Low Return Loss Research Articles

Design of a Compact Circular Microstrip Patch Antenna for WLAN Applications

This paper presents the design of a compact circular microstrip patch antenna for WLAN applications which covers the band 5.15 to 5.825 GHz. The antenna is designed using 1.4mm thick FR-4 (lossy)substrate with relative permittivity 4.4 and a microstrip line feed is used. The radius of the circular patch is chosen as 7.62mm. To reduce the size and enhance the performance of the proposed antenna, a circular slot is loaded on circular patch and a square slot is etched on the ground plane of dimension 30mm×30mm. Design of the antenna is carried out using CST Microsoft Studio Sonimulation Software. The proposed antenna resonates at 5.5 GHz with a wider bandwidth of 702 MHz and it provides low return loss of -31.58 dB, good gain of 3.23 dB and directivity of 4.28 dBi and high efficiency of around 79% against the resonance frequency. The geometry of the proposed circular antenna with reduced size and its various performance parameters such as return loss, bandwidth, VSWR, gain, directivity, efficiency and radiation pattern plots are presented and discussed

CPWG Fed with Octagonal Patch Antenna

A Co planner Wave Guide (CPWG) fed with octagonal patch antenna is modified from their respective rectangular patch are presented for WLAN application. The dielectric material applied in the design process for both co planar and micro strip patch antenna is FR4 Epoxy Glass, which has relative permittivity of 4.4 and substrate height 1.6mm. Antenna parameters used to check the performance. A comparison is made between the octagonal co-planar antenna and octagonal micro strip antenna available. Ansys HFSS is used for antenna design and analysis. Both designed antennas are suitable for wireless local area network application and the design parameters of the antenna are optimized to resonate at 3GHz frequencies for WLAN applications. It has been found that octagonal micro strip patch antennas have lower return loss and are more directive than co planar patch antenna. High directivity of octagonal micro strip antenna is due to the presence of ground plane under the substrate of antenna. The results obtained by simulations have also shown that octagonal co planar patch antennas have high radiation efficiency (a measure of the power radiated through the antenna as an electromagnetic wave to the power fed to the antenna terminals) and which implies a wider bandwidth as compared to an octagonal micro strip patch antennas. The radiation efficiency obtained for micro strip patch antenna is 24% and that for co planar patch antenna is 67%, the directivity for micro strip patch antenna is 3.75 dB and that for a co-planar patch antenna is 3.25 dB.

A wide band log periodic millimeter‐wave antenna for 5G femtocells applications

AbstractA wide band log periodic millimeter‐wave antenna is proposed for 5G femtocells applications. This log periodic antenna consists of circular patches with radius kept up at a proportion of scaling factor . The proposed antenna prototype is designed and simulated at a frequency range of 25 to 35.5 GHz with a fractional bandwidth of 34.73%. This proposed antenna exhibits low return loss at all frequency bands such as 26, 27.5, 29, 30, 32, 33, 35, and 38.1 GHz with reflection coefficient values such as , and dB including almost 101% radiation efficiency and attained maximum gain values such as , and dBi. Over the entire frequency band, the proposed antenna exhibits right‐hand circular polarization with an axial ratio of under 3 dB. Furthermore, the antenna is fabricated and measured the results where there is a better agreement with simulated results. This type of low‐profile antenna can be applicable for femto base stations for 5G communications.

Design and performance of four port MIMO antenna for IOT applications

In this paper, a four port MIMO antenna of compact split ring resonator (SRR) type with high degree of isolation among four ports on the antenna has been proposed for MIMO multiband applications. It is Tribands which operate at frequencies 1.44 GHz (−11 dB), 2.3GHz(−10 dB) and 4.2 GHz (−245 dB) respectively. This proposed MIMO antenna is designed with meander line for better gain and Split Ring Resonator (SRR) in the form of ring for high isolation between the antenna elements. A loaded stub is used to achieve the resonant frequency. The proposed MIMO antenna was simulated with IE3D EM software by Mentor graphics and the features such as impedance view, lower return loss, gain, radiation pattern and VSWR, etc are measured. The proposed antenna has better gain and provides higher isolation between multiple antenna elements.

