Annular Ring Patch Antenna Research Articles

Circularly polarized stub-loaded annular ring patch antenna for 2×2 MIMO satellite application

In this article, a stub loaded circularly polarized annular ring patch antenna which operates at 3–5 GHz band for 2×2 MIMO Satellite application is proposed. The evolution of antenna begins with a conventional annular ring patch antenna, addition of diagonal slots and integrated with λ/2 hair pin stub loaded annular ring patch to improve isolation and circular polarization. The antenna isolation is a critical parameter and important requirement of MIMO system. In satellite communications, circular polarization is used to improve the quality and reliability of the communication link between the satellite and the ground station. The antenna achieves circular polarization and mutual coupling through diagonal slots and stub-loaded design without any additional decoupling techniques. The overall size of the proposed MIMO antenna is 63 × 63 × 1.52 mm3 which is fabricated over Rogers RO3003 substrate. The proposed antenna design is simulated, fabricated, tested and analyzed for various parameters such as Reflection coefficient,Isolation Gain, radiation pattern, Axial ratio (AR), Envelope correlation coefficient (ECC), Diversity gain (DG), Channel capacity (CC) and total efficiency. The isolation of <−22 dB, gain of 7.1 dB, axial ratio<3 dB, diversity gain of 9.9 dB, ECC<0.002,CC of 11.23bps/Hz and efficiency>95% are obtained. The measured 10 dB impedance bandwidth of 270MHz and 3 dB AR bandwidth of 250MHz in the desired band are achieved. The simulated and measured antenna parameters are agreeable with each other. The results are found to be promising and having high potential in the 5G and Satellite MIMO.

Wideband Low-Profile Eight-Port Eight-Wave Annular-Ring Patch Antenna Based on Using Eight Dual-Shorted Dual-Resonant Ring Sectors for 8 × 8 MIMO Mobile Devices

A wideband eight-port eight-wave annular-ring (AR) patch antenna for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8\times $ </tex-math></inline-formula> 8 MIMO mobile devices is presented. The AR patch antenna is formed into eight dual-resonant 45o-ring sectors to radiate eight very-low-correlated or generally uncorrelated waves for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8\times $ </tex-math></inline-formula> 8 MIMO application. Each ring sector is loaded with two shorting pins and excited by a simple probe feed to generate its half- and quarter-wavelength resonant modes at close frequencies to form a dual-resonant wide operating band. Additionally, all 16 shorting pins of the eight ring sectors have a same distance to the patch center, thereby forming a shorting circle to function like a circular metal wall in the AR patch. This makes the surface currents coupled from the excited ring sector to adjacent sectors to be mainly confined inside the shorting circle. Therefore, with the eight probe feeds located outside the shorting circle in the AR patch, enhanced port isolation is obtained. With the proposed design, the eight-port AR patch antenna having a low profile of 1.4 mm (about <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.028\lambda $ </tex-math></inline-formula> at 5.9 GHz) and an outer diameter of 46 mm (about <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.91\lambda $ </tex-math></inline-formula> at 5.9 GHz) can generate eight very-low-correlated waves over a wide band of about 5.9-7.2 GHz (fractional bandwidth 20% based on 3:1 VSWR for mobile device application). Also, the proposed antenna has a back ground plane and is especially suitable for on-metal surface application. The use of a single proposed antenna can be conveniently applied for the mobile device or Internet-of-Things (IoT) device to cover such as 5.925-7.125 GHz for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8\times $ </tex-math></inline-formula> 8 MIMO operation in the possible new mobile communication spectrum.

Dual-Band Circularly Polarized Annular Ring Patch Antenna for GPS-Aided GEO-Augmented Navigation Receivers

A compact, single- feed, dual band, circularly polarized annular ring patch antenna coupled to a cross slot is proposed in this letter for GPS-aided GEO-augmented navigation (GAGAN) receivers covering L band, centered at 1176.45 MHz (L5) and 1575.42 MHz (L1) frequencies. The antenna consists of two annular rings configured by two small strips, which is coupled to a cross slot in the ground plane for gain enhancement. Circular polarization in both the bands is produced by introducing perturbations in outer annular ring and two orthogonal strips in the center space of inner annular ring. The proposed CP antenna radiates LHCP in both the desired frequencies. Two shorting pins are introduced near the feed to improve impedance matching. The simulated and measured reflection coefficient, gain, circular polarization, and axial ratio are in accord with each other. The measured 10 dB bandwidth is 2.7% (1168–1200 MHz) for the L5 and 2.5% (1560–1600 MHz) for L1. The AR bandwidth below 3 dB for the designed antenna is 1.5% (1156–1174 MHz) for L5 and 1% (1556–1572 MHz) for L1.

