High-frequency Bandpass Filter Research Articles

A Large Frequency Ratio Dual-Band Integrated Bandpass Filter Based on MCSICL Structure

In this paper, a dual-band integrated bandpass filter (DI-BPF) based on a mode composite substrate integrated coaxial line (MCSICL) is proposed for a large frequency ratio. The low-frequency bandpass filter is formed by incorporating an SICL line and a gap into the MCSICL, operating in the fundamental mode of the MCSICL. The high-frequency bandpass filter is formed by introducing grounded vias into the MCSICL, operating in the first high-order mode of the MCSICL. To guide the design, the equivalent circuit models of the low- and high-frequency bandpass filters are built. Based on the equivalent circuit models, the DI-BPF is synthesized for a large frequency ratio. The transitions from the DI-BPF to ground coplanar waveguides (GCPWs) are designed for the low- and high-frequency bandpass filters. The DI-BPF with the transitions is fabricated by the printed circuit board (PCB) process. Measurement results indicate a large frequency ratio of 23.16, with the isolation between the low- and high-frequency bandpass filters exceeding 30 dB from dc to 50 GHz.

A dual resonance high frequency bandpass filter

This paper presents a design of a dual resonance high-frequency bandpass filter using the Sonnet EM Simulator. The filter prototype is enhanced by adding the short stub in the center of the design. A parametric study shows the impact of choosing appropriate configuration characteristics. This is a dual resonance bandpass filter design, with center frequencies 7.8 GHz and 9.3 GHz. Performed input match S_11 at first resonance is-28.87 dB and insertion loss S_21 is -0.05 dB. The obtained results at second resonance are S_11=-8.97 dB and S_21=-2.74 dB. Due to its characteristics, this is a high-Q medium bandwidth dual resonance bandpass filter. The design is simulated and planning to be fabricated with 0.36 mm thickness and dielectric constant ?_r=1. This paper benefits from its compact size and simple geometry over the similar filters found in the literature.

Compact Combline Filter Embedded in a Bed of Nails

In this paper, we propose a compact topology for high-frequency bandpass filters using coaxial cavities embedded in a bed of nails, including a complete design procedure combining equivalent circuit models and full-wave simulators. The resonance generated around a shortened cylindrical nail of the bed hosting structure is used as the basic element of the proposed filter, which is fed through groove gap waveguides. For design purposes, an equivalent circuit model of the considered resonance is first obtained, and then the coupling levels between resonators are recovered with the distance between adjacent shortened nails. In order to validate the proposed structure and its design procedure, a filter prototype with a bandpass response (centered at 30 GHz and with relative bandwidth of 1.7%) has been designed, manufactured, and measured. Good experimental results, in terms of insertion losses (with a minimum value of 1.6 dB) and return losses (greater than 16.6 dB in the whole passband), have been achieved.

Design and Realization of a Compact High-Frequency Band-Pass Filter with Low Insertion Loss Based on a Combination of a Circular-Shaped Spiral Inductor, Spiral Capacitor and Interdigital Capacitor

In this study, the proposed bandpass filter (BPF) connects an interdigital and a spiral capacitor in series between the two symmetrical halves of a circular intertwined spiral inductor. For the mass production of devices and to achieve a higher accuracy and a better performance compared with other passive technologies, we used integrated passive device (IPD) technology. IPD has been widely used to realize compact BPFs and achieve the abovementioned. The center frequency of the proposed BPF is 1.96 GHz, and the return loss, insertion loss and transmission zero are 26.77 dB, 0.27 dB and 38.12 dB, respectively. The overall dimensions of BPFs manufactured using IPD technology are 984 × 800 μ m 2 , which is advantageous for miniaturization and integration.

A low-voltage low-power 0.25 µm integrated single transistor active inductor-based filter

In this paper we present a 0.25 µm BiCMOS Technology bandpass filter implementation based on a single transistor Active Inductor (AI). The high-Q AI integrated circuit is designed by the use of a single transistor with a compensation network that allows to control both the inductance and its series resistance value. The AI-based high frequency bandpass filter has a center frequency of 2000 MHz (useful for radio and radar applications) and a 3 dB bandwidth of about 6 MHz with a quality factor of about 330. Moreover, a discrete prototype of the same AI has been also designed and measured. Measurements results on the discrete board have shown a 3 dB bandwidth of about 10 MHz, a noise figure of 6 dB, a ?10 dBm P1 dB compression point with 80 dB dynamic range. The power supply is 1.2 V with a power consumption of 800 µW showing low-voltage low-power operation capability together with good general performances.

