Bandwidth Balancing Design of Miniaturized Tunable Coaxial Cavity Filter

2010 ◽  
Vol 40-41 ◽  
pp. 453-456
Author(s):  
Xin Hui Wu ◽  
Jing Li ◽  
Chang Hai Qin ◽  
Zhong Hai Zhang
Keyword(s):  
Insertion Loss ◽  
Bandpass Filter ◽  
Tunable Filter ◽  
Theoretic Analysis ◽  
High Quality ◽  
Coaxial Cavity ◽  
Coupling Structure ◽  
Novel Model

This paper proposes a method of the coupling modal, which is able to miniaturize the tunable cavity filter while keeping its bandwidth balancing. The filter consists of a tunable cavity dual-bandpass filter and a triangular twin-loop as its inter-cavities coupling structure. We analyzed and calculated the bandwidth of the filter changing with the size and position of the triangular twin-loop. To prove the advancement of the design, a tunable coaxial cavity dual-bandpass filter operating at 230MHz and 409MHz was fabricated and measured. The size is less then a half that of the conventional tunable filter with same specifications. The insertion loss is lower than 1.2dB at operating frequencies. And the bandwidth in lowband and highband are both more than 2.5MHz with the insertion loss less then 3dB. Experiment results and theoretic analysis agree well. This novel model can contribute to the miniaturization of RF and microwave systems with high quality.

A tunable open ring coupling structure and its application in fully tunable bandpass filter

2019 ◽  
Vol 11 (08) ◽  
pp. 782-786
Author(s):  
Zhonghai Zhang ◽  
Fei Zhao ◽  
Aiting Wu
Keyword(s):  
Bandpass Filter ◽  
Design Procedure ◽  
Tunable Filter ◽  
Operating Frequency ◽  
Coupling Structure ◽  
Open Ring ◽  
Tunable Coupling ◽  
Tunable Resonator ◽  
Good Agreement ◽  
Tunable Bandpass Filter

AbstractThis letter presents a novel tunable coupling structure to simplify the design complexity of the miniaturized fully tunable filter by using open ring and varactors. Based on the proposed novel tunable coupling structure, a fully tunable bandpass filter is implemented with independently tunable operating frequency and bandwidth. The tunable resonator and tunable coupling structure can be easily combined to improve Out-of-band suppression performance. The design procedure of a fully tunable bandpass filter consists of five tunable cavities and tunable coupling rings is also proposed. A prototype of the proposed fully tunable filter is built to verify the design experimentally. Good agreement between simulated and measured results is obtained.

A Wideband Bandpass Filter Integrated Single-Pole Double-Throw Switch with Wide Stopband

Frequenz ◽  
2018 ◽  
Vol 72 (11-12) ◽  
pp. 533-537 ◽  
Author(s):  
Jin Xu ◽  
Qi-Hang Cai ◽  
Zhi-Yu Chen
Keyword(s):  
Insertion Loss ◽  
Bandpass Filter ◽  
Fractional Bandwidth ◽  
Central Frequency ◽  
Resonant Frequencies ◽  
Capacitively Coupled ◽  
Filter Theory ◽  
Compact Size ◽  
Better Than ◽  
Coupled Resonator

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.

scholarly journals Dual band Stepped Impedance Interdigital Microstrip Filter for LTE Bands

2019 ◽  
Vol 4 (7) ◽  
pp. 28-30
Author(s):  
William Johnson ◽  
Cavin Roger Nunes ◽  
Savio Sebastian Dias ◽  
Siddhi Suresh Parab ◽  
Varsha Shantaram Hatkar
Keyword(s):  
Insertion Loss ◽  
Bandpass Filter ◽  
Dual Band ◽  
Band Pass Filter ◽  
Coupled Resonators ◽  
Microstrip Filter ◽  
Resonant Frequencies ◽  
Pass Filter ◽  
Band Pass ◽  
Low Insertion Loss

In this paper, a dual band microstrip bandpass filter has been proposed utilizing three edge coupled resonators, interdigital stubs and DGS technique. To enhance the coupling degree, two interdigital coupled feed lines are employed in this filter. The suppressing cell consists of stepped impedance ladder type resonators, which provides a wide stopband. The proposed suppressing cell has clear advantages like low insertion loss in the passband and suitable roll off. The frequency response of the filter looks like a standard dual band band-pass filter. The filter exhibits a dual passband with resonant frequencies at 2.2GHz and 3.45GHz covers LTE1 and LTE22 bands.

scholarly journals Sharp Skirt Dual-Mode Bandpass Filter with Overlay Plate to Control Upper Passband Edge

2019 ◽  
Vol 8 (6) ◽  
pp. 2357-2360
Keyword(s):  
Analytical Model ◽  
Insertion Loss ◽  
Return Loss ◽  
Bandpass Filter ◽  
Center Frequency ◽  
Dual Mode ◽  
Rf Receivers ◽  
Attenuation Level ◽  
Frequency Selective ◽  
Fixed Center

This paper presents design and analytical model for Sharp Skirt Dual-Mode Bandpass Filter for RF receivers. Proposed filter is designed using open stub loaded H shaped resonator. Based on analytical model insertion loss S21 and return loss S11 for proposed filter are demonstrated. Inductive Overlaying plate is proposed to control upper passband edge of proposed filter to improve frequency selectivity with fixed center frequency. The proposed filter has sharp frequency selective range from 5.1GHz to 9.2GHz. With overlay plate, frequency selective range is tuned to 5.1GHz-8.6GHz. Without overlaying plate the proposed filter has return loss greater than 10dB and insertion loss of 0.7dB. Lower and upper passband edges are at 5.1GHz and 9.2GHz with attenuation level of 52dB and 54dB respectively. With overlaying plate, the filter has same S 11 and S 21 parameters, but upper passband edge is shifted from 9.2GHz to 8.6GHz

scholarly journals Directivity Enhancement in Non-Reciprocal Bandpass Filters using an Evolutionary Algorithm

