Annular Microstrip Antenna Research Articles

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

Orthogonal slot-loaded coaxially stacked annular ring antenna with circular patch for multiband application

A coaxially stacked annular ring microstrip antenna (ARMSA) and circular microstrip antenna using L-probe feed and orthogonally slot-loaded at the inner periphery of the ARMSA is designed and fabricated for multiband application. The theoretical analysis of the proposed antenna has been carried out using modal expansion cavity model and circuit theory concept. Simulation of the proposed antenna has been performed using Ansoft HFSS software. The experimental results of input characteristic are obtained using Agilent™ vector network analyzer. The proposed antenna is resonating in L-band (1.88 GHz), S-band (2.51 GHz), and C-band (3.81 and 4.88 GHz) band with 6.38, 9.96, 2.62, and 3.27% impedance bandwidth, respectively. Theoretical and simulated results are in good agreement with experimental results.

Design and Analysis of Cavity Backed Annular Ring Microstrip Antenna for Personal Wireless Communication

Effect of cylindrical metallic cavity enclosure on resonant frequency of the annular ring microstrip antenna (ARMSA) having air-gap between substrate and ground plane is studied. The proposed antenna is analyze theoretically using modal expansion cavity model and circuit theory concept and verified by simulated results using Ansoft HFSS simulation software and experimental results. Theoretical and measured result of input characteristics shows good agreement with simulated results. Effect of cylindrical metallic cavity backing on resonance frequency of ARMSA is investigated for different air gap height and inner patch radius. The patch miniaturization of about 15 % is achieved using cavity backed ARMSA.

Wideband and compact slot loaded annular ring microstrip antenna using L-probe proximity-feed for wireless communications

A wideband orthogonally slot cut annular ring microstrip antenna fed by L-shaped probe is investigated using modal expansion cavity model and circuit theory approach. Simulation of the proposed antenna is performed using Ansoft HFSS and simulated results are compared with the measured and theoretical results. The impedance bandwidth of about 37.46% is observed at resonant frequency 3.15 GHz. The proposed antenna realizes an improvement in bandwidth of 13.46% and miniaturization in physical dimension about 10% from earlier reported structures. An improvement in bandwidth and miniaturization is due to thick substrate, L-probe feed, and orthogonally loaded slots. The measured results of fabricated antennas are in good agreement with simulated and theoretical results.

An accurate computation method based on artificial neural networks with different learning algorithms for resonant frequency of annular ring microstrip antennas

An annular ring compact microstrip antenna (ARCMA) constructed by loading a circular slot in the center of the circular patch antenna is a popular microstrip antenna due to its favorable properties. In this study, a method based artificial neural networks (ANNs) has been firstly applied for the computing the resonant frequency of ARCMAs. Multilayered perceptron model based on feed forward back propagation ANN has been utilized, and the constructed model have been separately trained with 8 different learning algorithms to achieve the best results regarding the resonant frequency of ARCMAs at dominant mode. To this end, the resonant frequencies of 80 ARCMAs with varied dimensions and electrical parameters in accordance with UHF band covering GSM, LTE, WLAN and WiMAX applications were simulated with a robust numerical electromagnetic computational tool, $$\hbox {IE3D}^\mathrm{TM}$$IE3DTM, which is based on method of moment. Then, ANN model was constructed with the simulation data, by using 70 ARCMAs for training and the remaining 10 for test. As the performances of the 8 learning algorithms are compared with each other, the best result is obtained with Levenberg---Marquardt algorithm. The proposed ANN model were confirmed by comparing with the suggestions reported elsewhere via measurement data published earlier in the literature, and they have further validated on an ARCMA fabricated in this study. The results achieved in this study show that ANN model learning with LM algorithm can be successfully used to compute the resonant frequency of ARCMAs without involving any sophisticated methods.

A novel and simple expression to accurately calculate the resonant frequency of annular-ring microstrip antennas

This paper proposes a novel and simple expression for effective radius of annular-ring microstrip antennas (ARMAs) obtained using a recently emerged optimization algorithm of artificial bee colony (ABC) in calculating the resonant frequency at dominant mode (TM11). A total of 80 ARMAs having different parameters related to antenna dimensions and dielectric constants was simulated in terms of the resonant frequency with the help of an electromagnetic simulation software called IE3D™ based on method of moment. The effective radius expression was constructed and the unknown coefficients belonging to the expression were then optimally determined with the use of ABC algorithm. The proposed expression was verified through comparisons with the methods of resonant frequency calculation reported elsewhere. Also, it was further validated on an ARMA fabricated in this study. The superiority of the presented approach over the other methods proposed in the literature is that it does not need any sophisticated computations while achieving the most accurate results in the resonant frequency calculation of ARMAs.

Analytical Study of Annular-Ring Microstrip Antennas Shorted With Thin Wires

A new theoretical analysis method is presented for annular-ring microstrip antennas with a short-circuited wall implemented as an array of thin cylindrical wires. Assuming wire spacing to be small compared to wavelength, the averaged boundary conditions are employed. An explicit characteristic equation, which determines resonant frequencies depending on wire spacing and radius is derived. A calculation technique for antenna input impedance is presented. Obtained results show good agreement between theoretical and experimental data. It is shown that the wire short-circuited wall can bring considerably different resonant properties compared to continuous metallic one.

