Performance of Frequency Division Multiplexing Readout System for AC-Biased Transition-Edge Sensor X-ray Microcalorimeters

Frequency division multiplexing (FDM) is a promising approach to read out a large format transition-edge sensor (TES) array for future astrophysical missions. We constructed a four channel FDM readout system using baseband feedback in the MHz band. We demonstrated the principle of our FDM method with an actual TES array, a multiplexing SQUID and LC band-pass filters under 100 mK. The resonant frequencies of LC filters were consistent with the design value with an accuracy of better than 3 %. We successfully obtained X-ray pulses from two TESs simultaneously but the energy resolution was degraded to about 100 eV at 5.9 keV and crosstalk effects were observed. The origin of the crosstalk effects is investigated by modified setups. Based on comparative experiments and numerical calculations, we conclude that the non-linearity of the SQUID is the cause of some of the crosstalk effects. Unlike the regular crosstalk effect from the adjoining channels, the crosstalk effect due to non-linearity observed in this paper occurs in all channels. Solving these problems will help us to obtain FDM readout with sufficient energy resolution.     

Direct synthesis of transmission line low-/high-pass filters with series stubs

A direct synthesis procedure is presented for the design of transmission line low-/high-pass filters with series stubs. The proposed prototype consists of a cascade of series stubs of electrical length θc alternating with uniform transmission lines of electrical length 2θc. An exact network synthesis technique is applied on the fully frequency-distributed transmission line filter structures. By short-circuiting these series stubs, a low-pass prototype can be established to synthesise the filters with both predictable in-band and out-of-band behaviours. Instead, if the series stubs are open-circuited, a quasi-high-pass or wide band-pass filter can be designed with specified frequency bandwidth and centre frequency. Based on the formulation of a transfer function, a set of closed-form design formula is derived so that the synthesis design can be carried out for the proposed filters with Chebyshev equal-ripple frequency responses in the concerned low- and high-pass bands. As design examples, two five-pole planar filters based on the low- and high-pass topologies are implemented by using hybrid slotline and coplanar-waveguide structures. After final optimisation is executed via full-wave electromagnetic software to take all the discontinuities into accounts, two designed filters are fabricated and measured to verify the proposed synthesis approach and confirm the theoretical predictions.     

采用IFIR技术的二级FRM滤波器的设计

为获得更好的频率瞄准式干扰效果，需设计一款过渡带尽量窄、带外衰减尽量大的带通滤波器，以避免发射干扰信号时产生的频率泄漏影响对信号的接收。由于现有硬件资源有限，且滤波器过渡带与带外衰减的设计方法无法满足高性能滤波器的设计要求，因此文章采用改进结构的二级有限脉冲响应内插-频率响应屏蔽(Interpolated FiniteImpulse Response-Frequency Response Masking,IFIR-FRM)滤波技术设计高性能带通滤波器，以满足水声对抗器材对频率瞄准技术的性能要求，同时降低了设计复杂度。仿真结果表明，该方法在降低窄带带通FRM滤波器计算复杂度方面效果明显，有效减少了乘法器的使用，降低了目标滤波器设计的阶数，达到频率瞄准式干扰工作模式的技术指标。     

Compact microstrip band-pass filters based on semi-lumped resonators

A new design approach for compact microstrip band-pass filter based on semi-lumped resonators are proposed. The resonators, which are coupled through quarter wavelength meander lines acting as admittance inverters, are shunt connected to the line. They consist of parallel combination of a grounded (inductive) stub and a narrow metallic strip followed by a capacitive patch to ground. With this topology, the necessary degree of flexibility to design narrow and broad-band-pass filters with compact dimensions and good out-of-band performance was obtained. Another key advantage of the devices, as compared to previous lumped or semi-lumped element- based structures reported by the authors, is the absence of ground plane etching. To illustrate the potentiality of the proposed approach, a third-order (30% fractional bandwidth) and a nineth-order (35% fractional bandwidth) Chebyshev band-pass filters have been designed and fabricated. The measured frequency responses are very symmetric and exhibit low in-band losses as well as good out-of-band rejection up to approximately 3f_o. Filter dimensions are as small as 0.40lambda times 0.12lambda (third-order prototype) and 0.62lambda times 0.16lambda (nineth-order prototype), lambda being the guided wavelength at f_o. With these dimensions and performance, and the possibility to synthesise microstrip filters with controllable bandwidth over a wide margin, it is believed that the reported approach can be of actual interest for the design of planar filters at microwave frequencies.     