J0402-1-6 波長可変ピコ秒超音波法の開発と酸化物薄膜の減衰評価法の提案([J0402-1]超音波計測・解析法の新展開(1))

Thin-film mechanical resonators are promising for high frequency bandpass filters. Amorphous oxide thin films are expected to be important candidates because they are free from grain scattering loss. However, it has been difficult to characterize their acoustic properties, especially attenuation, which is a key parameter for designing a high-Q resonator. Here, we present a novel methodology for evaluating ultrasonic attenuation of amorphous oxide thin films deposited on silicon substrate at very high frequencies between 200 and 300 GHz. This method uses the high sensitivity of the refractive index of light in silicon near to the wavelength near 400 nm. Detecting Brillouin oscillations from silicon substrate, which is caused by the transmitted acoustic wave, we can evaluate the frequency dependence of the attenuation coefficient in the thin film through an inverse calculation.

Rejecting high frequency disturbances with disturbance observer and phase stabilized control

This paper takes into consideration the rejection of narrow-band disturbances at two frequencies higher than servo bandwidth in order to obtain good positioning accuracy for a micro-actuator. A phase stabilized feedback controller combined with a disturbance observer structure is applied to achieve the rejection of the two disturbances. A high frequency bandpass filter is adopted in the disturbance observer in order to reject the high frequency disturbance, and simultaneously the stability of the feedback control loop is remained when the disturbance observer is added on to the external stabilized controller. The effectiveness of the combined control is investigated through simulation and experiment results, which show that this control scheme can reduce position error significantly and is better than using phase stabilized feedback control only or proportional-integral-derivative (PID) controller with notch filters.

A NOVEL CCII-BASED TUNABLE INDUCTANCE AND HIGH FREQUENCY CURRENT-MODE BAND PASS FILTER APPLICATION

In this paper, we introduce an implementation of a CCII-based grounded inductance operating in class AB. In order to get tunable characteristics of the design, a translinear CCII configuration is used as a basic block for its high level of controllability. A frequency characterization of the translinear CCII is done. In order to optimize its static and dynamic characteristics, an algorithmic driven methodology is developed ending to the optimal transistor geometries. The optimized CCII has a current bandwidth of 1.28 GHz and a voltage bandwidth of 5.48 GHz. It is applied in the simulated inductance design. We first consider the conventional topology of the grounded inductance based on the generalized impedance converter principle. Making use of the controllable series parasitic resistance at port X in translinear CCII, we design tunable characteristics of the inductance. The effect of current conveyor's nonidealities has been taken into account. A compensation strategy has been presented. It is based on the insertion of a high active CCII-based negative resistance and a very low passive resistance. The compensation strategy does not affect the inductance tuning process. Simulation results show that the proposed inductance can be tuned in the range [0.025 μH; 15.4 μH]. The simulated inductance has been applied in a fully integrated tunable high frequency band pass filter to illustrate the versatility of the circuit. The filter is electrically tunable by controlling the conveyor's bias current.

Electrical and Frequency Characteristics of Third-Overtone Vibration-Mode Surface Mount Device High-Frequency Filter Using Modified PbTiO3 Ceramics

In this study, a 3rd-overtone thickness-vibration-mode surface mount device (SMD) filter was manufactured using modified PbTiO3 system ceramics for application as an intermediate frequency (IF) filter with a split electrode and gap size. To investigate the effects of the split electrode and gap size on the filter characteristics of the 3rd-overtone-mode energy-trapped filter, ceramic wafers were fabricated by etching split rectangular electrodes with sizes (b ×d) of b=0.4, 0.6, 0.8 and 1 mm, d=0.3, 0.4, 0.5 and 0.6 mm and gap sizes (c) of the c=0.2, 0.3, 0.4 and 0.6 mm, respectively. Then, SMD ceramic filters were fabricated with the size of 3.7 ×3.1 mm2. SMD ceramic filter with the size of b=0.8 mm, d=0.4 mm and c=0.4 mm showed insertion loss of 2.951 dB, 3 dB bandwidth of 54.7 kHz and 20 dB stop bandwidth of 129.27 kHz. Also, these two filters were cascaded and their bandwidth characteristics were investigated by varying the coupling capacitance to check their applicability as high frequency band-pass filters. The cascaded filter showed a higher stop band, reduction of spurious response and increase of selectivity. With increasing coupling capacitance, insertion loss increased but spurious response decreased. The cascaded filter with a coupling capacitance of 15 pF showed insertion loss of 5.643 dB, 3 dB bandwidth of 55.089 kHz and 20 dB bandwidth of 83.608 kHz.

Local Oscillator Generation Circuit for Direct Conversion Transmitter

In this paper a fully monolithic on-chip local oscillator signal generation circuit is presented for eliminating the negative effect of coupling between bond-wires, package pins and output and input lines of the power amplifier output to the local oscillator input for direct conversion transmitters. The proposed circuit generates the local oscillator signal at frequencies 1710–1785 GHz which is harmonically uncorrelated from two input signals at 464 MHz and 1792–2088 MHz. The required building blocks are a frequency divider, a mixer and an active band-pass filter. Fully monolithic high frequency band-pass filters have not been available until recently, and the designed circuit is in fact one of the first applications reported for MMIC active filters in cellular phones. The circuit is designed with a 0.5 μm GaAs MESFET technology and the performance is verified with on-chip measurements.

