Search

A compact and novel quad-element inset-fed octagonal-shaped multiple input multiple output patch (QIOMP) antenna with a hexagonal-shaped slot is designed for ultra-wideband applications. The proposed MIMO antenna comprises four identical octagonal-shaped radiating elements. To achieve better diversity performance and low mutual coupling, radiating elements are positioned at the ideal distance. The proposed octagonal-shaped MIMO antenna is prototyped on a Fr-4 substrate with the overall dimensions of 32 × 32 × 1.6 mm3. It achieves an ultra-wide bandwidth (S11 < − 10 dB) of 13.9 GHz, operating from 2.5 to 16.7 GHz, except for the band notch from 8.9 to 9.2 GHz. The proposed antenna has a gain of 3.50 dBi, 4.40 dBi, 6.67 dBi, and 5.22 dBi at 4.8 GHz, 8.1 GHz, 10.5 GHz, and 14.1 GHz, respectively. At the operating frequencies, surface current distribution and radiation patterns are examined. The diversity performance of the QIOMP antenna is evaluated by reviewing several MIMO parameters, including an envelope correlation coefficient < 0.03, a diversity gain > 9.8, the total active reflection coefficient, and channel capacity loss < 0.05 bits/sec/Hz. The simulated and experimentally obtained results are presented and exhibit a high degree of concurrence. [ABSTRACT FROM AUTHOR]

In this paper, a microstrip Wilkinson power divider (MWPD) based on particle swarm optimization (PSO) algorithm is designed, simulated, and fabricated using novel resonators. In addition, attenuators and open-ended stubs are incorporated to generate a broad cut-off band and reduce unwanted harmonics. The proposed power divider has a central frequency of 1 GHz. The performance of each used resonator is analyzed based on lumped-element circuit models.The L and C parameters of the equivalent circuit of the used resonators are predicted and optimized with the assistance of the PSO method. The subsequent phase was the fabrication of the proposed MWPD, after which its performance was evaluated in the light of the results obtained from the simulation. It was discovered that there was a high degree of concordance between the two. On the other hand, the fabricated circuit has several benefits, including a suitable S12 of − 3.15 dB, a high return loss of less than − 24 dB at the operating frequency, a compact size of 0.058 λ g × 0.064 λ g , and the ability to remove undesired harmonics. The results show a high level of suppression of the unwanted harmonics (up to the 16th harmonic) and a great responsiveness in the passband, while having very low ripple. As a result, the proposed circuit may be used in a wide variety of electronic devices, such as radar transmitter and receiver circuits, and many other high-frequency systems. [ABSTRACT FROM AUTHOR]

In this paper, stepped slot-type grooves are utilized to develop coplanar waveguide (CPW) spoof surface plasmon polariton (SSPP) transmission lines (TLs). The equivalent circuit model is developed to analyze the effect of the stepped slot-type grooves. And it is found that all the three proposed SSPP TLs exhibit lower asymptotic frequency and more compact size than conventional SSPP TLs based on uniform grooves. Moreover, the dispersion features can be controlled flexibly by changing the impedance ratio of the stepped slot-type grooves. And among the three proposed SSPP TLs (Type A, Type B, and Type C), Type C SSPP TL has the most compact size. Consequently, based on Type C SSPP TL, an ultra-compact plasmonic low-pass filter (LPF) is designed to validate the design theory. Good agreement is observed between the simulated and measured results for which reflection coefficient is lower than − 10 dB in passband from 0 to 1.73 GHz and good shape factor of 1.09 for the transition from the passband to the stopband. Besides, the proposed plasmonic low-pass filter occupies very compact size, indicating that the proposed plasmonic filter can find potential applications in compact plasmonic system design. [ABSTRACT FROM AUTHOR]

