scholarly journals Tunable Lowpass Filter with RF MEMS Capacitance and Transmission Line

2012 ◽  
Vol 2012 ◽  
pp. 1-5
Author(s):  
Shimul C. Saha ◽  
Ulrik Hanke ◽  
Håkon Sagberg ◽  
Tor A. Fjeldly ◽  
Trond Sæther
Keyword(s):  
Transmission Lines ◽  
Parallel Plate ◽  
Rf Mems ◽  
Cutoff Frequency ◽  
Lowpass Filter ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Measurement Results ◽  
Low Pass ◽  
Lumped Elements

We have presented an RF MEMS tuneable lowpass filter. Both distributed transmission lines and RF MEMS capacitances were used to replace the lumped elements. The use of RF MEMS capacitances gives the flexibility of tuning the cutoff frequency of the lowpass filter. We have designed a low-pass filter at 9–12 GHz cutoff frequency using the theory of stepped impedance transmission lines. A prototype of the filter has been fabricated using parallel plate capacitances. The variable shunt capacitances are formed by a combination of a number of parallel plate RF MEMS capacitances. The cutoff frequency is tuned from C to X band by actuating different combinations of parallel capacitive bridges. The measurement results agree well with the simulation result.

scholarly journals Compact wide stopband microstrip lowpass filter using polygon patches and meandered lines

2020 ◽  
Vol 9 (1) ◽  
pp. 24
Author(s):  
Adel Musavy ◽  
Akram Sheikhi
Keyword(s):  
Insertion Loss ◽  
Cutoff Frequency ◽  
Lowpass Filter ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Rejection Level ◽  
Filter Size ◽  
Low Pass ◽  
Low Insertion Loss ◽  
Good Agreement

In this paper, a low pass filter based on T-Shaped resonator is presented. The T-Shaped resonator consists of meandered lines and rectangular patches. Also, the LC model and transfer function of the proposed resonator is presented. For suppression of spurious harmonics, a bandstop structure consists of hexangular patches and open stubs has been utilized. Finally, the wide stopband microstrip lowpass filter with cutoff frequency 2.72 GHz has been simulated, fabricated and measured. The LPF has good characteristics such as wide stopband and insertion loss lower than 0.18 dB in the passband region. The rejection level is less than -20 dB from 2.98 up to 21.3 GHz. The filter size is 10.5 mm×12.7 mm, or 0.131 λ<sub>g</sub>× 0.158 λ<sub>g</sub>, where λ<sub>g</sub> is the guided wavelength. The measured and simulated results of the filter is in good agreement with each other, which show the merits of low insertion loss and wide stopband.

scholarly journals Fractal-Shaped Metamaterials and Applications to Enhanced-Performance Devices Exhibiting High Selectivity

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
He-Xiu Xu ◽  
Guang-Ming Wang ◽  
Chen-Xin Zhang
Keyword(s):  
Transmission Lines ◽  
High Selectivity ◽  
Ground Plane ◽  
Cutoff Frequency ◽  
Microstrip Technology ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Transmission Zeros ◽  
Low Pass ◽  
Conductor Strip

Novel single negative metamaterial (MTM) transmission lines (TLs) are presented and studied in microstrip technology. They consist of a host TL in the conductor strip and a fractal-shaped complementary ring resonator (CRR) etched in the ground plane. Two types of fractal-shaped CRR are involved including the Moore and Hilbert. It is found that fractal perturbation in CRR results in lower and more transmission zeros in comparison with conventional CRR using nonfractal geometries. The single negative-permeability or -permittivity of these MTM TLs which associated with the resultant multitransmission zeros occurs by turns and should benefit devices with high selectivity requirement. Potential application of these MTM cells are illustrated by two examples, one is the microstrip stepped-impedance transformers (SIT) operating at 3.5 GHz with two edged attenuation poles to introduce selectivity; the other one is the Hi-Lo microstrip low-pass filter (LPF) with cutoff frequency 2.5 GHz exhibiting improved selectivity (77.3 dB/GHz). By constructing the low-impedance sections as hybrid prefractal shape and crown square, both the SITs and LPF obtained additional bandwidth enhancement and good matching. Consistent results between simulation and measurement have confirmed the design concept.

