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1.
This article presents two new types of tunable filters with constant absolute bandwidth using varactor‐loaded microstrip resonators. First, the second‐ and third‐order Butterworth tunable filters are designed based on the parallel coupled‐line J inverters. Second, a fourth‐order Chebyshev tunable filter is designed based on the alternative J/K inverters, in this design, two adjacent resonators are coupled with each other through a short‐circuited transmission line as the K inverter. The proposed two topologies can be easily extended to high‐order tunable filter. Three tunable bandpass filters with J and alternative J/K inverters, respectively, are built with a tuning range from ～1.8 to ～2.3 GHz. The measured second‐order filter has a 3‐dB bandwidth of 160 ± 6 MHz and an insertion loss of 2.4–3.8 dB. The third‐order filter shows a 3‐dB bandwidth of 197 ± 5 MHz and an insertion loss of 3.8–4.8 dB. The fourth‐order filter shows a 3‐dB bandwidth of 440 ± 5 MHz and an insertion loss of 2.1–2.6 dB. For all the designed filters, the measured results are found in excellent agreement with the predicted and simulated results. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:681–689, 2014. 相似文献
2.
Har Dayal 《国际射频与微波计算机辅助工程杂志》2004,14(1):64-72
This article discusses the development of an electronically tuned filter capable of a wide tunable frequency range and simultaneous 3-dB bandwidth variations at any frequency within its tuning range. Varactor-tunable filters are designed using high-dielectric, soft-substrate material for printed resonators as well as also high-Q ceramic resonators, and their test data are compared. Greater than 50% tuning range with low insertion loss at a center frequency in the L and S frequency bands is demonstrated with a 4:1 change in 3-dB bandwidth—30 to 120 MHz for printed resonators and 14 to 46 MHz for ceramic resonators. The concept of tuning a filter's 3-dB bandwidth with voltage is demonstrated and the effect of the bandwidth tuning elements on the tunable filter performance is discussed. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 14, 64–72, 2004. 相似文献
3.
The development of wireless communication standards necessitates optimal filter design for the selection of appropriate bands of frequencies. In this work, a compact in size pair of parallel coupled symmetric stepped impedance-based resonator is designed with supporting to the WiMAX communication standards. The coupled resonator is tuned to allow the frequency band between 3.4 GHz and 3.8 GHz, which is centered at 3.6 GHz. A parasitic effect of capacitively coupled feed structure is used for exciting the two symmetrical stepped impedance resonators. The bandwidth and selectivity of the filter are enhanced with the change of characteristic impedances and controlling the coupling gap between resonators. This design offers single narrow sharp passband selectivity as well as multiple stopband harmonic suppression arising as a result of multiple transmission zeros. The designed filter operates with a fractional bandwidth (FBW) of 11.47%. The proposed single narrowband bandpass filter provides better suppression in either side of the tuned frequency (3.6 GHz) without degrading the passband performance. Also, this novel filter offers an insertion loss of about −0.08 dB and a return loss of greater than −30 dB in passband. This approach is useful for eliminating unwanted spurious harmonics responses that enter the desired response. The suggested bandpass filter has been simulated using Advanced Design System (ADS) tool, and the measurement has been made using a network analyzer, and the results are reported. 相似文献
4.
In this paper, a novel design method for reconfigurable bandpass filter (BPF) with constant absolute bandwidth (ABW) based on neural network is proposed. A lumped-element circuit is used to design the reconfigurable BPF, which consists five series LC tanks. Three series tanks can provide three transmission poles, while two parallel tanks can introduce two same transmission zeros (TZs). This method allows designing BPFs with tunable center frequency and constant ABW. A set of inductance and capacitance values for the center frequency and ABW requirements are optimized by using neural network. Then, optimize the capacitance values to adjust the center frequency with fixed inductance values by the three series tanks and the TZ by the parallel tanks. In order to verify this design method, three varactor diodes are employed to achieve the reconfigurable BPFs with the constant ABW under different work states. Experiments show that this method can optimize multiple LC circuit parameters of BPFs, which meet design requirements, with the same ABW and different center frequencies effectively and accurately 相似文献
5.
