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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TL;DR: In this paper, a microstrip lowpass filter with compact size and an ultra-wide stopband is proposed, which can suppress the sixteenth harmonic response referred to a suppression degree of 15'dB.
Abstract: A new microstrip lowpass filter with compact size and an ultra-wide stopband is proposed. To achieve compact size and ultra-wide band rejection, both triangular patch resonators and radial patch resonators are introduced in the filter. To reduce the circuit size of the filter further, meander transmission lines are also adopted in the design. A demonstration filter with 3 dB cutoff frequency at 1 GHz has been designed, fabricated and measured. Results indicate that the proposed filter can suppress the sixteenth harmonic response referred to a suppression degree of 15 dB. Furthermore, the proposed filter exhibits a small size of 0.111 λg×0.091 λg, where λg is the guided wavelength at 1 GHz.
52 citations
TL;DR: The proposed switchable dual-band filter has four possible operating states, so the two pass bands can be activated or deactivated independently, and the central frequencies and bandwidths of the two desired passbands can be separately designed without time-consuming trial and error.
Abstract: This brief presents a compact switchable dual-band filter with four operating states. The filter is established by adding switching circuits to a concurrent dual-band filter. The original concurrent dual-band filter has hybrid coupling paths and uses two stepped-impedance quarter-wavelength resonators that are shared by the two passbands, so fewer resonators are required. In addition, the central frequencies and bandwidths of the two desired passbands can be separately designed without time-consuming trial and error. Two types of switching circuit are added to the original concurrent dual-band filter to obtain a switchable dual-band filter. The switching mechanisms are analyzed and discussed. The proposed switchable dual-band filter has four possible operating states, so the two passbands can be activated or deactivated independently. The simulated and measured results verify the performance of the proposed structure.
52 citations
TL;DR: In this paper, a triple-passband, dual-stopband filter consisting of six cascaded singlets is introduced in substrate integrated waveguide (SIW) technology, each singlet produces one independent transmission zero (TZ).
Abstract: A triple-passband, dual-stopband filter consisting of six cascaded singlets is introduced in substrate integrated waveguide (SIW) technology. Each singlet produces one independent transmission zero (TZ). Four of six TZs are placed within the filter passband, producing three passbands separated by two stopbands. The corresponding coupling matrix is synthesized based on a combination of well-known analytic and optimization methods. The SIW filter is designed for stopbands centered at 10.25 and 11.23 GHz, and passbands at 9.72, 10.76, and 11.76 GHz. The prototype is fabricated and measured. Good agreement between simulated and measured results is achieved.
52 citations
TL;DR: In this article, the authors presented the design and implementation of a 70 GHz millimeter-wave compact folded loop dual-mode on-chip bandpass filter (BPF) using a 0.18 mum standard CMOS process.
Abstract: This letter presents the design and implementation of a 70 GHz millimeter-wave compact folded loop dual-mode on-chip bandpass filter (BPF) using a 0.18 mum standard CMOS process. A compact BPF, consisting of such a planar ring resonator structure having dual transmission zeros was fabricated and designed. The size of the designed filter is 650 X 670 mum2. Calculated circuit model, EM simulated and measured results of the proposed filter operating at 70 GHz are shown in a good agreement and have good performance. The filter has a 3-dB bandwidth of about 18 GHz at the center frequency of 70 GHz. The measured insertion loss of the passband is about 3.6 dB and the return loss is better than 10 dB within the passband.
52 citations
TL;DR: In this article, a dual-mode dual-band bandpass microstrip filter using double square-loop structure is proposed, where two tuning patches placed symmetrically at the side of the perturbation patch are used to change the higher passband frequency, while while keeping the lower invariability.
Abstract: A dual-mode dual-band bandpass microstrip filter using double square-loop structure is proposed in this paper. Each of the square-loop forms a dual-mode resonator with controllable respective passband. Two tuning patches placed symmetrically at the side of the perturbation patch are used to change the higher passband frequency, while while keeping the lower invariable. Several attenuation poles in the stopband are realized to improve the selectivity of the proposed bandpass filter. The filter is evaluated by experiment and simulation with good agreement.
52 citations