一种基于微带槽天线的带阻性UWB天线的研究

提出了一种新颖的小型平面超宽带天线。该天线由微带槽天线的基本结构变形而来,为获得超宽带的频率特性,设计时馈电微带采用了圆弧形调谐枝节,金属底板的开槽设计成对称多边形之后通过数值计算获得最佳的天线几何尺寸。通过HFSS仿真和测试设计了一种频率覆盖3.1～10.6 GHz的超宽带UWB天线,其对包含在超宽带频段范围内的民用频率范围有一定的滤除作用,结构简单并且驻波特性良好,方向图具有准全向性。     

应用于早期乳腺肿瘤探测的小型化超宽带天线

设计了两款可以应用于早期乳腺肿瘤超宽带微波检测技术的超宽带天线。两款天线均为平面单极天线,分别由叉形、三角形金属贴片和槽口金属接地板构成,采用微带线对其进行馈电。经过仿真优化,两款天线的-10 dB回波损耗频率覆盖范围分别为4～10 GHz和5～10 GHz,且在此带宽内具有良好的全向性。对叉形极子天线进行了实物测量,试验数据与仿真结果相吻合。两款天线体积小、结构简单、加工简便,能够较好地满足微波成像检测乳腺肿瘤技术中天线阵列的设计要求。     

超宽带发射电路的设计研究

介绍了超宽带通信系统的关键电路的原理与设计,提出了超宽带发射与接收系统的原理与具体实施方案,以及UWB发射电路,接收等关键电路的设计方法,对于超宽带高速无线接入的实现,起到了关键的作用。     

一种微带馈电的双陷波超宽带天线

为适应超宽带通信的需求,设计了一种小型印刷超宽带天线。天线采用五边扇形金属贴片作为辐射贴片,通过开U形缝隙实现阻带特性,利用仿真软件HFSS对天线的阻抗特性及方向图进行研究。结果表明,该天线在3.0~14.0 GHz的频率范围内驻波比〈2,其中在3.25~4.10 GHz和5.3~5.86 GHz两个频率范围内有阻带特...     

一种小型超宽带微带天线

给出了一种小型化超宽带微带天线,该天线采用微带线对半圆形和矩形组成的阶梯状辐射单元进行馈电,基板背面为相似形缺陷地结构窗口。天线参数采用电磁仿真软件CST进行仿真和优化。所设计的小型化超宽带微带天线相对带宽达144.9%(2.15～13.47GHz),带内回波损耗均在-10dB以下,整个工作频段内天线的增益平均在4dB以上,天线的辐射方向图形状在频带内基本保持不变。该天线具有结构紧凑和形状简单的特点,易于加工和集成。最终实际制作了天线样品,并进行了测试,实测数据与仿真结果吻合良好。实验结果表明该微带天线具有良好的小型化和超宽带特性。     

一种新型的漂移阶跃恢复二极管脉冲源设计

提出了一种基于漂移阶跃恢复二极管（DSRD）、结构简单的新型大功率脉冲源电路.论述了阶跃恢复二极管的快速开关特性,分析了该新型脉冲源电路的工作原理,并进行了实验测试.实验结果表明,脉冲源电路能够产生峰峰值为760 V、脉宽（10％-10％）8 ns的平衡输出脉冲信号,具有脉冲重频高、振铃小、波形质量高、无需高压供电等特点,适用于深层探测超宽带时域脉冲探地雷达系统.     

一种新型的超宽带锥削缝隙天线设计

提出了一种微带线-槽线馈电形式的指数锥削缝隙天线,在辐射臂的外边缘引入半椭圆形缝隙来进一步提高天线低频段的定向性,获得了高增益和超宽带性能。利用HFSS12软件进行仿真,天线的极化方式为垂直极化,在2~13 GHz的工作频段内电压驻波比＜2,增益最高达11 dB,具备良好的定向性,仿真与实测结果基本吻合,表明该设计是有效、可行的。     

A new ultra-wideband fractal monopole antenna

The paper focuses on the peculiar dynamic behaviour of the recently developed 8 mm² TO-220-packaged, high-voltage, double-interdigitated (or rwo interdigi-tation levels—TIL) GTO thyristor. This novel power device was rated under both slightly and heavily inductive resistive loads, i.e. close to the real conditions encountered in practical power circuits employing GTO thyristors. Emphasis is laid on the ability of TIL GTOs to switch safely, with minimum power losses, a certain amount of anode current under high-voltage conditions and high commutation frequencies. The merits of TIL GTO thyristors are analysed in terms of their reliability and switching efficiency, which include the total power losses (conduction and switching losses), turn-on and turn-off gains and the switching speed. It is shown that thanks to their built-in self-protective features, these novel GTOs possess an enhanced current-handling capability at commutation frequencies up to 50kHz under extremely tough load conditions. The main implications of the results for power applications are outlined.     

A low-voltage ultra-wideband down-conversion mixer with improved power conversion gain

This article presents a wideband mixer using a TSMC 0.18?µm complementary metal-oxide semiconductor technology process for ultra-wideband (UWB) system applications. The measured 3-dB radio frequency (RF) bandwidth is from 3 to 8.4?GHz with an intermediate frequency of 10?MHz. The measurement results of the proposed mixer achieve 8.1?dB average power conversion gain ?5?dBm input third-order intercept point (IIP3) at 7.4?GHz and 12.4–13.3?dB double side band noise figure. The total dc power consumption of this mixer including output buffers is 3.18?mW from a 1?V supply voltage. The output current buffer consumption is about 2.26?mW with an excellent local oscillator-RF isolation of up to 40?dB at 5?GHz. The article presents a mixer topology that is greatly suitable for low-power operation in UWB system applications.     

A 0.7 V 6.66–9.36 GHz wide tuning range CMOS LC VCO with small chip size

The circuit designs are based on TSMC 0.18 μm CMOS standard technology model. The designed circuit uses transformer coupling technology in order to decrease chip area and increase the Q value. The switched-capacitor topology array enables the voltage-controlled oscillator (VCO) to be tuned between 6.66 and 9.36 GHz with 4.9 mW power consumption at supply voltage of 0.7 V, and the tuning range of the circuit can reach 33.7%. The measured phase noise is ?110.5 dBc/Hz at 1 MHz offset from the carrier frequency of 7.113 GHz. The output power level is about ?1.22 dBm. The figure-of-merit and figure-of-merit-with-tuning range of the VCO are about ?180.7 and ?191.25 dBc/Hz, respectively. The chip area is 0.429 mm² excluding the pads. The presented ultra-wideband VCO leads to a better performance in terms of power consumption, tuning range, chip size and output power level for low supply voltage.