COMPACT COUPLED LINEAR TAPERED LINE BANDPASS FILTER WITH TWO TRANSMISSION ZEROS

A new compact bandpass filter composed of two coupled linear tapered line resonators (LTLRs) is designed. The two resonators are arranged in different layers. The filter has two transmission zeros on both sides of the passband. It has small size and steep response below its passband. It is also shown that this filter has 0.6 dB low insertion loss at the centre frequency and 10.5% 3dB bandwidth.     

Development of new miniaturised bandpass filter having ultrawidebandwidth

A new, compact, very-broadband bandpass filter, consisting of two-parallel-conductor short-circuited spurline resonators, quarter-wavelength long, is described. Approximate design formulas for the filter are derived. The chain matrix of the resonators is also obtained and used in predicting the filter response. It is found that this filter possesses a very wide bandwidth, more than 5:1. A microstrip filter having a passband from 1.8 to 9.2 GHz has been designed and tested with less than 1 dB insertion loss. There is also a reasonably good agreement between the experimental and theoretical performances. The developed filter is very attractive for wideband microwave integrated circuits due to its compactness and very wide bandwidth     

Design of low-pass filter with 3-interations Koch fractal Pi-shaped DGS

A novel asymmetrical Pi-shaped defected ground structure (DGS) with 3-interations Koch fractal curves is proposed to design a microstrip low-pass filter (LPF) with ultra-wide stop-band (SB). The proposed LPFs with a single resonator and two cascaded resonators are both designed, simulated, manufactured and measured. Simulation and experiment results demonstrate that the designed LPF has a very sharp transition band (TB) and an ultra-wide SB performance compared with the existed similar symmetrical and asymmetrical DGS. The proposed LPF with two cascaded resonators is with a compact size of 36.8 mm×24.0 mm, a very low insertion loss of less than 0.7 dB under 1.9 GHz, and a wide SB from 2.2 GHz to 8 GHz with rejection of larger than 30 dB.     

A Ka-band narrow bandpass filter using LTCC technology

A Ka-band low-temperature co-fired ceramic (LTCC) narrow bandpass filter (BPF) is presented first. This BPF shows a very narrow 3 dB fractional bandwidth of 4.5% centered at 28.7 GHz. The advantages of multilayered LTCC technology such as high integration and vertical stacking capabilities were employed to design a three-dimensional interdigital end-coupled embedded microstrip narrow BPF. The difficulties in controlling the precise distance between two adjacent resonators in LTCC end-coupled BPF were overcome by locating the resonators on different layers. The measured insertion loss is 3 dB at 28.7 GHz.     

Novel Bandpass Filter Configuration Using Coupled Linear Tapered Line Resonators

A novel tapped bandpass filter composed of two‐coupled linear tapered‐line resonators (LTLRs) is proposed. Multistepped resonators are applied to analyzing LTLRs, which are difficult to analyze directly. Through this analysis method, fundamental characteristics of LTLRs and their filter design parameters can be easily derived. This new filter has insertion loss less than 0.6dB at 1.9 GHz, the return loss less than 18dB in the range 1.8‐1.93GHz and 12.3% 3dB bandwidth. Experimental results of fabricated filter are in good agreement with the design results.     

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。     

Compact microstrip low pass filter with flat group-delay using triangle-shaped resonators

In this paper, a compact microstrip lowpass filter (LPF) using triangle-shaped resonators is presented. The designed LPF includes three symmetric triangle-shaped resonators to provide a suitable passband and sharp response. A suppressing unit composed of several suppressing cells is designed to obtain a wide rejection band and low insertion loss in the passband. The fabricated LPF has been measured and indicts that it has −3 dB cut off frequency at 5.15 GHz. The rejection band has been expended from 5.51 GHz to 43.2 GHz with maximally flat return loss in this region nearby to 0 dB. Also, simulation and experimental results show that the proposed filter has a very flat group delay in the passband, which is the minimum value in comparison with the published works since 2017.     

Low-pass and high-pass filters using coaxial-type dielectric resonators

This paper proposes new low-pass and high-pass filters using coaxial-type dielectric resonators. The low-pass filter has a LC-type circuit structure and is composed of three inductances and two resonance circuits. The resonance circuits are the open-ended coaxial-type dielectric resonators whose length is λg/4. The high-pass filter has a CL-type circuit structure. Two high-pass filters are described, one of them is composed of three capacitances andtwo resonance circuits, the other is composed of five capacitances and four resonance circuits. The operating frequency range of the low-pass filter is 0.13–0.9 GHz and the cutoffency is 900 MHz, and the insertion loss is 0.3 dB. The corresponding quantities of the high-pass filter are 0.9–2.5 GHz, 900 MHz, and 0.3 dB, respectively.     

