Narrow passband high-temperature superconducting filters of highly compact sizes for personal communication service applications

A novel highly compact high-temperature superconducting filter based on spiral lumped elements was demonstrated for personal communication system applications. The filter consists of eight-pole microstrip resonators enclosed in a substrate 0.5 /spl times/ 5 /spl times/ 32 mm. The filter was designed to have a bandwidth of 17 MHz and a center frequency of 1760 MHz. A low insertion loss of 0.4 dB in the passband with an out-of-band rejection loss of about -70 dB was observed at 65 K. Measured characteristics of the filter showed good agreement with simulated responses.     

Efficient built-in redundancy analysis for embedded memories with 2-D redundancy

A novel redundant mechanism is proposed for embedded memories in this paper. Redundant rows and columns are added into the memory array as in the conventional approaches. However, the redundant rows and columns are divided into row blocks and column blocks, respectively. The reconfiguration is performed at the row (column) block level instead of the conventional row (column) level. Based on the proposed redundant mechanism, we first show that the complexity of the redundancy allocation problem is NP-complete. Thereafter, an extended local repair-most (ELRM) algorithm suitable for built-in implementation is proposed. The complexity of the ELRM algorithm is O(N), where N denotes the number of memory cells. According to the simulation results, the hardware overhead for implementing this algorithm is below 0.17% for a 1024/spl times/2048-b SRAM. Due to the efficient usage of the redundant elements, the manufacturing yield, repair rate, and reliability can be improved significantly.     

Multilayer spatial angular filter with airgap tuners to suppress grating lobes of 4/spl times/1 array antenna

A multilayer spatial angular filter with airgap tuners to suppress the grating lobes of a 4/spl times/1 array antenna is proposed. By using the airgap tuner, a commercial standard substrate can be chosen for the filter, to achieve its resonance condition, instead of /spl lambda//sub g//4 substrate. The measured beam patterns of the 4/spl times/1 array with the filter show that the grating and sidelobes are effectively diminished by 15 to 30 dB in the region of interest.     

Design and performance of a compact forward-coupled HTS microstrip filter for a GSM system

A practical design technique for a compact forward-coupled microstrip bandpass filter structure is introduced based on a computer-aided simulation and optimization software TUMIC. The structure consists of a parallel array of fully aligned half-wavelength resonators. Aimed at the application in the front-end receiver of a GSM base station, a 9-pole high-temperature superconductor filter with 2.6% fractional bandwidth at 1732.5 MHz was designed and fabricated using double-sided YBCO thin films on a 30-mm/spl times/30-mm/spl times/0.5-mm LaAlO/sub 3/ wafer. The S-parameter measurements show a good agreement with the simulated results. At 30 K, the filter has less than 0.4-dB insertion loss, 0.3-dB passband ripple, and better than 12-dB return loss.     

A 1-Mbit CMOS dynamic RAM with a divided bitline matrix architecture

A 1-Mb dynamic RAM has been fabricated using 1.2-/spl mu/m double-level metal CMOS technology. A novel divided bitline matrix architecture allows the conventional double-polysilicon planar memory cell to be used without sacrificing signal-to-noise (S/N) ratio or die efficiency. Optimized for high bandwidth, the device uses static column circuitry and a 256K/spl times/4 organization to achieve data rates >180 Mb/s at worst-case voltage and temperature conditions. The 5.97-mm/spl times/11.4-mm die incorporates a flexible laser blown fuse link redundancy scheme which can repair a wide variety of fabrication defects. Typical row access and cycle times are 85 and 190 ns, respectively, achieving >21-Mb/s bandwidth in the non-optimized row access mode. Although some DC power is dissipated in static circuitry, active power consumption has been kept to 225 mW (45 mA), and standby power consumption has been reduced to 2.5 mW (0.5 mA).     

The design and performance of CMOS 256K bit DRAM devices

The design and performance of CMOS 256K bit dynamic random access memory devices with 256K/spl times/1 and 64K/spl times/4 output configurations are presented. An advanced CMOS technology, with device scaling to the HMOS-III level, is used to provide effective solutions to critical device and circuit problems in DRAM design and to offer features not previously implemented in NMOS designs. The cell and die area are 70 /spl mu/m/SUP 2/ and 253 mil /spl square/ (6.3 mm /spl square/), respectively. The typical row access time is less than 100 ns. The p-channel memory array used in this design improves the memory refresh characteristics and reduces the soft error rates. The use of static and clocked CMOS circuits provides lower active power, wide operating margins, microwatt standby power, and high column data bandwidth. The 256K bit devices are designed with two output modes, namely, ripplemode and static column mode, selected by a metal mask option.     

