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1.
    
In this article, a modified fractal rectangular curve (FRC)‐shaped dielectric resonator antennas (DRA) with two different functionalities is reported. These antennas are split in the middle into two halves and are excited by a coaxial probe. In first configuration, the fractal geometry is used to achieve wide bandwidth from 3.5 to 5.0 GHz covering the body area network frequencies as well as the IEEE 802.11a WLAN frequencies. The average peak gain within the band is about 7 dBi. The second investigation involves miniaturization of rectangular DRA by using FRC along the cross‐sectional boundary. By this, a DRA at 3.2 GHz could be realized using second iteration of modified rectangular curve fractal geometry resulting in a 50% size reduction by maintaining same radiation characteristics. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2012.  相似文献   

2.
    
In this article, cylindrical segmented dielectric resonator antenna (CDRA) is proposed for ISM band applications. To obtain the proposed antenna, three different (120°, 60°, and 30°) segments of different cylindrical radius r1, r2, and r3 with stacked angular displacement are used for circular polarization with wideband frequency response. Quadrature phase shift of orthogonal field are observed when segment of cylinder is stacked with specific angular displacement. Various higher order modes are investigated. The simulated and measured impedance bandwidth of the proposed antenna is 90% (3.3 GHz‐8.7 GHz) and 83.4% (3.5 GHz‐8.5 GHz) respectively and the simulated and measured axial ratio bandwidth is 53.8% (3.8 GHz‐6.6 GHz) and 58.5% (3.5 GHz‐6.4 GHz), respectively. Proposed antenna attains 7.1 dBi measured peak gain at 8.5 GHz with more than 80% radiation efficiency in the frequency band. The fabricated prototype is experimentally measured and its results are found to be commensurable with the simulation results.  相似文献   

3.
    
A physically feasible new hybrid geometry for gain improvement with wideband characteristics is designed and validated experimentally in a conical shaped dielectric resonator antenna (DRA). It comprises of one superstrate and one reflector, with simple slot coupling technique for excitation. The reflector beneath the ground plane mainly accountable for significant gain improvement (～109%) by reducing the back radiation, whereas the superstrate dedicates for maintaining wideband (12.65%). The demonstrated result shows S 11 < ?10 dB band between 7.4 GHz and 8.4 GHz, with 11.25 dBi peak gain, which are well matched with their simulated counter parts. It also gives high co‐pol to cross‐pol difference (～40 dB) in broadside direction. This new geometry can be eligible for X‐band applications as well can usher the DRA researchers for further innovations.  相似文献   

4.
    
A compact high‐gain rectangular dielectric resonator antenna (RDRA) using metamaterial (MTM) as superstrate for C‐band applications is proposed in this article. The proposed antenna consists of coaxial‐fed RDRA with 50 unit cells of MTM arranged in 5 × 10 layout as superstrate. Each unit cell is constructed of two parallel eight‐shaped copper strips printed over both faces of a dielectric substrate to provide negative refractive index from 7.3 to 8.1 GHz covering the maximum bandwidth of RDRA. The extracted lumped equivalent circuit model of unit cell of MTM shows concurrence with electromagnetic simulations. The use of MTM superstrate increases the peak gain of the antenna by 89% through simulation and 86% experimentally. The measured results show that the proposed antenna achieves an impedance bandwidth of 16.1% over a band of 7.18‐8.44 GHz, with a peak gain of 14 dBi at 7.8 GHz.  相似文献   

5.
    
A wideband circularly polarized (CP) dielectric resonator antenna (DRA) loaded with the partially reflective surface for gain enhancement is presented in this article. First, the DRA is excited by a microstrip line through modified stepped ring cross‐slot to generate the circular polarization. Four modified parasitic metallic plates are sequentially placed around the DRA for greatly widening the axial‐ratio bandwidth. Then, a partially reflective surface is introduced for enhancing the gain performance and further improving the CP bandwidth as well. Finally, an optimized prototype is fabricated to verify the design concept. The measured results show that the proposed DRA achieves 54.3% impedance bandwidth (VSWR<2) and 54.9% 3‐dB AR bandwidth. Besides, its average and peak gains are 10.7 dBic and 14.2 dBic, respectively. Wide CP band and high gains make the proposed DRA especially attractive for some broadband wireless applications such as satellite communication and remote sensing.  相似文献   

6.
    
