scholarly journals Reconfigurable Ring Filter with Controllable Frequency Response

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Norfishah Ab Wahab ◽  
Mohd Khairul Mohd Salleh ◽  
Zuhani Ismail Khan ◽  
Nur Emileen Abd Rashid

Reconfigurable ring filter based on single-side-access ring topology is presented. Using capacitive tuning elements, the electrical length of the ring can be manipulated to shift the nominal center frequency to a desired position. A synthesis is developed to determine the values of the capacitive elements. To show the advantage of the synthesis, it is applied to the reconfigurable filter design using RF lumped capacitors. The concept is further explored by introducing varactor-diodes to continuously tune the center frequency of the ring filter. For demonstration, two prototypes of reconfigurable ring filters are realized using microstrip technology, simulated, and measured to validate the proposed concept. The reconfigured filter using lumped elements is successfully reconfigured from 2 GHz to 984.4 MHz and miniaturized by 71% compared to the filter directly designed at the same reconfigured frequency, while, for the filter using varactor-diodes, the frequency is chosen from 1.10 GHz to 1.38 GHz spreading over 280 MHz frequency range. Both designs are found to be compact with acceptable insertion loss and high selectivity.

2019 ◽  
Vol 14 (4) ◽  
pp. 448-455 ◽  
Author(s):  
Nanang Ismail ◽  
Teddy Surya Gunawan ◽  
Santi Kartika S ◽  
Teguh Praludi ◽  
Eki A.Z. Hamidi

Radar has been widely used in many fields, such as telecommunication, military applications, and navigation. The filter is one of the most important parts of a radar system, in which it selects the necessary frequency and blocks others. This paper presents a novel yet simple filter design for S-band radar in the frequency range of 2.9 to 3.1 GHz. The center frequency of the filter was designed at 3 GHz with a bandwidth of 200 MHz, insertion loss larger than -3 dB and return loss less than -20 dB. Fifth order microstrip hairpin bandpass filter (BPF) was designed and implemented on Rogers 4350B substrate which has a dielectric relative constant value of (εr)= 3.48 and substrate thickness of (h) =1.524 mm. One element of the square groove was added as Defected Ground Structure (DGS) which can decrease the filter size, reduce harmonization, and increase return loss. Two scenarios were used in the measurement, i.e. with and without enclosed aluminum casing. Results showed that BPF without casing obtained the insertion loss of -1.748 dB at 2.785 GHz and return loss of -21.257 dB in the frequency range between 2.785 to 2.932 GHz. On the other hand, BPF with casing shows a better performance, in which it obtained the insertion loss of -1.643 dB at 2.921 GHz and return loss of -19.529 in the frequency range between 2.820 to 3.021 GHz. Although there is small displacement of frequency and response value between the simulation and implementation, our BPF has the ability to work on S-band radar with a frequency range of 2 to 4 GHz. 


2017 ◽  
Vol 9 (10) ◽  
pp. 1931-1936 ◽  
Author(s):  
Kaijun Song ◽  
Yifang Zhou ◽  
Maoyu Fan ◽  
Yu Zhu ◽  
Yong Fan

A wide-stopband bandpass-filtering power divider with high-frequency selectivity has been proposed in this paper. The input and output feeding lines and eight 1/4 wavelength resonators are used to realize the signal transmission. In order to obtain good frequency selectivity, source-load coupling transmission path is used to generate transmission zeros near the passband. A four-way power divider with bandpass-filtering response and high-frequency selectivity is designed, fabricated, and measured. The measured results agree with the simulated ones closely in the desirable frequency range. The measured center frequency of the power divider is 2.38 GHz with input return loss of 31.2 dB, while the measured insertion loss is about 1 dB (not including ideal 6 dB four-way power dividing insertion loss). Moreover, the measured 3-dB bandwidth is 12% and the measured stopband attenuation is >15 dB from 2.59 to 7.7 GHz. In addition, two transmission zeros of 1.9 and 2.8 GHz are located near the passband. The measured output isolations are all >15.7 dB.


