Ultra-wide stopband lowpass filters using ring resonators

Author(s):  
Mohsen Hayati ◽  
Sajjad Mohanad Mustafa ◽  
Farzin Shama ◽  
Hamed Abbasi

Abstract A microstrip-based lowpass filter (LPF) containing modified ring structures has been presented. Ring resonators are used to form a sharp transition region. In addition, rectangular- and tapered-shaped suppressing cells are used to create an ultra-wide stopband region. By combining the designed ring resonator and suppressors, an LPF has been designed with −3 dB cut-off frequency at 1.83 GHz. A sharp transition region has been achieved from 1.83 (at −3 dB) to 2.1 GHz (at −60 dB). A stopband region has been concluded from 2 to 21 GHz (with the corresponding attenuation level of at least 20 dB). The measured insertion loss is better than 0.1 dB (equal to a return loss of 18.1 dB) in the passband region. The proposed circuit is fabricated and measured. The measured results have an appropriate adaption with the simulated results.

2016 ◽  
Vol 9 (3) ◽  
pp. 499-504 ◽  
Author(s):  
Mohsen Hayati ◽  
Mehrnaz Khodadoost ◽  
Hamed Abbasi

In this paper, a microstrip lowpass filter with wide stopband and sharp roll-off is presented. The proposed filter consists of a modified radial stub resonator which is cascaded by four suppressing cells. To reduce the overall size, the transmission lines are folded. The cut-off frequency of the proposed filter is 1.19 GHz. The transition band is approximately 0.2 GHz from 1.19 to 1.39 GHz with corresponding attenuation levels of 3–20 dB. The stopband is from 1.39 to 19 GHz with attenuation level of <20 dB. The insertion loss and return loss in the passband from DC to 0.8 GHz are better than 0.26 and 14 dB, respectively. The proposed filter is fabricated and measured. The simulated and measured results are in good agreement.


2012 ◽  
Vol 487 ◽  
pp. 125-129
Author(s):  
Kai Yu Zhao ◽  
Lin Li

A compact lowpass filter using two single-sided compact microstrip resonator cells (CMRCs)with low insertion loss and broad bandwidth is presented. The cutoff frequency is about 1.4 GHz, the insertion loss is less than 0.6 dB and the 20dB bandwidth is up to the range from 2.1 GHz to 9.8 GHz by means of introducing four transmission zeros through two CMRCs. In addition, the simulated results demonstrate that the proposed filter is characterized by a compact size, low insertion loss, sharp transition, low return loss and wide bandwidth.


2013 ◽  
Vol 5 (6) ◽  
pp. 713-719 ◽  
Author(s):  
Mohsen Hayati ◽  
Mozhgan Amiri ◽  
Zahra Faramarzi

In this paper, a novel compact microstrip lowpass filter (LPF) using diamond-shaped resonator with wide rejection and sharp transition band is presented. The proposed filter has −3 dB cut off frequency at 2.6 GHz. The maximum insertion loss is only 0.1 dB in the passband and the rejection band extends from 2.89 to 20.84 GHz with the attenuation level better than −21 dB. The transition band is only 0.288 GHz, from 2.606 to 2.894 GHz with corresponding attenuation levels of −3 and −20 dB, respectively. The filter size is 12.4 × 11.5 mm2. The proposed filter is fabricated and tested, where the measurement results are in good agreement with the simulation results. The proposed LPF has compact size, simple structure, wide rejection band, and low insertion loss, where all of these characteristics are essential for LPF in the modern communication circuits.


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


2019 ◽  
Vol 12 (2) ◽  
pp. 116-119
Author(s):  
F. Parment ◽  
A. Ghiotto ◽  
T.-P. Vuong ◽  
L. Carpentier ◽  
K. Wu

AbstractA compact transition between conductor-backed coplanar waveguide (CBCPW) and substrate integrated suspended line (SISL) is presented. Compared to the reported transitions from CBCPW to SISL, performance and compactness are improved. For demonstration purpose, a multilayer transition is designed and fabricated for operation up to 46 GHz. Experimental results, based on an electronic calibration and thru–reflect–line calibration allowing measurement in the 0.01–50 GHz frequency range, demonstrate an insertion loss of 0.59 ± 0.51 dB with a return loss of better than 10 dB in the 10 MHz to 46 GHz frequency range.