Surface plasmon polariton based band-pass and stop-band filters in symmetric double ring resonators

We carried out the numerical simulations on plasmonic filters composed by a Metal–Insulator–Metal (MIM) waveguide and a resonator of double rings. Both the band-pass filter and stop-band filters are discussed. The results show that the characteristic wavelengths of the band-pass or stop-band filter have red shift when the size of the resonator increases. The filters of double-ring resonator show better sensitivity on the wavelength than the one for the single ring. The simulations are based on the two-dimensional (2D) finite-difference time-domain (FDTD) method. The introduced filters have potential applications on optical integrated circuits.     

Imprinted laminate wafer-level packaging for SAW ID-tags and SAW delay line sensors

We have developed a wafer-level packaging solution for surface acoustic wave devices using imprinted dry film resist (DFR). The packaging process involves the preparation of an imprinted dry film resist that is aligned and laminated to the device wafer and requires one additional lithography step to define the package outline. Two commercial dry film solutions, SU-8 and TMMF, have been evaluated. Compared with traditional ceramic packages, no detectable RF parasitics are introduced by this packaging process. At the same time, the miniature package dimensions allow for wafer-level probing. The packaging process has the great advantage that the cavity formation does not require any sacrificial layer and no liquids, and therefore prevents contamination or stiction of the packaged device. This non-hermetic packaging process is ideal for passive antenna modules using polymer technology for low-cost SAW identification (ID)-tags or lidding in low-temperature cofired ceramic (LTCC) antenna substrates for high-performance wireless sensors. This technique is also applicable to SAW filters and duplexers for module integration in cellular phones using flip-chip mounting and hermetic overcoating.     

Theoretical and experimental study on a partially driven array antenna with simplified dipole elements

A novel design is proposed to reduce the number of driven elements by replacing them with passive elements or wires in an array antenna. The study is based on the analysis of electromagnetic wave fields by considering of the coupling between the half-wavelength dipoles. An array antenna of two driven elements and two passive elements is considered as a model. After optimising the element arrangement, the antenna gain can match that of the equivalent four-driven element case. The simulation result is confirmed by an experiment that uses dipoles with simplified matching technique. Feeding networks in a high-power radiating system are analysed in terms of the length and matching of feed lines, and the number of amplifiers.     

Investigation and Simulation of a Two-Channel Drop Filter with Tunable Double Optical Resonators

In this paper, a photonic crystal (PhC) two-channel drop filter based on two 2×2 & 2×3 ring resonators is proposed. This structure is made of Germanium rods in an air background at a two-dimensional (2D) square lattice. Refractive index is chosen in a way in which that device can be easily fabricated. The photonic crystal two-channel drop filter is composed using a horizontal waveguide and two ring resonators, which are placed symmetrically about the horizontal axis. These ring resonators operate as energy coupling and capture the electromagnetic energy propagated in bus waveguide at their resonance frequencies. The filter characteristics are calculated using 2D finite-difference time-domain (FDTD) and plane wave expansion (PWE) methods. We show a two-channel drop filter with two resonators, based on studied basic structures and achieving optimal modes for channel drop filters with one resonator. We have done this through choosing the proper radii for all rods of lattice, setting radii of coupling rods, lattice constant, and studying basic structures having different refractive indexes. Finally, we show 84 % and 100 % dropping efficiencies can be achieved at D and C ports in the communication window and 100 % in direct port. The size of this device is 14.56 μm (length)×11.96 μm (width). This small size makes it possible to use the device in multiplexer applications in future communication systems and in all-optical integrated circuits.     

