宽阻带三模谐振器微带带通滤波器设计

介绍了一种新颖的微带三模谐振器,由该谐振器构成的微带滤波器具有较宽的通带以及较好的带外抑制。对传统的单模微带环形谐振器结构进行优化,使谐振器在通带内具有三个谐振点,并且在通带边缘有四个对称衰减极点。引入的阶梯阻抗谐振单元使得微带三模谐振器具有良好的带外抑制。依据传输线原理对宽阻带三模谐振器进行了分析,并完成了中心频率为1090 MHz的宽阻带带通滤波器设计和加工,其实际测试结果与软件仿真结果具有良好的一致性。     

Design techniques for tunable transresistance-C VHF bandpassfilters

In this paper, a tunable wideband linear transresistance (R_m ) amplifier is proposed and analyzed. Using the tunable R_m amplifier, a new transresistance-capacitor (R_m-C) differentiator is designed. Considering the intrinsic capacitances of the MOS transistors as filter elements, this R_m-C configuration can he regarded as a very high frequency (VHF) bandpass biquadratic filter. The proposed biquad has a simple structure and thus occupies a small chip area and consumes little power. Moreover, higher-order VHF bandpass filters can be realized by directly cascading the biquads. Experimental results have successfully proven the capability of the proposed new filter implementation method in realizing VHF bandpass filters with the center frequency higher than 100 MHz when C_d=1 pF. The deviations of the measured center frequency f _o and quality factor Q of the fabricated bandpass filter from the simulated results are less than 8%. The deviation of the center frequency can be post-tuned by adjusting the control voltages V_CN and V_CP of the tunable R_m amplifier. With 1 pF differentiating capacitor, the center frequency of the fabricated VHF R_m-C bandpass filters can be tuned in a wide range larger than 30 MHz. The measured maximum signal level is 25 mV_rms and the dynamic range is 47 dB. The chip area is 0.05 mm² and power consumption is 5.05 mW with ±2.5 V power supply     

A 28-MHz wideband switched-capacitor bandpass filter with transmission zeros for high attenuation

A 28-MHz wideband switched-capacitor (SC) bandpass filter employs an N-path technique and implements transmission zeros in the transfer function to achieve high attenuation. A modified SC biquadratic filter architecture is proposed to achieve high-speed operation. Implemented in a 0.35-/spl mu/m CMOS process, the bandpass filter operates at 28-MHz center frequency with a 3.84-MHz bandwidth and adjacent-channel attenuation of more than 35 dB. At 3-V supply, the filter measures a dynamic range of 37 dB at the 1% THD3 point while dissipating 19.6-mW per pole and occupying a chip area of 1.65 mm/sup 2/.     

Electromechanical-Filter-Based Bandpass Sigma–Delta Modulator

This brief proposes an electromechanical-filter-based continuous-time (CT) bandpass (BP) sigma-delta modulator for wideband digitization at high intermediate frequency (> 70 MHz). Both the mechanically coupled microelectromechanical system and the longitudinally coupled surface acoustic wave (SAW) filters can be employed as loop filters. The advantages of the electromechanical filter are its low power consumption and accurate center frequency without the need for tuning. As a proof of concept, a fourth-order BP sigma-delta modulator is demonstrated with a 110-MHz SAW filter. Realized in a 0.35- mum SiGe heterojunction-bipolar-transistor bipolar complimentary metal-oxide-semiconductor technology, the prototype chip is clocked at 440 MHz and achieves 65-dB DR and 60-dB SNDR over 1 MHz, as well as 58-dB DR and 53-dB SNDR over the 3.84-MHz signal band. The total power consumption is 57 mW under a 3-V supply.     

Switched-capacitor high-Q bandpass filters for IF applications

Experimental results for a sixth-order switched-capacitor bandpass filter with a selectivity Q of 55 at a center frequency of 3.1 MHz are presented. A simple noise analysis of active bandpass filters composed of coupled identical resonators is introduced to explain the dynamic range reduction in high-Q active filters resulting from loose high-Q couplings between resonators. Theoretical predictions of noise in coupled resonator-type bandpass filters agree well with measured results. The prototype chip occupies 2 mm/SUP 2/ and dissipates 45 mW with a single 5-V supply.     