A novel compact dual‐band power divider with filtering responses is presented in this article. The proposed circuit utilizes coupled quarter‐wavelength stepped‐impedance resonators. By controlling these resonators, dual‐band operation can be realized. Furthermore, a resistor is connected between the two open ends of the input feed line to obtain good isolation at two bands. Source load coupling is utilized to enhance the selectivity. To verify the proposed idea, a filtering power divider with the operating frequencies of 2.4 and 5.8 GHz is implemented. Good agreement between the simulated and measured results validates the proposed idea. The total size of the circuit is 0.23λg × 0.28λg, where λg is the guide wavelength of 2.4 GHz. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:262–267, 2016. 相似文献
6.
介绍了一种带镜频抑制的可重构上变频器。它由FET混频器、压控振荡器(VCO)、低通滤波器及可调带通滤波器组合而成。这种上变频器能够将给定的中频信号变换成在一个宽的频率范围内期望的任意频率的射频信号,并保持高的镜频抑制水平。随着VCO输出频率的变化,镜频、本振和谐波频率同样发生变化并有可能产生混叠。 相似文献
7.
Tunable microstrip lowpass filters (LPFs) with a good performance are used in most telecommunication systems. In this article, a third‐order circuit with stepped impedance resonator is used to design LPF, and suppression cells are used to improve the performance of the filter in stopbands up to 20 GHz. The ?3 dB cut‐off frequency can be controlled in the range of 0.35 to 1 GHz with the tuning range of 96%. Rejection stopbands of 30 dB (type‐I) and 20 dB (type‐II) can be extended to more than 20 GHz. For the passband, the insertion loss variations are in the range of 0.35 to 2.12 dB. The proposed tunable LPF has a sharp roll‐off rate (42‐96 dB/GHz). The varactor‐tuned microstrip LPF is designed, simulated, fabricated, and measured. The results of simulation and measurement for the proposed LPF are in good agreement. The size of the proposed tunable LPF is small and the filter dimensions are equal to 0.267λg × 0.13λg. 相似文献
8.
A substrate integrated folded waveguide (SIFW) controllable mixed electric and magnetic coupling structure is proposed and investigated, which is suitable for millimeter‐wave pseudo‐elliptic filter applications. The proposed structure is built by a meandered slot‐line (MSL) combined with an inductive via‐hole in a SIFW cavity, which can support two closely‐spaced resonator modes and achieves a mixed coupling. By adjusting the physical sizes of the mixed coupling structure, the electric and magnetic coupling can be separately controlled and a controllable transmission zero (TZ) can be produced below/above the passband. Furthermore, detailed analysis of the SIFW cavity mode spectrum and the mixed coupling characteristics are presented. Finally, direct‐coupled and cross‐coupled fourth‐order pseudo‐elliptic filters are designed, fabricated and measured to verify the proposed mixed coupling structure. The experimental results show that the proposed filters have good performance, such as high frequency selectivity, compact size, wide upper stopband, and easy integration with other planar circuits. 相似文献
9.
针对数字下变频器资源消耗多、信号处理时间长、运算效率低和难以处理多种带宽信号等问题,在研究数字下变频和多相结构运算特点的基础上,提出一种多相带通滤波结构设计,并利用恒速乘法、乘法器复用和多速率输入输出控制等技术实现了这一结构。软硬件仿真表明:该结构不仅能够实现多种带宽信号的正交数字下变频,而且,具有很高的运算效率和硬件资源利用率、较短的信号处理时间。 相似文献
10.
针对现有的微带可调滤波器中心频率调节范围较窄的问题,依据梳状滤波器的原理和变容二极管的特性,设计出一种梳状线可调带通滤波器,经ADS仿真可得其中心频率可调范围达到0．49～5．08GHz、相对带宽仅为6．1％～9．4％,该梳状线可调带通滤波器具有中心频率调节范围很宽、结构简单、易于实现、易于扩展等优点,在工程上具有一定的推广应用价值。 相似文献
11.
