Tamasi Moyra - Academia.edu (original) (raw)

Papers by Tamasi Moyra

Handbook of Intelligent Computing and Optimization for Sustainable Development, 2022

2017 International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET), 2017

In this present work a conductor-backed coplanar waveguide (CB-CPW) bandpass filter (BPF) centere... more In this present work a conductor-backed coplanar waveguide (CB-CPW) bandpass filter (BPF) centered at 2.8 GHz is proposed which consists of symmetrical L-shaped resonator pairs, shorted stubs, and L-shaped defected slot line (DSL). The center frequency of the proposed BPF can be tuned from 2.1 GHz to 3.8 GHz by changing the lengths of the resonator pairs. The passband ripple and spurious harmonics of the BPF are suppressed by adjusting the shorted and open stub section. The sharpness of the BPF is improved by including DSL near the feed line that exhibits stopband near the upper cut-off frequency. Simulated and measured result exhibits a stop-band rejection lower than —16 dB till 20 GHz with passband insertion loss of 0.7 dB and return loss of 29.66 dB. The BPF has much reduced circuit area of 8 × 20.2 mm2 compared to work stated below, also has the group delay of 0.17 ns which remains almost flat for entire passband, fractional bandwidth of 60.71%, 30 dB shape factor of 2.98, 3 dB bandwidth of 1.7 GHz and roll-off factor of 17.12 dB/GHz. It is implemented on the FR4 substrate with dielectric constant εr = 4.4, substrate height = 0.8 mm and thickness of the CB-CPW conductor 0.02 mm. The BPF show better performance, and hence can be used for practical purposes such as in low-cost WLAN and WiMax devices.

IETE Journal of Research, 2021

In this article, a coplanar waveguide (CPW) based compact low loss notch filter (NF) with sharp r... more In this article, a coplanar waveguide (CPW) based compact low loss notch filter (NF) with sharp roll–off is proposed. At the beginning, the proposed NF is designed using an array of conventional Mu...

2017 8th International Conference on Computing, Communication and Networking Technologies (ICCCNT), 2017

In this present work, a microstrip patch antenna (MPA) using frequency selective surface (FSS) is... more In this present work, a microstrip patch antenna (MPA) using frequency selective surface (FSS) is proposed. The FSS acts as a reflection plane which is loaded onto a microstrip patch antenna to improve the performance of antenna. The single-layer FSS (SL-FSS) and double-layer FSS (DL-FSS) are respectively loaded onto the C-band microstrip patch antenna. After loading the FSS as the reflection plane, the gain is increased by 1.45dB and 3.97dB respectively and the directivity is also improved. The proposed antenna is designed to operate at the resonant frequency of 5.2 GHz. The antenna is simulated in HFSS using FR-4 substrate with a dielectric constant of 4.4, thickness of 0.8mm and loss tangent of 0.02. The proposed antenna can be used in WLAN applications.

EngRN: Computer-Aided Engineering (Topic), 2019

This paper presents a compact coplanar waveguide lowpass filter (LPF) of low insertion loss and w... more This paper presents a compact coplanar waveguide lowpass filter (LPF) of low insertion loss and wide attenuation band. The proposed study is designed by employing open stubs and Defected Ground Structures (DGS).Since, in Coplanar Waveguide (CPW) the signal plane and the ground plane are considered same hence in this paper the defect in the rear plane of the CPW is named as DGS. Initially the response of the proposed LPF without any DGS has been simulated using Method of Moment (MoM) based IE3D EM simulation software. Then, E-shaped DGSs are introduced in the ground plane for widening the attenuation band. DGSs are placed directly under the transmission lines to improve the passband characteristics and to suppress the higher order harmonics. The cut-off frequency of the proposed filter is 2.7 GHz, and the maximum insertion loss in the passband is 0.3 dB. The attenuation band of the LPF is extended up to 8 GHz with a minimum suppression level of -10 dB. The roll off factor obtained fo...

This paper presents the design procedure of a bandpass filter based on parallel coupled half wave... more This paper presents the design procedure of a bandpass filter based on parallel coupled half wave length resonator concept with full length coupling. For the purpose of miniaturization and to get high coupling the new model of parallel coupled bandpass filter has been introduced. Here, the third resonator is placed just beneath the first one & fifth beneath the third one. Similar condition is for even order resonators. Here, area of the microstrip filter is very less, i.e., it is a compact structure. Finally a bandpass filter having Fractional bandwidth of 20% is obtained. The proposed BPF filter has been fabricated and measured with an Agilent make vector network analyzer of model N5230A and also good agreement between simulated and measurement results have been obtained.