一种基于LTCC的高性能超宽带带通滤波器

提出了一种基于LTCC技术的高性能超宽带带通滤波器的实现方法。该滤波器电路采用交织结构,同时只采用了4个谐振级,有效降低了通带内插入损耗,增大了滤波器带宽。借助电路仿真以及电磁场三维仿真软件进行电路优化,实际测试结果与仿真结果吻合较好,中心频率为1 080 MHz,带宽为500 MHz,在通带内插入损耗优于1.6 dB。由于该滤波器频率较低,属于UHF波段,波长较长,采用半集总半分布式结构实现了滤波器的小型化,封装尺寸仅为3.4 mm×4.8 mm×1.5 mm。     

一种具有陡峭边带的宽带带通滤波器设计

基于一种新型的多模谐振器设计了一款宽带带通滤波器,该多模谐振器由鱼骨形谐振器及中心加载倒T形谐振器构成。滤波器的中心频率位于2.47 GHz,相对带宽为100%。滤波器具有极高的频率选择性,其边带滚降速度分别为232 dB/GHz和168 dB/GHz。此外,滤波器还具有较低插入损耗0.4 dB,紧凑的电路尺寸以及宽阻带抑制能力。     

Compact microstrip stepped impedance wideband bandpass filter

A novel wideband bandpass filter with a very compact size is presented in this article. Using a side-coupled stepped impedance resonator, wideband characteristics with adjustable centre frequency and 3-dB fractional bandwidth can be obtained easily. Finally, a filter sample is designed and fabricated to provide an experimental verification on the proposed topology. Good insertion/return losses, flat group delay, wide bandwidth as well as ultra compact size are achieved as demonstrated in both simulation and experiment, which makes this filter a very promising candidate for applications in future wideband communication system.     

A 2.5-V 57-MHz 15-tap SC bandpass interpolating filter with 320-MS/s output for DDFS system in 0.35-/spl mu/ hboxm CMOS

A switched-capacitor (SC) bandpass interpolating filter is proposed with the capability of achieving, simultaneously, channel selection and frequency up-translation, together with sampling rate increase, in a multirate configuration at high frequency. This filter has been designed for efficient use in a direct-digital frequency synthesis (DDFS) system with considerable rewards in terms of speed reduction of the digital core plus the digital-to-analog converter (DAC), as well as in the relaxation of the continuous-time (CT) smoothing filter order. It exhibits a 15-tap finite impulse response (FIR), with a bandpass frequency response centered at 57 MHz and a stop-band rejection higher than 45 dB. At the same time, it translates 22-24 MHz input signals at 80 MS/s, to the frequency range of 56-58 MHz in the output at 320 MS/s, allowing also a perfect operation at 400 MS/s, in 0.35-/spl mu/m CMOS technology. To implement a specific multi-notch FIR function, the filter architecture will comprise an effective low-speed polyphase-based interpolation structure with autozeroing capability, high-speed SC circuitry with fast opamps, and also ultra-low timing-skew multiple phase generation in order to achieve high-performance operation at high frequency. The prototype ICs present a signal-to-noise-and-distortion ratio (SNDR) of 61 dB, with a dynamic range of 69 dB, for 1% THD, and 61 dB, for 1% IM3. It consumes 2 mm/sup 2/ of active silicon area, 120 mW (analog) and 16 mW (digital) power, with a single 2.5-V supply, which corresponds to 8.6 mW of analog power per zero.     

一种新颖羊角形缺陷地结构宽带带通滤波器

为了得到小型化的带通滤波器,该文提出了一种新的羊角形缺陷地结构(DGS),并将其与耦合开路枝节线结合,设计并制作了一种新型宽带带通滤波器。该带通滤波器的中心频率为7.95GHz,3dB通带为5.25~10.65GHz,相对带宽达到了68%。与以往的宽带带通滤波器相比,它具有结构简单,尺寸小的特点,仿真和测量结果吻合较好。     

A 12-Pole Narrowband Highly Selective High-Temperature Superconducting Filter for the Application in the Third-Generation Wireless Communications