A wideband diplexer is designed and developed in suspended substrate medium using wide‐bandpass filters of 10–14 GHz and 14–18 GHz. Tight coupling between resonators is achieved by etching the resonators on the top and bottom layers of the substrate. The diplexer is designed by combining these filters on a common transformer. Each filter is channelised to avoid waveguide modes. Suspended substrate striplines (SSSs) are characterized using the Finite‐Difference Method (FDM). The theoretical and measured results of the diplexer are presented. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006. 相似文献
12.
A widely tunable bandpass filter adopting a novel fully tunable resonator is proposed in this letter. The fully tunable resonator is mainly consisted of an open ring, a frequency tuning structure, and a coupling tuning structure. Adopting the fully resonators, the center frequency, the input/output external Q value, and the coupling coefficients can be tuned at the same time. And the tuning range of a tunable filter adopting the novel fully tunable resonators can be expanded. The fully tunable resonators can be combined to achieve more excellent suppression performance. A widely tunable bandpass filter consisted of five fully tunable resonators with 86.5% frequency tuning range is designed, fabricated, and measured. The simulated results are in good agreement with the measured ones. 相似文献
13.
采用TSMC0.13μm CMOS工艺,设计了应用于移动数字电视调谐芯片的宽带VCO。能覆盖UHF和L频段的频率综合器只使用了一个VCO,从而使得芯片的面积和功耗得以减小。为了得到较低的相位噪声并且在宽的调谐范围内输出电压幅度恒定,移除了交叉耦合VCO的尾电流源采用直接电压偏置。VCO电源电压为2V,调谐范围为2.56G Hz-3.84G Hz,仿真结果表明在2.56G Hz和3.84G Hz频偏100K Hz时相位噪声分别为-105dBc/Hz和-95dBc/Hz,整个调谐范围内输出电压峰峰值变化8%,直流功耗15mW。 相似文献
14.
A novel half‐mode substrate integrated waveguide (HMSIW) based dual‐band bandpass filter (DBBPF) is proposed. Back to back connected two defected ground structure (DGS) resonators on the top layer of HMSIW cavity constitute the passband with two transmission zeros (TZs) at a lower frequency. The higher modes TE301 and TE302 of HMSIW cavity give the passband response at higher frequency using the mode shifting technique with slot perturbation. The source‐load coupling has been used to create finite frequency TZs to improve the selectivity of the second passband. Therefore, the proposed filter gives two widely separated passbands, center frequencies (CFs) at 5.83 and 18.1 GHz with an attenuation of greater than 10 dB between the passbands. The synthesized filter is fabricated using a low‐cost single layer PCB process, and the measured S‐parameters are almost mimic the EM‐simulation results. 相似文献
15.
A novel wideband microstrip bandpass filter (BPF) based on a coupled‐stub loaded resonator (CSLR) is presented in this article. The CSLR is constructed by attaching one short‐circuited parallel coupled microstrip line (PCML) in shunt to a high impedance microstrip line. The filter bandwidth can be conveniently controlled via reasonable adjusting of the impedance of PCML. Moreover, new defected microstrip structures (DMSs) introduced in the PCML functions as a means of adjusting the positions of transmission zeros, created by the PCML. The resonant mode and transmission zero chart are given, indicating that the higher modes could be suppressed by the transmission zeros. Finally, to validate the proposed method, two wideband BPF filters with and without DMSs centered at 3 GHz with 3 dB fractional bandwidth of 87% are designed and fabricated. The measured results show that both the return losses are better than 15.8 dB, while the BPF with DMSs has a ?19.4 dB isolation wideband from 1.57 to 4.23 . The measured results are in excellent agreement with full‐wave electromagnetic simulation results. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:122–128, 2015. 相似文献
16.
John R. Crute 《国际射频与微波计算机辅助工程杂志》2002,12(3):229-235
A simple design procedure is described for miniaturized microstrip bandpass filters on high‐εr substrates. Costs and design times are reduced by replacing experimental measurements with EM simulations. The procedure is confirmed through the design of a miniaturized microstrip hairpin‐coupled bandpass filter at 1.8 GHz on BaO? PbO? Nd2O3? TiO2 (εr=90.9) ceramic substrate. © 2002 Wiley Periodicals, Inc. Int J RF and Microwave CAE 12: 229–235, 2002. 相似文献
17.
