技术之一.对超宽带技术的应用及其在信号设计方面的研究作了综述,详细介绍了已有的有效的信号设计方法,并指出一些值得关注的研究内容.     

New method for high performance multiply-accumulator design

This study presents a new method of 4-pipelined high-performance split multiply-accumulator （MAC） architecture, which is capable of supporting multiple precisions developed for media processors. To speed up the design further, a novel partial product compression circuit based on interleaved adders and a modified hybrid partial product reduction tree （PPRT） scheme are proposed. The MAC can perform 1-way 32-bit, 4-way 16-bit signed/unsigned multiply or multiply-accumulate operations and 2-way parallel multiply add （PMADD） operations at a high frequency of 1.25 GHz under worst-case conditions and 1.67 GHz under typical-case conditions, respectively. Compared with the MAC in 32-bit microprocessor without interlocked piped stages （MIPS）, the proposed design shows a great advantage in speed. Moreover, an improvement of up to 32% in throughput is achieved. The MAC design has been fabricated with Taiwan Semiconductor Manufacturing Company （TSMC） 90-nm CMOS standard cell technology and has passed a functional test.     

Non-linear 2-DOF model and centre manifold theory to study limit cycle oscillations caused by drum-brake

Multiband orthogonal frequency division multiplexing (MB-OFDM) ultra wide-band (UWB) is a novel wireless communication technology. It has many advantages and is being actively researhed. In this study, we constructed and implemented a simulation model of UWB communication systems in Simulink. We found the MB-OFDM UWB system has the best performance in distance between 4 m to 10 m without the line-of-sight requirement.     

直扩多用户超宽带系统在室内衰落信道下的BER表达式

基于室内多径衰落信道统计模型,分析并仿真了直扩二相相移键控多用户超宽带无线通信系统的比特误码率性能.通过理论分析,推导出了系统比特误码率性能的解析表达式,该表达式表示为脉冲宽度、脉冲重复周期、用户数以及脉冲波形等信道参数和系统参数的函数,从而可以方便、统一地分析这些参数对系统性能的影响.仿真结果与基于理论分析的数值计算结果相当吻合,表明直扩二相相移键控超宽带系统的多址干扰为正态分布.     

900MHz无线通信模块的仿真与设计

以STC89c52单片机设计主控模块,以TI公司的ccll00芯片设计无线发射和接收模块,工作于915MHzISM频段,空中波特率为lOOKbps,利用HFSS仿真软件设计微带天线并进行仿真,得到S参数、驻波比、场强、三维远场辐射方向图等。同时利用smartRFstudio软件可测得天线场强,实际效果好于仿真结果,实现了915MHz无线通信,通信距离在10米以上。     

Supercontinuum Generation in DSF Pumped by Actively Mode-Locked Fiber Laser

The supercontinuum （SC） generation at the repetition rate of 10 GHz is presented. The SC is generated in a 4.2 km conventional dispersion-shifted fiber （ DSF）, which is produced with nonlinear effects and group velocity dispersion. The DSF is pumped by an actively mode-locked Er^3＋ -doped fiber laser with pulse width of 7. 97 ps. A novel SC pulse source with a bandwidth up to 125 nm is obtained, which covers the whole C, L bands and part of S band. The stable, narrow pulses with mean pulse-width of 9.7 ps and time-bandwidth product of 0. 48 are filtered out across the whole SC bandwidth. This supercontinuum pulse source is suitable for future high-speed optical communications.     

具有陷波特性的超宽带带通滤波器设计

针对超宽带无线通信系统,提出了一种结构新颖的具有陷波特性的微带线超宽带带通滤波器.该滤波器由级联1/4波长短截线和耦合阶跃阻抗谐振器构成,超宽带滤波器的带通滤波特性由1/4波长短截线结构产生,通过耦合阶跃阻抗谐振器实现通带内的窄带陷波特性.利用电磁仿真,验证了所设计的滤波器的性能.     

液体饱和蒸汽压测定实验的改进

针对目前静态法测定液体饱和蒸汽压实验中饱和蒸汽压数值读取不合理,汽液两相未充分平衡等问题,改变传统的调整U型管两端液面等高后再读取数字压力计的方法。改进后的实验装置只需在U型管的两侧标上刻度,待系统恒温、汽-液充分平衡后,读取数字压力计的数值、温度以及U型管两端液面的高度差就可得到该温度下的液体饱和蒸汽压。该方法可解决静态法测定液体饱和蒸汽压实验中调整U型管两端液面等高耗时,空气容易倒灌的问题。     

基于复合左右手结构的零阶谐振小型天线设计

论文中提出了一种基于复合左右手结构的零阶谐振小型天线,由四个等腰三角形贴片对称排列而成。使用软件仿真和优化得到天线零阶谐振频率为4.7GHz,并给出了各单元的具体参数。仿真结果,在中心频率4.7GHz处,天线的电压驻波比为1.16,天线增益为6.8dB,半功率波瓣宽度为83.1度。     

2.5GHz CMOS高速双模前置分频器设计

A high-speed dual-modulus divide-by-32/33 prescaler has been developed using 0.25 μm CMOS technology. The source-coupled logic (SCL) structure is used to reduce the switching noise and to ameliorate the power-speed tradeoff. The proposed prescaler can operate at high frequency with a low-power consumption. Based on the 2.5 V, 0.25 μm CMOS model, simulation results indicate that the maximum input frequency of the prescaler is up to 3. 2 GHz. Running at 2. 5 V, the circuit consumes only 4.6 mA at an input frequency 2.5 GHz.