Circular Microstrip Antenna Research Articles

Development of PSO-ANN Ensemble Hybrid Algorithm and Its Application in Compact Crown Circular Fractal Patch Antenna Design

The traditional methods of designing antennas are not suitable in case of fractal antennas due to non availability of accurate mathematical design expressions. Recently, ANN model relating the physical and electromagnetic parameters of the fractal antenna to be designed is used as objective function of the optimization algorithm and it has been shown as an effective approach. In presented paper, ANN ensemble model has been used as the objective function of a PSO algorithm to calculate the optimal dimensions of a circular fractal antenna for desired resonant frequency. It has been established that ANN ensemble has better performance than the constituent ANN models. The design accuracy of the proposed hybrid algorithm is validated through the simulation and experimental results of the designed antenna. The size reduction capability of the proposed fractal antenna is used to design an antenna for 5.8 GHz WLAN band with a size reduction of 41.64% compared to simple circular microstrip antenna. The miniaturization of the antenna will lead to the design of compact devices for wireless communication systems.

Compact circularly polarized inset-fed circular microstrip antenna for 5 GHz band

This paper proposes a compact circularly polarized microstrip antenna with Left-Hand Circular Polarization (LHCP) property for wireless communication system at 5.7GHz (U-NII 5GHz band). In this design, a tapered-slot is included and it can act as the second signal source of the antenna to generate circular polarization property and this can remove the need of the external second signal source. The axial ratio of ∼2 and the radiation pattern results prove that the designed antenna meets the LHCP criteria. Moreover, the inset feeder is selected and it demonstrates the improvement on bandwidth and input impedance of the antenna.

Miniaturization of a Circular Patch Microstrip Antenna Using an Arc Projection

A semicircle arc projection is introduced to miniaturize the patch in circular patch microstrip antennas. The idea has been inspired from the effectiveness of a cuboid ridge in size reduction of a rectangular patch microstrip antenna. A prototype of the proposed antenna together with a prototype of a conventional circular patch antenna has been fabricated and measured. The two antennas are compared, and the results are presented and discussed. A parametric study is also carried out on the characteristics of the arc projection.

Selection of Optimal Beam Forming Algorithm for Mobile Ad Hoc Networks

Ad hoc networks have drawn considerable attentions of researchers for the last few years. Various applications of ad hoc networks have been reported in the literatures including disaster management, battle field, environmental management, healthcare, and smart grid. Ad hoc networks have some limitations namely short operating life, unreliability, scalability, delay, high interference, and scarce resources. In order to overcome these limitations, numerous researches have been carried out. Smart antenna integration is one of them. It has been shown in the literatures that smart antenna can improve network’s capacity, increase network lifetime, reduce delay, and improve scalability by directing antenna radiation pattern in a desired direction. But, producing a desired antenna radiation pattern is not a simple task for resource constraint ad hoc networks. A careful selection of beam forming algorithm is required. In this paper we show that smart antenna system, consisting of circular microstrip antennas and arranged in a linear arrangement, is the most suitable choice for ad hoc network. We compare a number of smart antenna algorithms in this paper under different noisy conditions. We show that the Least Square Constant Modulus (LSCM) and Least Constant Modulus (LCM) algorithms outperform other algorithms in terms of directivity and minimized side lobes.

CUDA-based PSO-trained neural network for computation of resonant frequency of circular microstrip antenna

Resonant frequency is an important parameter in the design process of microstrip antenna (MSA). Artificial neural network (ANN) trained by particle swarm optimisation (PSO) algorithm (PSO-ANN) has been used to model the resonant frequency of circular MSA. In order to deal with the problem of long calculation time when training PSO-ANN, its parallel scheme in the graphic processing unit (GPU) environment is presented in this paper. The designed parallel PSO-ANN algorithm uses the particle behaviour parallelisation of PSO, corresponds one particle to one thread, and deals with a large number of GPU threads in parallel to reduce training time. This scheme is applied to model the resonant frequency of circular MSA under compute unified device architecture (CUDA). Experimental results show that compared with CPU-based sequential PSO-ANN, GPU-based parallel PSO-ANN has obtained more than 340 times speedup ratio with the same optimisation stability. Moreover, the modelling error can be remarkably reduced with a very limited runtime increment while substantially enlarging the number of particles on GPU side.

