High-power Filter Research Articles

Design of Power Supply System for High Power SAR Satellite

Synthetic Aperture Radar (SAR) satellite power system has the characteristics of high power, pulse power supply and fast response speed. Based on the combination of domestic and foreign SAR satellite power supply structures, a SAR satellite power supply system scheme with a composite bus architecture is proposed in this paper. By adding battery discharge regulators (BDR) between the platform bus and the SAR load bus as a grid-connected controller, the SAR load bus can supply power to the platform load, and the solar array and battery pack can be used efficiently while achieving dual bus output. Aiming at the composite bus, this paper also proposes an efficient high-power filter technology. Finally, the ground test results verify the correctness of the scheme, which can meet the different power supply requirements of the SAR satellite stable and pulse load equipment.

T1D -weighted ihMT imaging - Part I. Isolation of long- and short-T1D components by T1D -filtering.

To identify T1D -filtering methods, which can specifically isolate various ranges of T1D components as they may be sensitive to different microstructural properties. Modified Bloch-Provotorov equations describing a bi-T1D component biophysical model were used to simulate the inhomogeneous magnetization transfer (ihMT) signal from ihMTRAGE sequences at high RF power and low duty-cycle with different switching time values for the dual saturation experiment: Δt = 0.0, 0.8, 1.6, and 3.2 ms. Simulations were compared with experimental signals on the brain gray and white matter tissues of healthy mice at 7T. The lengthening of Δt created ihMT high-pass T1D -filters, which efficiently eliminated the signal from T1D components shorter than 1 ms, while partially attenuating that of longer components (≥ 1 ms). Subtraction of ihMTR images obtained with Δt = 0.0 ms and Δt = 0.8 ms generated a new ihMT band-pass T1D -filter isolating short-T1D components in the 100-µs to 1-ms range. Simulated ihMTR values in central nervous system tissues were confirmed experimentally. Long- and short-T1D components were successfully isolated with high RF power and low duty-cycle ihMT filters in the healthy mouse brain. Future studies should investigate the various T1D -range microstructural correlations in in vivo tissues.

Power Durability Enhancement and Failure Analysis of TC-SAW Filter With Ti/Cu/Ti/Cu/Ti Electrodes

In response to the rapid development of wireless communication, enhancement of temperature stability and power durability for surface acoustic wave (SAW) devices is both scientifically and technologically important in the 5G era. This paper discusses the utilization of 5-layer electrode Ti/Cu/Ti/Cu/Ti to the development of high power and low loss temperature-compensated surface acoustic wave (TC-SAW) filters. By modulating the microstructure of 5-layer electrode, the power durability can be increased to 1.7 times that of the conventional 3-layer electrode, while the life time to failure can be enhanced by 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> times. Through the cross section analysis of devices before and after power test, it is found that the deformation mainly concentrates on the bottom edge of electrode, whose result matches well with finite element method (FEM) simulation. The enhancement of power durability can be attributed to high resistance to cyclic stress in the bottom fine grain area. Furthermore, substrate failure areas due to Ti diffusion were also observed, which may be caused by the high temperature due to the current concentration around the electrode deformation. Our results show that the 5-layer electrode configuration is a promising solution for high power TC-SAW filter without deterioration of radio frequency performance and temperature coefficient of frequency.

Reliable, Compact, and Tunable MEMS Bandpass Filter Using Arrays of Series and Shunt Bridges for 28-GHz 5G Applications

This work presents radio frequency (RF) microelectromechanical system (MEMS)-based compact, high power, and reliable tunable bandpass filter for millimeter-wave RF front end. The design is fabricated on 635- $\mu \text{m}$ alumina substrate using surface micromachining process. All functional building blocks of the filter are fabricated and tested independently to ensure the optimum filter performances. Total area of the filter is only 2.3 mm2 including bias lines and pads. The proposed filter can be tuned to any frequency between 27 and 29 GHz and it demonstrates insertion loss of 1.92 dB and matching of 23.4 dB at 28 GHz with fractional bandwidth (FBW) of 6.7%. Filter also gives bandwidth tuning of 4.4 GHz with acceptable loss. Filter works satisfactorily up to 1 billion cycles with 1 W of power. Device reliability tested within a low-cost package. To the best of our knowledge, this is the first reported tunable MEMS bandpass filter in the literature which has undergone and presented with extensive reliability results.