2016 International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET), 2016

In this paper a generalized Chebyshev lowpass filter (LPF) is presented, and it has been modified... more In this paper a generalized Chebyshev lowpass filter (LPF) is presented, and it has been modified to produce better passband characteristics by introducing open stubs and Defected Ground Structure (DGS). The circuit model of the mentioned filter is demonstrated with its response for determining the element values of the lowpass prototype filter. The conventional lowpass filter provides a cut-off frequency at 7.7GHz with high insertion loss in the passband, which is practically and economically unacceptable. Thus, to reduce the insertion loss in the passband, reactive stubs are used in the metal plane and DGS is introduced in the ground plane with the existing LPF. Finally, the proposed lowpass filter provides excellent characteristics with negligible passband insertion loss and sharpness factor of 23dB/GHz and wide attenuation band. The substrate used for this design is Roger Duroid RO4350 with a thickness of 0.168mm and dielectric constant, εr of 3.48.

2017 International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET), 2017

In this present work, a dual-band microstrip patch antenna (MPA) using frequency selective surfac... more In this present work, a dual-band microstrip patch antenna (MPA) using frequency selective surface (FSS) is proposed. The MPA is designed using fractal shaped resonators with symmetrically arranged elliptical slots and partial ground structure that has gain of 3.01 dB. The FSS act as a reflection plane which is loaded onto a MPA to improve the performance of the antenna. The combined reflection plane is obtained by the periodic array of 2 × 3 unit cell in the x-y direction, which is is based on the combination of circular and square loop element. After loading FSS as the reflection plane, the gain is increased by the magnitude of 1.22 dB at 5.0 GHz and 1.6 dB at 10.6 GHz respectively. The proposed dual-band antenna operates at 5.0 GHz and 10.6 GHz respectively with better than 4 dB radiation gain for both of the bands. The antenna is simulated in HFSS using FR-4 substrate with a thickness of 1.6 mm and relative permittivity of 4.4. The overall size of the periodic structure of FSS i...

Iranian Journal of Science and Technology, Transactions of Electrical Engineering, 2020

A novel and miniaturized 4 × 4 butler matrix (BM) is proposed in this work. This proposed butler ... more A novel and miniaturized 4 × 4 butler matrix (BM) is proposed in this work. This proposed butler matrix is designed with four 3 dB quadrature (90°) forward wave coupled line coupler (FWCC) and two 45° Schiffman phase shifter. This BM is designed at center frequency of 2.4 GHz using FR4 substrate. The crossover of this BM has been replaced with a 0 dB FWCC. The performances of all couplers have been improved with the help of defected ground structures (DGS). Two C-shape and one I-shape DGSs are etched at the ground plane of each coupler, and two C-shape and one dumbbell shape DGSs are etched at the ground plane of 0 dB crossover which enhance the performance of the BM. This proposed BM provides a maximum bandwidth of 120 MHz at each port and occupies a total area of 0.677 λ 0 (84.74 mm) × 0.612 λ 0 (76.56 mm).

Electromagnetics, 2020

ABSTRACT In this work, a compact and wideband Schiffman phase shifter is proposed using a microst... more ABSTRACT In this work, a compact and wideband Schiffman phase shifter is proposed using a microstrip transmission line. This proposed phase shifter incorporates a rectangular complementary split-ring resonator (CSRR) and two open stubs. It is designed to get a phase shift of 90° with ±5° phase imbalance for the frequency range of 1.47–3.52 GHz. It shows a fractional bandwidth of 85.41% at the center frequency of 2.4 GHz. The proposed design occupied a total area of 0.067 λg2. The proposed structure is fabricated and validated, there is a good agreement between the simulated and measured results.