Performance analysis of circularly polarized dual annular ring patch antenna for MIMO satellite application

ABSTRACT In this paper, a dual annular ring patch antenna with high isolation for Multiple Input Multiple Output (MIMO) Satellite application at 4 GHz is presented. The mutual coupling reduction and circular polarization are achieved by some perturbations in annular ring patch and microstrip stubs between antennas. These perturbations will excite two modes which is orthogonal ie. equal amplitude and phase shift to make it circularly polarized. The antenna design is fabricated on a substrate with permittivity 4.4 and 1.6 mm thickness. The simulated results are studied and analyzed for the proposed antenna. The isolation of better than 30 dB, axial ratio lower than 3 dB and gain of about 3.4 dB are obtained. The performance characteristics are simulated, measured and analyzed with different antenna parameters. The validated antenna shows that the simulated and measured results are in good agreement with each other.

Four-Port Wideband Annular-Ring Patch Antenna Generating Four Decoupled Waves for 5G Multi-Input–Multi-Output Access Points

A four-Port annular-ring (AR) patch antenna generating four decoupled waves in 3.3-5.0 GHz (41% at 4.15 GHz) with antenna efficiency better than about 84% and envelope correlation coefficients (ECCs) less than 0.05 is presented for fifth-generation multi-input-multi-output (MIMO) access-point applications. The AR patch is placed 10 mm above the ground plane and its four ports are equally spaced by 90° (at φ = 0 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> , 90°, 180°, 270°) in the patch. Each Port is surrounded by a ring gap to achieve enhanced impedance matching. Additionally, four gap-coupled shorting (GCS) strips equally spaced by 90° (at φ = 45 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> , 135°, 225°, 315°) are added to short-circuit the patch to the ground plane, so that two adjacent ports are separated by one GCS strip. The arrangement makes the four ports capable of generating four decoupled waves with very low ECCs in 3.3-5.0 GHz. An extended design to achieve better isolation between ports is also addressed.

Cavity model analysis of differential dual‐polarised annular‐ring patch antenna

The four-port cavity model is presented to study a differential dual-polarised annular-ring patch antenna operating at higher order mode TM12. Acceptable agreements among calculated, simulated, and measured impedances and radiation patterns are obtained. Theoretical analysis shows that the differential port-to-port coupling impedance is zero, and its isolation is theoretically infinite. The differential input impedance is about four times of the single-ended input impedance at the resonant frequency of higher order mode TM12. The differential operation can suppress the adjacent modes TM02 and TM22 near the operating mode TM12 and lead to a more symmetrical E-plane radiation pattern and lower cross polarisation level.

A Simple and Efficient Approach to Compute the Operating Frequency of Annular Ring Patch Antennas by Using ANN with Bayesian Regularization Learning Algorithm

A Simple and Efficient Approach to Compute the Operating Frequency of Annular Ring Patch Antennas by Using ANN with Bayesian Regularization Learning Algorithm

Low-profile UHF RFID reader antenna with CP radiation and coupled feeding technique

A low profile annular-ring patch antenna with circularly polarized (CP) radiation for radio frequency identification (RFID) reader applications in the ultra-high frequency (UHF) band (922-928 MHz) is presented in this article. Perturbation method is applied by loading a pair of triangular open-notch into the outer circumference of ring patch, and good impedance matching can be determined by using the coupled feeding technique. The overall size of this proposed antenna is 150 mm × 150 mm × 10.4 mm. The measured results show desirable 10-dB impedance bandwidth and 3-dB axial ratio (AR) bandwidth of 3.5% (908-941 MHz) and 0.65% (922-928 MHz), respectively. Stable antenna peak gain and efficiency of 7.2 dBic and 87% are also exhibited, respectively.

Multi-band Annular Ring Microstrip Antenna with Defected Ground Structure for Wireless Communication

ring microstrip antenna (ARMSA) with a defected ground structure for multi-band operation is being proposed. Defected ground structure is produced by integrating a circular slot in the ground plane having different centre with the annular ring radiator patch. Microstrip line feed is used to excite the annular ring patch antenna placed on an FR4 substrate (dielectric constant er = 4). Results of the proposed antenna are carried out using Ansoft HFSS simulation software, and compared with the measured results, which shows good agreement. It is observed that the proposed antenna shows four bands at f1 = 2.92 GHz, f2 = 5.64 GHz, f3 = 8.21 GHz, and f4 = 10.53 GHz with an impedance bandwidth of 70%, 50%, 20% and 10% respectively. The proposed antenna is suitable for S, C and X band wireless communication system. Keywords-band, Annular Ring Microstrip Antenna, Defected Ground Structure, Microstrip line feed.