CUDA-based PSO-trained neural network for computation of resonant frequency of circular microstrip antenna

CUDA-based PSO-trained neural network for computation of resonant frequency of circular microstrip antenna

Gain Enhancement in Circular Microstrip Antenna via Linear Superposition of Higher Zeros

This letter presents a single-layer high-gain circular-microstrip antenna configuration. Broadside high gain is attributed to the linear superposition of the radiated fields by TM 12 and TM 14 modes. At first, it is shown by the theory of linear summation of modes that the high E-plane sidelobes in the radiation pattern of the TM 14 mode can be suppressed by adding the contribution of TM 12 mode. This is further confirmed by the simulations and measurements. Next, a simple single-layer circular-microstrip antenna configuration with a measured peak gain of 15 dBi and sidelobe level of -11 dB is presented.

Coaxial cavity waveguide antennas excited by stacked circular microstrip patches for use as prime-focus reflector feeds

A coaxial cavity antenna excited by a stacked circular microstrip antenna is investigated as a feed for prime-focus parabolic reflector antennas. The radiation pattern of the proposed cavity-backed antenna is saddle shaped, which widens the −10 dB beamwidths and increases the reflector efficiency especially for deep reflectors with small focal length-to-diameter ratios. With a single-probe feed, the co-polar radiation pattern is slightly asymmetric in the E-plane, but is made symmetric by a differential feeding technique, using two probes. The impedance bandwidth of the proposed feed antenna is 20%. The antenna was fabricated and tested, and it exhibited good agreement between simulation and measurement results. The gain factor of the feed was also studied with a circular-symmetric reflector and provided a gain factor of 79% at f/D = 0.375. This type of feed can be used as an alternative to conventional horn or waveguide feeds, where reduced size and light-weight are desirable with added advantage of easy integration with electronics.

A Comparison of Different Patch Geometry Effects on Bandwidth

In this study, a new microstrip patch geometry, called Seljuk star, is proposed. The performance of the designed antenna is compared with the performances of square and circular microstrip antennas, which are two other popular patch geometries in literature. The design procedure consists of two phases: First, the patch dimensions of circular and square antennas are taken as the same with Seljuk star dimension. Then the patch surface areas of antennas are fixed to the area of Seljuk star patch and patch dimensions are calculated for the new designs. The effect of different patch types on bandwidth are investigated. Rogers Duroid 6010 ( h = 3.175 mm, ɛ r =10.2) is chosen as the substrate of the antennas which are expected to have a bandwidth center at 5800 MHz. All antenna designs are simulated in HFSS. Each individual antenna is intended to be working at a single frequency, but during the simulations multiple resonance are obtained in many designs. Therefore, the bandwidth and frequency comparisons are done for each resonant frequency among themselves. In comparison to the circular patch geometry with the same surface area, bandwidth is improved 10.57 times, as a result. The deviation between the theoretical calculations and simulations is % 1.38 , which is the smallest deviation among all results. Based on this, it is observed that Seljuk star microstrip patch antenna has a better performance when its dimension or surface area is chosen as same with circular or square antennas. The proposed Seljuk star patch shape is believed to have a high potential to be used in future research.

Compact dual polarised V slit, stub and slot embedded circular patch antenna for UMTS/WiMAX/WLAN applications

A single probe-fed novel V slit, stub and slot embedded circular microstrip antenna with resonances in the three bands of UMTS, worldwide interoperability for microwave access (WiMAX) and WLAN is presented. The polarisation is circular in the UMTS band and linear in the other two bands. Asymmetrical V slits in the patch boundary along with an embedded circular slot in the patch centre are employed to introduce the perturbation necessary for circular polarisation. Impedance bandwidths (BWs) of 4.2, 2 and 6.2%, respectively, in the three bands centred at 2, 3.5 and 5.6 GHz are obtained. The axial ratio BW is 2.3% in the UMTS band. Moderate gains of 4.4, 3.5 and 2.8 dBi are obtained in the three bands. There is a patch size reduction of about 48% when compared with the conventional circular patch antenna at a fixed operating frequency. The radiation pattern is directional in the WiMAX band and nearly omnidirectional in the WLAN band.