Gearbox Fault Detection Using Real Coded Genetic Algorithm and Novel Shock Response Spectrum Features Extraction

This paper presents an intelligent fault detection method for gearbox. The method uses band-pass and wavelet filtering with real coded genetic algorithm (RCGA) and shock response spectrum (SRS) for features extraction. Vibration data acquired from gearbox are adaptively filtered through a band-pass and wavelet filters optimized by the RCGA. The filtering process unveils the fault pulses buried under huge background noise. Shock response spectrum is used to calculate the amount of shock produced by these pulses over a frequency band of interest for features extraction. The proposed method is a combination of intelligent and conventional search techniques, which shows a high performance and accurate fault detection results. The effectiveness, feasibility, and robustness of the proposed method are demonstrated on experimental data. The RCGA has successfully achieved an average speed up factor of 74 %, as compared to conventional genetic algorithms (GA) while preserving the quality of results.     

Synthesis of the low-temperature co-fired ceramic bandpass filters and diplexer with transmission zeros

The multilayered microwave filters are developed with the assistance of two transmission zeros. Besides a coupled line connected to one capacitor, another capacitor cross coupled between the source and load ports is utilised for the proposed filters. By properly adjusting the coupling coefficients between the coupled line and two capacitors, two transmission zeros would appear on the lower side, the higher side or on both sides of the passband skirt. Thus, the characteristics can be employed for diplexers or dual-band filters to make dual-mode portable telephones. Moreover, to miniaturise the circuit sizes and improve their performances, multilayered structure and the low-temperature co-fired ceramic technology are adopted for filter fabrication. The theorem of filter synthesis and procedures of filter design are also presented. Finally, the proposed structure is validated by an agreement between measured results of fabricated filters and the electromagnetic simulation.     

外推法天线增益测量的核心算法及实验研究

基于外推法测量原理研究了外推法天线增益测量核心算法,重点在于天线互耦的滤波抑制、功率级数展开式的拟合和任意距离下的天线增益求解.此外,还基于以上核心算法设计了一款外推法天线增益测量界面,为外推法天线增益的精密测量提供便利.最后,开展了 W波段标准天线的增益校准实验,增益测量结果与NPL的测量偏差小于0.04 dB,实现...     

Geometric approach for designing optical binary amplitude and binary phase-only filters

An analytic solution for real optimal filters is known, and the special case of optimal binary phase-only filters can be solved by a fast binning algorithm but no analytic solution is known. We establish a geometric solution for the design of optimal binary amplitude filters (OBAF's) and optimal binary phase-only filters (OBPOF's) for any object. The optimal filter is found in terms of maximizing the field strength at the origin in the correlation plane. We found that it is possible to construct a unique convex polygon by using an ordered set of phasors from the filter object's Fourier transform. This process leads eventually to an exact solution for the filter-design problem. We show that the maximum distance across the polygon divides the phasors into two groups: For the OBAF, it determines the group that is passed or blocked; for the OBPOF, it determines which group is passed with a zero or a pi phase shift. The shape of the convex polygon gives qualitative information on the criticalness and the tightness needed in the design process. It provides good insight into the binning-process algorithm and permits us to bound the error in the binning process. Design examples through computer simulation and applications in fingerprint identification are presented.     

多通带滤波技术及冷轧钢板振纹监测

分析数字带通滤波器的特点，结合低通、带通滤波器的设计特点，构造一种多通带的数字滤波器。这种滤波器能快速有效的提取出多个频段信息，并且能柔性地选择频段的上下限和频段数。分析冷轧钢板振纹的基本特点，再根据冷轧钢板振纹的在线监测要求实时显示出多个频段信息的特点，就需要一种高效的多通带滤波技术。鉴于此特点，设计一款基于VB. Net平台的冷轧钢板振纹在线监测软件，将所关心的低、中、高频段显示出来便于观察。此系统已经在某钢厂的冷轧车间中得到应用，结果证明对多频段的信号提取是比较理想的。     

Systematic design approach for capacitively coupled microelectromechanical filters

A design procedure for microelectromechanical (MEMS) band-pass filters is formulated that takes into account specifications set for carrier-to-interference ratio (C/I) and insertion loss. Since suppressing intermodulation distortion to maximize C/I in MEMS filter design typically leads to increased loss and vice versa, it is necessary to aim at a feasible compromise in filter performance that meets all of the requirements. In order to meet specifications that are typical for a handheld communication terminal, an integrated receiver architecture, where filter input and output impedances other than 50 omega can be used, is found to be more feasible than resistively terminating the front-end filter at source and load to 50 omega.     

