宽阻带小型化双频带通滤波器

文中提出了一种具有宽阻带的紧凑型双频带通滤波器,它采用了折叠短路枝节负载谐振器、紧凑型微 带单元谐振器(CMRC)和阶跃阻抗谐振器结构。由于多个谐振器产生了五个可控传输零点(TZ),该滤波器实现了两个 通带之间的良好隔离度以及宽阻带特性。制作并测试了尺寸紧凑的双频带通滤波器实验样品,测试结果显示,第一通 带和第二通带的中心频率/ 插入损耗分别为0. 66 GHz/0. 8 dB 和1. 73 GHz/0. 7 dB,阻带频率高达10. 5 GHz,抑制水平 超过15 dB。     

一种通带可控的双频SIW滤波器设计

提出了一种通过加载T形槽实现双频可控的基片集成波导带通滤波器。滤波器的双频特性由SIW腔内对称的T形槽线谐振器微扰TE101和TE102模得到。通过改变槽线谐振器的物理尺寸可以实现对滤波器两个通带中心频率的灵活控制。为了验证上述方法的可行性,设计了一个中心频率为3.77 GHz和9.27 GHz的双频滤波器。实测得该双频滤波器两个通带的回波损耗优于11 dB,在3.77 GHz时插入损耗为0.8 dB,第一通带的相对带宽可达13%。仿真和测试结果吻合较好,证实了设计方法的有效性。     

基于CSRR-QMSIW谐振器的双通带滤波器的设计

为满足滤波器在双频带通信系统中发展的要求,提出了一种基于1/4模基片集成波导(QMSIW)加载互补开口谐振环(CSRR)的新型双通带滤波器。根据CSRR谐振器的传输特性,实现以其谐振频点为中心的第一个通带;设计QMSIW谐振腔的边长,实现以该腔体谐振频点为中心的第二通带;设计QMSIW腔体间的耦合方式,在两通带之间和高阻带处各引入一个传输零点,加强两通带隔离度和带外抑制。设计了一款两通带的中心频率分别为8.1 GHz和11.5 GHz,且有效尺寸仅为15 mm×8 mm,插入损耗低于0.4 dB,高阻带衰减达64 dB,两通带隔离度达46 dB。     

30-GHz millimeter-wave carrier generation with single sideband modulation based on stimulated Brillouin scattering

A new technique to generate a millimeter（mm）-wave carrier of 32.57 GHz(f_LO=10.85 GHz) with single sideband modulation（SSB） for radio-over-fiber（RoF） systems is experimentally demonstrated by using stimulated Brillouin scattering（SBS）.The SSB is realized by directly amplifying the +3rd sideband of the modulated optical carrier in the process of SBS.The pump wave is provided through a double Brillouin scattering frequency shifting configuration.The use of the same laser source to generate the pump wave ensures the stability of the mm-wave generation system since the relative frequency shift between them can be eliminated.In addition, the mm-wave carrier obtains an RF power gain of 21 dB with the SBS amplification and a 3-dB bandwidth of 10kHz.     

一种基于SIR结构的三通带带通滤波器

应用双指耦合结构和枝节加载谐振器（Stub-loaded Resonator,SLR）实现了一款基于阶梯阻抗谐振器（Stepped Impedance Resonator,SIR）的滤波器。该滤波器具有3个通带,带外抑制较好,工作频段提高。通过调整阻抗比可调节第二、三通带的谐振频率;SLR结构能够增加通带数量;SLR结构和双指耦合结构均能改善滤波器的S参数。HFSS软件仿真表明,3个通带的中心频率分别为3.5 GHz、6.6 GHz、9.2 GHz,对应的分数带宽分别为5.7%、3%、2%,S11分别为-18 dB、-22 dB、-24 dB,通带内的S21分别为-1.8 dB、-1 dB、-1 dB。电路的测量结果与仿真结果较为吻合。该滤波器在5G通信的低频段具有应用前景。     