Analysis of Annular Ring Microstrip Antenna with Air Gap and Uniaxial Substrate Superstrate Layers

Analysis of superstrate loaded, air gap tuned annular ring microstrip antenna is performed and effects of air gap tuning on the resonant frequency are investigated. Results obtained indicate that due to air gap tuning, resonant frequency can be incrementally or decrementally changed depending on the adjustment of anisotropy ratio of substrate and superstrate layers. Results can be used to obtain tunable, wideband antenna operation.

Annular ring microstrip patch antenna with finite ground plane for ultra-wideband applications

A design of annular ring microstrip antenna with finite ground structure is proposed in this paper. The proposed geometry offers impedance bandwidth of 2.362 GHz and has stable radiation patterns for all resonant frequencies in the operational band. It is also found that shape and dimension of the finite ground plane is a key factor in improving the bandwidth of the proposed geometry. The geometry is low profile and has simple structure, therefore can be used for lower band of ultra-wideband applications.

Reconfigurable microstrip annular ring antenna for circular polarization diversity

ABSTRACTThis article presents a novel design of a microstrip annular ring antenna with reconfigurable circular polarization (CP) diversity by switching one corner perturbation segment. The proposed antenna has a construction of a single‐feed annular ring as a radiator and frequency perturbing elements at one diagonal edge. To achieve the condition with left‐ and right‐handed CP diversity, the perturbations of the proposed antenna uses the concept of positively and negatively slot‐loaded annular ring. By controls of two diodes' states in the perturbation, both of CP senses have been easily alternated. The simulated and measured results show good and symmetrical radiation patterns at each resonant frequency. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1706–1709, 2014

Analysis of Broadband L-probe fed Microstrip Antennas

suspended microstrip antenna on thicker substrate is realized by using non-contact L-probe feeding technique. The guidelines for selecting total L-probe length are not available in the reported literature. In this paper, an analysis of broadband L-probe fed variations of microstrip antenna like, circular microstrip antenna, annular ring microstrip antenna, rectangular microstrip antenna, E-shaped microstrip antenna and half E-shaped microstrip antenna, is presented. It was observed that, total L-probe feed length nearly equals quarter wavelength at the resonance frequency of equivalent patch. Further using this quarter wavelength approximation, L-probe fed rectangular and circular microstrip antennas were re- designed at different frequencies which results into the broadband response with formation of loop inside the VSWR = 2 circle. The comparison between two non-contact feeding techniques of microstrip antenna, namely proximity feed and L-probe feed is presented. The two have similar performance in terms of bandwidth and radiation pattern, with proximity feeding technique to be the simplest method to be implemented in thicker substrates. Keyword microstrip antenna, Circular microstrip antenna, Annular ring microstrip antenna, E-shaped microstrip antenna, Broadband microstrip antenna, L-probe feed upon the ratio of vertical strip length to its horizontal length for the given patch substrate thickness. The design guidelines for properly selecting the strip vertical and horizontal lengths are not reported in the available literature. In this paper, various reported broadband designs of L-probe fed RMSA, U- slot cut CMSA, annular ring MSA, E-shaped MSA and half E-shaped MSAs are discussed. Further using their optimized designs the formulation for total L-probe length in terms of operating wavelength of the resonance frequency of the radiating patch is proposed. The total L-probe length was found to be around quarter wave in length at the patch resonance frequency. Using this approximation, RMSAs and CMSAs were re-designed at different frequencies. This results in broader BW with formation of loop in the impedance locus inside the VSWR = 2 circle. For RMSA, the comparison between the non-contact proximity feeding and L-probe feeding technique is presented. It was observed that in terms of operating BW and radiation pattern characteristics, both these techniques yields nearly the same performance, however as against L-probe feeding, the proximity feeding is simpler to implement especially in thicker substrates. The proposed study was carried out using IE3D software (18) and to validate the simulated results, measurements were carried out using finite square ground plane of side length 40 cm. The input impedance response was measured using R & S vector network analyzer.

Dual-band Circularly Polarized Aperture Coupled Annular-ring Microstrip Antenna for GNSS Applications

In this paper, a dual-band circularly polarized stacked annular-ring microstrip antenna which covers the bands of Galileo (E5a, E5b, E1, E2, L1), GPS (L1, L2, L5) and GLONASS (L1, L2, L3) is presented. The antenna is composed of two concentric annular-ring patches that are etched on a substrate to generate a dual-band response. Four H-shaped apertures are added to improve the coupling between the microstrip lines and rings. And a wide-band feeding network is used to broaden the axial-ratio bandwidth. Good agreement is achieved between the simulation and measurement, which shows that the return loss of the proposed antenna is less than -15 dB in the whole band and the 3-dB axial-ratio (AR) bandwidths for the lower and upper band are 12.5% and 20.8% respectively. The measured results confirm the validity of the designed antenna which is suitable for Global Navigation Satellite System.