High-Power Filter Design in Waveguide Technology: Future Generation of Waveguide Satellite Filters in Payloads Handling Increasing Bit Rates and Numbers of Channels

To design a filter for a particular application, many issues must first be considered. Which technology will be the most convenient? What design technique will provide better results for a particular set of frequency specifications? Once the device has been designed, will it fulfill all of the (not only electrical) requirements? It is not always easy to answer such questions in advance. In this article, we try to shed some light on these questions when our aim is the design of filters for high-power operation.

Multilevel NPC Converters in Parallel Connection for Power Conditioning Systems

This paper investigates a multilevel combined NPC converter for medium-and high-power energy storage systems and active power filters. The proposed multilevel NPC converter is composed of a parallel connection of multiple NPC converters using the current sharing reactors and involves the phase shifted PWM strategy for better energy quality performance. Using the switching function-based mathematical model, the proposed multilevel converter is evaluated to show the energy quality performance and fault tolerance of an energy storage system or active power filter. In addition, the switching frequency of circulating currents is analyzed to obtain its relationship with the converter parameters and maximum sharing reactor current ripple. The performance of the proposed multilevel converter is verified by simulation.

Predicting contrast effects following reliable spectral properties in speech perception.

Vowel perception is influenced by precursor sounds that are resynthesized to shift frequency regions [Ladefoged and Broadbent (1957). J. Acoust. Soc. Am. 29(1), 98-104] or filtered to emphasize narrow [Kiefte and Kluender (2008). J. Acoust. Soc. Am. 123(1), 366-376] or broad frequency regions [Watkins (1991). J. Acoust. Soc. Am. 90(6), 2942-2955]. Spectral differences between filtered precursors and vowel targets are perceptually enhanced, producing spectral contrast effects (e.g., emphasizing spectral properties of /ɪ/ in the precursor elicited more /ɛ/ responses to an /ɪ/-/ɛ/ vowel continuum, and vice versa). Historically, precursors have been processed by high-gain filters, resulting in prominent stable long-term spectral properties. Perceptual sensitivity to subtler but equally reliable spectral properties is unknown. Here, precursor sentences were processed by filters of variable bandwidths and different gains, then followed by vowel sounds varying from /ɪ/-/ɛ/. Contrast effects were widely observed, including when filters had only 100-Hz bandwidth or +5 dB gain. Average filter power was a good predictor of the magnitudes of contrast effects, revealing a close linear correspondence between the prominence of a reliable spectral property and the size of shifts in perceptual responses. High sensitivity to subtle spectral regularities suggests contrast effects are not limited to high-power filters, and thus may be more pervasive in speech perception than previously thought.

High Power Combline Filter for Deep Space Applications

An S-band, compact, high power filter, for use in the Mars Orbiter Mission (MOM) of Indian Space Research Organization (ISRO), has been designed and tested for multipaction. The telemetry, tracking, and commanding (TT&amp;C) transponder of MOM is required to handle continuous RF power of 200 W in the telemetry path besides simultaneously maintaining an isolation of greater than 145 dBc to its sensitive telecommand path. This is accomplished with the help of a complex diplexer, requiring high power, high rejection transmit path filter, and a low power receive path filter. To reduce the complexity in the multipaction-free design and testing, the transmit path filter of the diplexer is split into a low rejection filter integral to the diplexer and an external high rejection filter. This paper highlights the design and space qualification phases of this high rejection filter. Multipaction test results with 6 dB margin are also presented. Major concerns of this filter design are isolation, insertion loss, and multipaction. Mission performance of the on-board filter is normal.

A high-power spatial filter for Thomson scattering stray light reduction

The Thomson scattering diagnostic on the High Beta Tokamak-Extended Pulse (HBT-EP) is routinely used to measure electron temperature and density during plasma discharges. Avalanche photodiodes in a five-channel interference filter polychromator measure scattered light from a 6 ns, 800 mJ, 1064 nm Nd:YAG laser pulse. A low cost, high-power spatial filter was designed, tested, and added to the laser beamline in order to reduce stray laser light to levels which are acceptable for accurate Rayleigh calibration. A detailed analysis of the spatial filter design and performance is given. The spatial filter can be easily implemented in an existing Thomson scattering system without the need to disturb the vacuum chamber or significantly change the beamline. Although apertures in the spatial filter suffer substantial damage from the focused beam, with proper design they can last long enough to permit absolute calibration.