Versatile architecture for current-mode biquadratic filters in CMOS technology

A versatile programmable current-mode architecture for realising a given second order biquadratic filter is proposed. The architecture consists of programmed interconnections of three basic building blocks: transconductance cells, buffered current mirrors and current buffer cells. In the case of stand-alone IC chips, transfer function coefficients are set through external control voltages, and in the case of an analogue/digital mixed mode VLSI environment, through internal control voltages. Designs for a video-band lowpass notch filter and a high-frequency bandpass filter realisable using 1.2 micron CMOS technology and consuming, respectively, 1.96 mW and 2.36 mW of power, are presented as illustrations. It is expected that optimised designs will lead to reduced power consumption.

High frequency bandpass filter using polycrystalline diamond

Because of its high Young's modulus, diamond has the highest acoustic velocity of all materials, and thus for surface acoustic wave (SAW) devices diamond can be expected to be one of the candidates for passive component applications. Polycrystalline diamond 40 μm thick was deposited on a silicon substrate by hot-filament chemical vapour deposition. After the diamond surface had been polished, 100 nm of Al was deposited and fabricated into interdigital transducers, utilizing conventional photolithography and etching processes. This was followed by the deposition of a ZnO thin film, which served as a piezoelectric material to generate SAWs. Finally, an SAW device using a ZnO/diamond system was fabricated for the first time. With the high SAW velocity of the ZnO/diamond system being up to 8600 m s, −1 a 1.07 GHz bandpass filter was successfully demonstrated using 2 μm line and space interdigital transducers; additionally −25 dB insertion loss was observed. This preliminary result suggests that, by utilizing diamond, high frequency (2–5 GHz) bandpass filters can be made available, and broad applications in the optical and personal communication systems can be expected.

Finite gain compensated double-sampled switched-capacitor integrators for high-Q bandpass filters

A technique for the compensation of the operational amplifier (op-amp) finite gain error in the switched-capacitor (SC) integrator is proposed. Two possible SC integrators implementing the proposed technique are given. Both implementations allow the use of the double-sampling technique to increase by a factor of two the maximum speed of operation. The compensation operation consists in memorizing a sequence of output values of the SC integrator, and using them in the proper clock period to compensate the error due to the nonideal virtual ground. The compensation is mostly effective in a narrow frequency range centered around one specific frequency. The circuits implementing this technique are therefore particularly useful for high-Q high-frequency bandpass filters. The case of a biquadratic bandpass filter is reported as an example.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Single switch dual output DC-DC converter performance

The performance of the single-switch dual-output DC-DC converter is evaluated. This converter regulates two independent DC outputs supplied from a single DC voltage source using a power semiconductor switch. Two discrete proportional feedback control loops regulate the duration of on switching and off switching. The duty cycle of the switch controls one output voltage, supplied from a low-pass filter, while the switching frequency regulates the other output voltage, supplied from a higher-frequency bandpass filter. The control algorithm is implemented with an Intel 8096 microcontroller. The experimental data demonstrate the actual circuit performance and confirm the simulation results. Both experiments and simulation show that an increase in the load current on the 12 V output results in an increase in the duty cycle, whereas an increase in the load current on the 5 V output results in a change in the switching frequency. The experimental prototype demonstrates operation over a load current range from about 40% to 100% with a +or-25% variation in the 24 V input. Full load currents are 12 A and 2.5 A on the 12 V and 5 V outputs, respectively. The switching frequency ranged from approximately 29 kHz to 264 kHz, and the duty cycle ranged from 0.35 to 0.72.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A correlated noise reduction algorithm for dual-energy digital subtraction angiography.

It has long been recognized that the problems of motion artifacts in conventional time subtraction digital subtraction angiography (DSA) may be overcome using energy subtraction techniques. Of the variety of energy subtraction techniques investigated, non-k-edge dual-energy subtraction offers the best signal-to-noise ratio (SNR). However, this technique achieves only 55% of the temporal DSA SNR. Noise reduction techniques that average the noisier high-energy image produce various degrees of noise improvement while minimally affecting iodine contrast and resolution. A more significant improvement in dual-energy DSA iodine SNR, however, results when the correlated noise that exists in material specific images is appropriately cancelled. The correlated noise reduction (CNR) algorithm presented here follows directly from the dual-energy computed tomography work of Kalender who made explicit use of noise correlations in material specific images to reduce noise. The results are identical to those achieved using a linear version of the two-stage filtering process described by Macovski in which the selective image is filtered to reduce high-frequency noise and added to a weighted, high SNR, nonselective image which has been processed with a high-frequency bandpass filter. The dual-energy DSA CNR algorithm presented here combines selective tissue and iodine images to produce a significant increase in the iodine SNR while fully preserving iodine spatial resolution. Theoretical calculations predict a factor of 2-4 improvement in SNR compared to conventional dual-energy images. The improvement factor achieved is dependent upon the x-ray beam spectra and the size of blurring kernel used in the algorithm.(ABSTRACT TRUNCATED AT 250 WORDS)