基于双模开环谐振器的双频带滤波器设计

基于开环双模谐振器设计了一种双频带通滤波器,由两个中心重合的正方形开口环谐振器组成。分析该谐振器的奇偶模谐振频率与传输零点,每个通带内有两个谐振模式。该滤波器中心频率分别为4.5 GHz和6.5 GHz,3 dB相对带宽FBW分别为11%、5%,两通带带内插入损耗分别小于0.6 dB、1.4 dB,带内回波损耗分别优于19.5 dB、16.5 dB,高频处阻带抑制达到50 dB,两通带之间隔离度达到53 dB,尺寸仅为6 mm×11 mm×1.09 mm。     

高非线性光纤中受激布里渊散射的抑制和光参量放大

受激布里渊散射 (SBS)的抑制是实现光纤参量放大的重要技术要求 ,已有文献报道多采用对抽运光进行相位调制的方法 ,将光功率分散到多个频率分量上来达到这一目的。提出一种二次调相的方法 ,在已有 2GHz相位调制的商品光源上施加 36 5MHz的二次相位调制 ,将高非线性光纤 (HNLF)的受激布里渊散射阈值由未加任何调制时的 10dBm至少提高到 2 3 5dBm ,达到了参量放大的要求。在此基础上 ,进行了连续波 (CW )抽运的光纤参量放大实验。实验中采用长度为 14 5 0m ,非线性系数γ =11 9W-1km-1,色散斜率S =0 0 15 5ps/(nm2 ·km)的高非线性光纤 ,使用外腔可调谐激光器 (ECL)作为信号光源 ,小信号增益带宽达到 2 6nm(增益 >10dB) ,峰值增益达到2 4dB。同时还观察到了由于非线性拉曼放大作用造成的长波长信号光增益大于短波长信号光增益的不对称性。     

A Dual-Band Bandpass Filter Based on Generalized Negative-Refractive-Index Transmission-Lines

A dual-band bandpass filter is presented. The filter is composed of generalized negative-refractive-index transmission-lines (NRI-TL) realized in microstrip. The filtering mechanism relies on all four of the generalized NRI-TLs' left-handed and right-handed passbands. Under the closed stopband condition, two passbands are achieved. A complete design procedure is described. A fabricated example measures 0.25lambda_o0.25lambda_o, where omega_o is the wavelength of the center frequency of the stopband. Maximum insertion loss in the passbands (centered around 4 GHz) is measured at 1.5 dB.     

Compact dual-band bandpass filter using trisection hairpin resonator for GPS and WLAN applications

A compact dual-band bandpass filter using trisection hairpin-shape resonators has been designed and fabricated. Measured results are in good agreement with electromagnetic simulation results and verify that two central frequencies of the fabricated filter are located at about 1.57 GHz (GPS application) and 2.40 GHz (WLAN application). The measured return losses in both 1.57 and 2.40 GHz bands are higher than 16 dB while the measured insertion losses are about 1 dB in the two passbands. The circuit size of the proposed filter occupies only 26 times 26 mm (sime0.22lambda_g times 0.22lambda_g).     

基于折叠型SIR 谐振器的双通带滤波器设计

文中提出了一种基于折叠型SIR 谐振器的双通带频率可控的微带滤波器,它由SIR 谐振器特性结合 传输线理论实现。该滤波器设计为具有两个自由度,调节谐振器的导带宽度可以对两个通带之间的频率及其间隔 进行调节。文中还研究了调整谐振器导带长度对滤波器频率特性的影响。测试结果表明,该微带滤波器有两个通 带,其中心频率分别为2. 79 GHz 和3. 90 GHz,带内最小插入损耗分别为-0. 96 dB 和-3. 0 dB,带内最小回波损耗分 别为-42 dB 和-18 dB,相对带宽分别为5. 7%和6. 7%。仿真和测试结果的一致性证实了滤波器设计的有效性。     

Stimulated Brillouin scattering excited by a modulated pump wave insingle-mode fibers

The effects of modulation on the gain of stimulated Brillouin scattering (SBS) are discussed. Three different modulation techniques, i.e. frequency shift keying (FSK), amplitude shift keying (ASK), and phase shift keying (PSK) are considered. The results show that the SBS threshold depends on the ratio between the spontaneous Brillouin linewidth and the bit rate. The SBS threshold for ASK and FSK is 6 dB higher at high bit rates, whereas the SBS threshold for PSK increases by 10dB for each factor of 10 increase in the bit rate     

Dual-band step-impedance bandpass filter for multimode wireless LANs

A step-impedance bandpass filter is presented for multimode wireless LANs. The filter has a new dual-band feature of two tunable passbands at desired frequencies and high out-of-band suppression, generated by incorporating step-impedance resonators in a comb-filter topology. It saves more than half the circuit size compared with the switch-type dual-band topology. The simulation and measurement results show the dual-band feature of two passbands at 2.45 and 5.75 GHz with 85 dB suppression at 3.5 GHz.     