Comparison of power handling capabilities of sliced and conventional microstrip line filters

We examined a high power filter using a sliced microstrip line. We simulated the current distribution in the microstrip line by using electromagnetic field analysis software. The current flowing along the outer edge of the sliced microstrip line was less concentrated than in the conventional microstrip line. The electric test power of the sliced microstrip line filter was larger than that of the conventional filter. The electric proof power of the filter can be estimated from the current flowing along the outer edge of the microstrip line.

Capacitor Characterization Study for a High Power, High Frequency Converter Application

Recent advances in SiC power devices and high temperature magnetic and insulation materials has led to an increase in activity to develop compact, high switch rate power system components that can operate at temperatures in excess of 200°C. These efforts have highlighted the need to develop capacitor technology for high power, high frequency power filter applications, which can experience cycling over a wide range of temperature (−55 °C to 250 °C). A modeling and simulation capability was used to investigate device architecture and electrical performance relationships for a select group of wound and stacked devices, which were then evaluated for use in a power conditioning application. A finite element analysis of the device architectures was used to develop a better understanding of how magnetic fields and thermal profiles affect the performance of the capacitors in maintaining a low ripple voltage at high switch rates (&amp;gt;20 kHz). Both predicted electrical properties and empirical data were utilized as SPICE simulation input parameters to evaluate the performance of the different capacitors in an interleaved DC-DC boost converter model. Of interest is developing a better understanding of how the device architecture and its electrical properties affect its performance as a filtering device in a high power, high frequency application.

Design of a High-Power Superconducting Filter Using Resonators With Different Linewidths

This paper presents a design method to develop a high-power superconducting microstrip filter with different linewidth resonators. The linewidth of every resonator is optimized using this method to meet the same maximum current density. Thus, the power-handling capability of the five-pole filter on a limited substrate size can reach a maximum value. The design method is verified by the electromagnetic simulation of the current density distribution. The high-power superconducting filter is designed and fabricated on a 38 mm times 30 mm times 0.505 mm LaAlO3 substrate. The maximum resonator linewidth is 7 mm, and the minimum one is 1.6 mm. The filter has a center frequency of 2006 MHz and a narrow bandwidth of 1.0%. The measured power level is up to 35 dBm at 65 K without an evident change in insertion loss.

High power IGBT bridge application for the harmonic suppression on the load side of the power supply system of the Spanish Stellarator TJ-II

TJ-II is a medium size stellarator of the heliac-type, which is successfully in operation at CIEMAT in Madrid, since March 1998. This machine allows operation in a wide range of magnetic field configurations. This fusion device comprises seven inductively coupled coil systems, which produce the magnetic fields required for the confinement of the plasma. These coils are powered separately by 12-pulsed thyristor converters. The DC currents in the coils have a content of harmonics and sub-harmonics and these harmonics should be kept at very low level because of negative influence on the plasma confinement. The paper describes the design, calculations and tests of an active high power filter for the harmonic suppression.

A new soft-switching technique for buck, boost, and buck~boost converters

A new soft switching technique for buck, boost and buck-boost converters using a coupled inductor is proposed in this paper. The principles of operation of these converters are analyzed in detail. An additional winding is added on the same core of the main inductor for the purpose of commutation. By using hysteresis current control, zero voltage switching (ZVS) conditions are ensured over wide load range. The main inductor current is kept in continuous conduction mode (CCM) with small ripple, which allows high output power and small filter parameters. Also, the switching frequency is kept constant when load changes. Prototypes of buck, boost, and buck-boost converters have been built to verify the proposed concept. The experimental results are presented and they verify the analysis.

ＬＣ分布定数回路型ノイズフィルタ

We discuss a new concept for a wide-frequency-range noise filter based upon multiple reflection in serially connected LC distributed-constant delay lines. One LC distributed delay line in a matched circuit propagates the signal without energy loss. A group of delay lines with mismatched connections, however, shows attenuation. To study this phenomenon, we measured models made of coaxial cables. Several zero attenuation points, having reflection lengths proportional to whole numbers were observed. A large attenuated region (−5 to −15 dB) was observed in the 200 MHz to 6 GHz range. This result indicates a possibility of noise filters using delay lines with small values of inductive and capacitive distributed constants. A high-power (2000 V, 150 A) noise filter based on the principle was designed and evaluated. The high-power filter showed more than 20 dB attenuation in The 50 MHz to 6 GHz frequency range.