In this paper, a wideband circularly polarized two-layer concentric cylindrical dielectric resonator antenna (CDRA) is proposed for C-band applications. To generate the circular polarization in the CDRA, the proposed antenna is excited with four turn helical wire. The helix excites the two orthogonal modes (HE11δ) in quadrature phase, which result in the circular polarization. The four different design cases are investigated and the best one is fabricated and measured. The impedance bandwidth is improved when two-layer concentric CDRA is used. The simulated and measured bandwidth of the proposed antenna varies from 3.60 to 6.03 GHz with impedance bandwidth of 50.46% and 3.65 to 6 GHz (48.70% impedance bandwidth) respectively, while axial ratio impedance bandwidth are 43.13% (4.20–6.51 GHz) and 38.82% (4.40–6.52 GHz) respectively. The proposed antenna attains 10.9 dBi measured peak gain at 4.5 GHz. The fabricated prototype is experimentally measured and its results are found to be in good agreement with the simulation results.  相似文献   

7.
    
The main objective of the present article is to improve the bandwidth of a low profile Cylindrical Dielectric Resonator Antenna (CDRA) and operate it for WLAN and “C” band applications. An inverted umbrella shaped CDRA excited by a microstrip feedline with single stub is proposed here. Efficient coupling has been achieved by means of a single stub microstrip feed between DRA and the feed. The new shape of DRA and a single stub microstrip feed improves the bandwidth significantly as high as 28% from 5 to 6.67 GHz which is quite useful for both WLAN and “C” band applications. The proposed antenna is simple in construction, easy to fabricate, low profile and thickness of CDRA is only 5 mm. A parametric study is performed using Ansoft HFSS simulation software to optimize the antenna performance. The proposed CDRA is fabricated and the characteristics of the antenna are measured.  相似文献   

8.
    
A single feed, four element rectangular Dielectric Resonator Antenna (DRA) array, with beam switching capability is proposed. A wide impedance bandwidth of more than 25% at the center frequency of 1.95 GHz is achieved. Each DRA has two excitation strips and four parasitic patches. The six cases are discussed; each case corresponds to a diverse radiation pattern. The antenna beam is switched in azimuth (θ = 45°) at Φ = 0°, 60°, 120°, 180°, 240°, and 300°. The antenna gain is found to be more than 7 dB in most of the frequency band of interest. A passive prototype is developed and tested to validate simulation results. The comparison between the simulated and measured reflection coefficients and the radiation patterns for the six cases is presented. A good agreement between the measured and simulated results is observed. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:519–530, 2016.  相似文献   

9.
    
This article outlines a compressive review on investigation carried out targeting to gain, circular polarization (CP), and mutual coupling reduction in dielectric resonator antenna (DRA). The DRA has already been created a separate position in antenna engineering domain because of its adept characteristics, such as wide bandwidth, high efficiency, low‐loss, and mainly 3D‐design flexibility which is rarely available in conventional antennas. In this context, the research on gain, circular polarization, and mutual coupling are quite interesting and being carried out from the last two decades. The ultimate aim of this article is to (i) give an overview of different techniques adopted in context to gain, CP, and mutual coupling reduction; (ii) give a compressive review of notable research carried out targeting to these three characteristics; and (iii) find out the research gap concentration for furtherance of the same.  相似文献   

10.
    
The simulation and experimental studies of an aperture‐coupled wideband dual segment rectangular dielectric resonator antenna with metamaterial for C‐band applications are presented in this paper. The antenna consists of Alumina (Al2O3) ceramic as upper segment and Teflon as lower segment. The combination of circular‐shaped coplanar split‐ring resonator and conducting strip has been used as metamaterial superstrate. With the use of metamaterial superstrate, the bandwidth of the antenna is increased by 48% through simulation and 22% experimentally. The broadside radiation pattern of the antenna is converted into directive radiation pattern with reduced beamwidth when metamaterial superstrate is used. The peak gain of the antenna is also enhanced by 33% through simulation and 31% experimentally with the use of metamaterial superstrate. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:646–655, 2014.  相似文献   

11.
    