Design and Simulation of Switched Capacitor Filter for Speed Change Parameter Converter

2013 ◽  
Vol 562-565 ◽  
pp. 1132-1136
Author(s):  
Xiao Wei Liu ◽  
Jian Yang ◽  
Song Chen ◽  
Liang Liu ◽  
Rui Zhang ◽  
...  
Keyword(s):  
Stop Band ◽  
Cutoff Frequency ◽  
Rapid Change ◽  
Pass Band ◽  
Cmos Process ◽  
Switched Capacitor ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
The Time Domain

In this paper, we design a high-order switched capacitor filter for rapid change parameter converter. This design uses a structure which consists of three biquads filter sub-units. The design is a 6th-order SC elliptic low-pass filter, and the sample frequency is 250 kHz. By the MATLAB Simulink simulation, the system can meet the design requirements in the time domain. In this paper, the 6th-order switched capacitor elliptic low-pass filter was implemented under 0.5 um CMOS process and simulated in Cadence. The final simulation results show that the pass-band cutoff frequency is 10 kHz, and the maximum pass-band ripple is about 0.106 dB. The stop-band cutoff frequency is 20 kHz, and the minimum stop-band attenuation is 74.78 dB.

Q-Band Compact Driver and Power Amplifier MMICs Matched by ?-type Low-Pass Filter Using Lumped Elements

1998 ◽  
Author(s):  
Shin Chaki ◽  
Takao Ishida ◽  
Yasuharu Nakajima ◽  
Yoshinobu Sasaki ◽  
Yasuo Mitsui
Keyword(s):  
Power Amplifier ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Lumped Elements

RF-MEMS-based switchable low pass filter

2003 ◽  
Author(s):  
S. Kanthamani ◽  
R. SenthilNathan ◽  
Gowri Kumar ◽  
S. RamyaShankari ◽  
V, Sigappi ◽  
...  
Keyword(s):  
Rf Mems ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass

Improved Stator Flux Estimation for Direct Torque Control of Induction Motor Drives

2016 ◽  
Vol 7 (4) ◽  
pp. 1049
Author(s):  
Yahya Ahmed Alamri ◽  
Nik Rumzi Nik Idris ◽  
Ibrahim Mohd. Alsofyani ◽  
Tole Sutikno
Keyword(s):  
Induction Motor ◽  
Cutoff Frequency ◽  
Direct Torque Control ◽  
Motor Drives ◽  
Torque Control ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Flux Estimation ◽  
Stator Flux

<p>Stator flux estimation using voltage model is basically the integration of the induced stator back electromotive force (emf) signal. In practical implementation the pure integration is replaced by a low pass filter to avoid the DC drift and saturation problems at the integrator output because of the initial condition error and the inevitable DC components in the back emf signal. However, the low pass filter introduces errors in the estimated stator flux which are significant at frequencies near or lower than the cutoff frequency. Also the DC components in the back emf signal are amplified at the low pass filter output by a factor equals to . Therefore, different integration algorithms have been proposed to improve the stator flux estimation at steady state and transient conditions. In this paper a new algorithm for stator flux estimation is proposed for direct torque control (DTC) of induction motor drives. The proposed algorithm is composed of a second order high pass filter and an integrator which can effectively eliminates the effect of the error initial condition and the DC components. The amplitude and phase errors compensation algorithm is selected such that the steady state frequency response amplitude and phase angle are equivalent to that of the pure integrator and the multiplication and division by stator frequency are avoided. Also the cutoff frequency selection is improved; even small value can filter out the DC components in the back emf signal. The simulation results show the improved performance of the induction motor direct torque control drive with the proposed stator flux estimation algorithm. The simulation results are verified by the experimental results.</p>

scholarly journals A CMOS Low Pass Filter for SoC Lock-in-Based Measurement Devices

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5173 ◽  
Author(s):  
Jorge Pérez-Bailón ◽  
Belén Calvo ◽  
Nicolás Medrano
Keyword(s):  
Dynamic Range ◽  
Current Trend ◽  
Cutoff Frequency ◽  
Oxide Semiconductor ◽  
Constant Current ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Compact Size ◽  
Low Pass ◽  
Lock In

This paper presents a fully integrated Gm–C low pass filter (LPF) based on a current steering Gm reduction-tuning technique, specifically designed to operate as the output stage of a SoC lock-in amplifier. To validate this proposal, a first-order and a second-order single-ended topology were integrated into a 1.8 V to 0.18 µm CMOS (Complementary Metal-Oxide-Semiconductor) process, showing experimentally a tuneable cutoff frequency that spanned five orders of magnitude, from tens of mHz to kHz, with a constant current consumption (below 3 µA/pole), compact size (<0.0140 mm2/pole), and a dynamic range better than 70 dB. Compared to state-of-the-art solutions, the proposed approach exhibited very competitive performances while simultaneously fully satisfying the demanding requirements of on-chip portable measurement systems in terms of highly efficient area and power. This is of special relevance, taking into account the current trend towards multichannel instruments to process sensor arrays, as the total area and power consumption will be proportional to the number of channels.

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