Application of TBCCO based HTS devices to digital cellular communications

Linear microstrip resonators suffer from high peak current density inside the resonators which limit the power handling characteristics and hence their use in cellular transmitter applications. To realise higher power filter and combiner networks for cellular applications it is possible to use two dimensional microstrip resonators (such as disks) to equalise the internal current distribution. We have designed and tested such microstrip resonators, fabricated from TBCCO 2212 thin films deposited by RF sputtering onto 50 mm diameter LaAlO/sub 3/ substrates. The R/sub s/ of such films has been measured at 5.5 GHz using a sapphire dielectric resonator and shown to be less than 1 m/spl Omega/ scaled to 10 GHz and at 80 K. The power handling of disk resonators designed for operation in the PCS and DCS1800 cellular bands has been shown to be superior to that of linear resonators fabricated from similar material. The operation of such devices using high power levels and realistic signals encountered in 2/sup nd/ generation digital cellular systems (e.g., DQPSK and GMSK) will be presented. The application of these devices to 3/sup rd/ generation wide band CDMA systems will also be discussed.

The Use of New Stripline Structure in the Design of HTS Microwave Filters

The use of high temperature superconducting (HTS) materials in microwave filters makes it possible to realize smaller and higher performance filters compared to those that make use of conventional materials. This is generally true only at low and moderate power levels, but at normally used telecommunication transmitters power levels (20–50 W) the HTS filters do not work very well, if at all. There have been many attempts to demonstrate high power filters, but these have met with little success. We propose a new dual-stripline structure, where the current distributes into two equal current carrying layers. The consequence of this is that, with the same total current in one layer, the dual-line can carry twice as much current and four fold power.

Microstrip disk resonators for filters fabricated from TBCCO thin films

Microstrip disk type resonators have been designed and tested. These have been fabricated from TBCCO 2212 thin films deposited by DC sputtering onto 2 cm square LaAlO/sub 3/ substrates. The R/sub s/ of such large area films has been measured at 40 GHz using a copper end wall replacement cavity and shown to be less than 200 /spl mu//spl Omega/ scaled to 10 GHz and at 80 K. Q values of 2 to 6 GHz disk resonators have demonstrated considerable improvements when compared to both linear HTS microstrip resonators and comparable copper disk resonators. Additionally, preliminary results for the performance of such disk resonators as a function of microwave power will be presented for application in high power filters.

Planar HTS structures for high-power applications in communication systems

The use of rotational symmetric modes of superconductive disk (ring) resonators in order to increase the power handling capability of planar filters has been proposed. Several YBCO disk resonators on LaAlO3 and sapphire substrates have been measured as one- and two ports. The unloaded Q-factor of the resonators has been measured to be greater than 105 up to the oscillating power of 50 kW. Experimental results obtained show that a disk resonator can be used as a building block for low insertion loss, sharp skirt high-power planar filters at low GHz frequency range and temperatures of around 60 K.

Power handling capability improvement of high-temperature superconducting microwave circuits

The focus of High Temperature Superconducting (HTS) microwave circuit development has now shifted to improving the high power handling capability. This paper reviews our latest results in this area including: HTS material improvement; new concepts and rules for HTS high power circuit design; and the latest high power filter test results. For HTS materials, the surface resistance versus rf magnetic field test results and the third harmonic test results for both YBa/sub 2/Cu/sub 3/O/sub 7/ and Tl/sub 2/Ba/sub 2/CaCu/sub 2/O/sub 8/ thin films are presented. For HTS microwave circuits, novel design concepts and rules for high power HTS filters are discussed. Several compact planar HTS filters were designed, fabricated, packaged and tested. The performance of a 3-pole, 1.3% equal-ripple bandwidth planar HTS filter showed no measurable degradation for transmitted power levels up to 74 watts at 77 K. The performance of a 2-pole, 1% equal-ripple bandwidth planar HTS filter showed no measurable degradation for transmitted power levels up to 115 watts at 77 K. To our knowledge, these test results represent the highest power handling of compact planar HTS filters operating at 77 K, sufficient for use in telecommunication transmitters.