In this article, dual mode triple band hybrid cylindrical dielectric resonator antenna (CDRA) for different wireless applications is investigated. It is seen that annular ring shaped patch along with T‐shaped printed line behaves as a magnetic and electric dipole concurrently and create HE11δ and HE12δ mode in the proposed CDRA. Both of the hybrid modes radiate in broadside direction. The concept of hybrid antenna (the combination of annular ring patch and CDRA) is used to achieve triple‐band feature in the proposed antenna. Ansoft HFSS‐EM simulator is used to optimize the proposed antenna. Optimized simulated results have been practically confirmed by using the archetype of proposed antenna. The proposed radiator is applicable in three different frequency bands, that is, 2.24‐2.56 GHz, 3.28‐4.18 GHz, and 5.36‐5.8 GHz. It is appropriate for WLAN (2.4/5.8 GHz) and WiMAX (2.5/3.3/5.5 GHz) applications.  相似文献   

12.
    
In this article, we have proposed the closed form expressions for the optimized dimensions of different parts of the metallic stepped septum in a circular waveguide. Using these relations, a dual circularly polarized (CP) horn can be realized with good AR bandwidth, impedance bandwidth, and interport isolation. The relations are generalized for application at all frequency bands. Using these relations, horns have been designed and simulated at different frequency bands. Prototypes have been fabricated at some frequency bands and are experimentally validated. This design yields impedance bandwidth (S11 ≤ ?10 dB) of about 18%, AR bandwidth more than 15%, and interport isolation about 24 dB at the band center. Experimental data for the Ka‐band prototype are provided in detail. At the design frequency, the measured axial rations are <1 dB revealing cross‐polar discrimination over 25 dB.  相似文献   

13.
    
In this article, we investigate an optically transparent broadband water antenna, which is composed of a cross‐shaped slot feeding structure and a thin layer of water supported by a transparent dielectric slab. This water antenna can be analyzed as an embedded stacked dielectric resonator (DR) antenna (DRA) mounted on a ground plane. Two distinct resonator modes—namely, DRA mode and dielectric‐loaded slot (DLS) mode—are excited to achieve a good impendence matching over a very wide frequency range. A prototype antenna is designed, fabricated, and measured. Measured results demonstrate that the designed water antenna exhibits a broad impedance bandwidth of about 37% from 1.07 to 1.56 GHz with antenna efficiency better than 65% and broadside radiation characteristics with low cross‐polarizations.  相似文献   

14.
    
In this article, the design and analysis of a double‐ridged conical horn antenna with high gain and low cross polarization for wideband applications is presented. Double‐ridged pyramidal horn antennas have been investigated in many references. There are no papers in the literature which are devoted to design and analysis of double‐ridged conical horn antenna. The designed antenna has a voltage standing wave ratio (VSWR) less than 2.1 for the frequency range of 8–18 GHz. Moreover, the proposed antenna exhibits extremely low cross polarization, low side lobe level, high gain, and stable far‐field radiation characteristics in the entire operating bandwidth. A new technique for synthesizing of the horn flare section is introduced. A coaxial line to circular double‐ridged waveguide transition is introduced for coaxial feeding of the designed antenna. The proposed antenna is simulated with commercially available packages such as CST microwave studio and Ansoft HFSS in the operating frequency range. Simulation results for the VSWR, radiation patterns, and gain of the designed antenna over the frequency band 8–18 GHz are presented and discussed. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.  相似文献   

15.
    
In this paper, two Dielectric Resonator Antenna (DRA) models fed through a pair of diagonally coupled asymmetric L‐slots are incorporated on the ground plane of size 44 X 44 mm2 with a strip line feed underneath the substrate are presented. The proposed DRA‐1 is a triband antenna, resonates at 5.2GHz, 6.7GHz and 9.85GHz with a gain of 5.6dBi, 5.66dBi and 9.8dBi respectively. The bandwidth offered at Circularly Polarized (CP) band by DRA‐1 is 1.95 GHz (6‐7.95 GHz). The proposed second model DRA‐2 operates at 5 GHz, 6.4 GHz, 7.8 GHz and 10.3 GHz with a peak gain of 5.5dBi, 5dBi, 6.1dBi and 7.8dBi respectively. The quad‐band DRA‐2 offers two CP bands with bandwidths of 1.3GHz (7‐8.3 GHz) and 1.2 GHz (9.8‐11 GHz). The multiple operating bands of the proposed DRAs are appropriate for different wireless applications such as WLAN, C‐Band and X‐Band range of frequencies.  相似文献   

16.
    