Iranian Journal of Science and Technology, Transactions of Electrical Engineering, 2019

This work presents a UWB balanced-to-unbalanced (BTU) power divider (PD) using coupled lines and ... more This work presents a UWB balanced-to-unbalanced (BTU) power divider (PD) using coupled lines and an additional shunt TL in the middle. The even-mode and odd-mode ABCD parameters of BTU PD produce the required analytical design equations. Later, the use of stub-loaded coupled lines in the shunt transmission line enhanced the passband response. The structure is further optimised by varying the impedance and electrical length of the middle shunt transmission line. For verification, a prototype is simulated, fabricated and measured. The proposed BTU power divider occupies size of 0.36 9 0.52 k 2 g with 95.6% FBW. The measured results agree with the simulated results.

International Journal of RF and Microwave Computer-Aided Engineering, 2019

A compact low-cost lowpass filter (LPF) with sharp roll-off and wide attenuation band using stepp... more A compact low-cost lowpass filter (LPF) with sharp roll-off and wide attenuation band using stepped impedance resonator loaded with interdigital fingers and U-shaped resonator is recommended in this article. The proposed LPF has a cutoff frequency of 1.2 GHz with a sharp roll-off 135 dB/GHz and passband insertion loss 0.35 dB. An array of two different shapes of defected ground structures are etched in the ground plane for introducing additional transmission zeroes to enhance the stopband performance. The relative stopband suppression is achieved up to 171% with a suppression factor of 2. The proposed structure is modelled, fabricated, and measured. The measurement results are found to be well-matched with the simulated ones. Eventually, a high figure of merit of 21 600 is achieved.

Advances in Modelling and Analysis C, 2018

In these work, a cheap and compact Low-Pass filter (LPF) with wide stopband is designed using mod... more In these work, a cheap and compact Low-Pass filter (LPF) with wide stopband is designed using modified hairpin resonator. The first transmission zero is obtained from the transfer function (TF) analysis of the hairpin resonator. Further, open stubs are added to widen the stopband. An approximate LC equivalent circuit of the proposed structure is derived and the response is in accord with simulated result. A prototype of the proposed LPF is fabricated on FR4 substrate. The proposed LPF has-3 dB cutoff frequency at 1.1 GHz with wide stopband ranging from 1.6 GHz to 11.5 GHz. The size occupied by the proposed LPF is 15.8 mm x 14.3 mm. In the passband region, the insertion loss is-0.3 dB and return loss is better than-25 dB. The proposed LPF is measured and there is a good agreement between the simulated and measured results.

AEU - International Journal of Electronics and Communications, 2017

This paper presents an electrically tunable bandpass filter which provides nearly constant absolu... more This paper presents an electrically tunable bandpass filter which provides nearly constant absolute bandwidth (CABW) within the center frequency tuning range. The proposed tunable band pass filter (BPF) is designed on a low cost FR4 substrate with mixed coupled 3 rd order open loop ring resonators, high frequency varactor diodes, chip capacitors and some RF chokes. The center frequency of the BPF is tunable from 1.9 GHz to 2.52 GHz with 3 dB absolute bandwidth of 201.5±1.5 MHz. The measured insertion loss of the proposed BPF is found less than 3 dB within the tuning range. There is a good agreement found between the simulated and measured results of the proposed BPF.

Waves in Random and Complex Media, 2016

Abstract This study demonstrates the parasitic effect observed in the passband of a bandpass filt... more Abstract This study demonstrates the parasitic effect observed in the passband of a bandpass filter (BPF) using a defected ground structure (DGS). This parasitic effect has been compensated by employing step discontinuity in the microstrip feed line. By implementing this technique, the performance of a pseudocombline BPF of 5 GHz operating frequency and a fractional bandwidth of around 15% together with a DGS cell is improved. The filter provides less than −1 dB insertion loss in the operating frequency and a stop band attenuation of about −20 dB on average. When the final BPF structure is simulated, fabricated, and measured, good agreement is observed between the simulated and measured results. The BPF proposed is applicable in the wireless LAN and RADAR systems.

