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Equivalent Lumped-Element Circuit of Aperture and Mutually Coupled Cylindrical Dielectric Resonator Antenna Array

Equivalent Lumped-Element Circuit of Aperture and Mutually Coupled Cylindrical Dielectric Resonator Antenna Array

Normally, single element DRA acts as a low gain antenna, but it has a broad radiation pattern. In some applications, high gain antennas are the major requirement for efficient long distance communication. Like conventional low gain antennas, DRA gain can also be enhanced by placing it in an array configuration. Several different shapes of DRAs have been proposed in the literatures i.e., cylindrical [2], rectangular [3] and triangular [4]. Among these shapes, cylindrical dielectric resonator antenna (CDRA) is widely used, due to its simple field structure as compared to rectangular DRA [5], and it is directional as compared to the rectangular and circular DRAs (i.e., rectangular and circular DRAs are bidirectional) [6]. The CDRA is characterized by its height h, radius a and permittivity ε r as shown in Figure 1(a).
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Multi-Band Cylindrical Dielectric Resonator Antenna Using Permittivity Variation in Azimuth Direction

Multi-Band Cylindrical Dielectric Resonator Antenna Using Permittivity Variation in Azimuth Direction

A dual- and triple-band cylindrical dielectric resonator antenna (CDRA) using varying permittivity in azimuth-direction fed by coaxial probe is proposed in this paper. The proposed structure is constructed using different materials having different permittivites in azimuth direction in cylindrical dielectric resonator (DR). The operating band can be scaled up or down by adjusting the design parameters. Dual-band and triple-band with equal segment CDRA have been fabricated using commercially available microwave laminates to validate the simulation results. In terms of radiation pattern, dual-band CDRA shows less cross-polar influence around 40 dB down in the direction of maximum radiation in yz-plane.
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Aperture and Mutual Coupled Cylindrical Dielectric Resonator Antenna Array

Aperture and Mutual Coupled Cylindrical Dielectric Resonator Antenna Array

Engineering, Universiti Sains Malaysia, Penang 14300, Malaysia Abstract—A 1 × 3 element linear array using cylindrical dielectric resonator antennas (CDRAs) is designed and presented for 802.11a WLAN system applications. The top and bottom elements of CDRA array are excited through the rectangular coupling slots etched on the ground plane, while the slots themselves are excited through the microstrip transmission line. The third element (i.e., central CDRA) is excited through the mutual coupling of two radiating elements by its sides. This mechanism enhances the bandwidth (96.1%) and gain (14.3%) as compared to aperture coupled technique. It is also observed that the side lobe levels are reduced over the designed frequency band. Using CST microwave studio, directivity of 10.5 dBi has been achieved for operating frequency of 5.6 GHz. Designed antenna array is fabricated and tested. Simulated and measured results are in good agreement. The equivalent lumped element circuit is also designed and presented using Advanced design system (ADS) for this proposed array.
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A Varactor-Tuned Aperture Coupled Dual Band Cylindrical Dielectric Resonator Antenna for C-Band Application

A Varactor-Tuned Aperture Coupled Dual Band Cylindrical Dielectric Resonator Antenna for C-Band Application

This article presents tuning of the operating frequency of an aperture coupled cylindrical dielectric resonator antenna (CDRA) by using a varactor diode. The aperture-coupled source is mostly used for DRAs because of its possibility of combination with monolithic microwave integrated circuits (MMICs). The varactor is used as a load to alter the resonant frequency of the antenna. Varactor diode has better switching speed, reliability and lowers applied voltage. It offers a capacitance that can be continually tuned by varying the diode bias voltage. Hence the effective electric length changes leading to the shift of antenna resonance to the higher frequencies.
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Integrated Ultra-Wideband Plannar Monopole with Cylindrical Dielectric Resonator Antennas

Integrated Ultra-Wideband Plannar Monopole with Cylindrical Dielectric Resonator Antennas

Abstract—An ultra-wideband (UWB) planar monopole antenna integrated with a narrow-band (NB) cylindrical dielectric resonator antenna (DRA) is presented. The proposed antenna consists of a UWB monopole excited by a coplanar waveguide (CPW) transmission line, acting as a ground for a DRA excited by a slot. The mode HEM 11δ is excited in the NB DRA. To validate the concept of integration, an antenna is fabricated and measured. The measured results demonstrate that the UWB antenna provides a 2 : 1 voltage standing wave ratio (VSWR) bandwidth for 3.05–11 GHz, integrated with a dual-band NB antenna. Moreover, the two ports have the same polarization and a reasonable isolation (less than −10 dB) between each other. This is a promising candidate for applications in cognitive radio, where the UWB antenna can be used for spectrum sensing and the NB antenna for communication operation.
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A Novel Compact Fractal Ring Based Cylindrical Dielectric Resonator Antenna for Ultra Wideband Application