基于宽频率范围数字系统的需求,在0.13μm工艺下设计了一款宽输出范围、低抖动八相位锁相环。首先通过数学建模优化环路带宽,在系统级减小环路噪声;在振荡器中引入了前馈传输管单元以提高振荡频率并降低振荡器相位噪声;最后利用具有伪静态结构的D触发器来降低鉴相器和分频器的功耗并提高其抗噪声能力。仿真结果表明,VCO输出频率在1.2 GHz时相位噪声为-95dBc/Hz@1MHz,FOM功耗为4.5PJ@2GHz。 相似文献
18.
传统恒温差式热式流量计受到测量电路本身限制,最大加热电流受限,因此测量范围有限。设计研制了一种结合恒温差法和恒功率法的热式质量流量计。该流量计是基于托马斯理论,对功耗和温差进行采集,从而测得流量。相比于传统恒温差式质量流量计,该流量计在低流速时通过对桥式电路电压差采集,以控制数字电位器改变输入总电压,从而实现探头间温度差恒定,测量功耗测得流量;而在高流速时,通过数字电位器控制功率恒定,探测电路各个参数,从而计算得到温度差,测得流量。该流量计针对内径80 mm的管道,测量范围为0~1500 m3/h,量程约为传统恒温差式流量计的1.3倍,相对误差小于1%,满足实际使用需求。相比于传统恒功率式流量计,该流量计测低流速时精度更高。 相似文献
19.
Chunfeng Fan;Jiahui Han;Ke Gong;Xuehui Hu;Qing Liu;Yufang Liu; 《国际射频与微波计算机辅助工程杂志》2024,2024(1):7924319
A novel and simple design method of wide-passband filters with wide stopband based on half-wavelength (λ/2) resonators coupled by a short connected line (SCL) is proposed and analysed in this paper. Different from the traditional parallel-coupled structure filters, SCL is proposed to realize a strong coupling between two adjacent resonators and suppress the parasitic passbands simultaneously. And the eigenmode analysis method and impedance ratio characteristics are both used to reveal the mechanism of wide-stopband implementation. To further expand the stopband, filters based on step-impedance resonators (SIRs) with SCL are proposed and analysed in detail. To verify the proposed design method and wide-stopband filtering structures, three 4-pole filters with uniform-impedance resonators (UIRs), SIRs with same impedance ratio, and SIRs with different impedance ratios are designed, fabricated, and measured. The proposed filters can realize a wide stopband up to 5.8f0 with rejection level better than 20 dB. Moreover, the proposed filters can easily realize a wide bandwidth. 相似文献
20.
Yasir I. A. Al‐Yasir Yuxiang Tu Naser Ojaroudi Parchin Ahmed M. Abdulkhaleq Jamal Kosha Atta Ullah Raed A. Abd‐Alhameed James M. Noras 《国际射频与微波计算机辅助工程杂志》2019,29(8)
New multi‐standard wide band filters with compact sizes are designed for wireless communication devices. The proposed structures realize dual‐wideband and quad‐wideband characteristics by using a new skew‐symmetrical coupled pair of asymmetric stepped impedance resonators, combined with other structures. The first and second dual‐wideband filters realize fractional bandwidths (FBW) of 43.2%/31.9% at the central frequencies (CF) of 1.875/1.63 GHz, and second bandwidths of 580 MHz/1.75 GHz at CF of 5.52/4.46 GHz, respectively. The proposed quad‐band filter realizes its first/second/third/fourth pass bands at CF 2.13/5.25/7.685/9.31 GHz with FBW of 46.0%/11.4%/4.6% and 5.4%, respectively. The wide pass bands are attributed to the mutual coupling of the modified ASIR resonators and their bandwidths are controllable by tuning relative parameters while the wide stop band performance is optimized by the novel interdigital cross coupled line structure and parallel uncoupled microstrip line structure. Moreover, the quad band is generated by introducing the novel defected rectangle structure. These multi‐standard filters are simulated, fabricated and measured, and measured results agree well with both simulated results and theory predictions. The good in‐band and out‐of‐band performances, the miniaturized sizes and simple structures of the proposed filters make them very promising for applications in future multi‐standard wireless communication. 相似文献