Journal of Electromagnetic Waves and Applications, 2017

Abstract This paper presents a compact and low-cost balanced bandpass filter (BPF) operating at 4... more Abstract This paper presents a compact and low-cost balanced bandpass filter (BPF) operating at 4.9 GHz with high selectivity using mixed coupled ‘U’ shaped resonators, parallel coupled feed line, open and centrally loaded short circuited stubs, respectively. The odd–even mode decoupling scheme and the weakly coupled resonator concepts are utilized for the analysis and validation of differential mode (DM) and common mode (CM) equivalent circuits of the proposed BPF. The passband CM response of the balanced BPF is suppressed above 30 dB by employing grounded stubs in the symmetry plane, which converts the CM response to an all stop characteristic. The second harmonics generated by the BPF is also suppressed using open stubs located near the feed lines. The proposed balanced BPF is fabricated on an FR4 substrate (εr = 4.4, h = 1.6 mm, tan δ = 0.02), which provides 10.7% measured 3 dB fractional bandwidth (FBW) and minimum 1.2 dB insertion loss in the passband (4.7–5.2 GHz). A good agreement is found between the simulated and measured results.

2016 International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET), 2016

This paper presents the design of microwave lowpass filters (LPFs) using modified split ring reso... more This paper presents the design of microwave lowpass filters (LPFs) using modified split ring resonator (SRR) that acts a metamaterials structure. A positive relation is shown between the length and width of the rectangular split ring resonator with the respective frequency. Initially, a conventional LPF of 4.5GHz has been designed. Later on, the low impedance line of the filter is replaced by a modified SRR structure to produce sharp cut-off, small insertion loss and better selectivity. Then with the help of parametric study, finally an LPF of 2.4GHz cut-off frequency has been designed for GPS. The split ring resonator (SRR) proposed in this paper, is a modified metamaterials structure that provides flat passband and sharp cut-off. The filters are implemented on the FR4 substrate with dielectric constant εr = 4.4, substrate height h=1.59mm and thickness of microstrip conductor 0.02mm.

2015 2nd International Conference on Signal Processing and Integrated Networks (SPIN), 2015

ABSTRACT The modern microwave communication system demands good antenna performance with variety ... more ABSTRACT The modern microwave communication system demands good antenna performance with variety of application. One antenna should serve the purpose of many antennas to reduce the resource cost and installation cost. For this reason the concept of multiband antenna arises. In this paper the attention has been given towards the design of a dual band antenna. In this paper a modified E-shaped compact size probe-feed microstrip antenna is proposed for dual band operation in C-band and X-band with increased bandwidth. The return loss, VSWR and gain is also improved in this antenna design compare to previous work on dual band design. HFSS 13.0 is used for simulation and analysis purpose. Though the proposed design is about dual band operation but the simulated result shows two resonant frequencies of 4.8 GHz and 6 GHz in C-band and 9.2 GHz in X-band which is an another advantage compare to previous work. The performance of this multilayer E-shape antenna is depends on the E-shape of the conducting patch, location and dimension of the layers and location and dimension of the probe feed. The operating frequency of the antenna is 4 GHz. An increased gain of 7 dB is achieved in this antenna.

2015 2nd International Conference on Signal Processing and Integrated Networks (SPIN), 2015

In this paper a miniaturized 3 dB branch line coupler (BLC) is proposed. The miniaturization is d... more In this paper a miniaturized 3 dB branch line coupler (BLC) is proposed. The miniaturization is done by adding open stub to the series and parallel transmission line of the conventional 3 dB coupler such that the proposed T-shaped structure is equivalent to the conventional 3 dB branch line coupler. The equivalent circuit is obtained by comparing the ABCD parameters of the T-shaped and conventional transmission line. As the area is less there is a possibility of coupling between the stubs of series and parallel transmission line. Based on the flexibility of the designer the structure is designed in a way to minimal the effect of coupling between the stubs of the series and parallel transmission lines. The proposed structure has reduced size than the conventional coupler and has fair response at 2.5 GHz.

International Journal on Electrical Engineering and Informatics, 2011

The shape of a popular split-ring defected ground structure (DGS) is modified by etching two conc... more The shape of a popular split-ring defected ground structure (DGS) is modified by etching two concentric split-ring defective pattern which have different size and inverse split direction in the ground plane underneath a microstrip line. The frequency characteristics of proposed DGS unit show an attenuation zero close to the attenuation pole frequency. As a result, better transition sharpness is observed. An equivalent lumped L-C network is proposed to model the introduced DGS unit and corresponding L-C parameters are extracted. A 3 rd order quasi-elliptic lowpass filter is designed by cascading the three investing DGS units under High-Low impedance microstrip line and the generated first harmonic has been removed with the help of defected microstrip structure (DMS) underneath the cascading DGS unit.