A Novel Compact Fractal Ring Based Cylindrical Dielectric Resonator Antenna for Ultra Wideband Application

Abstract—This paper presents a novel compact Koch snowflake fractal ring based Dielectric Resonator Antenna (DRA) for ultra wideband application. Firstly, Koch snowflake fractal geometry is implemented on the conventional Cylindrical Dielectric Resonator Antenna (CDRA). Further, the performance of the DRA is enhanced by fractal ring created on the snowflake geometry. With the application of the fractal and the fractal ring geometry, the Q-factor of DRA is reduced, thus the bandwidth of DRA is increased. The proposed antenna offers a wide impedance bandwidth of 90% ranging from 4.7 GHz–12.4 GHz. The effect of the fractal geometry enhances the gain of DRA. The proposed antenna achieves radiation efficiency more than 78%, throughout the bandwidth. Interestingly, the proposed configuration reduces the DRA volume by 76.63% with reduced volume of 7.91 cm 3 . The experimental verification of the proposed structure shows good agreement between simulated and measured results.
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A Novel Hybrid Design of Printed Hemi-Cylindrical Dielectric Resonator Monopole Antenna with Multibands Operation

A Novel Hybrid Design of Printed Hemi-Cylindrical Dielectric Resonator Monopole Antenna with Multibands Operation

which include a removed-air-volume from a cylindrical dielectric resonator [1], a modified cylindrical dielectric resonator excited with a slot [2–4] and microstrip-fed line [5, 6], a quarter-wave monopole loaded with an annular dielectric resonator [7, 8], and also using hybrid dielectric resonators excited by a simple monopole antenna [9, 10]. A hemispherical dielectric resonator (HDR) antenna excited with a thick slot at the short circuited end of waveguide is recently analyzed in [11] using the Green’s function approach and the method of moments (MOM). Another MOM numerical study of split cylindrical dielectric resonator antennas on a conducting ground plane excited by a coaxial probe with a bandwidth of 35% is previously presented in [12]. In addition, the other analytical simulations on the various DRAs were presented in [13, 14]. In these studies, not only, the analyses on the DRA with multiband operation have been not done, but also, the majority of the used dielectrics have low permittivity which simplifies the design.
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Wideband Sierpinski Carpet Fractal Shaped Cylindrical Dielectric Resonator Antenna for X Band Application

Wideband Sierpinski Carpet Fractal Shaped Cylindrical Dielectric Resonator Antenna for X Band Application

A new broadband cylindrical dielectric resonator antenna is realized using drilling off Sierpinski carpet fractal shaped holes in the original cylindrical dielectric resona- tor. By shifting the feed position from the circumference to an inset position it is seen that matching over a wide- band covering the entire X-band becomes uniform. In this design, impedance bandwidth of 50% is obtained. In addition, the antenna cost is very low as an attempt has been made to realize DRA using low dielectric permitti- vity material like Teflon. With these features, this design Figure 8. Return loss plot of inset fed Sierpinski carpet
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The Relation Between Lumped-Element Circuit Models for Cylindrical Dielectric Resonator and Antenna Parameters Using Mbpe

The Relation Between Lumped-Element Circuit Models for Cylindrical Dielectric Resonator and Antenna Parameters Using Mbpe

Abstract—Finite-Difference Time Domain (FDTD) is used to calculate the input impedance of the cylindrical dielectric resonator (DRA) antenna withdifferent dimensions. A lumped- element circuit model for the input impedance calculation is proposed. The genetic algorithm is used to calculate the elements of the equivalent circuit. The Model-Based Parameter Estimation (MBPE) technique is used to find the variation of each element in the equivalent circuit with varying the physical dimensions of the antenna. The use of this method reduces the time required for calculating the input impedance of the cylindrical DRA in eachvariation of the antenna dimension.
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Investigation of Wideband Two Elements Dual Segment Half-Cylindrical Dielectric Resonator Antenna (DS h
-CDRA) with RCS Analysis

Investigation of Wideband Two Elements Dual Segment Half-Cylindrical Dielectric Resonator Antenna (DS h -CDRA) with RCS Analysis