一种新型复合结构的四分之一波长带通滤波器

提出了一种基于共面波导(Coplanar Waveguide,CPW)和微带线复合结构的四分之一波长带通滤波器(Bandpass Filter,BPF)。该带通滤波器由两个终端开路的T形微带馈线结构和四个交叉耦合的四分之一波长CPW谐振器组成。通过仿真优化得到其特性曲线图,并分析比较了不同参数对其滤波性能的影响。仿真结果表明,该带通滤波器在其2.97～3.03 GHz的通带内的最小插损低于0.4dB,回波损耗大于30dB,同时其带外衰减都大于25dB。这种滤波器结构紧凑,尺寸小,性能好,可应用于很多微波系统中。     

High Performance Microstrip Low Pass Filter for Wireless Communications

A microstrip low-pass filter using T-shaped resonators is designed to achieve an ultra-sharp transition band and high suppression level. The performance of the resonators is investigated based on an LC equivalent circuit and a transfer function to compute the equations of the transmission zeros. This filter has an acceptable stopband with high insertion loss (28 dB) by adopting a rectangular suppressor. Also, the width of the transition band is 0.09 GHz (with – 3 and ? 40 dB attenuation levels), that exhibits a very high sharpness (ξ = 411 dB/GHz). The proposed filter with a 3 dB cut-off frequency (f_c) of 1.32 GHz presents a high return loss in the passband (17 dB) and high figure of merit of 57,073. The designed filter is fabricated and measured, demonstrating sufficient agreement between the simulation and experimental results.

     

Design of an asymmetrical dual-band WLAN filter in liquid crystal polymer (LCP) system-on-package technology

A single-input-single-output (SISO) dual-band filter operating at ISM 2.4-2.5GHz and UNII 5.15-5.85GHz frequency bands, using the novel "dual behavior resonators" technique has been developed. Exploiting the strong second resonant frequency of resonators to realize the filtering response, allows for achieving the asymmetric shape and the good rejection between the two bands. The insertion loss and return loss at the central frequency are -2.4 dB and -15 dB for the 2.4-GHz band, respectively, and -1.8 dB and -10 dB for the 5-GHz band, respectively. The filter has been fabricated using the novel liquid crystal polymer (LCP) based multilayer packaging technology, enabling a low cost SOP implementation.     

New compact wideband bandpass filter using three parallel-coupledlines

A new miniature bandpass filter, comprising three-conductor short-circuited spurline resonators of approximately a quarter-wavelength long, with a very wide bandwidth approaching multioctaves is reported for the first time. The chain matrix of the filter resonator is derived. The new filter has been developed using microstrip line with less than 1 dB insertion loss over a passband from 2 to 8 GHz. Reasonably good agreement between the measured and calculated results is observed     

Compact microstrip lowpass filter with very sharp roll-off using meandered line resonators

In this paper, a new compact size microstrip lowpass filter (LPF) with a very sharp roll-off is presented to apply in the modern wireless networks. The proposed LPF is designed using the series main resonators with meandered lines based on inductor-capacitor (LC) equivalent circuit analysis. The main goal is to achieve maximum-sharp roll-off by maintaining a wide stopband bandwidth and high return loss (RL). The main resonator of the proposed filter is consisted of two meandered line hairpin resonators (MLHR), and a meandered line T-shaped resonator (MLTR). The designed suppressor is composed of two coupled radial stubs to create a wide stopband. Low return loss in the passband, which has been created by the main resonator, is resolved by the suppressor structure with high return loss. The measured results show a ??3 dB cut-off frequency of 1.93 GHz. The very sharp transition band starts at 1.93 to 1.97 GHz (from ??3 to ??20 dB). The stopband is from 1.97 to 19.9 GHz (with the suppression level of ??20 dB). Also, the total size of the proposed LPF is only 13.3?×?10.1 mm².

     

Compact size and low insertion loss Chebyshev-function bandpassfilters using dual-mode patch resonators

A compact Chebyshev-function bandpass filter using dual-mode patch resonators is proposed. The filter presents 75% size reduction compared with the conventional Chebyshev bandpass filter using two square patch resonators. Because of inset feeding and only one coupling gap being required, the new filters can achieve a low insertion loss of 1.1 dB and reduce the fabrication uncertainties     

一种新型介质谐振器带通滤波器

本文阐述一种能与微波集成电路结合使用的新型介质谐振器带通滤波器。这种滤波器是目前能用于微波集成电路的性能最佳的一种窄带滤波器。本文对这种滤波器作了理论分析;并导出了有关滤波器设计的主要公式;给出了一至四谐振器带通滤波器的实测性能。例如:一个相对带宽为 0.2％的 5cm三谐振器滤波器,其带内插损为 0.8dB左右,带外衰减大于50dB,30dB与 3dB的带宽比约为 3.3。     

