scholarly journals A Compact Widely Tunable Bandpass Filter Dedicated to Preselectors

Electronics ◽  
2021 ◽  
Vol 10 (18) ◽  
pp. 2315
Author(s):  
Mirosław Magnuski ◽  
Dariusz Wójcik ◽  
Maciej Surma ◽  
Artur Noga

This article presents a novel compact widely tunable bandpass filter. The filter consists of two resonators that are double-coupled, inductively, where the coupling inductances are elements of the input and output networks. The application of double-coupling enabled the transmission zero next to the upper cutoff frequency. This makes the filter useful for applications in preselector networks used in receiving systems with a low to intermediate frequency with the desired channel frequency lower than the image channel frequency. The article shows the practical realisation of the varactor-tuned example filter fabricated as a microstrip planar network of an overall size of 0.03λg × 0.045λg. The tuning range of the proposed filter is from 410 MHz to 880 MHz with the fractional bandwidth equal to 7.5–8.1% and an in-band insertion loss better than −3.4 dB. The achieved IP3 value exceeds 17.5 dBm.

2015 ◽  
Vol 57 ◽  
pp. 89-97
Author(s):  
Liangzu Cao ◽  
Guangwen Li ◽  
Jian Hu ◽  
Lixia Yin

Frequenz ◽  
2018 ◽  
Vol 72 (11-12) ◽  
pp. 533-537 ◽  
Author(s):  
Jin Xu ◽  
Qi-Hang Cai ◽  
Zhi-Yu Chen

Abstract This paper proposes a wideband bandpass filter (BPF) integrated single-pole double-throw (SPDT) switch by using the capacitively coupled LC resonators with loaded p-i-n diodes. The BPF-integrated on-state channel can be synthesized by using the coupled resonator filter theory, and the off-state channel with high suppression is built due to the misaligned resonant frequencies of LC resonators. As an example, a BPF-integrated SPDT switch is designed and fabricated with the central frequency of 1 GHz and the 3 dB fractional bandwidth of 29.7 %. The on-state channel has a measured insertion loss of 1.23 dB, and a 20 dB rejection wide stopband from 1.47 GHz to 8.6 GHz. The off state channel has a 43 dB suppression around 1 GHz. The isolation between two ports is better than 52.4 dB. The fabricated BPF-integrated SPDT switch size including bias circuits but excluding feeding lines has a compact size of 0.086 λg×0.096 λg.


Electronics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 440 ◽  
Author(s):  
Huang ◽  
Yuan

A novel method to design a wideband substrate integrated waveguide (SIW) bandpass filter (BPF) with compact size, wide stopband and high selectivity is presented. In this method some unique electromagnetic band-gap (EBG) cells are periodically etched on the top layer of SIW to realize a wide passband propagating below the equivalent waveguide cutoff frequency. By changing the configuration of EBG cells, undesired harmonics in upper stopband can be suppressed and a wideband BPF with wide stopband can be obtained. By symmetrically loading two complementary split ring resonators (CSRRs) on the tapered gradient lines of the input/output ports, a transmission zero near the passband can be introduced, and it makes the frequency selectivity of upper sideband improve significantly. As a verification, a wideband SIW BPF with a 3.02 GHz absolute bandwidth (ABW) and a 64.7% fractional bandwidth (FBW) centered at 4.67 GHz is designed, simulated, manufactured, and measured. The results of the experiment and simulation are in good agreement.


IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 82286-82293
Author(s):  
Xiaoxiao Chen ◽  
Yongle Wu ◽  
Yuhao Yang ◽  
Weimin Wang

2017 ◽  
Vol 9 (9) ◽  
pp. 1821-1826 ◽  
Author(s):  
Dharmendra Kumar Jhariya ◽  
Akhilesh Mohan ◽  
Manoranjan Sinha

In this paper, a novel two-stage fish spear-shaped multimode resonator (MMR)-based ultra wideband (UWB) bandpass filter (BPF) is presented. The fish spear-shaped MMR is loaded with stepped impedance resonator in order to improve the out-of-band performance of the proposed filter. The proposed UWB BPF filter has fractional bandwidth better than 110%. In order to validate the present design approach, the filter is fabricated on RT/Duroid 5880 having dielectric constant 2.2, thickness 0.787 mm and loss tangent of 0.0009. The measured passband bandwidth of the filter is from 3.3 to 11.85 GHz, with insertion loss of 1.5 dB and return loss better than 12 dB in the passband. The proposed filter has sharp selectivity and upper stopband with 20 dB attenuation from 12 to 24 GHz.


2013 ◽  
Vol 49 (16) ◽  
pp. 1007-1008 ◽  
Author(s):  
B.L. Zhao ◽  
Z.T. He ◽  
X.B. Wei ◽  
Y. Shi

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