This paper presents a new concept of bandpass filter design based on quarter-wave resonator which covers ISM band (2.4-2.48 GHz) can be used for applications such as wireless fidelity (Wi-Fi) and Global System for Mobile communication (GSM). A fifth-order Butterworth bandpass filter is designed using standard filter coefficients with fractional bandwidth of 50% for the center frequency of 2.1 GHz. Filter design is achieved using quarter-wave resonator, and the obtained response satisfies the desired filter specifications. The insertion loss of 21 dB is achieved at the cutoff frequency of 2.1 GHz. The passband frequency of 1.877 GHz to 2.772 GHz is achieved in the proposed design. The standard coefficients of the Butterworth filter were modified to propose a new type of asymmetrical filter coefficients. The designed filter has better response than existing method in terms of bandwidth and insertion loss. The designed Bandpass filter has a passband frequency of 1.8 GHz to 2.7 GHz. Therefore, the designed bandpass filter can be used for both Wi-Fi and GSM applications simultaneously.


Author(s):  
Tamilselvan S ◽  
Oudaya coumar S

This paper is about a dual band single notch filter to eliminate the effect of WLAN in UWB range. A novel square resonator with interdigital coupling at both sides plays a key role in this filter design. Design and EM Simulation of the dual band notch filter's characteristics are discussed in this paper. The proposed dual band notch filter produces excellent bandwidth from 2 GHz to 5 GHz and from 5.5 GHz to 8 GHz. The filter rejects the band of frequency from 5 GHz to 5.5 GHz which is very narrow band in which the filter eliminates the effect of WLAN (IEEE 802.11a). Also the out band performance of the proposed dual band filter meets the requirement of FCC's mask. The simulation analysis of the proposed filter is performed by electromagnetic solver. The return loss, insertion loss, group delay and phase of the filter are simulated and their performances are analyzed. The overall dimension of the filter is achieved to be 39mm x 3.2mm x 1.6mm on accounting the above features. The fractional bandwidth of the notch filter is calculated from the bandwidth and the center frequency and it is obtained about 115%. The S parameter results of the filter such as return loss (S11) in stop band is about -24 dB and insertion loss (S21) is about -28 dB is obtained.


Author(s):  
Б.А. Беляев ◽  
А.М. Сержантов ◽  
Ан.А. Лексиков ◽  
Я.Ф. Бальва ◽  
Р.Г. Галеев

A new monolithic design of a miniature bandpass filter has been developed for the multilayer PCB technology fabrication. The use of multi-conductor stripline resonators in the design provides not only miniaturization, but also high selectivity of the device, which is demonstrated on a prototype filter of the fourth order. The center frequency of the passband of the manufactured filter is f0 = 546 MHz, the fractional bandwidth is Δf / f0 = 25%, the insertion loss is 0.8 dB. The filter has an extended high-frequency stop band, which at a level of ‒30 dB extends up to a frequency of 10f0. The dimensions of the filter are 15.0×12.0×4.3 mm3 (0.027λ0×0.021λ0 ×0.007λ0, where λ0 is the wavelength in vacuum at the frequency f0), and its mass is only 1.8 g. The filter's characteristics and ease of construction for surface mounting prove its high prospects.


Electronics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 51
Author(s):  
Min-Hang Weng ◽  
Chin-Yi Tsai ◽  
De-Li Chen ◽  
Yi-Chun Chung ◽  
Ru-Yuan Yang

This paper presents a miniaturized bandpass filter, which uses half mode substrate integrated waveguide (HMSIW) structure with embedded step impedance structure (SIS). By embedding the stepped impedance structure into the top metal of the waveguide cavity, the center frequency can be quickly shifted to a lower frequency. The operating center frequency of the proposed bandpass filter (BPF) using HMSIW resonators with embedded SIS is tunable as functions of the parameters of the SIS. The design curve is provided. A filter example of the center frequency of the filter at 3.5 GHz is fabricated and measured, having the insertion loss |S21| less than 3 dB, and the return loss |S11| greater than 10 dB. The transmission zeros are located at 2.95 GHz and 3.95 GHz on both sides of the passband, both of which are lower than 30 dB. The simulation result and the measured response conform to the proposed design concept. The proposed HMSIW filter design is in line with the current 5G communication trend.