Sidelobe Reduction of TM12Mode of Circular Patch via Nonresonant Narrow Slot

A technique to reduce the $E$ -plane sidelobe of the TM12 mode of circular microstrip patch is presented. It involves the use of a single nonresonant narrow slot embedded at the patch center. The fundamental working principle is the linear superposition of the radiated field by the patch and the embedded slot. The sidelobe level (SLL) and the peak gain are found to be dependent on the slot length. Effects of various design parameters like slot length, dielectric constant and substrate thickness on SLL and peak gain are investigated. Measurements results are provided to confirm these findings. In addition to this, to show the merit and utilization of the proposed technique, a novel single layer, easy to design and fabricate high gain circular microstrip antenna configuration is also proposed. It is a simple slot loaded circular patch having a peak gain $\sim 11$ dBi with SLL as low as −20 dB. Depending upon the substrate parameters, peak gains as large as 13 dBi can be attained.

Bandwidth and Mutual Coupling Analysis of a Circular Microstrip MIMO Antenna Using Artificial Neural Networks

A ground plane reduced circular microstrip antenna resonating at multiband of frequencies 3.5, 5.2, 6.3 and 8.4 GHz is developed. The proposed antenna gives a wide impedance bandwidth of 75% in the frequency range 3.2 to 7 GHz, covering a part of the UWB operating frequency range. The antenna is coaxially fed, supported by a rectangular strip above the ground plane. The effect of strip width on the variation in impedance bandwidth of the proposed antenna is studied using artificial neural networks, and a comparative study is made. A \({2\times2}\) multiple input multiple output system is designed using the developed antenna, and the mutual coupling of the proposed antenna system is analyzed for various separations and frequencies by using artificial neural networks.

Sectored annular ring microstrip antenna with DGS for circular polarization

ABSTRACTA novel and simple design of circularly polarized sectored annular ring microstrip antenna with coplanar and concentric circular microstrip antenna is presented. The proposed antenna has single microstrip line feed with defected ground structure. Simulation analysis has been carried out using Ansoft High Frequency Structure Simulator (HFSSTM) software and measurement is carried out using the AgilentTM Vector Network Analyser (N5230A:PNA‐L). Parametric analysis of return loss and axial ratio versus frequency for different physical parameter of antenna has been studied. Experimental results of the proposed antenna show the 34.61% impedance bandwidth and 8.08% axial ratio bandwidth at 2.6 GHz center frequency with 6.96 dB peak gain. Simulated results are in good agreement with measured results. Due to low profile and simple geometry, it can be applicable for S‐band application effectively as wireless LAN, Wi‐Fi, Bluetooth, Zig‐Bee, and radio frequency identification antennas. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:569–573, 2016

Epsilon-Negative Transmission-Line-Based Annular-Ring-Loaded Circular Microstrip Antenna With Improved Performances

A novel epsilon-negative transmission line (ENG TL)-based annular-ring-loaded (ARL) circular microstrip antenna (CMSA) is proposed in this letter. Compared to a conventional CMSA, the proposed structure offers improved impedance bandwidth by exciting the TM11 modes on both the driven CMSA and the coupled ENG TL-based annular ring. Due to the enlarged radiation aperture, the gain is correspondingly enhanced. Moreover, the proposed structure exhibits lower levels of radiation along the horizon and toward the backside as compared to conventional CMSA. The mutual coupling characteristics of the proposed antenna are also investigated, and the simulated results show that the E-plane mutual coupling between the proposed ENG TL-based ARL CMSAs decreases much more rapidly with spacing than that for conventional CMSAs. To validate the proposed concept, prototypes with a center operating frequency of 6.5 GHz are fabricated and tested. Good agreements are achieved between simulation and measurement.

