Design of the Wide Dual-Band Rectangular Souvenir Dielectric Resonator Antenna

The perturbation approach is presented here for the first time for the analysis of an inhomogeneous circularly polarized rectangular dielectric resonator (DR) antenna (DRA). The inhomogeneous permittivity is created by perturbing a rectangle-shaped region of different material inside the rectangular dielectric resonator antenna (RDRA). The orthogonal degenerate modes with a phase difference of TE111x, and TE111y, are excited simultaneously for achieving circular polarization. A simple expression for the calculation of the resonant frequency and optimal axial ratio point for a circularly polarized (CP) inhomogeneous RDRA is presented here. Theoretical results obtained from the proposed theory are compared with theoretical, simulated, and experimental data available in the literature. The proposed analysis results show optimal axial ratio point calculations within a 1% range of the simulated and experimental data, which is better than the previous transverse transmission line reported method, having an error of approximately 4%. The advantages, accuracy, and simplicity of perturbation theory for DR are discussed in detail. The proposed theory can be easily extended for higher order modes and other shapes of material perturbation and anisotropic DRAs. The proposed technique will help in incorporation of the perturbation in the DR so that CP radiation can be obtained in an easy way.

High profile rectangular dielectric resonator antennas (RDRAs) with length to height ratio of two or less are not suitable for low profile applications because of low usable bandwidth and poor gain of the RDRAs. This paper presents an improvement in the useable bandwidth and gain of the RDRAs using an horn mounted on the RDRA. The horn is fabricated with plastic sheet and painted with silver epoxy. It is observed that the RDRA mounted with horn achieves almost 100 % greater gain than that of RDRA without horn at the resonating frequencies and that too with good return loss. It is also observed that the impedance bandwidth is increased slightly. The simulation results show that the gain achieved using RDRA mounted with horn is 13.53 and 12.85 dBi while the 10 dB return impedance bandwidth is 4.4 and 5.9 % at 5.7 and 8.1 GHz respectively.

A wideband rectangular hybrid dielectric resonator antenna (DRA) is proposed. The rectangular DRA is excited with monopole. The top of the DRA is covered with the rectangular parasitic element. Impedance bandwidth ranging from 6.32GHz to 24.865GHz is achieved. The gain of the proposed antenna varies from 4.23 to 5.32dBi over the operating band.

A wideband low-profile connected rectangular ring dielectric resonator (DR) antenna (DRA) array is presented for millimeter-wave (mmWave) applications. It consists of four rectangular ring DRA elements. The DRA elements are excited by microstrip feedlines through four slots on the ground plane. A slot mode, the DRA <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm {TE}}^{\text {y}}_{1\delta 1}$ </tex-math></inline-formula> mode, and the perturbed <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm {TE}}^{\text {y}}_{3\delta 1}$ </tex-math></inline-formula> mode are simultaneously excited, giving a wideband design. To avoid the alignment problem, the DRAs are connected to their adjacent elements through dielectric arms. It is found that the position of the dielectric arms has significant effects on the antenna performance. To demonstrate the idea, a prototype with a dielectric constant of 20.8 was designed, fabricated, and tested for licensed mmWave bands (24.25–29.5 GHz). A reasonable agreement between the measured and simulated results is observed. The measured 10 dB impedance bandwidth ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\vert \text{S}_{11}\vert \le - 10$ </tex-math></inline-formula> dB) is 31.6% (22.52–30.97 GHz), with a measured boresight realized gain being higher than 8 dBi from 22.5 to 30 GHz. The measured mutual couplings between the DRA elements of the array are lower than −20 dB in the operating frequency range. Furthermore, our prototype has a low profile of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.074~\lambda _{0}$ </tex-math></inline-formula> , where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{0}$ </tex-math></inline-formula> is the wavelength in air at the center frequency.

