Planar compact elliptic‐function low‐pass filter using high‐permittivity ceramics substrate

Abstract

when just using the method of CDA. The result shows that the maximum strain variation is about 9.4 and the resolution is about 5.7 , which is better than the direct peak detection. In order to enhance the resolution of the system, two 201 st -order digital low-pass FIR filters with cutoff frequency of 10 Hz are applied on the detected scanning voltage and PD signal, respectively, to remove the high-frequency noise and improve the signalto-noise ratio (SNR). Then the CDA method, which has the effect of averaging, is used to determine the peak signal. The maximum strain variation is 2.2 and the resolution is 1.39 , which are better than just using the CDA method, are shown in Figure 3(c). Comparing the results of Figures 3(a), 3(b), and 3(c), we can conclude that by combining the CDA and digital FIR filter, the resolution of the demodulation system is greatly enhanced. In order to verify the effectiveness of the technique, a series of stepped strains with step size of 36 and time interval of 2.5 s are applied on the FBG sensor. The experiment results are shown in Figures 4(a) and 4(b). It is clearly observed that with FIR and CDA, the measured strains are more resoluble than that of the method without FIR and CDA. CONCLUSIONIn conclusion, a fiber Bragg grating (FBG) strain-sensor demodulation system based on a wavelength-tunable fiber-ring laser has been developed. By using the digital FIR filter to improve the SNR and CDA peak-detection algorithm, the resolution of the strain system was greatly improved. An enhanced strain resolution of 1.39 was achieved, which is much better than the resolution (10.1 ) of the direct peak-detection method. resolution, wavelength-division multiplexed in-fiber Bragg grating sensor system, IEEE Electron Lett 32 (1996), 924. 4. M.G. Xu, H. Geiger, and J.P. Dakin, Modeling and performance analysis of a fiber Bragg grating interrogation system using an acoustooptic tunable filter,

Compact semilumped elliptic‐function low‐pass filter using microstrip meander line

“…Therefore, the semilumped type, using transmission line and chip capacitor, can be employed to reduce the size of low-pass filter. Recently, a compact semilumped low-pass filter using single transmission line and chip capacitor was proposed in [1], and an elliptic-function low-pass filter using hairpin resonator was designed in [2]. In [3], a meander line was used for compact low-pass filter.…”

Design and fabrication of MEMS lowpass filter exploiting space mapping algorithm

“…Planar microstrip LPF has attracted great attention due to its advantages of small size, low‐cost and easy of fabrication. To date, several structures have been reported to obtain high‐performance lowpass filters 1‐14 . In Reference 3, a microstrip low‐pass filter using a stepped impedance hairpin resonator with a pair of coupled stepped impedance resonators (SIRs) inside is presented.…”

“…In Reference 3, a microstrip low‐pass filter using a stepped impedance hairpin resonator with a pair of coupled stepped impedance resonators (SIRs) inside is presented. Filters designed by cascading symmetric hairpin resonators with low impedance microstrip lines are reported in References 1 and 6. In Reference 7, a stepped impedance hairpin resonator with radial stubs is presented to obtain a wide‐stopband low‐pass filter.…”

Using high permittivity ceramic substrates to fabricate a miniaturized bandpass filter with capacitive load

“…However, further miniaturization becomes more difficult for this filter. Planar filters using high-permittivity ceramic substrate, such as parallel-coupled filter [2], interdigital filter [3], combline filters [4], and hairpin filter [5][6][7][8][9], provide good miniaturization ability. Generally speaking, a conventional half-wavelength open-line microstrip resonator is too large to be used in modern communication systems such as personal communication systems at 900 and 1800 MHz, and wireless location area networks at 2.4 and 5.3 GHz [2].…”