Compact and Wide Stopband Lowpass Filter Using Open Complementary Split Ring Resonator and Defected Ground Structure

A compact (0.16 λg x 0.08 λg) and wide stop¬band lowpass filter design using open complementary split ring resonator (OCSRR) and defected ground structure (DGS) is presented in this paper. Low pass filter is con-structed using two cascaded stages of OCSRR. Since the rejection bandwidth of the OCSRR is narrow, tapered dumbbell shaped DGS section is placed under the OCSRR to enhance the bandwidth. The cutoff frequency (fc) of the proposed lowpass filter is 1.09 GHz. The rejection band¬width of the filter covers the entire ultra wideband spec¬trum. Hence the spurious passband suppression is achieved up to 10 fc. The designed filter has been fabri¬cated and validated by experimental result

The Beauty of Symmetry: Common-mode rejection filters for high-speed interconnects and balanced microwave circuits

Common-mode rejection filters operating at microwave frequencies have been the subject of intensive research activity in the last decade. These filters are of interest for the suppression of common-mode noise in high-speed digital circuits, where differential signals are widely employed due to the high immunity to noise, electromagnetic interference (EMI) and crosstalk of differential-mode interconnects. These filters can also be used to improve common-mode rejection in microwave filters and circuits dealing with differential signals. Ideally, common-mode stopband filters should be transparent for the differential mode from DC up to very high frequencies (all-pass), should preserve the signal integrity for such mode, and should exhibit the widest and deepest possible rejection band for the common mode in the region of interest. Moreover, these characteristics should be achieved by means of structures with the smallest possible size. In this article, several techniques for the implementation of common-mode suppression filters in planar technology are reviewed. In all the cases, the strategy to simultaneously achieve common-mode suppression and all-pass behavior for the differential mode is based on selective mode-suppression. This selective mode suppression (either the common or the differential mode) in balanced lines is typically (although not exclusively) achieved by symmetrically loading the lines with symmetric resonant elements, opaque for the common-mode and transparent for the differential mode (common-mode suppression), or vice versa (differential-mode suppression).MINECO, Spain-TEC2013-40600-R, TEC2013-41913-PGeneralitat de Catalunya-2014SGR-15

Common-mode suppressed differential bandpass filter based on open complementary split ring resonators fabricated in microstrip technology without ground plane etching

A differential (or balanced) bandpass filter based on open complementary split ring resonators (OCSRRs) coupled through admittance inverters is presented in this article. Pairs of OCSRRs are symmet- rically placed in a mirror configuration between the strips of the differential line and are modeled by means of two series connected parallel resonators. For the differential (odd) mode, there is a virtual ground at the connecting plane between the OCSRR pairs, and the structure is roughly described by the canonical model of a bandpass filter, consisting of a cascade of shunt resonators coupled through admittance inverters. It is demonstrated that, through a proper design of the OCSRR stages, the common mode noise in the vicinity of the differential filter pass band can be efficiently suppressed. Due to the differential mode operation of the filter, it is not necessary to incorporate metallic vias to ground the OCSRRs. Moreover, as compared to other differential filters based on OCSRRs, defected ground structures are not present in the proposed filters. To illustrate the potential of the approach, two balanced bandpass filters are designed, fabricated, and characterized

An Inter digital- Poison Ivy Leaf Shaped Filtenna with Multiple Defects in Ground for S-Band bandwidth Applications

The proposed work, a filtenna for s band application is implemented. It is designed by embedding an Interdigital band pass filter (IDBPF) and leaf shaped antenna which are operated in S band. The IDFBPF is having seven resonators with one end shorted through dual vias. It offers a bandwidth of 1.3GHz from 1.65GHz to 2.95GHz.  A Dumbbell shaped DGS (Defected Ground Structure) provided in ground to improve the filter characteristics.  Measured pass (BRL) band return loss (S11) & insertion loss (S12) are -18dB & -4.6dB correspondingly. Further, leaf shaped antenna is designed based on modified polar transformation equation; it has 2.7 GHz bandwidth from 1.3 GH to 3 GHz and has a gain of -5.45dBi, and return loss (S11) of -19.5 dB. The filtenna is obtained by integrating the IDBBPF in the fodder line of the leaf designed antenna. The final model has 1.2 GHz operating bandwidth from 02.30 GHz to 03.50 GHz with peak arrival damages at 2.4GHz and 3.1GHz with -20dB and-24dB respectively. The designed filtenna has a pass band gain of -5.3dBi. The shift in operating band is due to combining the filter with antenna. The proposed model is invented on FR4 substrate having a wideness of 01.60 mm and having a dimension of 0.25 0.58 ?02. In this final model two complementary slip ring resonators (CSRR) are used in addition with four dumbbell structures as defects in the ground plane to avoid ripples in return loss (S11) graph. A high degree of concordance exists between empirically measured and simulated outcomes. The radiation band is showing its application in S band wireless mobile communications, Wi-Fi and ISM 2.4GHz band

Design of substrate integrated waveguide based bandpass filters and power dividers