In this paper, a portable tri-band MIMO antenna with 1 × 1 and 2 × 2 inputs and outputs is developed for wireless applications. A decagon-shaped ring and two U-shaped radiating structures make up the proposed antenna, which can generate three resonance frequencies. Without utilizing any decoupling structures, the suggested antenna achieves improved isolation. The coplanar waveguide structure supplies all of the antennas, which are printed on the front side of the FR-4 substrate, which has a surface area of 18 × 18 mm. The suggested antenna serves a wide range of applications, including WLAN (5.2 GHz), Wi-max (5.5 GHz), and 5G n34 band, with an impedance bandwidth of − 10 dB over 1.98–2.03 GHz, 3.55–3.70 GHz, and 4.8–6.4 GHz (2 GHz). For tri-band MIMO antenna, the gain is (0.28 dB, 1.3 dB and 2.7 dB) and efficiency is (80%, 83%, and 91.5%). For MIMO, tri-band antennas are placed in rotational symmetry with respect to the adjacent ports. Distance between MIMO tri-band antenna is 20 mm. Isolation for tri-band MIMO antennas is (− 40 dB, − 28.5 dB and − 27 dB). ECC for tri-band MIMO antenna is 0.003. The fabricated antenna and simulated results agree quite well. As a result, the suggested antenna can be employed for WLAN and 5G applications. [ABSTRACT FROM AUTHOR]

In this article, a compact super-wideband flexible textile antenna is proposed. It operates over an extremely broad frequency range from 3.16 to 50 GHz. The proposed design is characterized by its simple geometry, consisting of an offset rectangular patch, which is incorporated with three slots to enhance its performance, while a circular parasitic patch is positioned on the opposite side of the substrate. The proposed antenna prototype is fabricated on a footprint of 30 mm × 25 mm × 1 mm, which measures an electrical dimension of 0.31λ0 × 0.26λ0 × 0.012λ0 at 3.16 GHz. As per measurements, a wide bandwidth of 15.82:1 from 3.16 to 50 GHz is achieved with a peak gain of 7.70 dBi at 23.05 GHz. Furthermore, the ADS software is employed to create and analyze the equivalent circuit model of the designed antenna whose simulation studies are executed using CST software. The suggested antenna's overall performance is described by investigating the effects of structural bending and also proximity to the human body. Moreover, it provides acceptable values of specific absorption rate, ensuring lower absorption, which are under the safety standard limits for RF exposure. The measured results correlate with simulated results. Owing to its simple topology, compact size, super-wideband behavior, and high gain, endorse its suitability for low-power requirement applications in the real world. [ABSTRACT FROM AUTHOR]

This paper proposes a spoof surface plasmon polariton (SSPP) low-pass filter by etching butterfly-shaped cells on the middle line of a coplanar waveguide (CPW). The transmission and dispersion characteristics of the structure are analyzed. This design has a perfect low-pass transmission with tunable cutoff frequency. The angle and radius of the butterfly grooves are two variables that can adjust the cutoff frequency. The existence of two parameters is helpful to design a constant-width transition between the CPW and CPW-SSPP structures. It can be obtained by varying the angle of the butterfly grooves, while their radius is fixed. The introduced butterfly SSPP achieves a cutoff frequency reduction of 33% in comparison with its conventional rectangular counterpart with the same lateral size. It also has less phase velocity and more slow-wave effects than the rectangular SSPPs. Consequently, both transverse and longitudinal dimensions can be reduced by using the butterfly grooves. Moreover, the transition length is significantly reduced. The measured results show a 3-dB bandwidth from 0 to 10 GHz, a return loss of greater than 13.76 dB, an insertion loss of less than 1.6 dB, and an out-of-band rejection of higher than 15 dB from 10.2 to 14.5 GHz. The proposed circuit with the compact size, low loss, groundless structure, excellent slow-wave effect, and compact transition with excellent mode conversion can be applicable to the future communication systems. [ABSTRACT FROM AUTHOR]