WITHDRAWN: Modelling and design of fractal antenna of multiband applications

Abstract This paper introduces the design as well as modelling of a multiband planar antenna based on fractal shapes. Sierpinski carpet as well as Minkowski fractal geometries are applied to a square shaped patch antenna. The result from this combination is multiband, small size, high gain as well as low return loss antenna. The proposed antenna cover multi-frequency bands such as, 3.4, 4.03, 5.8, 6.48, 6.78, 7.32, 8.26, 9.21, 10.09 GHz. Antenna parameters as well as performance have been calculated as well as tested by using FEKO software, where it is full wave electromagnetic software based on advanced numerical methods.

A Compact Microstrip Wearable Dual-Band Antenna

Body-centric communication systems are said to be one of the most emerging areas in wireless communication. It has a major impact in areas like, health monitoring; position monitoring, real-time video feed networks, which makes body-centric wireless communication one of the most attractive research areas. However, having the human body in the network, the system becomes more complex. Each element of the system demands special attention in the designing and implementation process. The main purpose of this work is to design the dual-band (2.95 GHz and 5.7 GHz) micro-strip wearable antenna. The proposed design is a combination of rectangular and F-shaped configuration designed on the FR4 Epoxy dielectric substrate of 1.6 mm thickness, the relative permittivity of 4.4, and dielectric loss tangent of 0.02. The antenna design is simulated and analyzed to get low return loss, high gain, and low VSWR. One of the significant features of the designed wearable antenna is its compact size. The size of the substrate is reduced to 35*35mm. When it is compared with the existing design, it was found that the proposed design has a reduced size of the substrate. The CST microwave studio software is used as a tool for simulation. The human phantom model has to be introduced in the future to design and check the effect of electromagnetic radiation on the human body using SAR standard.

Comparative Analysis of Microstrip Patch Antenna of Wearable IOT Devices for Health Care

The Advances in the biomedical applications demands an antenna having highefficiency and gain, low return losses and Specific Absorption Ratio (SAR) to beassociated with the wearable and implantable devices for the accurate data transferwithout any data drift. For this, multi-band MIMO (multi-input multi output)applications, the antenna design with the target parameters is a challenging task toestablish a rich and reliable wireless communication setup with the monitoring systemin SHM of both biomedical and industrial sectors. Higher SAR will create the hazardsto the human body. The gain of the antenna and return loss figures depends on thesignal loss in the human tissues. Another important design challenge is the antennasize, which should be convenient to carry. Usually, Micro strip patch antenna is usingfor such type of applications as it satisfies most of the design parameters. But thebandwidth and gain of MSP are very limited. Hence there is huge scope to enhancethe gain and bandwidth of the micro strip patch antenna to fit for the biomedicalinvasive applications. Artificial materials having negative permittivity andpermeability will yield a negative refractive index will do better than the existingmaterials in the antenna design for the ISM band(2.45-5.8GHz) and satellites (11-13GHz).

New design of wideband microstrip branch line coupler using T-shape and open stub for 5G application

A new design of wideband branch-line coupler (BLC) using T-shape with open stub microstrip line is proposed. The branch line coupler is integrated with low and high impedance λ/4 transmission lines to achieve the comparatively compact size of (27.2 mm × 16.5 mm). operating the bandwidth in simulated of BLC from 2.9 to 4 GHz is obtained 30.22% with a frequency center of 3.5 GHz. Meanwhile, the measured bandwidth of the BLC is cover from 2.8 GHz to 4.22 GHz is equal 33.40% at the center frequency 3.55 GHz respectively. The BLC simulated has low isolation and high return loss of -29.28 dB and -30.69 dB at the center frequency 3.5 GHz.Whereas, the measured result has a simple difference in the return loss and isolation are -27.43dB and -24.46 dB at the frequency 3.55GHz respectively. This BLC design has a good coupling factor of -2.97 and insertion loss of -3.65 dB. Furthermore, it obtains an excellent amplitude and phases different between two output of ±0.1 and 93.6°±3.4° with high performance. There is a good agreement between the simulated result and the measured result. This branch line coupler design used for 5G applications for future wireless communication systems.