Abstract—In this paper dual segment half Cylindrical Dielectric Resonator Antennas (DS h-CDRA), deploying homogenous elements, are designed and analyzed for wide-band applications. At first a single element is analyzed followed by two element DS h-CDRA. Further, Radar Cross Section (RCS) analysis is performed for different angles and frequencies. The proposed antennas are excited from the center of the ground plane using a coaxial probe feed, which results in TM 01δ as a mode of excitation in cylindrical DRA. The input impedance and radiation characteristics are determined and compared with measured results, which shows good agreement. The proposed DS h-CDRA provides measured wide bandwidth ( ≈ 98%) from 5.0 GHz to 11.5 GHz with gain of 4.85 dBi, and it is found constant throughout the operational band (with omnidirectional radiation pattern). The designed antennas performance has also been compared with two element h-CDRA and found even better for the same volume and effective radiation area. The RCS analysis has been performed for monostatic and bistatic mode at different frequencies and angles. The proposed antenna has been found suitable for 5.0 GHz WLAN and WiMAX wireless application.
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Triple-Band Dual-Polarized Hybrid Cylindrical Dielectric Resonator Antenna with Hybrid Modes Excitation

Triple-Band Dual-Polarized Hybrid Cylindrical Dielectric Resonator Antenna with Hybrid Modes Excitation

generated in CDRA due to its low quality factor. These modes are not advantageous in the case of antenna because it affects the radiation characteristics of other fundamental modes. Similarly, it is not easy to generate higher order modes (which is useful in the case of antenna) with the help of a simple feed structure [5, 6]. In order to avoid these difficulties, the concept of hybrid DRA comes into existence, which represents combination of DRA with other resonating structures [7, 8]. Similarly, Khalily et al. presented a hybrid CDRA (split half CDRA with fork shape monopole) for multiband applications [9]. Cylindrical DRA along with parasitic slots on ground plane was proposed by Sharma and Gangwar [10]. Recently, dual-polarized antennas are the most favorable topic of the researchers due to their several advantages such as orientation insensitive, getting more information by radar from targets, etc. In order to achieve dual polarizations along with multiband characteristics, some of the studies have been carried out by different researchers such as aperture fed grooved modified RDRA (Rectangular Dielectric resonator antenna), probe-fed semi eccentricannular shaped DRA and metal covered CDRA [11–13].
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Higher Order Mode Layered Cylindrical Dielectric Resonator Antenna

Higher Order Mode Layered Cylindrical Dielectric Resonator Antenna

∼ 28 . 3% and 9.5% in conjunction with a high gain of up to 13.9 dBic, which could have not been achieved at the absence of the outer dielectric coat. Increasing the impedance bandwidth by coating the antenna with a layer of lower permittivity is expected and have been reported in the literature. However, gain enhancement, wider axial ratio bandwidth, and improved fabrication tolerance have not been demonstrated earlier for a layered cylindrical DRA. Furthermore, two prototypes with outer layer thicknesses of δ a = 7 . 5 mm and 17 mm have been considered. The first demonstrates a design with practical dimensions for the X-band frequency range. On the other hand, the potential of the second design could be exploited further at higher frequencies, for example at 60 GHz where the outer layer radius will be reduced to 4 mm.
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A Wideband High-Gain Stacked Cylindrical Dielectric Resonator Antenna

A Wideband High-Gain Stacked Cylindrical Dielectric Resonator Antenna

The configuration of the proposed DRA is shown in Figure 1. It is prototyped on Rogers RO4350 substrate with dielectric permittivity of 3.66 and thickness of 0.762 mm. The feeding mechanism adopts a narrow slot (7.6×0.6 mm) centrally etched on a copper metallic ground with a size of 120 × 120 mm. The 50 Ω feeding microstrip line (width W = 1.7 mm) is etched at the center of the slot and terminated with an open stub of length L stub = 3.6 mm.

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Simulation and Experimental Investigators on Rectangular, Circular and Cylindrical Dielectric Resonator Antenna

Simulation and Experimental Investigators on Rectangular, Circular and Cylindrical Dielectric Resonator Antenna

the simulated resonant frequency. Besides that, both return losses have almost the same matching level and lower than − 25 dB that showed good matching level. Both curves are in good agreement. As discusses earlier in the Section 2.2, the predicted resonant frequency by using dielectric waveguide model is 8.83 GHz. By comparing with the simulated and measured results, the frequency is nearly the same. The difference between theory and experiment resonant frequency is only 90 MHz or around 1%. Simulated bandwidth at − 10 dB return loss is 116 MHz whereas the measured bandwidth is lower with only 18 MHz. The measured result has a narrower bandwidth as compared to the measured one. This is due to the bad surface finishing of the rectangular dielectric resonator which tends to chip at the edge of the rectangular surface. Consequently, it affects the dielectric properties of DRA and S-parameter value.
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Embedded Dual band Cylindrical Dielectric Resonator Antenna

Embedded Dual band Cylindrical Dielectric Resonator Antenna

The dielectric resonator antennas (DRAs) have attracted wide attentions in various applications, as armored filters or oscillators [1,2], They offer several advantages in terms of high radiation efficiency and Q factor. Indeed, when a resonator is placed in a cavity, it presents a high quality factor, which allows the realization of a highly selective filter.