In this work a compact size capacitive load dual band planar inverted-F implant antenna is presented. The suggested antenna is modeled on RO3010 substrate that has a thickness of 2 mm, dielectric constant of 10.2, and tangent loss of 0.0023 to operate at both the Medical Implant Communications Services (MICS) and Industrial, Scientific, and Medical (ISM) bands. A capacitive load is inserted between the patch and the ground plane to get a dual band and compact size implant antenna. The idea behind the capacitive load is to support a simple structure with a dual band and compact size in addition to get a gain enhancement. The antenna size is 20 × 12 × 2 mm3. The antenna designed in this work operates at 402 MHz with a return loss of − 23.23 dB over a frequency band [397.15–409.4 MHz] for MICS band and operates at 2.42 GHz with a return loss of − 20 dB over a frequency band [2.37–3 GHz] for ISM band. The simulated gain is − 27.52dBi at 402 MHz for MICS band and − 1.85dBi at 2.42 GHz for ISM band. The proposed antenna has a good performance inside three-layered tissue model. The Computer Simulation Technologies (CST) Microwave studio is used to model and simulate the proposed antenna. [ABSTRACT FROM AUTHOR]

Rectangular Dielectric Resonator Antenna (RDRA) is utilized for the wireless communications system because of its miniaturized size and low profile. This paper presents a design and simulation of slotted RDRA for satellite communication. The major aim of the work is to attain a high gain and radiation efficiency. Hence, the parasitic patch is introduced in this work to achieve this requirement. In this work, the RDRA is designed with a compact size of 10 × 10 × 3 mm, which operates at 17.04 GHz for satellite communication applications. The design is evaluated on the substrate ROGERS RT DUROID 5880, and the antenna comprises Alumina (Al2O3) ceramic material. The slotted design provides better impedance bandwidth and gain. The entire work is simulated in Ansys HFSS software. The performance measures like gain, return loss, radiation pattern, VSWR and directivity are simulated and fabricated. The proposed design provides circularly polarized characteristics at 3 dB and better radiation efficiency of 100%. At last, the fabricated design prototype is analyzed and provides better performance. The simulated and fabricated outcomes proved that the proposed slotted RDRA is efficiently exploited for satellite communication. [ABSTRACT FROM AUTHOR]

In this research work, a circularly polarized (CP) monopole antenna is designed for Ultra-Wideband (UWB) applications. The CP UWB antenna is be made up of a reformed ring patch and ground plane. The slots and stubs are inserted in the ground to achieve CP in the UWB antenna. This antenna attained an Axial Ratio Bandwidth (ARBW) of 5 GHz (4.0–9.0 GHz) that lies in the UWB frequency range that is from 3.1 to 10.6 GHz. The designed antenna has a radiation efficiency of around 80% for the complete UWB frequency range. The CP UWB antenna is designed and fabricated using the FR4 with a compact size of 32 × 30 × 1.6 mm3 and with a peak gain of 6.8 dBi. Tested results are in good resembles with simulated ones. [ABSTRACT FROM AUTHOR]

In this paper, we have designed and fabricated a novel microstrip diplexer. It has two quite close channels at 1.67 GHz and 1.88 GHz make it suitable for FDD schemes and GSM applications. The proposed structure includes two coupled meandrous open loop resonators which are coupled to spiral cells. An approximated LC model of the presented resonator is proposed and analyzed to give some information about the resonator behavior. Based on the obtained information, the proposed diplexer is optimized and miniaturized. It occupies a small size of 0.036 λg2. Despite of having close channels, the low insertion losses of 0.43 dB and 0.35 dB are obtained for the first and second bands, respectively. For verifying the simulation results and designing method, the diplexer is fabricated and measured, where the measurement and simulation results show a good agreement. [ABSTRACT FROM AUTHOR]

A novel microstrip dual-band bandpass filter (BPF) with bended microstrip lines, rectangular resonators and stepped impedance resonator (SIR) is designed, analyzed and fabricated. This circuit provides two pass-bands with the center frequencies of 3.6 and 5.7 GHz. Moreover, the LC equivalent circuits of the basic and main resonators are meticulously computed so as to present an analytical description. The surface current distributions of the proposed filter are shown to verify the performance of the filter and provide physical insight. The measured data of the proposed filter indicate that the insertion losses are better than 0.53 and 0.67 dB and the return losses are 25 and 24.7 dB in the first and second bands, respectively. One of the most outstanding features of the proposed filter is that the upper band can be tuned between 5.7 and 8.4 GHz without any increment in the circuit size. The compact size, wide upper stop-band bandwidth, low insertion loss, sharp transition bands, and high attenuation level in the stop-bands are the other marked positive points of the designed filter. Finally, a suitable agreement between the simulated and measured S-parameters can be observed. [ABSTRACT FROM AUTHOR]