Rectangular notch loaded dual band annular ring patch antenna

In this article, a dual band annular ring patch antenna is theoretically investigated using the equivalent circuit concept.Two symmetrical rectangular notches are etched in radiating ring patch with respect to feed point. It is observed that the resonant frequency is directly proportional to the notch width and notch length. The bandwidth of the antenna at lower and higher ends are 134 MHz(1.815-1.681GHz) and 212MHz (2.849-2.637GHz) respectively for given antenna specifications. The calculated results are compared with the IE3D simulation software and previously reported results based on Artificial Neural Network (ANN). The theoretical results obtained from the proposed analysis are in good agreement with the simulated and ANN based results.

Analysis of L-probe Proximity Fed Annular Ring Patch Antenna for Wireless Applications

In the present paper, annular ring patch antenna with L-probe feeding has been analyzed using modal expansion cavity model. The proposed antenna shows wide band and ultra wide band operation which depends on the position of L-probe feeding and position of the shorting pin. For the fundamental $$\hbox {TM}_{11}$$ TM 11 mode, the bandwidth and gain is found to be 38.85 % and 7.8 dBi while for higher order $$\hbox {TM}_{12}$$ TM 12 mode bandwidth is obtained 58.71 % with corresponding gain of 6.1 dBi. The effect of shorting pin on the proposed antenna is also studied and it is found that the radiating structure is more compact in nature and improves the bandwidth upto 47.37 % with 8.0 dBi gain. Further, the proposed antenna has broadside radiation pattern over the entire bandwidth. The theoretical results are compared with IE3D simulated results which are in good agreement.

Genetic‐based design of a tetra‐band high‐efficiency radio‐frequency energy harvesting system

In this study, we exploit genetic algorithms to design a rectenna required to harvest ambient radio-frequency (RF) energy from four different RF bands in critical (ultra-low power) conditions. For this purpose a set of multi-resonant annular-ring patch antennas are pixel-wise described inside an electromagnetic simulator to provide the `population' of individuals among which the genetic tool is able to select the most adapted one with respect to the design specifications. The further use of circuit-level non-linear simulation tool, based on Harmonic balance technique, allows the rigorous multi-band design of the whole rectenna system in RF stationary conditions at several received power levels. The result is a novel compact, lightweight and highly efficient tetra-band rectenna, able to harvest RF energy from GSM 900, GSM 1800, UMTS and WiFi sources available in the ambient. At these frequency bands high radiation efficiency is desired as an essential prerequisite for optimally handling very low-power densities. Very good agreement with measurements of both the radiating and rectifying designs is demonstrated in real office scenarios. Finally the rectenna is connected to a power management unit and the resulting assembly is tested in terms of stored energy while harvesting from a mobile cell-phone call.

Behavioral characteristics of composite-antenna-structure covering three bands under compression load

A composite-antenna-structure covering three bands of global positioning system (1.575 GHz), digital multimedia broadcasting (2.62 GHz) and direct broadcast satellite (11.7–13.5 GHz) was designed and fabricated as a part of the structure surfaces. A new concept of antennas integrated into a composite sandwich structure provides a design that is an electrically and structurally effective multi-functional antenna structure. We designed two types of antennas. One is an annular ring patch antenna for global positioning system and digital multimedia broadcasting. The other is a microstrip patch antenna for direct broadcast satellite. In the design process, the effects of the composites and adhesive films are considered for in the design processes, because structural materials affect the antenna performance. Additionally, the composite-antenna-structure was designed by considering the coupling effect in a strict substrate. The measured results of buckling tests have provided useful information regarding not only the compression behavioral characteristics but also its degradation in electrical performance before and after the test. The experimental results have shown good results for compressive tolerance, though the specimens after compression loading returns to their original shape before failure. Additionally, an acoustic emission system is implemented in the buckling test system to study the inner behavior of the composite-antenna-structure for the reliability of secure mechanical performance. The antenna performance, as measured by the return loss and radiation pattern, remained excellent after the compression tests. These electrical performance results suggest that antennas with composite laminates will function well despite damage.

Experimental Study of Composite-Antenna-Structures with High Electrical and Mechanical Performances

Embedding of an antenna within a structural surface is an excellent way to improve structural efficiency and antenna performance. We study the impact characteristics of a Composite-Antenna-Structure (CAS) and the degradation in the performance of the antenna after impact testing. We used an annular ring patch antenna designed to operate in two bands: GPS (1.575GHz) and DMB (2.62GHz). When 20J of impact energy was applied to the CAS surface, the maximum contact force was 4kN, and the CAS proved resistant to impact. The antenna performance, measured by the return loss and radiation pattern, remained excellent after the impact tests.

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.