Handbook of Intelligent Computing and Optimization for Sustainable Development, 2022

2017 International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET), 2017

In this present work a conductor-backed coplanar waveguide (CB-CPW) bandpass filter (BPF) centere... more In this present work a conductor-backed coplanar waveguide (CB-CPW) bandpass filter (BPF) centered at 2.8 GHz is proposed which consists of symmetrical L-shaped resonator pairs, shorted stubs, and L-shaped defected slot line (DSL). The center frequency of the proposed BPF can be tuned from 2.1 GHz to 3.8 GHz by changing the lengths of the resonator pairs. The passband ripple and spurious harmonics of the BPF are suppressed by adjusting the shorted and open stub section. The sharpness of the BPF is improved by including DSL near the feed line that exhibits stopband near the upper cut-off frequency. Simulated and measured result exhibits a stop-band rejection lower than —16 dB till 20 GHz with passband insertion loss of 0.7 dB and return loss of 29.66 dB. The BPF has much reduced circuit area of 8 × 20.2 mm2 compared to work stated below, also has the group delay of 0.17 ns which remains almost flat for entire passband, fractional bandwidth of 60.71%, 30 dB shape factor of 2.98, 3 dB bandwidth of 1.7 GHz and roll-off factor of 17.12 dB/GHz. It is implemented on the FR4 substrate with dielectric constant εr = 4.4, substrate height = 0.8 mm and thickness of the CB-CPW conductor 0.02 mm. The BPF show better performance, and hence can be used for practical purposes such as in low-cost WLAN and WiMax devices.

IETE Journal of Research, 2021

In this article, a coplanar waveguide (CPW) based compact low loss notch filter (NF) with sharp r... more In this article, a coplanar waveguide (CPW) based compact low loss notch filter (NF) with sharp roll–off is proposed. At the beginning, the proposed NF is designed using an array of conventional Mu...

2017 8th International Conference on Computing, Communication and Networking Technologies (ICCCNT), 2017

In this present work, a microstrip patch antenna (MPA) using frequency selective surface (FSS) is... more In this present work, a microstrip patch antenna (MPA) using frequency selective surface (FSS) is proposed. The FSS acts as a reflection plane which is loaded onto a microstrip patch antenna to improve the performance of antenna. The single-layer FSS (SL-FSS) and double-layer FSS (DL-FSS) are respectively loaded onto the C-band microstrip patch antenna. After loading the FSS as the reflection plane, the gain is increased by 1.45dB and 3.97dB respectively and the directivity is also improved. The proposed antenna is designed to operate at the resonant frequency of 5.2 GHz. The antenna is simulated in HFSS using FR-4 substrate with a dielectric constant of 4.4, thickness of 0.8mm and loss tangent of 0.02. The proposed antenna can be used in WLAN applications.

EngRN: Computer-Aided Engineering (Topic), 2019

This paper presents a compact coplanar waveguide lowpass filter (LPF) of low insertion loss and w... more This paper presents a compact coplanar waveguide lowpass filter (LPF) of low insertion loss and wide attenuation band. The proposed study is designed by employing open stubs and Defected Ground Structures (DGS).Since, in Coplanar Waveguide (CPW) the signal plane and the ground plane are considered same hence in this paper the defect in the rear plane of the CPW is named as DGS. Initially the response of the proposed LPF without any DGS has been simulated using Method of Moment (MoM) based IE3D EM simulation software. Then, E-shaped DGSs are introduced in the ground plane for widening the attenuation band. DGSs are placed directly under the transmission lines to improve the passband characteristics and to suppress the higher order harmonics. The cut-off frequency of the proposed filter is 2.7 GHz, and the maximum insertion loss in the passband is 0.3 dB. The attenuation band of the LPF is extended up to 8 GHz with a minimum suppression level of -10 dB. The roll off factor obtained fo...

This paper presents the design procedure of a bandpass filter based on parallel coupled half wave... more This paper presents the design procedure of a bandpass filter based on parallel coupled half wave length resonator concept with full length coupling. For the purpose of miniaturization and to get high coupling the new model of parallel coupled bandpass filter has been introduced. Here, the third resonator is placed just beneath the first one & fifth beneath the third one. Similar condition is for even order resonators. Here, area of the microstrip filter is very less, i.e., it is a compact structure. Finally a bandpass filter having Fractional bandwidth of 20% is obtained. The proposed BPF filter has been fabricated and measured with an Agilent make vector network analyzer of model N5230A and also good agreement between simulated and measurement results have been obtained.