具有小中心频率比的紧凑型双频带滤波器

采用平面双模谐振器设计了一款新颖的具有小中心频率比的紧凑型双频带滤波器。该滤波器的两个工作频段的中心频率分别为5G WiFi的两个有用频段5.2 GHz和5.8 GHz,中心频率比为1:1.1。实现了具有四个传输零点的双通带响应,其中位于两个频带中间的两个传输零点由谐振器自身产生,很好地抑制了通带间的无用频段。另外两个传输零点由源负载耦合结构产生。加工并测试了该滤波器,两个通带的3 dB相对带宽为5.8%和5.2%,通带内的插入损耗小于0.8 dB,四个传输零点分别位4.52, 5.50,5.50和6.50 GHz,实验和仿真结果吻合,验证了结构的有效性。     

单层平面基片集成波导双通带滤波器的仿真研究

提出了一种基于单层基片集成波导谐振腔的双通带滤波器。滤波器由传统折叠排列的6个谐振腔组成。通过在通带内设置一对传输零点,将传统滤波器的通带一分为二,实现了双通带。仿真结果表明滤波器的两个通带分别工作于9.85 GHz和10.08 GHz,在相对带宽分别为1.29%和1.76%的通带内,插入损耗小于1.68 dB和1.3 dB,回波损耗大于24 dB和14 dB,通带之间的隔离大于17 dB。该滤波器在无线通讯系统中具有良好的应用前景。     

Miniaturized dual-band bandpass filter with good frequency selectivity using SIR and DGS

A miniaturized dual-band bandpass filter (BPF) using stepped impedance resonator (SIR) and defected ground structure (DGS) is presented. In order to get two desired passbands, two different transmission paths and source–load cross coupling have been implemented. One path is the SIR, and the other is the DGS. Meanwhile, it is easy to obtain good frequency selectivity by introducing several transmission zeros. The coupling scheme and current distributions are applied to demonstrate the flexible design approach. A dual-band BPF is designed, simulated, and fabricated to demonstrate the performance of the proposed dual-band filter. The measured results show that the fabricated dual-band BPF has two passbands centered at 2.41 and 3.52 GHz with the fractional bandwidth of 5.8 and 7.7%, respectively. The measured insertion loss is about 2 dB and 2.2 dB at the lower and upper passbands. The measured results show good agreement with the simulated ones.     

A highly miniaturized LTCC dual-band UWB filter using independent transmission zeros and lowpass filters

In this paper, a compact dual-band ultra-wideband (UWB) filter has been newly designed and fabricated for 3.1–4.75 GHz and 6.0–8.5 GHz UWB system applications by embedding all passive lumped elements into low temperature co-fired ceramic (LTCC) substrate. In order to reduce its size/volume and prevent parasitic electromagnetic (EM) coupling between the embedded passive elements, it was newly designed by using a modified 3rd order Chebyshev filter topology and J-inverter transformation technology. Moreover, in order to completely reject the wireless local area network (WLAN) bands of 2.4 GHz and 5.15 GHz, an independent transmission zeros technology was applied. For forming the higher passband, lowpass filters were also applied with two LC resonant circuits by using roll-off characteristics by independent transmission zeros. The measured insertion losses in the lower and upper passbands were better than 2.5 and 2.3 dB, respectively. Return loss and group delay were better than 8 dB and 0.61 ns, respectively in all the passbands. Independent transmission zeros that occurred at 5.17 and 5.42 GHz provided suppression of 22 dB at the WLAN band. The size/volume of the fabricated LTCC dual-band UWB filter was 3.65×2.35×0.65 (H) mm³.     