Electromagnetic performance of three-dimensional woven spacer microstrip antenna with various conductive fibers in extreme temperatures

Due to its excellent light-weight, mechanical, and electromagnetic performance, the three-dimensional woven spacer microstrip antenna (3DWS-MA) has become a promising communication device to be applied in aerospace or high-speed vehicles. To explore the electromagnetic performance of 3DWS-MA in extreme environments, microstrip antennas based on three-dimensional woven glass fiber/epoxy spacer composites (3DWSC) with different conductive yarn (copper wire, nickel-coated carbon yarn and carbon nanotube yarn) were manufactured and tested at various temperatures (from –196°C to 150°C). The results showed that the 3DWSC exhibited superb dielectric properties ([Formula: see text]) with a low volume density of 0.5 g[Formula: see text]cm−3, rendering good electromagnetic performance of the prepared antenna (S11 value of –23 dB and gain of 7 dB). When the temperature increased from –196°C to 150°C, the dielectric constant of 3DWSC increased from 1.57 to 1.67, resulting in the decrease of resonance frequency of 3DWS-MAs (maximum offset is 60 MHz). In addition, the resistance changing ratios of the conductive fibers also reached 105% with the temperature increase, resulting in degradations of S11 values (maximum 17 dB). Furthermore, among the three types of 3DWS-MAs, the 3DWS-MA (carbon nanotube yarn) exhibited the most stable S11 value at low temperatures (from –196°C to 0°C), while the 3DWS-MA (copper) showed low return loss and stable resonance frequency at high temperatures (from 20°C to 150°C).

A Patch Antenna Design for Giga Frequency Unmanned Aerial Vehicles Application

In this paper a present time developing application is used that is a UAV Antenna in aerospace technology. These antennas play a vital role in this WIMAX technology. A patch antenna is designed such that all the dimensions should be shrinked yet efficient in radiation in comb shape and this proposed antenna is used at 4.2GHz frequency range. A CST tool is used for designing and simulating our antenna all the dimensions taken for proposed antenna are comparatively less when compared to conventional models. Low return loss, gain, bandwidth and VSWR are optimized by using this design the efficiency is also enhanced by 95% which makes our antenna suitable to the UAV WIMAX applications. Surface current is also one of the major parameter which is reduced by our proposed model.

Design and Analysis of Novel Tri-Band Band Pass Filter for GSM, WiMax and UWB Applications

In this paper, we have presented the design and analysis of a Tri-band band pass filter at L, S and C bands. A cascaded form of a basic six mode resonator and hair pin resonator is used for the design. The cascaded layout ensures that it can generate higher bandwidth in the high frequency region (third band). This filter is operated at 1.85, 3.5, 4.4 and 5.7 GHz for GSM, WiMAX and UWB applications respectively. The layout is simulated with the help of Agilent ADS software. Then the Triband Band Pass Filter is fabricated in the PCB and experimentally tested with the help of Network Analyzer. The simulated results are well fit with the experimentally obtained results by us. Our proposed Triband band pass filter is well performing in terms low insertion loss (IL), low return loss (RL), higher band width (BW).

Design of compact transition from conical to coaxial transmission lines with a low return loss

ABSTRACT In this paper, a simple design method for compact transition from conical to coaxial lines with a uniform impedance and low reflection in the standard ASTM D4935 jig for shielding measurement of planar materials is introduced. The proposed structures with even a short conical line exhibit a more uniform impedance and lower return loss and consequently expand the measurable frequency range. By two-port network analysis using a full-wave numerical simulator, the proposed structures are examined and validated in terms of the voltage standing wave ratio that indicates the reflection of the coaxial and conical junction. In addition, a time-domain reflectometry analysis is performed using the simulated S-parameters. Through this, the distributed characteristic impedances at the conical and coaxial lines are calculated and the difference from the theoretical values is analysed. To verify the accuracy of simulation analysis, the simulation results are compared with the measurement results using a commercial ASTM jig.