Circuit World ◽  
2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Keyur Mahant ◽  
Hiren K. Mewada ◽  
Amit V. Patel ◽  
Alpesh Vala ◽  
Jitendra Chaudhari

Purpose This paper aims to present, design and implement a novel half-mode substrate integrated waveguide (HMSIW)-based narrow bandpass filter, which offers advantages like low insertion loss, compact size and high selectivity. Proposed filter will be used in the K-band automotive radar application. Design/methodology/approach The filtering response in the proposed design is achieved by inserting inductive posts in the HMSIW cavity. Ansoft high frequency structure Simulator (HFSS) is used for the simulation of the proposed structure, which is a three-dimensional full-wave solver using the finite element method (FEM). The proposed filter is fabricated on the dielectric material RT duroid 5,880 with the dielectric constant ɛr = 2.2, dissipation factor t and = 4 × 10–4 and height h = 0.508 mm. Findings Frequency tuning is also carried out by changing the lateral distance between two inductive posts. Moreover, a comparison of the proposed structure with the previously published work is presented. Proposed method provides the unique advantages such as low insertion loss, high selectivity and compact in size. Originality/value Indigenous method has been used for the development of the filter. Proposed filter will be used in transmitter subsystem of the K-band radar system operating at the center frequency of 11.2 GHz. Measurement results are well-matched with the simulated one. Obtained measured result shows return loss of 20.39 dB and insertion loss of 1.59 dB with 3 dB fractional bandwidth (FBW) of 2.58% at the center frequency of 11.2 GHz.


Frequenz ◽  
2020 ◽  
Vol 74 (7-8) ◽  
pp. 263-270
Author(s):  
Cao Zeng ◽  
Xue Han Hu ◽  
Feng Wei ◽  
Xiao Wei Shi

AbstractIn this paper, a tunable balanced-to-balanced in-phase filtering power divider (FPD) is designed, which can realize a two-way equal power division with high selectivity and isolation. A differential-mode (DM) passband with a steep filtering performance is realized by applying microstrip stub-loaded resonators (SLRs). Meanwhile, six varactors are loaded to the SLRs to achieve the center frequency (CF) and bandwidth adjustment, respectively. U-type microstrip lines integrated with stepped impedance slotline resonators are utilized as the differential feedlines, which suppress the common-mode (CM) intrinsically, making the DM responses independent of the CM ones. A tuning center frequency from 3.2 to 3.75 GHz and a fractional bandwidth (12.1–17.6%) with more than 10 dB return loss and less than 2.3 dB insertion loss can be achieved by changing the voltage across the varactors. A good agreement between the simulated and measured results is observed. To the best of authors' knowledge, the proposed balanced-to-balanced tunable FPD is first ever reported.


2015 ◽  
Vol 8 (2) ◽  
pp. 179-184 ◽  
Author(s):  
Valeria Nocella ◽  
Luca Pelliccia ◽  
Paola Farinelli ◽  
Roberto Sorrentino ◽  
Mario Costa ◽  
...  

A robust and tuneless micromachined waveguide diplexer operating in the frequency range 71–86 GHz is here presented. The diplexer is based on multiple coupled cavities and it is manufactured using micromachining technology on two staked silicon layers. The diplexer consists of two filters combined to a common waveguide port via an E-plane T-junction. The two eight-order band-pass filters are centered at 73.5 and 83.5 GHz. The fractional bandwidths for two bands are 8.8 and 7.8% at higher- and lower-band, respectively. The measured insertion loss is below 0.7 dB for both the filters and the diplexer isolation is better than 55 dB, as required. The proposed technology allows for a very compact device (<20 × 20 × 1.5 mm) and the first prototypes were proved to be very robust to manufacturing tolerances and environmental tests, thus leading to an excellent tuneless manufacturing yield in future production. The diplexer will be employed in next generation terrestrial radio-link communications front-ends.


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