基片集成波导正弦渐变槽单脉冲天线

为拓展工作带宽,以传统正反渐变槽天线为基础,利用基片集成波导馈电,该文提出了两种高增益、宽频带的正弦渐变槽天线。利用矩形波导3 dB定向耦合器和90移相器工作原理设计了半模基片集成波导单脉冲馈电网络,进而得到了对称型和非对称型正弦渐变槽单脉冲天线,带宽均超过了3.0 GHz,带内和波束最大增益在9.0 dBi左右,差波束零深在10.0 GHz处均低于-20 dB。其中,非对称型正弦渐变槽单脉冲天线具有更宽的工作频带和更平稳的天线增益,可以广泛应用于微波定向探测系统中。     

Design of the Compact Dual-Band Bandpass Filter With High Isolation for GPS/WLAN Applications

In this letter, a novel compact dual-band bandpass filter (BPF) is designed to achieve the characteristic of low insertion loss and high isolation for global position system (GPS)/wireless local area network (WLAN) applications. This BPF is implemented by properly selecting the impedance ratio (R) and physical length ratio $(alpha)$ of the asymmetric stepped-impedance resonator (SIR) with one step discontinuity. The coupling coefficient between the coupled asymmetric SIRs is calculated by using full-wave simulator IE3D. The proposed filter has very good measured characteristics including a low insertion loss of 1.1 dB for both passbands, a high isolation insertion loss of 55 dB between the two passbands and a wide stopband rejection of 38 dB from 2.7 to 5.3 GHz. Good agreement with responses of electromagnetic (EM) simulation and measurement is compared.      

Photonic Frequency Upconversion by SBS-Based Frequency Tripling

We describe a photonic frequency upconversion by the stimulated Brillouin scattering (SBS)-based frequency tripling method. The frequency tripling and the photonic frequency upconversion are simultaneously obtained by incorporating a dual-electrode electrooptic modulator (EOM) and a single optical source. Each electrode of the dual-electrode EOM is driven by both an intermediate frequency (IF) and a microwave radio frequency (RF) signal, respectively, along with the optical frequency tripling scheme. The dual-electrode EOM generates appropriate optical sidebands, while the IF signal is conveyed by the pump signal. After the successive SBS shifting process, one of the third optical sidebands is amplified by the narrow gain spectrum of SBS. The carrier signal at 32.493 GHz with narrow linewidth, which is amplified by 20 dB while the other signals are suppressed more than 20 dB, is obtained after photodetection. From the simultaneous frequency upconversion and tripling, an IF signal at 1 GHz is upconverted around the 32.493-GHz signal, which is tripled from the RF signal (10.831 GHz). To verify the ability of conveying broadband data that is limited in the previous method based on SBS, the upconversion of a pilot tone at 1 GHz is demonstrated, which means that the data rate exceeds 1 Gb/s. The proposed photonic frequency upconversion shows the spurious free dynamic range of 75.1 dBldrHz^2/3 , which is suitable for a wireless personal communication system adopting the analog fiber-optic link.     

Compact UWB Filter With Double Notch-Bands Using Multilayer LCP Technology

A novel ultra wideband (UWB) bandpass filter with double notch-bands is presented in this paper. Multilayer schematic is adopted to achieve compact size. Stepped impedance resonators (SIRs), which can also suppress harmonic response, are designed on top and second layers, respectively, and broadside coupling technique is used to achieve tight couplings for a wide passband. Folded SIRs that can provide desired notch-bands are designed on the third layer and coupled underneath the second layer SIRs. The designed prototype is fabricated using multilayer liquid crystal polymer (LCP) technology. Good agreement between simulated and measured response is observed. The fabricated filter has dual notch-bands with center frequencies of 6.4/8.0 GHz with 3 dB bandwidths of 9.5%/13.4% and high rejection levels up to 26.4 dB and 43.7 dB at 6.4/8.0 GHz are observed, respectively. It also has low-insertion losses and flat group delay in passbands, and excellent stopband rejection level higher than 30.0 dB from 11.4 GHz to 18.0 GHz.