Analysis and Design of a Diplexer for Satellite Communication System

This paper presents the design and analysis of a diplexer for satellite communication system based on hybrid spoof surface plasmon polariton (SSPP) and substrate integrated waveguide (SIW) transmission lines. The proposed diplexer consists of a SSPP printed line composed of H-shaped periodical grooved strips to operate as a low pass filter and a SIW to operate as a high pass filter. The operating frequency bands of the proposed diplexer are from 11.7 to 12.75 GHz for the downlink (DL) band, and from 17.3 to 18.35 GHz for the uplink (UL) band. These frequency bands correspond to the operating frequencies in Nile Sat 201 system. The frequencies of the DL and UL bands are adjusted independently by tuning the structure parameters of SSPP and SIW sections, respectively. The proposed hybrid SSPP-SIW diplexer is fabricated and measured. Simulated and measured results show good channel isolation, low return loss and low insertion loss in the required frequency bands.

Compact microstrip lowpass filter with very sharp roll-off using meandered line resonators

In this paper, a new compact size microstrip lowpass filter (LPF) with a very sharp roll-off is presented to apply in the modern wireless networks. The proposed LPF is designed using the series main resonators with meandered lines based on inductor-capacitor (LC) equivalent circuit analysis. The main goal is to achieve maximum-sharp roll-off by maintaining a wide stopband bandwidth and high return loss (RL). The main resonator of the proposed filter is consisted of two meandered line hairpin resonators (MLHR), and a meandered line T-shaped resonator (MLTR). The designed suppressor is composed of two coupled radial stubs to create a wide stopband. Low return loss in the passband, which has been created by the main resonator, is resolved by the suppressor structure with high return loss. The measured results show a − 3 dB cut-off frequency of 1.93 GHz. The very sharp transition band starts at 1.93 to 1.97 GHz (from − 3 to − 20 dB). The stopband is from 1.97 to 19.9 GHz (with the suppression level of − 20 dB). Also, the total size of the proposed LPF is only 13.3 × 10.1 mm2.

A SIMPLE MICROSTRIP TO WAVEGUIDE TRANSITION FOR MM-WAVE 5G BASE STATION ANTENNA

A compact patch type microstrip-to-waveguide transition at the mm-wave band is proposed using a planar proximity coupling structure. Small patches are put inside the apertures to enhance the suppression of reflection. The bandwidth of 3% (850MHz) at S11≤ -10 dB is obtained. As a result of the simulation, low transmission loss and high return loss are realized at the design frequency of 28 GHz for mmWave 5G application.

Investigation of structural, chemical, morphological and dielectric properties of sol–gel derived ZnAl2O4 nanoparticles

The need for miniaturization and low-weight global positioning system (GPS) patch antennas has led scientists to look for suitable dielectric materials. Zinc aluminate (ZnAl 2 O 4 ) composite dielectric ceramic is a suitable material for the microwave applications by virtue of their high-quality factor, low return loss, and better conductivity. In this paper, we report structural, chemical, morphological, and dielectric properties of sol–gel derived ZnAl 2 O 4 nanoparticles. The prepared nanoparticles found wurtzite crystallinity of ZnO with its crystallite size 10 nm. The morphological study revealed the spherical nanocrystals having their average diameter of 14 nm. Furthermore, we have performed the dielectric permittivity and loss of the prepared ceramic and found decreased with the increased frequency.

A theoretical design of ultra‐wideband multisection Wilkinson power divider using Euler polynomials

AbstractWhen the broadband impedance matching techniques are applied to the Wilkinson power divider, it operates in a larger frequency range and covers many communication bands. In this study, an ultra‐wideband (UWB) multisection Wilkinson power divider (WPD) circuit has been designed. Euler method has applied to the circuit that had equal power dividing feature on its two output ways. In the three‐section of the WPD, the Euler function has been modeled as a reflection coefficient on the output branches. The Euler polynomials have been used to calculate the characteristic impedance of each section. The isolation resistors have been calculated by odd‐even mode analysis according to the line impedances. In the Euler WPD, center frequency was 2.45 GHz and the limits for the return loss and isolation was selected as 15 dB and 20 dB, respectively. The bandwidth was measured as 0.75 to 3.80 GHz. The percent bandwidth of the WPD was calculated as 124.5%. Along the operation band interval, the minimum insertion loss measured lower than 0.75 dB. The design has been compared with a quarter wave (QW) WPD. It has been shown that the Euler method can achieve higher bandwidth, lower return loss and better Isolation than the conventional WPD.