An ultra-selective high-temperature superconducting bandpass filter was designed and fabricated to satisfy the demands of the third-generation wireless communications. This filter was designed to have 12-pole quasi-elliptic response with 4.68-MHz bandwidth in the third-generation communications band (a fractional bandwidth of 0.0023). Full-wave simulations were conducted by using Sonnet software. A novel, compact, and low radiation resonator with a high-quality (Q) factor value was developed to reduce the parasitical coupling. In order to satisfy the demand of high band-edge steepness, three pairs of transmission zeros at finite frequencies were introduced in the cascaded quadruplet coupling structure. The filter was fabricated on a 2-in-diameter 0.43-mm-thick sapphire wafer with double-sided YBCO films. The measurements showed that the passband center frequency (f₀) of the filter is 2.038 GHz at 67 K with a midband insertion loss of 0.67 dB and the return loss better than 15 dB. The measured response of the filter also exhibited ultra-high band-edge steepness of 140-220 dB/MHz. Better than 60 dB of out-of-band rejections for frequencies very close to the band edge (|f-f₀|>2.7 MHz), better than 90 dB at frequencies 7.5 MHz away from the center frequency and up to 100 dB of wideband rejections were achieved     

Compact bandpass filter based on two meandered parallel-coupled lines in different lengths

A new compact bandpass filter based on two meandered parallel-coupled lines of different lengths in shunt is presented, using the signal-interference technique, this filter obtains a low insertion loss and sharp rejection. A set of analytical formulas and guidelines for the design of the bandpass filter are provided in two theoretical analysis methods. According to the number of attenuation poles of the reflection coefficients in the passband, it can be summed up two types of filters. To validated this topology, two wideband bandpass filters centered at 3 GHz are built to verify the theoretical prediction, the measured frequency response of the filter agrees excellently with the predicted result.     

一种宽带信号数字下变频的实现方法

在宽带、超宽带应用中,单一信号带宽达几百兆赫兹;或者在不同中频同时调制多个信号产生的宽带信号也达数百兆赫兹,用常规的数字下变频方法很难实现。文章提出了一种基于DFT滤波器组的高效数字下变频结构,分析了该解调算法的特点和实现性能。对已知信号带宽和中频的宽带信号,对比了DFT滤波器组和多相分解算法的性能。对信号带宽和中频均在变化的信号,给出了实现思路。最后,给出了该DFT滤波器组的硬件实现方案。     

一种具有陷波特性的超宽带带通滤波器

采用修改的多模谐振器(MMR)结构,在输入端与输出端开槽形成交叉耦合,实现了一种结构紧凑、频率选择性较高的超宽带(UWB)带通滤波器。修改的多模谐振器能产生5个模式和2个在高低截止频率附近的传输零点,提高了频率选择性。在滤波器的基础上,通过加载谐振器,形成在8.11 GHz处具有陷波特性的超宽带带通滤波器。利用HFSS13.0验证设计原理。仿真结果表明,该超宽带带通滤波器通带为2.61~11.21 GHz,陷波频率为8.11 GHz,能有效抑制X频段(7.91~8.31 GHz)卫星通信系统对超宽带通信系统的影响,适用于超宽带无线通信系统。     

A Wideband ΔΣ Digital-RF Modulator for High Data Rate Transmitters

A wideband software-defined digital-RF modulator targeting Gb/s data rates is presented. The modulator consists of a 2.625-GS/s digital DeltaSigma modulator, a 5.25-GHz direct digital-RF converter, and a fourth-order auto-tuned passive LC RF bandpass filter. The architecture removes high dynamic range analog circuits from the baseband signal path, replacing them with high-speed digital circuits to take advantage of digital CMOS scaling. The integration of the digital-RF converter with an RF bandpass reconstruction filter eliminates spurious signals and noise associated with direct digital-RF conversion. An efficient passgate adder circuit lowers the power consumption of the high-speed digital processing and a quadrature digital-IF approach is employed to reduce LO feedthrough and image spurs. The digital-RF modulator is software programmable to support variable bandwidths, adaptive modulation schemes, and multi-channel operation within a frequency band. A prototype IC built in 0.13-mum CMOS demonstrates a data rate of 1.2 Gb/s using OFDM modulation in a bandwidth of 200 MHz centered at 5.25 GHz. In-band LO and image spurs are less than -59 dBc without requiring calibration. The modulator consumes 187 mW and occupies a die area of 0.72 mm².     