Low-loss LTCC cavity filters using system-on-package technology at 60 GHz

In this paper, three-dimensional (3-D) integrated cavity resonators and filters consisting of via walls are demonstrated as a system-on-package compact solution for RF front-end modules at 60 GHz using low-temperature cofired ceramic (LTCC) technology. Slot excitation with a /spl lambda/g/4 open stub has been applied and evaluated in terms of experimental performance and fabrication accuracy and simplicity. The strongly coupled cavity resonator provides an insertion loss <0.84 dB, a return loss >20.6 dB over the passband (/spl sim/0.89 GHz), and a 3-dB bandwidth of approximately 1.5% (/spl sim/0.89 GHz), as well as a simple fabrication of the feeding structure (since it does not require to drill vias to implement the feeding structure). The design has been utilized to develop a 3-D low-loss three-pole bandpass filter for 60-GHz wireless local area network narrow-band (/spl sim/1 GHz) applications. This is the first demonstration entirely authenticated by measurement data for 60-GHz 3-D LTCC cavity filters. This filter exhibits an insertion loss of 2.14 dB at the center frequency of 58.7 GHz, a rejection >16.4 dB over the passband, and a 3-dB bandwidth approximately 1.38% (/spl sim/0.9 GHz).     

Extended-stopband bandpass filter using both half- and quarter-wavelength resonators

A novel quasielliptic microstrip bandpass filter (BPF) using both half- and quarter-wavelength resonators is proposed. With the quarter-wavelength (/spl lambda//4) resonators placed in the interstage, the filter spurious passband can be pushed up to 3 f/sub 0/ where f/sub 0/ stands for the passband center frequency. To improve the stopband characteristics, a modified stopband-extended filter is implemented, utilizing the multiple transmission zeros placed at specified frequencies to achieve good frequency selectivity and out-of-band rejection. The modified filter provides a 22.5-dB rejection level from 1.14 f/sub 0/ to 5.2 f/sub 0/.     

Autoassociative neural networks and noise filtering

We introduce linear autoassociative neural (AN) network filters for the removal of additive noise from one-dimensional (1-D) time series. The AN network will have a (2M+1)/spl times/L/spl times/(2M+1) architecture, and for M fixed, we show how to choose the optimal L value and output coordinate from square error estimates between the AN filter outputs and the clean series. The frequency response of AN filters are also studied, and they are shown to act as matched band filters. A noise variance estimate is also derived from this analysis. We numerically illustrate their behavior on two examples and also compare their theoretical performance with that of optimal Wiener filters.     

Miniature broadband bandpass filters using double-layer coupled stripline resonators

A novel double-layer coupled stripline resonator structure is introduced to realize miniature broadband bandpass filters. Filters with relative bandwidth up to 60% and size less than /spl lambda//8/spl times//spl lambda//8/spl times/h (/spl lambda/ is wavelength at the midband frequency; h is the substrate height, which is much smaller than /spl lambda//8) can be fulfilled using such resonators. Two possible filter configurations are proposed in this paper: combline and interdigital. The filter synthesis procedure follows the classical coupling matrix approach that generates very good initial responses. Optimization by the mode-matching method and fine tuning in Ansoft's High Frequency Structure Simulator are combined to improve the filter performance. Two filter design examples are given to validate the feasibility. Low temperature co-fired ceramic (LTCC) technology is employed to manufacture the filters. Experimental results of the two manufactured filters are presented. The effects of LTCC manufacturing procedure on the filter performance are also discussed.     

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。     

Precision fabrication techniques and analysis on high-Q evanescent-mode resonators and filters of different geometries

High-Q evanescent-mode resonators and filters are realized by both silicon micromachining and layer-by-layer polymer processing. Capacitively loaded cavities can be reduced to a size much smaller than a wavelength, but still have a much higher unloaded Q than lumped elements. The loaded resonators are utilized for reduced-size filters with a low insertion loss enabled by the relatively high-Q factor. The small fabrication tolerances of silicon micromachining and polymer stereolithography processing enable the realization of highly loaded evanescent-mode resonators and filters. A 14-GHz resonator micromachined in silicon has a volume of 5 mm /spl times/ 5 mm /spl times/ 0.45 mm, representing a resonant frequency reduction of 66.8% compared to an empty cavity of the same dimensions. The polymer-based fabrication is used to create resonators of different three-dimensional geometries with Q's up to 1940 and frequency reductions up to 49.9%. An insertion loss of 0.83 dB is measured in a 1.69% bandwidth filter created by polymer processing with a frequency reduction of 47% compared to an unloaded cavity. The frequency sensitivity to fabrication tolerances of these structures is also analyzed.     

A 16-kbit nonvolatile charge addressed memory

A 16-kbit nonvolatile charge addressed memory (NOVCAM) is described. A unique cell design allows a high-density memory array layout without reduced line widths or spacings. A cell size of 0.5 square mils is produced by a seven mask process with 6-/spl mu/m polysilicon gates, 10-/spl mu/m aluminum gates, and 10-/spl mu/m minimum spacing on all mask levels. Charge addressed write and read operations are implemented with a very simple interface between the memory array and a two-phase dynamic shift register. The memory is organized as 256 columns by 64 rows. Two 64-bit shift registers provide data access to the memory array via a 2:1 column decoder. With single polysilicon processing the memory array is 50/spl times/161 mils; the 16-kbit chip is 131/spl times/200 mils.     

