Topic
Butterworth filter
About: Butterworth filter is a research topic. Over the lifetime, 6187 publications have been published within this topic receiving 69070 citations.
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Patent•
18 Jul 1974TL;DR: In this paper, a low-pass microwave filter consisting of a two-conductor transmission line including at least two cascaded tapered sections is described. But the filter does not exhibit the usual rapid transition between the pass band and stop band which is a general characteristic of conventional low pass microwave filters utilizing reflective harmonic structures.
Abstract: A low pass microwave filter comprised of a two conductor transmission line including at least two cascaded tapered sections wherein one of the conductors in each filter section has a tapered surface, preferably linear, and having an electrical length substantially equal to one half the wavelength of the center frequency of operation. Geometrically and performance-wise the subject filter is unsymmetrical with respect to its input and output ports. The filter does not exhibit the usual rapid transition between the pass band and stop band which is a general characteristic of conventional low pass microwave filters utilizing reflective harmonic structures.
21 citations
TL;DR: In this paper, a folded fourth-order filter with quasi-elliptic response is developed by introducing cross-coupling and source-load coupling, while maintaining a compact construction for simple computer numerical control (CNC) milling process.
Abstract: A high-performance waveguide bandpass filter operating at W-band is presented. This folded fourth-order filter with quasi-elliptic response is developed by introducing cross-coupling and source–load coupling, while maintaining a compact construction for simple computer numerical control (CNC) milling process. The filter fabricated within aluminium block shows an insertion loss of about 1.2 dB in a 3 dB fractional bandwidth of 5.5% from 90.1 to 95.2 GHz, which are very close to the simulated results in the full W-band.
21 citations
TL;DR: In this article, the authors describe current-mode third-order Butterworth filter topologies realized with unity gain active elements and minimum number of passive components, where all capacitors and resistors are equal valued.
Abstract: This paper describes current-mode third-order Butterworth filter topologies realized with unity gain active elements and minimum number of passive components. All capacitors and resistors are equal valued. The core of the circuit realizes HP, BP and LP functions easily. The filter exhibits high output impedance. Experimental results are included to verify theory.
21 citations
03 Jun 2007
TL;DR: In this article, a stripline parallel-coupled bandpass filter with parasitic elements on a multilayer LTCC substrate is presented, which achieves a center frequency of 59.1 GHz, a bandwidth of 6.9 %, and an insertion loss of 5 dB that includes input and output transitions.
Abstract: This paper presents a compact stripline parallel-coupled bandpass filter with parasitic elements on a multilayer LTCC substrate. The parasitic elements are formed above and below the first section and the last section of the filter. These parasitic elements effectively increase the coupling between adjacent parallel lines, resulting in a compact and low loss filter. The proposed filter is fabricated on four layers of a 50-mum LTCC substrate. The intrinsic area of the filter is just 1.6 mm by 0.7 mm. A fabricated prototype three-pole bandpass filter chip achieves a center frequency of 59.1 GHz, a bandwidth of 6.9 %, and an insertion loss of 5 dB that includes input and output transitions. The return losses are below -10 dB in the pass band. The figure-of-merit of the fabricated bandpass filter is the highest of all reported 60-GHz-band filters even though it has the smallest size. The proposed filter well suits a highly integrated millimeter-wave LTCC system-on-package.
21 citations