Frequency Characteristics of Misaligned Tl2Ba2CaCu2O8 Thin-Film Intrinsic Josephson Junction Arrays Irradiated by Millimeter-Wave

We have investigated the millimeter wave irradiation characteristics of misaligned Tl₂Ba₂CaCu₂O₈ thin-film intrinsic Josephson junction arrays at a liquid nitrogen temperature in an antenna system by both simulation and experiments. The dielectric substrate was regarded as a dielectric resonance antenna to improve high-frequency electromagnetic coupling between the intrinsic Josephson junction array and a horn antenna. A useful model for simulating the microwave system was devised to demonstrate and analyze the optimization of the irradiation in the antenna system. The electric field distribution in the antenna system was computed and displayed. Also, the near-field and far-field frequency characteristics of the receiving antenna and transmitting antenna were calculated and analyzed to study the mechanism of the irradiation. In the experiment, by detecting the suppressed critical current of the IJJA, an optimum transmission frequency range was measured and the frequency characteristic was studied in the transmitting and receiving antenna system. The critical current of the IJJA was suppressed to 37 % and the optimum coupling effect was achieved at 74.8 GHz. And the electromagnetic simulation matched up well with the experimental result. Potential reasons of the acceptable nuances between the simulation and experiment results were also taken into account. The influence the size of the microbridge had on the frequency characteristic of the dielectric antenna were elaborately discussed.     

同轴腔体双频合路器设计与实现

提出了一种同轴腔体的双频合路器的设计,采用方腔同轴结构构成的并联带通滤波器来实现.运用综合加优化的方法(以路仿真和场仿真、优化相结合的方法)得出合路器两路滤波器的耦合和输入输出结构参数,并进行了加工制作及测量,得到的仿真和实测结果基本一致.     

Frequency-weighting filter selection for H2 control ofmicrogravity isolation systems: A consideration of the “implicitfrequency weighting” problem

Many space-science experiments need an active isolation system to provide them with the requisite microgravity environment. The isolation systems planned for use with the International Space Station (ISS) have been appropriately modeled using relative position, relative velocity, and acceleration states. In theory, frequency-weighting design filters can be applied to these state-space models, in order to develop optimal H₂ or mixed-norm controllers with desired stability and performance characteristics. In practice, however, since there is a kinematic relationship among the various states, any frequency weighting applied to one state will implicitly weight other states. These implicit frequency-weighting effects must be considered, for intelligent frequency-weighting filter assignment. This paper suggests a rational approach to the assignment of frequency-weighting design filters, in the presence of the kinematic coupling among states that exists in the microgravity vibration isolation problem     

Development of an L-Band HTS Duplexer Sub-system with Novel Stepped Impedance Resonators

This paper presents the design, fabrication, and performance of a high-temperature superconductor (HTS) duplexer sub-system at L-band. The HTS duplexer sub-system contains a low noise amplifier (LNA) and an HTS duplexer. The HTS duplexer consists of a T-junction and two eight-pole filters with a bandwidth of 40 MHz centered at 1245 MHz and 1305 MHz, respectively. A novel, compact, and low radiation stepped impedance resonator was developed to reduce the parasitical coupling of the filters. The HTS duplexer was fabricated on a LaAlO₃ substrate. The insertion loss of the duplexer is 0.2 dB, and the 60/3 dB shape factor is better than 1.4:1. The out-of-band rejection and the isolation between the two channels of the duplexer are better than 60 dB. The noise figure of the HTS duplexer sub-system is 0.3 dB at 80 K.     

Application of correlation filters for texture recognition

We propose a new statistical method to design spatial filters to recognize and to discriminate between various textures. Unlike existing correlation filters, the proposed filters are not meant to recognize specific shapes or objects. Rather, they discriminate between textures such as terrains, background surfaces, and random image fields. The filters do not require any on-line statistical computations for extracting texture information. Therefore optical (or digital) correlators can be used for fast real-time texture recognition without segmentation. The procedure is based on the assumption that textures can be modeled as stationary random processes over limited regions of an image. The optimum filter coefficients are determined by use of eigenvector analysis. Several examples are given to illustrate the proposed scheme.