Resonator size effects on the TFBAR ladder filter performance

Thin-film bulk acoustic resonators with different resonator sizes are simulated and measured. Their effects on ladder filter performance are also presented. Aluminum nitride and platinum are used as piezoelectric material and electrodes, respectively. As the shunt resonator size increases, out-of-band rejection performance has been improved. The 3/2 stage filters that have twice or three times larger resonators reveal 6 dB and 11 dB out-of-band rejection improvements, respectively.     

A new compact LTCC bandpass filter using negative coupling

This letter presents the design and realization of a new compact bandpass filter (BPF) fabricated on multilayered ceramic substrates. This BPF features coupled resonators with negative coupling coefficients. A BPF with center frequency 2.45 GHz is designed and fabricated. Its size is only 2.0 mm/spl times/1.8 mm/spl times/0.67 mm when implemented by a standard low temperature co-fired ceramic technology. The size reduction is due to the higher coupling coefficient between the negatively-coupled resonators than the positively-coupled ones, allowing tighter space between the resonators. The measured insertion losses of the previous BPF were less than 3dB and return losses more than 18dB in the passband. The measured result agrees very well with the electromagnetic (EM) designed response.     

A 13-b 1.1-MHz oversampled DAC with semidigital reconstruction filtering

A digital-to-analog converter (DAC) composed of a cascaded digital /spl Sigma//spl Delta/ modulator and the combination of a semidigital/digital finite-impulse response (FIR) and an infinite-impulse response (IIR)-SC/RC filter is described. The architecture enables the analog linear reconstruction of 16/spl times/ oversampled digital signals. With the analog section implemented in CMOS 0.18-/spl mu/m and the digital part programmed into a field-programmable gate array (FPGA), the modulator plus reconstruction filter achieves a peak SNR of 78 dB. The spurious-free dynamic range reaches 80 dB and stays better than 73 dB within the 1.104-MHz signal band. A missing-tone-power ratio of 70 dB, demonstrated for a signal with 15-dB peak-to-average ratio, proves that the solution is suitable for ADSL-CO transmitters.     

Compact microstrip resonators for 900 MHz frequency band

A technique to reduce the size of planar resonators is investigated using a transmission line model and a finite-difference time-domain (FDTD) method. New miniaturized square microstrip resonators are proposed for 900 MHz band. The resonators offer low impedance sections leading to a better handling of power. The feasibility of compact filters using the proposed resonators is demonstrated. The input/output coupling lines of a two-pole filter have been positioned in a way that produces a filter response with transmission zeros on the both sides of the pass-band. Sharper skirts and higher out-of-band rejection are obtained for four-pole filters with cross-coupled resonators.     

A study of dual-mode bandpass filter integrated in BGA package for single-chip RF transceivers

This paper presents a study of a dual-mode bandpass filter integrated in a ball grid array (BGA) package for the single-chip solutions of radio frequency (RF) transceivers. The novel in-package filter, except for the economical advantage of mass production and automatic assembly, has potential benefit to the system-level board miniaturization and the system-level manufacturing facilitation. The simulated and measured performance of the in-package filter is presented. The effects of the different physical parts of the package on the filter performance are investigated. Experimental results show that the in-package filter of size 15/spl times/15/spl times/1.905 mm/sup 3/ achieved 3-dB percentage bandwidth of 14% and insertion loss of 2.07 dB at 5.25 GHz.     

应用于毫米波无线接收系统的高集成化LTCC AIP设计

介绍了一种基于低温共烧陶瓷工艺的新型高度集成毫米波无源接收前端,该前端由阵列天线、馈电网络和带通滤波器构成.上述无源器件以天线集成封装方式经过一体化设计,并应用于毫米波无线系统.首先,设计了2×2线极化空气腔阵列天线,通过采用新颖的内埋空气腔体结构,使天线最大增益提高了2.9 dB.其次,将具有双层谐振结构的三阶小型化发卡型带通滤波器和天线馈电网络进行一体化设计.该滤波器测试结果显示:插入损耗为1.9dB,3 dB相对带宽为8.1％(中心频率为34 GHz).最后将上述天线和滤波网络进行一体化设计,实现了三维无线接收前端.在集成结构中,通过采用金属柱栅栏抑制了寄生模式.测试结果显示天线最大增益可达14.3dB,通过集成滤波馈电网络,其阻抗带宽为2.8 GHz.该新型一体化集成前端系统具有良好的射频性能,可作为全集成无源前端应用于Ka波段无线系统中.