2021 ◽  
Author(s):  
Prantik Dutta ◽  
Arun Gande ◽  
Gopi Ram
Keyword(s):  
Evolutionary Algorithm ◽  
Insertion Loss ◽  
Return Loss ◽  
Bandpass Filter ◽  
Trial And Error ◽  
Swarm Optimization ◽  
Lumped Element ◽  
Trial And Error Method ◽  
Error Method ◽  
Maximum Directivity

In this letter, a non-reciprocal filter with enhanced directivity is analyzed methodically and the filter parameters are optimized using an evolutionary algorithm. The return loss, insertion loss, and isolation characteristics of the filter exhibit a trade-off that makes manual tuning a trial-and-error method. The veracity of the numerical modeling is conformed by designing a 150 MHz lumped element non-reciprocal bandpass filter based on the parameters extracted using an evolutionary algorithm based particle swarm optimization (PSO). The simulated and measured results comply well with the modeling and the results exhibit maximum directivity of 28.2 dB without degradation in insertion loss (1.1 dB) and return loss (16.2 dB) within the passband. The algorithm can be utilized in designing non-reciprocal filters having different center frequencies and bandwidths.

Miniaturized Dual-Band Bandpass Filter Using Embedded Dual-Mode Resonator with Controllable Bandwidths

Frequenz ◽  
2016 ◽  
Vol 70 (9-10) ◽  
Author(s):  
Chuanming Zhu ◽  
Jin Xu ◽  
Wei Kang ◽  
Zhenxin Hu ◽  
Wen Wu
Keyword(s):  
Insertion Loss ◽  
Degrees Of Freedom ◽  
Bandpass Filter ◽  
The Other ◽  
Dual Band ◽  
Dual Mode ◽  
Transmission Zeros ◽  
Low Insertion Loss ◽  
Multiple Transmission ◽  
Mode Resonator

AbstractIn this paper, a miniaturized dual-band bandpass filter (DB-BPF) using embedded dual-mode resonator (DMR) with controllable bandwidths is proposed. Two passbands are generated by two sets of resonators operating at two different frequencies. One set of resonators is utilized not only as the resonant elements that yield the lower passband, but also as the feeding structures with source-load coupling to excite the other to produce the upper passband. Sufficient degrees of freedom are achieved to control the center frequencies and bandwidths of two passbands. Moreover, multiple transmission zeros (TZs) are created to improve the passband selectivity of the filter. The design of the filter has been demonstrated by the measurement. The filter features not only miniaturized circuit sizes, low insertion loss, independently controllable central frequencies, but also controllable bandwidths and TZs.

Miniaturized Wideband Bandpass Filter based on Capacitor-loaded One-eighth Wavelength Coupled Line

2021 ◽  
Vol 36 (7) ◽  
pp. 865-871
Author(s):  
Jin Shi ◽  
Jiancheng Dong ◽  
Kai Xu ◽  
Lingyan Zhang
Keyword(s):  
Insertion Loss ◽  
Simple Structure ◽  
Bandpass Filter ◽  
State Of The Art ◽  
Center Frequency ◽  
Fractional Bandwidth ◽  
Coupled Line ◽  
Transmission Zeros ◽  
Compact Size ◽  
Multiple Transmission

A novel miniaturized wideband bandpass filter (BPF) using capacitor-loaded microstrip coupled line is proposed. The capacitors are loaded in parallel and series to the coupled line, which makes the filter just require one one-eighth wavelength coupled line and achieve filtering response with multiple transmission poles (TPs) and transmission zeros (TZs). Compared with the state-of-the-art microstrip wideband BPFs, the proposed filter has the advantages of compact size and simple structure. A prototype centered at 1.47 GHz with the 3-dB fractional bandwidth of 86.5% is demonstrated, which exhibits the compact size of 0.003λ2 g (λg is the guided wavelength at the center frequency) and the minimum insertion loss of 0.37 dB.

scholarly journals A Technique for Tunable Filters with Low Insertion Loss and Narrow Bandwidth

2018 ◽  
Vol 38 ◽  
pp. 03039
Author(s):  
Chang Zhou ◽  
Chen Ji ◽  
Gen Ping Wu
Keyword(s):  
Insertion Loss ◽  
Return Loss ◽  
Tunable Filters ◽  
Tunable Filter ◽  
Center Frequency ◽  
Pin Diodes ◽  
Lc Filters ◽  
Narrow Bandwidth ◽  
Low Insertion Loss ◽  
Resonant Capacitor

A technique for tunable filters with low insertion loss and narrow bandwidth is proposed in the form of comb-line structure. Both resonant capacitor with pin-diodes and resonant inductance in the tunable filter were analyzed and the main source of insertion loss was obtained. A series of filters with same pin-diodes, center frequency, absolute bandwidth and low return loss was simulated. The results showed that, by changing the values of the resonant capacitor and inductance, insertion loss of the filter can be greatly restricted. This technique will allow the design of tunable LC filters with low insertion loss and narrow bandwidth.

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