Ankara : The Department of Electrical and Electronics Engineering and the Graduate School of Engineering and Science of Bilkent University, 2013.Thesis (Master's) -- Bilkent University, 2013.Includes bibliographical references leaves 69-76.A microwave system is, in general, designed by using fundamental components such as filters, couplers, dividers, etc. Due to the fact that wavelength becomes comparable with lumped element dimensions, at microwave frequencies distributed elements are used for building these components. Microstrip based devices can be used up to certain frequencies. However, when radiation loss increases, waveguide based devices are used which are bulky and costly. Recently, substrate integrated waveguide (SIW) based devices have attracted the attention of many researchers due to low cost, lightweight and efficient high frequency characteristics. SIW is the printed circuit realization of a waveguide. SIW is fabricated on a dielectric material with top and bottom sides are conductors, and two linear arrays of metallic vias form the side walls. In this thesis, by using SIW structure, iris type bandpass filters are designed, analyzed and fabricated for verification. After that, complementary split ring resonator (CSRR) and dumbbell type defected ground structure (DGS) etched filters that are available in the literature are investigated and verified with simulations. Having investigated different filter topologies in the literature, a novel SIW based bandpass filter is proposed, where its second harmonic is suppressed using a dumbbell type DGS underneath the microstrip feed line. The filter is demonstrated with a fabricated prototype, where the simulated and measured results agree well. Furthermore, SIW based power dividers available in the literature and the corrugated SIW (CSIW) architecture which uses open-circuit ended quarter-wavelength stubs instead of vias as the sidewalls, are investigated. CSIW architecture is implemented to a power divider structure available in the literature and a novel CSIW based high isolation power divider is designed and demonstrated with a fabricated prototype. Good agreement between simulated and fabricated results are observed.Kurudere, SinanM.S

Passive Planar Microwave Devices

The aim of this book is to highlight some recent advances in microwave planar devices. The development of planar technologies still generates great interest because of their many applications in fields as diverse as wireless communications, medical instrumentation, remote sensing, etc. In this book, particular interest has been focused on an electronically controllable phase shifter, wireless sensing, a multiband textile antenna, a MIMO antenna in microstrip technology, a miniaturized spoof plasmonic antipodal Vivaldi antenna, a dual-band balanced bandpass filter, glide-symmetric structures, a transparent multiband antenna for vehicle communications, a multilayer bandpass filter with high selectivity, microwave planar cutoff probes, and a wideband transition from microstrip to ridge empty substrate integrated waveguide

A Comprehensive Survey on “Various Decoupling Mechanisms With Focus on Metamaterial and Metasurface Principles Applicable to SAR and MIMO Antenna Systems”

Nowadays synthetic aperture radar (SAR) and multiple-input-multiple-output (MIMO) antenna systems with the capability to radiate waves in more than one pattern and polarization are playing a key role in modern telecommunication and radar systems. This is possible with the use of antenna arrays as they offer advantages of high gain and beamforming capability, which can be utilized for controlling radiation pattern for electromagnetic (EM) interference immunity in wireless systems. However, with the growing demand for compact array antennas, the physical footprint of the arrays needs to be smaller and the consequent of this is severe degradation in the performance of the array resulting from strong mutual-coupling and crosstalk effects between adjacent radiating elements. This review presents a detailed systematic and theoretical study of various mutual-coupling suppression (decoupling) techniques with a strong focus on metamaterial (MTM) and metasurface (MTS) approaches. While the performance of systems employing antenna arrays can be enhanced by calibrating out the interferences digitally, however it is more efficient to apply decoupling techniques at the antenna itself. Previously various simple and cost-effective approaches have been demonstrated to effectively suppress unwanted mutual-coupling in arrays. Such techniques include the use of defected ground structure (DGS), parasitic or slot element, dielectric resonator antenna (DRA), complementary split-ring resonators (CSRR), decoupling networks, P.I.N or varactor diodes, electromagnetic bandgap (EBG) structures, etc. In this review, it is shown that the mutual-coupling reduction methods inspired By MTM and MTS concepts can provide a higher level of isolation between neighbouring radiating elements using easily realizable and cost-effective decoupling configurations that have negligible consequence on the array’s characteristics such as bandwidth, gain and radiation efficiency, and physical footprint

The beauty of symmetry : common-mode rejection filters for high-speed interconnects and band microwave circuits

Common-mode rejection filters operating at microwave frequencies have been the subject of intensive research activity over the last decade. These filters are of interest for the suppression of common-mode noise in high-speed digital circuits, where differential signals are widely employed due to the high immunity to noise, electromagnetic (EM) interference, and crosstalk of differential-mode interconnects. These filters can also be used to improve common-mode rejection in microwave filters and circuits dealing with differential signals. Ideally, common-mode stopband filters should be transparent for the differential mode from dc up to very high frequencies (all pass), preserve the signal integrity for such mode, and exhibit the widest and deepest possible rejection band for the common mode in the region of interest. Moreover, these characteristics should be achieved by means of structures with the smallest possible size

An Investigation of Ultra-Wideband Filters for Cognitive Radio Networks

The requirement for radio spectrum has been increasing and this has resulted in the materialization of wireless applications with enhanced features and higher data rate. The spectrum is scant, and the current radio spectrum regulation is making its use inefficient. This necessitates the development of new dynamic spectrum allocation policies to better exploit the existing spectrum. According to the present spectrum allocation regulations, specific frequency bands are allocated to particular services and only approved users are granted access to licensed bands. Cognitive radio (CR) is expected to modernize the mode spectrum is allocated. In a CR network, the intelligent radio part allows secondary users (unlicensed users) to access spectrum bands allocated to the licensed primary users with the avoidance of interference. A solution to this inefficiency has been highly successful in the ISM (2.4 GHz), the U-NII (5–6 GHz), and microwave (57–64 GHz) bands, by making the unused spectra accessible on an unlicensed basis. However, in order to obtain spectra for unlicensed operation, new sharing concepts have been introduced to allow the usage of spectra by secondary users under the prerequisite that they limit their interference to the primary users. This would start by studying techniques employed in the design of UWB filters. This study is aimed to investigate the filters for overlay and underlay CR. This paper presents a comparative study of ultra-wideband filters for Cognitive Radio Networks