A Wideband Superconducting Filter Using Strong Coupling Resonators for Radio Astronomy Observatory

A 12-pole wideband superconducting microstrip bandpass filter, which has a fractional bandwidth of 38% and a center frequency of 1455 MHz, is presented for the Miyun 50-m radio astronomy telescope, Beijing, China. A novel resonator, which can not only generate very large coupling, but also push its first spurious resonant peak away from the passband, is introduced. A new style interleaved coupling structure is proposed and successfully used in this study to realize the remarkably required strong coupling. To achieve high edge slope on the high side of the passband, as required, a single transmission zero was introduced. The filter was fabricated on a 36 mm$,times,$ 30 mm$,times,$ 0.5 mm double-sided YBa$_{2}$ Cu$_{3}$ O$_{7}$ film deposited on an MgO substrate. The measured results showed that the filter had 0.05-dB minimum insertion loss, 0.08-dB passband ripple, and 23-dB return loss at a temperature of 40 K. The first spurious peak did not appear until 2632 MHz. The overall measured performance showed good agreement with the simulation.      

Quasi-elliptic filter characteristics of an asymmetric defected ground structure

An asymmetric defected ground structure (DGS) with respect to a microstrip line is proposed. Its unit cell consists of two square slots connected with a rectangular slot by meandered transverse slots. The simulated, measured and equivalent circuit responses have been presented. The unit DGS pattern under microstrip line produces wide rejection bandwidth and high sharpness factor. Its elliptic band-reject filter response is modelled by appropriate LC equivalent circuit. Two such DGS cells under a microstrip line produce 3-pole quasi-elliptic bandstop filter response, which shows deeper attenuation without appreciable change in pole frequencies in comparison to single cell structure. Unit DGS pattern under coupled gap microstrip lines produces band-accept filtering characteristics. The frequency characteristics show a quasi-elliptic highpass filtering characteristics with sharp lower transition knee. Accordingly, an LC equivalent circuit is proposed. A cascaded band-accept and band-reject filter is proposed for designing a wideband bandpass filter. The bandwidth and centre frequency of the bandpass filter can be varied by choosing different set of DGS dimensions.     

基于LTCC的超宽带巴伦滤波器小型化设计

该文设计了一种基于低温共烧陶瓷(LTCC)技术的小型化超宽带巴伦(Balun)滤波器。该巴伦滤波器由一个五阶带通滤波器和基于Marchand巴伦改进型巴伦级联组成,带通滤波器采用耦合谐振式的设计方法,设计成宽带高抑制巴伦滤波器,在二阶、三阶和四阶谐振之间创新采用电感级联的拓扑结构,使相对带宽在48%以上。巴伦输入与输出之间的耦合采用一种并联堆叠式耦合螺旋传输线,增强了传输线之间的耦合,并拓宽了巴伦的带宽。结果表明,该巴伦滤波器通带为1.71～2.76 GHz,插损均小于2.3 dB;在50～669 MHz,抑制大于35 dB;在669～1 245 MHz,抑制大于17 dB;在3 205～3 400 MHz,抑制大于27 dB;在3 400～6 000 MHz,抑制均大于30 dB。两个输出端口信号的相位差和幅度差分别为180°±15°(1 710～2 340 MHz)、180°±10°(2 500～2 760 MHz)和±1.0 dB,具有较高的通用性和良好的应用市场。     

Variable Bandpass Filters Using Varactor Diodes

A rectangular waveguide type variable bandpass filter for the 4-GHz bandpass has been proposed and tested. The bandpass width varies from 260 MHz to 1.02 GHz for a filter using varactor diodes. Two microstrip variable bandpass filters for the 6-GHz and 4-GHz bands are also proposed and tested. The passband width varies from 310 MHz to1.24 GHz for a varactor-diode coupled filter, and it varies from 380 MHz to 2.18 GHz for a filter which is composed of low-pass and high pass filters connected in cascade. The center frequency of the three filters can be changed arbitrarily.     

On the use of Nauta's transconductor in low-frequency CMOS gm-C bandpass filters

This paper discusses the use of a transconductor, first proposed by Nauta for high frequency applications, in low frequency CMOS g_m -C bandpass filters. The behavior of the transconductor is examined in detail, showing that the robust implementation of higher-order low-voltage filters is possible for center frequencies in the lower megahertz region. The experimental results are presented of the realization of two prototypes, a 0.6-μm CMOS 18th-order real bandpass filter and a 0.35-μm CMOS 7th-order complex (14th-order bandpass) filter, both with a center frequency of 3 MHz and a passband of 1 MHz. These filters comply with the specifications for the channel-select stage of the Bluetooth short-range radio receiver