2016 International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET), 2016

In this paper a generalized Chebyshev lowpass filter (LPF) is presented, and it has been modified... more In this paper a generalized Chebyshev lowpass filter (LPF) is presented, and it has been modified to produce better passband characteristics by introducing open stubs and Defected Ground Structure (DGS). The circuit model of the mentioned filter is demonstrated with its response for determining the element values of the lowpass prototype filter. The conventional lowpass filter provides a cut-off frequency at 7.7GHz with high insertion loss in the passband, which is practically and economically unacceptable. Thus, to reduce the insertion loss in the passband, reactive stubs are used in the metal plane and DGS is introduced in the ground plane with the existing LPF. Finally, the proposed lowpass filter provides excellent characteristics with negligible passband insertion loss and sharpness factor of 23dB/GHz and wide attenuation band. The substrate used for this design is Roger Duroid RO4350 with a thickness of 0.168mm and dielectric constant, εr of 3.48.

2017 International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET), 2017

In this present work, a dual-band microstrip patch antenna (MPA) using frequency selective surfac... more In this present work, a dual-band microstrip patch antenna (MPA) using frequency selective surface (FSS) is proposed. The MPA is designed using fractal shaped resonators with symmetrically arranged elliptical slots and partial ground structure that has gain of 3.01 dB. The FSS act as a reflection plane which is loaded onto a MPA to improve the performance of the antenna. The combined reflection plane is obtained by the periodic array of 2 × 3 unit cell in the x-y direction, which is is based on the combination of circular and square loop element. After loading FSS as the reflection plane, the gain is increased by the magnitude of 1.22 dB at 5.0 GHz and 1.6 dB at 10.6 GHz respectively. The proposed dual-band antenna operates at 5.0 GHz and 10.6 GHz respectively with better than 4 dB radiation gain for both of the bands. The antenna is simulated in HFSS using FR-4 substrate with a thickness of 1.6 mm and relative permittivity of 4.4. The overall size of the periodic structure of FSS i...

Iranian Journal of Science and Technology, Transactions of Electrical Engineering, 2020

A novel and miniaturized 4 × 4 butler matrix (BM) is proposed in this work. This proposed butler ... more A novel and miniaturized 4 × 4 butler matrix (BM) is proposed in this work. This proposed butler matrix is designed with four 3 dB quadrature (90°) forward wave coupled line coupler (FWCC) and two 45° Schiffman phase shifter. This BM is designed at center frequency of 2.4 GHz using FR4 substrate. The crossover of this BM has been replaced with a 0 dB FWCC. The performances of all couplers have been improved with the help of defected ground structures (DGS). Two C-shape and one I-shape DGSs are etched at the ground plane of each coupler, and two C-shape and one dumbbell shape DGSs are etched at the ground plane of 0 dB crossover which enhance the performance of the BM. This proposed BM provides a maximum bandwidth of 120 MHz at each port and occupies a total area of 0.677 λ 0 (84.74 mm) × 0.612 λ 0 (76.56 mm).

Electromagnetics, 2020

ABSTRACT In this work, a compact and wideband Schiffman phase shifter is proposed using a microst... more ABSTRACT In this work, a compact and wideband Schiffman phase shifter is proposed using a microstrip transmission line. This proposed phase shifter incorporates a rectangular complementary split-ring resonator (CSRR) and two open stubs. It is designed to get a phase shift of 90° with ±5° phase imbalance for the frequency range of 1.47–3.52 GHz. It shows a fractional bandwidth of 85.41% at the center frequency of 2.4 GHz. The proposed design occupied a total area of 0.067 λg2. The proposed structure is fabricated and validated, there is a good agreement between the simulated and measured results.