This article presents a compact hybrid X‐band radiator, by combining the multiple resonances of two resonating and radiating structures, namely (a) a cylindrical dielectric resonator (CDR) and (b) a new type of slot geometry along with a U‐shaped microstrip feedline. Excitation of a few higher order modes in CDR structure is also observed and further investigated. The detailed performance analysis of the proposed geometry has been carried out both in frequency and time domains. Some design guidelines have been formulated which enable the design of the antenna for different bands. The proposed structure offers 46.3% (S11 ≤ ?10 dB and Voltage Standing Wave Ratio (VSWR) < 2) (measured) impedance bandwidth and about 4.5 dBi peak gain. The proposed antenna has the potential to be an ideal candidate for X‐band sensor applications.  相似文献   

17.
    
Design and development of wideband concentric half‐split cylindrical dielectric resonator antenna (CDRA) using permittivity variation in radial direction has been proposed in this article. The homogeneous, two‐layer and three‐layer concentric half‐split CDRAs have been discussed separately. The effect of antenna parameters such as layer arrangement, geometrical parameters, and probe length are investigated. To validate the results, two‐layer and three‐layer concentric half‐split CDRA have been fabricated using commercially available microwave laminates. In each case, the input reflection coefficient, radiation pattern, and antenna gain are simulated and measured. Good agreements between simulated and measured results have been obtained. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:321–329, 2015.  相似文献   

18.
    
This article shows a compressed chronological overview of dielectric resonator antennas (DRAs) emphasizing the developments targeting to bandwidth performance characteristics in last three and half decades. The research articles available in open literature give strong information about the innovation and rapid developments of DRAs since 1980s. The sole intention of this review article is to, (a) highlight the novel researchers and to analyze their effective and innovative research carried out on DRA for the furtherance of its performance in terms of only bandwidth and bandwidth with other characteristics, (b) give a practical prediction of future of DRA as per the past and current state‐of‐art condition, and (c) provide a conceptual support to the antenna modelers for further innovations as well as miniaturization of the existing ones. In addition some of the significant observations made during the review can be noted as follows; (a) hybrid shape DRAs with Sierpinski and Minkowski fractal DRAs seems comfortable in obtaining wideband as well as multiband, (b) combination of multiple resonant modes (preferably lower modes) can lead to wider impedance bandwidth, (c) at proper matching wider patch with slotted dielectric resonator can exhibit better bandwidth.  相似文献   

19.
    
A dual‐port reduced size multiple input multiple output (MIMO) Dielectric Resonator Antenna (DRA) has been studied and proposed. The MIMO antenna consists of a Rectangular Dielectric Resonator antenna, which is fed by two symmetrical feed lines for orthogonal mode excitation. The proposed antenna is suitable for operation over various long term evolution (LTE) bands. A measured bandwidth of 264 MHz for |S11| S‐parameters. Based on these results, it can be concluded that the proposed antenna can be a suitable candidate for MIMO applications. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:495–501, 2015.  相似文献   

20.
    
A novel dual‐band MIMO dielectric resonator antenna with high port isolation for WiMAX and WLAN applications is designed and investigated. The proposed antenna operates at 3.5 and 5.25 GHz bands. High port isolation is achieved using hybrid feeding mechanism that excites two orthogonal modes at each frequency bands. The measured impedance bandwidth of the proposed antenna covers the entire WiMAX (3.4–3.7) GHz and WLAN (5.15–5.35) GHz bands. The scalable behavior along with the frequency ratio of the antenna has also been investigated in this work. The measured isolation between antenna ports is ?52 dB at the lower band and ?46 dB at the upper band, respectively. Envelope correlation coefficient, diversity gain and mean effective gain have also been investigated. Moreover, measured results are in good agreement with the simulated ones.  相似文献   

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