国外简讯

1.3GHz的SAW器件美国康涅狄格州声子公司采用亚微米晶片光刻技术制成工作频率达1.3GHz的SAW器件.ID1300型色散延迟线中心频率为1.3GHz,带宽500MHz,色散时间达0.56μs,对线性FM信号的最大压缩脉冲输出响应为3ns.此器件未采用加权法,体积为15.2×5.6×19.1mm,器件为密封式,完全满足军品规范的要求.     

极窄脉冲320MHz SAW色散线

在雷达中,早期脉冲压缩SAW色散延迟线是共线型直列结构,要实现极窄脉冲压缩必须进行高频大带宽调频;这将使器件性能严重恶化。文中采用了倾斜型又指结构,在LiNbO_3基片上,研制了中心频率f_0=320MHz,带宽c~△=150MHz 的色散延迟线。其压缩脉冲主辨宽度为10Hz,主副辨比六于26db。文中对器件进行了分析,并给出了实验结果。     

L波段单片SAW宽带信号形成器

L波段宽带信号形成器是现代超宽带雷达、电子对抗等系统的关键基础器件.采用声表面波(SAW)色散延迟线技术是实现超宽带信号形成器的重要技术途径.该文介绍了一种中心频率为1.55 GHz,带宽≥420 MHz;时延≥0.84 μs的L波段单片SAW宽带信号形成器. 通过对SAW线性调频延迟线换能器拓扑结构优化、阻带抑制和宽带匹配,使得宽带SAWDDL器件的插入损耗低达-38 dB ,阻带抑制高达50 dB(到3 GHz),时域直通隔离度大于90 dB,单端驻波小于2.     

基于声表面波色散延迟线的频谱探测系统

利用声表面波(SAW)技术设计的Chirp变换频谱仪(CTS)具有低功耗、高稳定性等优势,特别适用于深空探测领域。该文提出了一种大带宽的CTS系统。由数模转换器(DAC)和四倍频器产生2 GHz带宽的展宽线Chirp信号,其色散特性与1 GHz带宽的声表面波色散延迟线特性匹配。搭建了实时处理带宽为1 GHz、频率分辨率为100 kHz的频谱分析仪,并对在大带宽下CTS出现的响应不均衡展开探讨。分析了系统各部分对CTS的影响,通过实验验证了响应不均衡出现的原因。测试结果表明,该文设计搭建的1 GHz带宽CTS系统的频率分辨率可达115.512 kHz。     

K波段BAW器件技术研究

通过优化高频换能器设计、极薄压电薄膜制备等技术,试制出了K波段BAW延迟线样品。其工作中心频率为23.8 GHz,插入损耗为51.9 dB,带宽为1 122 MHz,延迟时间为299 ns,直通抑制为29 dB,3次渡越抑制为40 dB。     

重组嵌合受体anti-erbB2 scFv-CD28-ξ全基因合成及其真核表达载体的构建

通过优化换能器拓扑结构,探索长延时传声介质的双面光刻及探针提取S参数进行网络匹配等技术,改进了声体波微波延迟线换能器设计及制作工艺.研制出中心频率为4.3 GHz,带宽为200 MHz,延迟时间为1.999 7μs,插入损耗仅26 dB,直通抑制45 dB,3次渡越抑制42 dB的声体波微波延迟线.     

长延迟反射栅色散延迟线

本文报道了用于电子对抗系统的表面波反射栅色散延迟线的制作情况。器件采用离子束刻蚀沟槽栅的制作工艺,整个刻蚀过程由计算机控制,制作出的器件其主要性能参数为:展宽线中心频率80MHz,色散时间126μs,色散带宽21MHz,插入损耗37dB;压缩线中心频率28MHz,色散时间63μs,色散带宽10.5MHz,插入损耗43dB;配对压缩后,旁瓣抑制可达34—36dB。     

2μs低损耗声体波微波延迟线

通过优化换能器拓扑结构,探索长延时传声介质的双面光刻及探针提取S参数进行网络匹配等技术,改进了声体波微波延迟线换能器设计及制作工艺.研制出中心频率为4.3 GHz,带宽为200 MHz,延迟时间为1.999 7μs,插入损耗仅26 dB,直通抑制45 dB,3次渡越抑制42 dB的声体波微波延迟线.     

倾斜反射阵列相关器技术研究

介绍了倾斜反射阵列相关器(SRAC)设计技术，并采用该技术在YZ-LiNbO3基片上制作了中心频率60MHz，带宽35MHz，色散时间40ps的声表面波沟槽反射栅色散延迟线，实现了60％的相对带宽，同时采用了幅度及相位补偿技术，改善了器件的幅频及相频特性，实现了主副瓣比35dB。     

基于色散光纤环级联结构的可调谐带通微波光子滤波器

提出并验证了一种宽调谐带宽的带通微波光子滤波器设计方案。该滤波器借助可调谐光纤光栅Sagnac环对宽带光源进行均匀切割,产生波长间隔可调的连续光载波作为滤波器的抽头,结合色散光纤环级联结构,实现滤波器的可重构性。研究结果表明,在光电调制器和光电探测器的频率带宽足够大的情况下,当光纤光栅Sagnac环的臂长差在0.50~8.28mm内变化、可调谐光纤延迟线的最小变化步长为0.01mm时,该方案能够实现滤波器中心频率在8.0506~1333.2000GHz内调谐,调谐步长为161.01MHz,边瓣抑制比达到27dB。     

EBG-based dual mode resonator filter

Periodic etched pattern on the ground plane underneath the ring resonator are incorporated to realize a miniaturized ring filter with stronger rejection of higher harmonic passbands. Two square microstrip ring filters, with and without periodic etched pattern on the ground plane, were designed with a bandwidth of 135 MHz centered at 2.4 GHz and 3 GHz respectively. A rejection of at least 25 dB of the second harmonic passband has been achieved for the filter with periodic etched pattern.     