This article presents a new dual C-shaped rectangular dielectric resonator (DR) based antenna for generation of wideband circularly polarized (CP) radiation. The proposed antenna comprises of a pair of C-shaped rectangular dielectric DR and a metal strip with a coaxial probe. By utilization of a metal strip at the side surface of C-shaped rectangular DR, the wideband CP radiation is achieved from the proposed dielectric resonator antenna (DRA). Fundamental orthogonal modes (TExδ11 and TEy1δ1) are excited using the rectangular DRA with a metal strip for the generation of CP fields. The proposed antenna with dual C-shaped rectangular CP DRA provides the measured −10 dB reflection coefficient bandwidth of 30.07% (3.22 GHz-4.36 GHz) with measured 3-dB axial ratio bandwidth of 14.81% (3.25 GHz-3.77 GHz) at the boresight. The proposed antenna covers the useful Wi-MAX band.

The antennas for wireless communication devices have undergone a tremendous expansion from the external monoband resonant antenna to the internal non-resonant multi-band antenna. In this paper, a dual-band dielectric resonator antenna for high-speed applications is proposed. Due to the complex edge-shaped boundary between the dielectric and air in a rectangular dielectric resonator antenna, a complex closed form of expression is difficult to achieve. To address this problem a half-cut cylinder is placed over the rectangular dielectric to achieve excellent radiation characteristics. This proposed antenna provides a wide dual-band response with fractional impedance bandwidth of 21.92% and 19.09%while operating from7.32 GHz to 9.12 GHz and 10.71 GHz to 12.95 GHz. It provides an average gain of 3dBi with high gain stability in the entire operating frequency band. The radiation efficiency is found to be 96% due to low ohmic and dielectric losses. The cross-polarization is around 20 dB lesser than the co-polarization. Its gain and directivity can further be enhanced by implementing serial and parallel array structures. This design uses HFSS 14.0 commercial electromagnetic simulation tools.

In this paper, a dual-band antenna (one is narrowband and another one is wideband) has been proposed using fundamental and higher order modes of a rectangular dielectric resonator antenna (RDRA). The proposed RDRA operates at 3 GHz for narrowband operation (BW = 5.08%) and gives the wideband performance for the frequency range of 5.20 GHz-6.37 GHz (BW = 20%).Dielectric waveguide model is used to compute the resonance frequency of two radiating mode TE111 and TE113 of RDRA.TE111 mode is responsible for narrowband response and two hybrid mode combine with TE113 gives the wideband response. The antenna offers a peak gain of 2.15 dBi at 3 GHz and 6.54 dBi at 6.26 GHz.

In this paper, the rectangular dielectric resonator antenna (DRA) is excited by a circular microstrip patch, instead of a traditional probe into the dielectric resonator. A microstrip cross with four pins located on the lower substrate is used to generate a radiation null (RN) at 3.84 GHz. A circular microstrip with four pins located on the upper substrate is used to generate a RN at 2.67 GHz. The proposed wide-/dual-band DRA are designed without the need of drilling a hole in the dielectric resonator and with the filtering function. The configuration, the simulated reflection coefficients, the realized gains and the normalized radiation characteristic of the proposed DRAs are studied and analyzed.

A novel dual-band dielectric resonator antenna(DRA) with dual-polarization is presented in this paper. It consists of a dielectric resonator, a square ground and a well designed feeding network. This antenna makes use of HEM111 mode and HEM113 mode to realize dual-band characteristics. Dual polarization is realized by exciting two orthogonal ports, and the port isolation is better than 65dB over the band of interest. For each port, the −10 dB impedance bandwidth of the lower and upper bands are given by 1.83–1.99GHz and 2.58–2.63GHz respectively. It can also achieve a peak gain of 6.5dB at the upper hemisphere for both modes.

The omnidirectional rectangular dielectric resonator (DR) antenna (DRA) using its higher-order quasi-TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">015</sub> mode is proposed for the gain enhancement. It was designed, fabricated and measured for 5.8-GHz WLAN applications. Its measured bandwidth and antenna gain of the proposed DRA are 4.84% and 3.63 dBi, respectively.