2019 ◽  
Vol 12 (1) ◽  
pp. 21-33
Author(s):  
M. Hayati ◽  
AS. Abdipour ◽  
AR. Abdipour

AbstractIn this paper, a microstrip lowpass filter adopting two main resonators with steep transition band and wide rejection band has been introduced. The first main resonance cell consists of meandered transmission lines which are loaded by modified T-shaped patches. The second main resonator is composed of high-impedance lines loaded by polygon patches. To obtain a steep skirt performance, the first and second resonators have been combined. Moreover, employing eight high–low impedance folded stubs and two rectangular open-stubs as suppressing cells has resulted in improving the stopband features. To comprehend the frequency behavior of the employed resonators and also their combination, the formulas of the transmission coefficient, reflection coefficient, and the transmission zeros of their equivalent LC circuits have been extracted, separately. According to the measurement results, the −3 dB operating frequency of this filter is 1.65 GHz. Moreover, a relative stopband bandwidth equal to 166% with a corresponding attenuation level of 23 dB and a sharp roll-off rate (393.61 dB/GHz) have been achieved. In the passband region from DC to 1.632 GHz, the insertion loss and return loss are better than 0.0763 and 15.85 dB, respectively, proving an acceptable in-band performance. Finally, the implemented structure brings about a high figure-of-merit equal to 81 672.


2015 ◽  
Vol 8 (2) ◽  
pp. 185-191 ◽  
Author(s):  
Teng Li ◽  
Wenbin Dou

In this paper, a novel wideband right-angle transition between thin substrate integrated waveguide (SIW) and rectangular waveguide (RWG) based on multi-section structure operating at center frequency 31.5 GHz is presented. A multi-section SIW with a rectangular aperture etched on the broad wall and two stepped ridges embedded in the RWG flange are introduced to obtain a wide impedance matching. The simulations show that the bandwidth with return loss better than 20 dB is about 17 GHz. In order to verify our designs, two back-to-back transitions with different lengths are fabricated and measured. The experimental results agree well with simulations. The proposed component shows an insertion loss less than 0.44 dB and a return loss better than 14.5 dB over 12.15 GH, which corresponds to 38.57% bandwidth.


2013 ◽  
Vol 385-386 ◽  
pp. 1292-1295
Author(s):  
Xu Han ◽  
Jian Hua Xu

A planar power divider operating over the whole Ku-band is presented. The proposed device utilizes a T-microstrip junction combined with defected ground structure and an elliptical patch at the centre of the T-junction. An isolation resistor is connected across the slotted ground plane. The simulated results of the divider show equal power split, insertion loss is less than 0.3dB, return loss of all ports are better than 15dB, and isolation is better than 15dB over the whole Ku-band.


2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Mohammed A. Aseeri ◽  
Meshaal A. Alyahya ◽  
Hatim A. Bukhari ◽  
Hussein N. Shaman

A microstrip lowpass filter based on transmission line elements for UWB medical applications is proposed in this paper. The filter is constructed of two symmetric shunt open-circuited stubs and three series unit elements. The filter is designed to exhibit an elliptic function response with equal ripple in the passband and the rejection band. A prototype is successfully designed, fabricated, and measured, where a good agreement is attained. The filter shows a high filtering selectivity and an ultra-wide stopband up to 20 GHz with an attenuation level of more than 20-dB. The filter is compact and has a low insertion loss and an ultra-wideband (UWB) rejection which makes it attractive for many technologies such as UWB medical applications.


2014 ◽  
Vol 668-669 ◽  
pp. 799-802
Author(s):  
Hai Yan Jin ◽  
Teng Yue

The paper presents a design of rectangular waveguide-SIW transition, which provides a broadband and low insertion loss performance. The broadband transition is realized by using double-rhombus antenna probe inserted into rectangular metal waveguide. The transition is simulated and measured at 9-20GHz. The measured results show that a good agreement with simulation and an insertion loss less than 2.8 dB and a return loss better than 10 dB are obtained at 10–18.5 GHz for a back-to-back structure.


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