Iranian Journal of Science and Technology, Transactions of Electrical Engineering, 2019

This work presents a UWB balanced-to-unbalanced (BTU) power divider (PD) using coupled lines and ... more This work presents a UWB balanced-to-unbalanced (BTU) power divider (PD) using coupled lines and an additional shunt TL in the middle. The even-mode and odd-mode ABCD parameters of BTU PD produce the required analytical design equations. Later, the use of stub-loaded coupled lines in the shunt transmission line enhanced the passband response. The structure is further optimised by varying the impedance and electrical length of the middle shunt transmission line. For verification, a prototype is simulated, fabricated and measured. The proposed BTU power divider occupies size of 0.36 9 0.52 k 2 g with 95.6% FBW. The measured results agree with the simulated results.

International Journal of RF and Microwave Computer-Aided Engineering, 2019

A compact low-cost lowpass filter (LPF) with sharp roll-off and wide attenuation band using stepp... more A compact low-cost lowpass filter (LPF) with sharp roll-off and wide attenuation band using stepped impedance resonator loaded with interdigital fingers and U-shaped resonator is recommended in this article. The proposed LPF has a cutoff frequency of 1.2 GHz with a sharp roll-off 135 dB/GHz and passband insertion loss 0.35 dB. An array of two different shapes of defected ground structures are etched in the ground plane for introducing additional transmission zeroes to enhance the stopband performance. The relative stopband suppression is achieved up to 171% with a suppression factor of 2. The proposed structure is modelled, fabricated, and measured. The measurement results are found to be well-matched with the simulated ones. Eventually, a high figure of merit of 21 600 is achieved.

Advances in Modelling and Analysis C, 2018

In these work, a cheap and compact Low-Pass filter (LPF) with wide stopband is designed using mod... more In these work, a cheap and compact Low-Pass filter (LPF) with wide stopband is designed using modified hairpin resonator. The first transmission zero is obtained from the transfer function (TF) analysis of the hairpin resonator. Further, open stubs are added to widen the stopband. An approximate LC equivalent circuit of the proposed structure is derived and the response is in accord with simulated result. A prototype of the proposed LPF is fabricated on FR4 substrate. The proposed LPF has-3 dB cutoff frequency at 1.1 GHz with wide stopband ranging from 1.6 GHz to 11.5 GHz. The size occupied by the proposed LPF is 15.8 mm x 14.3 mm. In the passband region, the insertion loss is-0.3 dB and return loss is better than-25 dB. The proposed LPF is measured and there is a good agreement between the simulated and measured results.

AEU - International Journal of Electronics and Communications, 2017

This paper presents an electrically tunable bandpass filter which provides nearly constant absolu... more This paper presents an electrically tunable bandpass filter which provides nearly constant absolute bandwidth (CABW) within the center frequency tuning range. The proposed tunable band pass filter (BPF) is designed on a low cost FR4 substrate with mixed coupled 3 rd order open loop ring resonators, high frequency varactor diodes, chip capacitors and some RF chokes. The center frequency of the BPF is tunable from 1.9 GHz to 2.52 GHz with 3 dB absolute bandwidth of 201.5±1.5 MHz. The measured insertion loss of the proposed BPF is found less than 3 dB within the tuning range. There is a good agreement found between the simulated and measured results of the proposed BPF.

Waves in Random and Complex Media, 2016

Abstract This study demonstrates the parasitic effect observed in the passband of a bandpass filt... more Abstract This study demonstrates the parasitic effect observed in the passband of a bandpass filter (BPF) using a defected ground structure (DGS). This parasitic effect has been compensated by employing step discontinuity in the microstrip feed line. By implementing this technique, the performance of a pseudocombline BPF of 5 GHz operating frequency and a fractional bandwidth of around 15% together with a DGS cell is improved. The filter provides less than −1 dB insertion loss in the operating frequency and a stop band attenuation of about −20 dB on average. When the final BPF structure is simulated, fabricated, and measured, good agreement is observed between the simulated and measured results. The BPF proposed is applicable in the wireless LAN and RADAR systems.

Journal of Electromagnetic Waves and Applications, 2017

Abstract This paper presents a compact and low-cost balanced bandpass filter (BPF) operating at 4... more Abstract This paper presents a compact and low-cost balanced bandpass filter (BPF) operating at 4.9 GHz with high selectivity using mixed coupled ‘U’ shaped resonators, parallel coupled feed line, open and centrally loaded short circuited stubs, respectively. The odd–even mode decoupling scheme and the weakly coupled resonator concepts are utilized for the analysis and validation of differential mode (DM) and common mode (CM) equivalent circuits of the proposed BPF. The passband CM response of the balanced BPF is suppressed above 30 dB by employing grounded stubs in the symmetry plane, which converts the CM response to an all stop characteristic. The second harmonics generated by the BPF is also suppressed using open stubs located near the feed lines. The proposed balanced BPF is fabricated on an FR4 substrate (εr = 4.4, h = 1.6 mm, tan δ = 0.02), which provides 10.7% measured 3 dB fractional bandwidth (FBW) and minimum 1.2 dB insertion loss in the passband (4.7–5.2 GHz). A good agreement is found between the simulated and measured results.