Pareto‐optimal design of UHF antenna using modified non‐dominated sorting genetic algorithm II

In this study, the ultra-high-frequency (UHF) antenna for partial discharge (PD) detection is optimised to simultaneously satisfy the requirements of low return loss and high fidelity factor (FF) in the frequency band of interest by using the modified non-dominated sorting genetic algorithm II (MNSGA-II). Based on the labour division strategy, the MNSGA-II adopts an adaptive crossover and mutation possibilities instead of the fixed ones, resulting in the significant improvement of convergence rate and exploration ability. One of the Pareto-optimal solutions is presented as the authors’ proposed UHF antenna, whose performance is compared with those of both the antenna optimised by genetic algorithm and the existing wideband antennas. The experimental results show that the proposed antenna with a compact size of 0.201 λ L × 0.198 λ L realises the reflection coefficient less than −10 dB from 490 MHz to 1.52 GHz, and its FFs in the face-to-face and side-by-side scenarios are 0.897 and 0.845, respectively. Furthermore, the simulation results reveal that the high FF of antenna greatly increases the accuracy of PD source localisation. It indicates that the MNSGA-II provides an excellent solution to the multiobjective optimisation problems in antenna design.

Design and analysis of a modified rectangular-shaped lowpass filter based on LC equivalent circuit

In this paper, a new compact microstrip lowpass filter (LPF) with a sharp roll off and wide stopband is presented. The structure is composed of a defected rectangular-shaped resonator and a rectangular shape resonator as a suppressing cell. All resonators and their additional components are analyzed based on their LC equivalent circuits, and the role of each section and its equivalent circuit are described. The LPF with 3 dB cutoff frequency at 1.44 GHz has advantages such as low insertion loss and high return loss. Based on the measurement results, the proposed LPF has a sharp transition band that is 0.22 GHz from −3 to −20 dB. On the other hand, the measured value of the group delay in the whole passband is only 47 ns, which is one of the essential advantages of this filter. The designed LPF has been simulated, fabricated and, measured. There is a proper agreement between simulation and measured results.

Design and development of cross dipole antenna for satellite applications

Abstract In this paper, a cross dipole antenna is proposed, designed, and developed for satellite communication applications. The design incorporates an alternative feeding mechanism of the coaxial/probe feeding technique with balun. The primary objective of this paper is to develop the high gain antenna with an array configuration for satellite communication. The performance parameters of an antenna such as return loss, radiation pattern, gain and directivity are investigated for cross dipole antenna and 1 × 2, 1 × 4 array configurations. It operates for Ku band (12–18 GHz) and produces a high gain with low return loss. The proposed antenna has five useful bands and exhibits a peak directive gain of 13.21 dBi at 12.4 GHz with a bandwidth of 0.89 GHz. Additional bands are also offering a gain of 11.23 dBi with a bandwidth of 0.849 GHz at 10.6 GHz, 6.59 dBi with a bandwidth of 0.6 GHz at 11.5 GHz, 12.13 dBi with a bandwidth of 1.37 GHz at 14.2 GHz and 10.47 dBi with a bandwidth of 1.3 GHz at 15.8 GHz. The cross dipole antenna is analyzed for 1 × 2, 1 × 4 array configuration in order to improve the overall gain. The proposed antenna is fabricated on FR4 substrate with a dielectric constant of 4.4 and loss tangent (tan δ) of 0.007 with the thickness of 1.6 mm. The size of the proposed antenna is 72 × 84 mm. The proposed antenna meets the requirements of an antenna which is operating at Ku band; hence, it is found to be suitable for real time applications.