In this paper, a novel wideband bandpass filter using half-mode substrate integrated waveguide (HMSIW) structure loaded by complementary Z-shaped resonator (CZR) is proposed. The working principle of the proposed filter is based on the evanescent-mode propagation. The CZR unit-cell behave as a magnetic dipole, which is able to generate a backward-wave passband region below the cut-off frequency of the SIW-CZR structure. Since, the electrical size of the proposed CZR unit-cell is larger than the conventional complementary electric-LC unit-cell with the same size, therefore this unit-cell is a good candidate to miniaturize the SIW structure. As well as, the SIW filter loaded by the proposed CZR unit-cell presents a wider bandpass compared to the SIW filter loaded by the conventional resonant metamaterial unit-cells. In order to validate the ability of the proposed CZR unit-cell in size reduction and increasing bandwidth, the proposed one- and two-stage HMSIW-CZR filters have been fabricated and tested. The measured S-parameters of the fabricated filters are in a good agreement with the simulated ones. It is the first time that the CZR unit-cells were combined with the SIW structure to miniaturize the SIW structure and increase the bandwidth. The total size of the proposed two-stage filter is 0.62 λg × 0.26 λg. [ABSTRACT FROM AUTHOR]

In this paper, a novel compact microstrip dual-band (DB) bandpass filter with high selectivity for wireless local area networks applications is proposed. The design procedure is based on unbalanced composite right/left-handed (UCRLH) transmission lines (TLs). The DB features can be achieved by unbalancing the CRLH transmission line. The necessary conditions to obtain a discontinuous transition between the left- and right-handed bands, intended to provide UCRLLH TL, are investigated. The application of this technique to design of compact DB filters is illustrated. The structure of the proposed DB filter is implemented by a series interdigital capacitor located between two microstrip lines that shorted to the ground plane by vias. The vias with microstrip lines acting as a shunt connected inductor while the series capacitor is realized by interdigital capacitor. The design procedure based on a simple equivalent circuit is also introduced. The proposed filter has advantages such as compact size, easy fabrication, high selectivity, low insertion loss, high return loss and, design flexibility. To validate the proposed technique, the proposed DB filter has been fabricated and tested. Good agreement has been found between simulation and measurement results. The total size of the proposed UCRLH DB filter is 0.17 λg × 0.048 λg, where λg is the guided wavelength of the lower pass-band. The size of the proposed DB filter is more compact in comparison with known similar filters. [ABSTRACT FROM AUTHOR]

In this paper, a novel compact ultra-wideband (UWB) antenna with a quad band-notched function using S-SCRLHs (splited simplified composite right/left-handed) resonator is presented. The S-SCRLHs resonator, which exhibits quadruple resonance, is realized by coupling double S-SCRLH resonator. Then, the S-SCRLHs resonator is integrated into a UWB antenna consisting of modified circular patch. The proposed UWB antenna operates under the frequency range of 3.0-10.7 GHz. This proposed antenna displays a VSWR < 2(the voltage standing wave ratio) across the entire UWB band and compact dimensions of 25 × 20 mm, which is 0.2λ (free space) at 3.0 GHz. By changing the dimension of S-SCRLHs resonator, the notched frequencies can be adjusted appropriately in four bands of 3.6-3.8 GHz (WiMAX), 4.5-4.9 GHz (C-band), 5.6-6.0 GHz (WLAN), and 7.2-7.6 GHz (X-band). The antenna can be applicable in the UWB receiver systems where the four kinds of interference signals corresponding to the four bands can be suppressed. The gain varies from 2.1 to 4.5 dBi with gain values of −2.8, −2.6, −1.5 and −2.4 dBi at respective four notch frequencies. The radiation efficiency is no less than 84% throughout the operational bandwidth. The proposed antenna achieves omnidirectional radiation patterns while also providing rejection at desired notches. [ABSTRACT FROM AUTHOR]