Dielectric resonator (DR) antennas have many desirable features, such as low cost, low profile, high radiation efficiency, large operating bandwidth and low losses, which make them prospective devices for millimeter wave applications. One of the most useful features of the DR antennas is their ability to produce multiple radiation patterns via the excitation of different resonant modes. While these modes in spherical and cylindrical DRs have been well studied, there is little information available in the literature about the modes in the rectangular DRs. We apply the FDTD method to study the resonant modes in rectangular DR antennas. Standing wave patterns of electric and magnetic field components have been simulated and the mode charts for different mode types constructed. The resonant fields in DR antennas are equivalent to those created by combinations of magnetic or electric dipoles located in the DRs. The possibility to excite TM modes in rectangular DR antennas is demonstrated and it is shown that higher order TM modes can function as arrays of vertical electric dipoles that can be used to design DR antennas with radiation along the azimuth plane.

The TE <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$_{\delta 01}^{x}$</tex> </formula> mode excited in a rectangular dielectric resonator antenna (DRA) with metal coating is presented. This mode was first proposed in a hybrid DRA in our previous work. To compare it to the traditional dominant mode and further show its characteristics, a set of simple rectangular DRAs with and without metal coating was designed, fabricated, and measured in this letter. These DRAs are mounted on the ground plane and fed by a coupling slot. Due to specific field distributions, the TE <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$_{\delta 01}^{x}$</tex></formula> mode can work at a much lower frequency than the traditional one in the rectangular DRA with the same dimensions. In addition, broadside radiation pattern and good radiation efficiency over the operating bandwidth are also obtained.

This paper proposes a dual-band circularly polarized (CP) rectangular dielectric resonator antenna (DRA) for 5G millimeter wave wireless communications. The proposed DRA consists of a novel modified cross-flower exciting (MCF) slot and a rectangular ceramic dielectric resonator (DR). With the help of the compact MCF feeding slot, the fundamental modes TEδ11x/TE1δ1y and higher-order modes TEδ13x/TE1δ3y of the DR can be excited to achieve CP dual-band characteristics. In addition, the MCF slot works as a radiator at 26 GHz and 39 GHz to enhance the DRA bandwidth. More importantly, these two operational bandwidths can be controlled independently at the lower and upper bands. The proposed DRA is designed, fabricated and measured. The measured results show that the proposed dual-band CP DRA achieves 3 dB axial-ratio (AR) bandwidths of 19.8% and 7.8% with peak gains of 5.62 dBic and 6.74 dBic for the lower and upper bands.

For the first time, a unilateral rectangular dielectric resonator (DR) antenna (DRA) is designed using two DR modes, namely the fundamental $\boldsymbol{TE}_{\boldsymbol{\delta }11}^{\boldsymbol{x}}$ mode and higher-order $\boldsymbol{TE}_{2\boldsymbol{\delta }1}^{\boldsymbol{y}}$ mode. The former and latter provide the broadside and quasi-omnidirectional radiation patterns, respectively. By combining the radiation fields of the two resonant modes, unilateral radiation with wide 3 dB beamwidths can be obtained. For demonstration, a unilateral rectangular DRA was designed in 2.4 GHz WLAN band. Across the WLAN band, the DRA has a measured front-to-back ratio (FTBR) of higher than 15 dB. It is found that the measured maximum FTBR of the DRA is 36.6 dB, whereas the measured 3 dB beamwidths of the two principal radiation planes are both wider than 174°.

The dielectric resonator antenna (DRA) is quite useful for high frequency applications where ohmic losses become a serious problem for conventional metallic antennas. In addition, they offer higher bandwidths than microstrip patch antennas used in the same frequency range. There are many techniques for increasing the bandwidth of DRAs and many of them increase the complexity of the structure. The paper is concerned with the excitation of two modes with similar radiation characteristics in the same DRA. By adjusting the ratio of the diameter to the height, the modes can be made to resonate close to each other and the bandwidth is thereby increased. The characteristics of the cylindrical DRA and the rectangular DRA are compared. The results show that, by exciting two simultaneous modes, the bandwidth of a DRA can be increased without extensively modifying the geometry.