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Stacked Conical-Cylindrical Hybrid Dielectric Resonator Antenna for Improved Ultrawide Bandwidth

Stacked Conical-Cylindrical Hybrid Dielectric Resonator Antenna for Improved Ultrawide Bandwidth

Abstract—Conical and cylindrical dielectric resonator elements are vertically stacked and excited by a simple coaxial monopole. Compared to all earlier configurations, the proposed geometry significantly improves the impedance bandwidth. The ultrawideband response is enhanced due to the multiple resonances occurring by the suggested hybrid antenna. The footprint area of the antenna is only 63.6 mm 2 or 25 . 44 × 10 − 3 λ 2 o at the lowest operating frequency. The performance of the antenna is verified experimentally and numerically. Presented results show that the proposed hybrid monopole-DRA has a measured impedance bandwidth up to 148.6% ( S 11 < − 10 dB) along with consistent monopole-like
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Circularly Polarized Cross-Slot-Coupled Stacked Dielectric Resonator Antenna for Wireless Applications

Circularly Polarized Cross-Slot-Coupled Stacked Dielectric Resonator Antenna for Wireless Applications

Abstract: This paper presents a stacked cylindrical dielectric resonator antenna with wide circular polarization (CP) bandwidth (axial ratio < 3dB) of 16.0%. This wide CP bandwidth is achieved by stacking low permittivity dielectric (9.2) resonator on high permittivity dielectric (9.8) resonator to obtain improved impedance and axial ratio bandwidths as compared to conventional DRA. It is also shown that the asymmetrical structure used in the geometry results in a very high impedance bandwidth (more than 100%) in the frequency range of 2.1 GHz-12.0 GHz but at the expense of distorted CP operation on the off-broadside. This essentially covers the FCC band of operation (3.1GHz to10.6 GHz).
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Review Paper on Dual Band Dielectric Resonator Antenna for Wireless Application

Review Paper on Dual Band Dielectric Resonator Antenna for Wireless Application

Abstract: In Today’s wireless era, need of a highly optimized antenna having compact size, low cost, high efficiency, larger bandwidth is must. This increases demand of designing antennas having such benefits. This research study is a short description carried out in the past few years and latest progression of Dielectric Resonator Antenna for different uses. Special character of Dielectric Resonator Antenna provides compactness, high gain, and negligible metallic and surface losses. It also gives wider bandwidth. In modern communication, Dielectric Resonator Antenna is utilized for many implications as radar technology, nano-technology, wireless communication and satellite communication. This paper represents a study of simulation of a Dielectric Resonator based on its cylindrical shape for wireless application. Various technique of cylindrical Dielectric Resonator Antenna is described in this paper.
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Dielectric Resonator Antenna Mounted on a Circular Cylindrical Ground Plane

Dielectric Resonator Antenna Mounted on a Circular Cylindrical Ground Plane

Abstract—In this paper, the radiation characteristics of the single- element cylindrical dielectric resonator antenna mounted on the surface of a metallic hollow circular cylindrical structure is investigated. The effect of the radius of curvature on the return loss, input impedance, standing wave ratio, and radiation pattern is explored. Mutual coupling between two identical cylindrical dielectric resonator antennas on a cylindrical structure in different configurations is determined. To reduce the mutual coupling between the two antennas, the surface of the cylinderical ground plane is defected by cutting slots, or inserting quarter wavelength grooves between the two antennas. The finite element method and the finite integration technique are used to calculate the radiation characteristics of the antenna.
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A Dielectric Resonator Antenna Array Using Dielectric Insular Image Guide

A Dielectric Resonator Antenna Array Using Dielectric Insular Image Guide

By removing the shielding and with proper feeding schemes, these DRs are found to be functioning as efficient radiators. In fact, the theoretical investigations on the radiation characteris- tics of DRs were carried out long ago in the 1960s as a sideline and practically suppressed for the prevailing application of oscillators and filters until 1983 [3], [4]. In this year, S. Long et al. published a paper on the cylindrical dielectric resonator antenna (DRA) which studied and examined at length the radiation performances of DRs as antennas [5]. After that, they continued with the research on this subject to explore DRAs in other shapes: rectangle [6] and hemisphere [7]. All their serial work laid the foundation for future extensive investigations on various aspects of DRAs in various forms [8], [9].
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