Study of a microstrip antenna on anisotropic metamaterials

The annular ring microstrip antennas on metamaterial substrates are modeled and analyzed using full-wave analysis in conjunction with Ansoft HFSSTM. The influence of the permeability tensor of the split ring resonator medium on the resonant characteristics of the antenna is considered. Numerical results for typical resonant frequency behavior and return loss are presented as function of the metamaterial properties and antenna structural parameters.

A COMPACT STACKED CIRCULARLY POLARIZED ANNULAR-RING MICROSTRIP ANTENNA FOR GPS APPLICATIONS

A novel design of circularly polarized (CP) annular-ring microstrip antenna (ARMSA) working in TM11 mode is presented. The CP radiations of the proposed antenna are implemented by a 90 - branch-line hybrid coupler placed at the inner part of the ARMSA. Since the ARMSA has narrow bandwidth and high-input impedance, a circular parasitic patch suspended above the ring is employed for not only improving the impedance matching and bandwidth, but enhancing the performances of axial ratio (AR). Due to the utilizing of parasitic patch and circular hybrid, the measured results are shown to attain a 10-dB return loss bandwidth of 31.2% (1300{1780MHz) and a 3-dB AR bandwidth of 19.2% (1360{1650MHz) respectively. The CP gain is 8.2dB at 1.575GHz. The proposed antenna is low proflle and has a simple structure, therefore, it can be a good candidate for GPS portable terminal applications.

Dual-Band Circularly Polarized Annular-Ring Microstrip Antenna for GNSS Applications

A dual-band circularly polarized antenna fed by four apertures that covers the bands of GPS (L1, L2, L5), Galileo (E5a, E5b, E1, E2, L1), and GLONASS (L1, L3) is introduced. A lotus-shaped aperture is added to optimize the coupling between the microstrip lines and the rings. Three wideband planar baluns are used to achieve good axial ratio (lower than 2.1 dB in both bands) and VSWR (41.2%). The measured results of the annular-ring microstrip antenna show good performance of a dual-band operation, and they confirm the validity of this design, which meets the requirement of Global Navigation Satellite System (GNSS) applications.

Ferrite loaded UHF sleeve monopole integrated with a GPS patch antenna for a handset

AbstractThis article describes the design of a compact ferrite loaded UHF sleeve monopole antenna covering 225–450 MHz that is colocated with GPS annular ring microstrip antennas on top of a handset. This antenna provides both communications and navigational capabilities to the user and is intended for military and commercial applications. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2513–2516, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27102

A Compact Annular Ring Microstrip Antenna for WSN Applications

A compact annular ring microstrip antenna was proposed for a wireless sensor network (WSN) application in the 2.4 GHz band. In this paper the major considerations of the conformal antenna design were the compact size and the impact on antenna's performance of a steel installation base. By using a chip resistor of large resistance (120 Ω) the antenna size was reduced to 38% of that a conventional annular ring patch antenna. With the addition of the steel installation base the resonant frequency of the antenna increases about 4.2% and the bandwidth reduces from 17.5% to 11.7% by adjusting the load resistance simultaneously. Several key parameters were discussed and optimized, and the antenna was fabricated and its performance measured. The antenna is well matched at 2.4 GHz with 34.2 dB return loss and –2.5 dBi peak gain. Meanwhile, it exhibits excellent radiation patterns with very low cross-polarization levels.

Full-Wave Analysis of Annular Ring Microstrip Antenna on Metamaterial

The propagation characteristics of the fundamental mode of annular ring microstrip antenna (ARMSA) on metamaterial substrate are determined via spectral domain analysis. Green's functions of the structure in Hankel transform domain are determined by using Hertz vector formulation. Numerical results of resonant frequencies and return losses are found as functions of the metamaterial properties and some geometrical parameters.

SINGLE-FEEDING CIRCULARLY POLARIZED TM21-MODE ANNULAR-RING MICROSTRIP ANTENNA FOR MOBILE SATELLITE COMMUNICATION

A novel TM21-mode circularly polarized (CP) annular- ring microstrip antenna (ARMSA) is presented. The annular ring is designed working at TM21 mode, and conical radiation pattern is obtained. At the inner of annular ring, a simple ring-shaped feeding line is arranged to implement impedance matching and CP operation. Therefore, the antenna has good impedance and CP performance, as well as a compact structure. The measured results indicate that the antenna has high low-elevation gains and omnidirectional azimuth coverage. The peak gain reaches 4.3dBic at elevation angle of 47 - , and in the range of 10 - {70 - , the gain is above 0dBic. The impedance bandwidth for S11 • i10dB is 2.3% at 1.601GHz. The proposed antenna can be used in mobile earth-station equipment for satellite positioning and communication systems in global or local.

Concentric Annular-Ring Microstrip Antenna With Circular Polarization

In this letter, we present a concentric annular-ring microstrip antenna that covers the bands of Galileo (E5a, E5b, E1, E2, L1), GPS (L1, L2, L5), and GLONASS (L1, L3). This microstrip antenna is fed by four apertures that improve the coupling. Broad band phase shifters and Wilkinson power combiners are used to generate the required circular polarization.