Impact evaluation of composite-antenna-structure with embedded dual-band annular ring patch antenna

In this study, a composite-antenna-structure (CAS) for a dual band of global positioning system (1.575 GHz) and digital multimedia broadcasting (2.63–2.655 GHz) was designed and fabricated as a part of a structural skin. The annular ring antenna type is available in two frequency bands, depending on the critical point view at the feeding and resonant areas. Consequently, the CAS was investigated by impact tests because the efficiency of using a protective layer needed to be confirmed. Embedding an antenna within a structural surface is an excellent way to improve both mechanical efficiency and electrical performance. The measured results not only show the impact characteristics at critical points of this CAS but also the degradation in its electrical performance after the impact test. The experimental results indicated that impact tolerance was significantly increased by the use of composite laminates. The radiation pattern strongly depended on whether composite laminates protected the antenna elements. When 20 J of impact energy was applied to the CAS surface, the specimen with the composite laminates gave twice as much contact force. The antenna performance, as measured by the return loss and radiation pattern, remained excellent after the impact tests. These electrical performance results suggest that antennas with composite laminates will function properly despite local damage.

Frequency adjustable microstrip annular ring patch antenna with multi-band characteristics

This study introduces a frequency-tunable dual-band microstrip annular ring patch antenna design for wireless local area network (2.45 GHz) and Worldwide Interoperability for Microwave Access (3.5 GHz) applications. The proposed antenna produces realisable gain higher than 5 dBi and return loss better than 10 dB for the stated applications. The antenna design consists of an annular ring patch loaded with a slot or gap. This loaded ring excites higher-order modes around the dominant mode (TM11) of the annular ring thus making this design capable of dual-band operation. This design is realised on a 1.57 mm thick polytetrafluoroethylene substrate using a coaxial probe feed. In this study, a novel technique for independent frequency tuning has also been introduced by cutting grooves on the periphery of the ring at the desired locations. Furthermore, the design capability of multi-band operation (2.45 GHz/3.5 GHz/5.5 GHz) has also been explained in the later part of the study. Antenna operation has been verified with the help of two commercially available EM solvers (CST Microwave Studio and Ansoft HFSS Designer) and measurements. A close agreement has been found between the simulated and the measured results.

Dual-Band Circularly Polarized Stacked Annular-Ring Patch Antenna for GPS Application

A dual-band circularly polarized stacked annular-ring patch antenna is presented in this letter. This antenna operates at both the GPS L1 frequency of 1575 MHz and L2 frequency of 1227 MHz, whose frequency ratio is about 1.28. The proposed antenna is formed by two concentric annular-ring patches that are placed on opposite sides of a substrate. Wide axial-ratio bandwidths (larger than 2%), determined by 3-dB axial ratio, are achieved at both bands. The measured gains at 1227 and 1575 MHz are about 6 and 7 dBi, respectively, with the loss of substrate taken into consideration. Both simulated and measured results are presented. The method of varying frequency ratio is also discussed.

Broadband Circularly Polarized Annular-Ring Microstrip Antenna

A wideband circularly polarized (CP) annular-ring patch antenna with two proximity-coupled L-probe feeds orientated to have phases of 0deg and 90deg, using a broadband 90deg hybrid feed, is proposed. It is found that the current distribution for CP operation can be improved by cutting a smaller concentric circular slot on the original larger circular patch to form an annular-ring patch. With such an arrangement, the proposed antenna delivers a wider axial ratio (AR) bandwidth than that of the conventional circular patch with the identical feeding technique. Considering the common overlapped bandwidth limited by the impedance, AR and gain, the proposed annular-ring patch antenna exhibits an effective bandwidth of 38% from 1.5 to 2.2 GHz, which is wider than the corresponding bandwidth of 29.7% from 1.35 to 1.82 GHz for the conventional circular patch. Moreover, the effective bandwidth of 38% for the proposed annular-ring antenna is also much wider than those for the other annular-ring patch antennas in the literature.

A New Coupling Mechanism for Circularly Polarized Annular-Ring Patch Antenna

A novel coupling technique for circularly polarized annular-ring patch antenna is developed and discussed. The circular polarization (CP) radiation of the annular-ring patch antenna is achieved by a simple microstrip feed line through the coupling of a fan-shaped patch on the same plane of the antenna. Proper positioning of the coupling fan-shaped patch excites two orthogonal resonant modes with 90 phase difference, and a pure circular polarization is obtained. The dielectric material is a cylindrical block of ceramic with a permittivity of 25 and that reduces the size of the antenna. The prototype has been designed and fabricated and found to have an impedance bandwidth of 2.3% and a 3 dB axial-ratio bandwidth of about 0.6% at the center frequency of 2700 MHz. The characteristics of the proposed antenna have been by simulation software HFSS and experiment. The measured and simulated results are in good agreement.