2016 International Conference on Wireless Communications, Signal Processing and Networking (WiSPNET), 2016

This paper presents the design of microwave lowpass filters (LPFs) using modified split ring reso... more This paper presents the design of microwave lowpass filters (LPFs) using modified split ring resonator (SRR) that acts a metamaterials structure. A positive relation is shown between the length and width of the rectangular split ring resonator with the respective frequency. Initially, a conventional LPF of 4.5GHz has been designed. Later on, the low impedance line of the filter is replaced by a modified SRR structure to produce sharp cut-off, small insertion loss and better selectivity. Then with the help of parametric study, finally an LPF of 2.4GHz cut-off frequency has been designed for GPS. The split ring resonator (SRR) proposed in this paper, is a modified metamaterials structure that provides flat passband and sharp cut-off. The filters are implemented on the FR4 substrate with dielectric constant εr = 4.4, substrate height h=1.59mm and thickness of microstrip conductor 0.02mm.

2015 2nd International Conference on Signal Processing and Integrated Networks (SPIN), 2015

ABSTRACT The modern microwave communication system demands good antenna performance with variety ... more ABSTRACT The modern microwave communication system demands good antenna performance with variety of application. One antenna should serve the purpose of many antennas to reduce the resource cost and installation cost. For this reason the concept of multiband antenna arises. In this paper the attention has been given towards the design of a dual band antenna. In this paper a modified E-shaped compact size probe-feed microstrip antenna is proposed for dual band operation in C-band and X-band with increased bandwidth. The return loss, VSWR and gain is also improved in this antenna design compare to previous work on dual band design. HFSS 13.0 is used for simulation and analysis purpose. Though the proposed design is about dual band operation but the simulated result shows two resonant frequencies of 4.8 GHz and 6 GHz in C-band and 9.2 GHz in X-band which is an another advantage compare to previous work. The performance of this multilayer E-shape antenna is depends on the E-shape of the conducting patch, location and dimension of the layers and location and dimension of the probe feed. The operating frequency of the antenna is 4 GHz. An increased gain of 7 dB is achieved in this antenna.

2015 2nd International Conference on Signal Processing and Integrated Networks (SPIN), 2015

In this paper a miniaturized 3 dB branch line coupler (BLC) is proposed. The miniaturization is d... more In this paper a miniaturized 3 dB branch line coupler (BLC) is proposed. The miniaturization is done by adding open stub to the series and parallel transmission line of the conventional 3 dB coupler such that the proposed T-shaped structure is equivalent to the conventional 3 dB branch line coupler. The equivalent circuit is obtained by comparing the ABCD parameters of the T-shaped and conventional transmission line. As the area is less there is a possibility of coupling between the stubs of series and parallel transmission line. Based on the flexibility of the designer the structure is designed in a way to minimal the effect of coupling between the stubs of the series and parallel transmission lines. The proposed structure has reduced size than the conventional coupler and has fair response at 2.5 GHz.

International Journal on Electrical Engineering and Informatics, 2011

The shape of a popular split-ring defected ground structure (DGS) is modified by etching two conc... more The shape of a popular split-ring defected ground structure (DGS) is modified by etching two concentric split-ring defective pattern which have different size and inverse split direction in the ground plane underneath a microstrip line. The frequency characteristics of proposed DGS unit show an attenuation zero close to the attenuation pole frequency. As a result, better transition sharpness is observed. An equivalent lumped L-C network is proposed to model the introduced DGS unit and corresponding L-C parameters are extracted. A 3 rd order quasi-elliptic lowpass filter is designed by cascading the three investing DGS units under High-Low impedance microstrip line and the generated first harmonic has been removed with the help of defected microstrip structure (DMS) underneath the cascading DGS unit.