Neurocomputational Models for Parameter Estimation of Circular Microstrip Patch Antennas

Neurocomputational models eliminates the complex, lengthy and time consuming mathematical procedures for design, analysis and calculating performance parameters of Microstrip antenna. No single ANN based model has been proposed till date for calculating all parameters of circular microstrip antennas simultaneously. This paper presents a Neuro-Computational (NC) approach for estimation of all performance parameters such as Return Loss (RL), Voltage Standing Wave Ratio (VSWR), resonant frequency (fr), Band-Width (BW), Gain(G), Directivity(D) and antenna efficiency(η) of Circular Microstrip Patch Antenna (CMPA) simultaneously. The difficulty in calculating the parameters of these antennas lies due to the involvement of a large number of physical parameters including their associated optimal values. It is indeed very difficult to formulate an exact numerical solution merely on practical observations based empirical studies. In order to circumvent this problem, an alternative solution is achieved using artificial neural network (ANN). Feed-Forward Back-Propagation Artificial Neural Network (FFBP-ANN) trained with Levenberg-Marquardt algorithm is used for estimation of different performance parameters of CMPA. The results of NC estimation are in very agreement with simulated, measured and theoretical results.

A Compact Dual-Band Antenna for Wireless Body-Area Network Applications

A novel compact dual-band antenna for wireless body-area network (WBAN) is presented. The miniaturization is realized by bisecting a quadrant circular microstrip antenna along the fictitious magnetic wall, while the electric field distribution at 2.45 GHz is preserved. By slitting an open-ended quarter-wavelength slot, a second resonant mode at 5.8 GHz is excited. The proposed antenna is fabricated and measured both in free space and on-body. Enhancement in bandwidth and radiation patterns is observed for on-body performance compared to that in free-space. Measured fractional bandwidths of 1.2% and 2.0% are obtained at the two bands, respectively, when the antenna is mounted on-body, along with the corresponding simulated radiation efficiency values of 60% and 76%. The robust on-body performance reveals the proposed antenna as a good candidate for low-data-rate WBAN applications.

On the Design of Slot Cut Circularly Polarized Circular Microstrip Antennas

Circularly polarized microstrip antenna is frequently realized by cutting the slot inside the patch and feeding it along the diagonal axis. In the reported literature, procedure to design them at any given frequency is not available. In proposed work, circularly polarized slot cut circular microstrip antenna at 900 MHz is discussed. By studying the surface current distributions at two orthogonal modes, formulations in their resonant length are proposed. The frequencies calculated using them closely agree with simulated results. Using proposed formulation, procedure to design circular polarized antennas at different frequencies is presented that gives circular polarized response. Thus, proposed work will be helpful to design similar circular polarized circular microstrip antenna at any desired frequency.

Comparison of Rectangular and Circular Microstrip Antenna’s Array for a WIFI and RFID Applications at 2.45 GHZ and 5.8 GHZ

Radio Frequency Identification (RFID) is a technology mainly used for the identification of labeled objects and to follow their location. A RFID tag is composed by integrated circuits IC, and antennas. Antennas of transceiver system generally used for WIFI/RFID application are of microstrip type. In this article, we have compared two microstrip antennas (rectangular and circular) powered by a microstrip inset feed line with a 2.45 GHZ resonance frequency. Then, we have compared a rectangular antenna’s array with two radiating elements resonating on two different frequencies with a circular antenna’s array that has two radiating elements functioning on two frequencies 2.45 GHZ and 5.8 GHZ.

Design of a Tri-band Slotted Circular Microstrip Antenna with Improved Bandwidth for Wideband Applications

This paper presents a tri-band rectangular slotted circular micro strip antenna for wideband applications. The antenna operates at 2.96, 6.42 and 7.33 GHz frequency bands for VSWR<1 with an improved impedance bandwidth of 41.23%. The antenna has been designed and simulated on an FR4 substrate with dielectric constant (er) of 4.4 with an overall size of 50 × 40 × 3.5 mm 3 . The study of bandwidth improvement is presented in this paper by introducing the slots on surface of circular patch. The measured bandwidths for -10 dB reflection coefficient are 410 MHz (2.80-3.21 GHz) and 3.07 GHz (5.91-8.98 GHz). The simulated results show that the proposed antenna provides good performance in term of return loss and radiation pattern for wideband applications.

Dual‐reconfigurable microstrip antenna for polarisation agility and diversity

A novel design of a circular ring microstrip antenna using dual-reconfigurable perturbation to obtain polarisation agility and diversity is reported. The proposed antenna employs two couples of slots and stubs at a diagonal corner for generating and alternating right-/left-handed circular polarisations, respectively. By switching the anti-parallel bridged pin diodes of the implemented antenna, polarisation agility and diversity are successfully demonstrated.