Insertion loss of electronically variable magnetostatic wave delaylines

An investigation is presented of insertion loss and constant variable delays in electronically variable magnetostatic-volume-wave delay lines. The delay line has a conductor-dielectric-YIG-dielectric-conductor structure. Variable delays up to 300 MHz bandwidth have been obtained in a single volume-wave delay line by adjusting the direction and magnitude of the biasing DC magnetic field in a plane containing the normal to the YIG film and the direction of wave propagation. Insertion loss as a function of frequency has been obtained for different biasing field angles and also for the angles corresponding to variable constant delays. Good agreement between theoretically obtained insertion loss and experimental results is found. Electronically variable magnetostatic-wave delay lines have promising applications in broadband phased-array antennas at 1-20 GHz     

Broadband electronically tunable planar active radiating elementsand spatial power combiners using notch antennas

A Gunn device has been integrated with two types of active planar notch antennas. The first types uses a coplanar waveguide (CPW) resonator an a stepped-notched antenna with bias tuning to achieve a bandwidth of 275 MHz centered at 9.33 GHz with a power output of 14.2±1.5 dBm. The second type uses a CPW resonator with a varactor for frequency tuning to achieve a bandwidth of over 1.3 GHz centered at 9.6 GHz with a power output of 14.5±0.8 dBm. This is equivalent to over 14% electronic tuning bandwidth. Both configurations exhibit a very clean and stable output signal. A theoretical circuit model was developed to facilitate the design. The model agrees well with experimental results. Injection-locking experiments on the second configuration show a locking gain of 30 dB with a locking bandwidth of 30 MHz at 10.2 GHz. Power combining experiments of two-varactor-tuned CPW active notch antenna elements in a broadside configuration have achieved well over 70% combining efficiency throughout the wide tuning range. The circuits have advantages of small size, low cost, and excellent performance     

Electronically tunable nondispersive magnetostatic wave delay line

An electronically tunable, nondispersive magnetostatic wave delay line consisting of cascaded magnetostatic backward volume waves and magnetostatic surface waves delay lines has been designed and realised. The distinguishing feature of the device is a wide continuously tunable time delay range of ±30% with the central value of 58 ns. An obtained bandwidth for constant time delay is ~300 MHz at a 3.15 GHz centre frequency. A deviation from constant delay is <±5%     

An X-band acousto-optic variable delay line for radar targetsimulation

The design and characterization of a 54-μs, continuously-variable, acousto-optic (AO) delay line developed for radar testing applications is presented. Design goals for the delay line include over 10 MHz of instantaneous bandwidth, 1.2 GHz of tunable bandwidth operating at X-band, 45 dB of dynamic range, and electronically-controllable delay selection to simulate dynamic radar targets with radial range rates up to 500 m/s. In addition, the device was designed to have phase noise and spurious signal levels compatible with high performance radars. To achieve these goals, a 33-MHz center frequency variable delay line was constructed and coherent frequency translation was used to provide operation at S-band. Operating principles for this new intermediate frequency (IF) delay line are presented, and key component issues are discussed. A computer design and analysis tool is described that predicts delay line performance. Experimental results are presented at both the IF and at X-band     

Recent developments in two-port YIG delay lines

A new type of two-port YIG delay line has been designed and realized which makes use of the YIG acoustic birefringence in order to obtain the smallest level of losses for the transmitted signal through the YIG bar. A minimum value of 26 dB was measured at 2.5 GHz for a 3.5-µs delay and a 3-dB bandwidth of 160 MHz.     

K波段宽带声体波延迟线的设计与优化

通过优化K波段声体波换能器设计,突破200 nm极薄压电薄膜制备和微带线匹配等技术,研制了K波段体声波延迟线样品。研究结果表明,样品的中心频率大于23 GHz,带宽大于1 000 MHz,延迟时间295 ns,外形尺寸约25 mm×16 mm×14 mm,是目前国内外已报道的工作频率最高的声体波延迟线。     

Rayleigh-wave delay line using two grating-array transducers at 2.55 GHz

Grating-array transducers are used to launch acoustic surface waves at 2.55 GHz on a LiNbO3 substrate. The insertion loss of a 1.5 ?s delay line is equal to 39 dB with matching stubs at input and output. The 3 dB bandwidth is equal to 87 MHz. For this frequency range, array transducers are easier to fabricate than standard interdigital transducers. Performances of the two types of transducers are compared.     

Dual-band monopole antenna with shorted parasitic element

A printed dual-band C-shaped monopole antenna with a shorted parasitic element is proposed. The proposed antenna can provide two separate impedance bandwidths of 156 MHz (about 6.4% centred at 2.45 GHz) and 2048 MHz (about 37% centred at 5.5 GHz), making it easily cover the required bandwidths for wireless local area network (WLAN) operation in the 2.4 GHz band (about 3.4% bandwidth required) and 5.2/5.8 GHz bands (about 13% bandwidth required). Furthermore, the proposed antenna shows a low-profile of 635 mm above the ground plane. Details of the proposed antenna design and experimental results are presented and discussed.