基于QMSIW小型化带通滤波器设计

为有效减小X波段基片集成波导(SIW)滤波器的尺寸和插入损耗,提出了基于四分之一模基片集成波导(QMSIW)和共面波导(CPW)混合结构的小型化带通滤波器。为了提高滤波器的选择性和带外抑制,将两个CPW合并到两个级联的QMSIW谐振器中,由于两个CPW谐振器之间的耦合是电耦合,有助于产生两个传输零点,因而具有较高的选择性。该小型化滤波器尺寸仅为8.1 mm×15.4 mm,中心频率为8.7 GHz,相对带宽是16.1%,仿真测得插入损耗为0.83 dB,带外抑制大于40 dB。     

Conductor-loss limited stripline resonator and filters

We report on stripline resonators on thin dielectric membranes that show dispersion-free, conductor-loss limited performance at 13.5 GHz, 27.3 GHz, and 39.6 GHz. The unloaded-Q (Q_u) of the resonators increases as √f with frequency and is measured to be 386 at 27 GHz. The measured results agree well with a new conformal mapping analysis. The stripline resonators are used in a micromachined state-of-the-art planar interdigitated bandpass filter at K-band frequencies. Excellent agreement has been achieved between the microwave model at 850 MHz and the 20 GHz filter. The micromachined filter exhibits a passband return loss better than -15 dB and a conductor-loss limited 1.7 dB port-to-port insertion loss (including input/output CPW line loss) at 20.3 GHz     

A single-chip GaAs MMIC image-rejection front-end for digitalEuropean cordless telecommunications

An active image-rejection filter is presented in this paper, which applies actively coupled passive resonators. The filter has very low noise and high insertion gain, which may eliminate the use of a low-noise amplifier (LNA) in front-end applications. The GaAs monolithic-microwave integrated-circuit (MMIC) chip area is 3.3 mm² . The filter has 12-dB insertion gain, 45-dB image rejection, 6.2-dB noise figure, and dissipates 4.3 mA from a 3-V supply. An MMIC mixer is also presented. The mixer applies two single-gate MESFETs on a 2.2-mm² GaAs substrate. The mixer has 2.5-dB conversion gain and better than 8-dB single-sideband (SSB) noise figure with a current dissipation of 3.5 mA applying a single 5-V supply. The mixer exhibits very good local oscillator (LO)/RF and LO/IF isolation of better than 30 and 17 dB, respectively, Finally, the entire front-end, including the LNA, image rejection filter, and mixer functions is realized on a 5.7-mm ² GaAs substrate. The front-end has a conversion gain of 15 dB and an image rejection of more than 53 dB with 0-dBm LO power. The SSB noise figure is better than 6.4 dB, The total power dissipation of the front-end is 33 mW. The MMIC's are applicable as a single-block LNA and image-rejection filter, mixer, and single-block front-end in digital European cordless telecommunications. With minor modifications, the MMIC's can be applied in other wireless communication systems working around 2 GHz, e.g., GSM-1800 and GSM-1900     

Improved and compact 0.7 GHz tune-all bandpass filter

A compact tune-all bandpass filter is presented. This electronically tuned filter is based on series-coupled slow-wave resonators. It allows wide simultaneous and continuous tunings of centre frequency (+/-15% around 0.7 GHz) and bandwidth (from 50 to 100 MHz) with insertion loss IL<5.4 dB and return loss RL>11 dB. This two-pole bandpass filter exhibits also a very small surface of only 7.3times10^-3 lambda₀ ² and a -20 dB stop-band that extends up to 10 GHz     

HTS coplanar meander-line resonator filters with a suppressed slot-line mode

The design and experimental results of a four-pole coplanar waveguide (CPW) quasi-elliptic filter using high-temperature superconductor (HTS) films are presented. Quarter-wavelength meander-line resonators are used in the filter topology. Although the resonators are aligned in two lines, no bond-wire bridges are required to balance the ground planes in the design and measurement. The slot-line mode of the filter was shifted to be higher than its third harmonic. The filter is highly miniaturized and the performance is significantly improved by the use of superconductors. The main circuit of the filter only has an area of about 6.6 mm /spl times/ 2.4 mm on a magnesium oxide substrate, coated with 600-nm-thick YBCO HTS thin film on single side of the substrate. The 3-dB bandwidth is about 1.6% centered at 2.95 GHz. The performance measured at 30 K, without any tuning, gives an insertion loss of better than 0.4 dB and a return loss of about 12 dB in the passband. The first spurious mode is about triple the center frequency.