LOW PROFILE DIELECTRIC RESONATOR ANTENNA BACKED BY SUBSTRATE INTEGRATED WAVEGUIDE CAVITY

There are many commercial applications, such as mobile radio and wireless communications that use microstrip antennas. Microstrip antennas however have limitations in size, bandwidth, and efficiency. On the other hand, the dielectric resonator (DR) antenna is attractive due to its small-size, high radiation efficient, and ease of excitation.[1-3] Three dielectric properties of materials must be considered for DR antenna used: a high permittivity, a high quality factor, and a near zero temperature coefficient of resonant frequency. The size of the DR antenna decreases with increasing the permittivity of the dielectric resonator. The quality factor is representative of the antenna losses. Typically there are radiation, conduction, dielectric, and surface wave losses. Therefore the total quality factor is influenced by these losses. The DR antenna offers very high radiation efficiency due to its low dielectric loss and it has no metallic loss. A near zero temperature coefficient of resonant frequency are for high temperature stability. In traditionally, the DR with relatively small permittivity around 10 is chosen for DR antenna to enhance the radiation capability.[4-10] However, low profile DR antenna with relatively low resonant frequency can be achieved by using high permittivity. Recently, dual band antenna has been implemented for applications in WLAN (wireless local area network, 2.4–2.484 GHz), ISM (Industrial, Scientific, Medical) and Bluetooth at low band. Additionally, the dual band antenna can be applied at high band, such as HIPERLAN (high-performance radio local area network, 5.15–5.35 GHz) and Unlicensed National Information Infrastructure (UNNI) applied. In this paper, we present the design of a dual band hybrid antenna consists of a rectangular slot and a circular disk high permittivity dielectric resonator for operating at the ISM band and UNNI band. Details of the proposed antenna and experimental results are present. The characteristics of dual band hybrid antenna, such as return loss, input impedance, radiation pattern, and gain, have been measured and discussed.

This paper presents the design of a low-profile dielectric resonator antenna (DRA) for wideband systems. The antenna consists of three dielectric segments, each with different permittivity, residing over a ground plane. The impedance bandwidth of this DRA was enhanced by introducing an air-region inside the middle segment. The volume of the proposed DRA was reduced by adding a finite planar conducting wall. A full ground plane was used to ensure that most of the power radiates to upper hemisphere. The computed results show a VSWR bandwidth of 86% from 4.0–10.2 GHz, while peak gain is in the range of 5–7 dBi.

A novel low profile dielectric resonator antenna (DRA) is presented in this study for broadband applications. An asymmetric E‐shaped dielectric resonator is analysed and optimised numerically as a wideband radiator. The fundamental mode is excited along with three nearest higher modes inside the DRA. A detailed impedance transformation is discussed to merge these modes collectively resulting in a single wideband operation. A microstrip fed conformal strip is used to stimulate the DRA. The proposed DRA is fabricated and tested. For |S11| ≤ −10 dB, the DRA offers a frequency band of 6.0–10.2 GHz with an impedance bandwidth of 52%. The measured and calculated results are compared and found in good match. The DRA's radiation characteristics are measured at different frequencies. A stable radiation pattern is observed throughout the band of operation. The measured gain of the wideband antenna is ranging from 4.5 to 8.1 dBi.

A compact low-profile conformal dielectric resonator antenna (DRA) excited by coaxial probe is presented in this paper. This paper presents the design, analysis, and experimental validation of a low-profile Dielectric Resonator Antenna (DRA) operating in the C and X bands. The proposed antenna is configured on a convex conformal ground plane, providing enhanced radiation characteristics. The proposed arrangement provides a wide impedance bandwidth of around 36%, that covers the frequency range from 6.9 GHz to 9.7 GHz, with TE11δ mode and TE23δ higher-order mode can be observed corresponding to the resonant frequencies of 7.2 GHz and 9.2 GHz, respectively. Furthermore, a maximum realised gain of 8.4 dBi is attained at 8.3 GHz. The proposed antenna offers a wide impedance bandwidth with more than 90% radiation efficiency throughout the bandwidth. Additionally, a good agreement is observed between the simulated and measured results and proposed DRA has a compact and low-profile of 0.16λg, where λg is the wavelength of the lower cut-off frequency.

In this paper an slot excited cylindrical Dielectric Resonator Antenna (DRA) backed by a substrate integrated waveguide (SIW) cavity is numerically investigated based on Finite Element Method (FEM). It consists of a DRA placed on the conducting back plane of the SIW cavity. A resonator slot is used to couple energy from the cavity to the DRA. By merging two resonant frequencies of the slot and the DR, a wide operating bandwidth is achieved. A parametric study of the slot size, feed line length and dimensions of the DRA on the radiation performance of the antenna is carried out. Results show that the proposed structure exhibits as much as bandwidth of 26% for S11<; -10 dB. Gain of the antenna structure is at least 5 dB over the whole operation band and its radiation efficiency is more than 95%.

A low profile dielectric resonator antenna (DRA) with wide impedance bandwidth is proposed by introducing the air regions. This proposed DRA is fed by two symmetrical slots. The DRA modes can be excited and merged to broaden the impedance bandwidth by inserting air regions insider the DRA. This DRA can achieve impedance bandwidth of 45.8% covering the frequency band of 3.2-5.1GHz. At the same time, it has very low profile of about 0.07λ <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf> . A relatively stable gain is obtained around 6.25 dBi.

In this article, a differentially fed dual-polarized dielectric resonator antenna (DRA) subarray excited by a substrate integrated waveguide (SIW) cavity is proposed. A #-shaped slot etched on the top wall of the SIW cavity is used to achieve the differential excitation due to the intrinsic field distribution of TE120 mode in the SIW. Based on the proposed antenna subarray, a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times $ </tex-math></inline-formula> 2 dual-polarized 2-D multibeam DRA antenna array with simple structure is designed, fabricated, and measured, which can achieve high cross-polarization discrimination (XPD) in the direction of maximum radiation. To reduce substrate loss, the printed ridge gap waveguide (PRGW) technology is used to feed the SIW cavity. Two orthogonal PRGW Butler matrices are placed at different layers so as to realize 2-D beamforming scanning with dual-polarization. The SIW cavity is placed in the air gap of PRWG, which can increase the stability of the antenna structure. By cleverly combining the SIW cavity and PRGW structure, the proposed multibeam antenna array has the advantages of high XPD and high radiation efficiency. Measured results show that an impedance bandwidth of 10% (28.5–31.5 GHz) and a peak gain of 11.8 dBi are obtained. Also, the measured XPDs are 28.3 dB at the center frequency and larger than 19.2 dB over the band of operation. Besides, the measured radiation efficiency of 67% is achieved for both the polarizations at 30 GHz.

A dielectric resonator antenna (DRA) with the loading of metasurface (MS) is proposed for low-profile, wide-bandwidth and compact-size. Firstly, an MS structure consisting of $6\times6$ periodic metallic patch cells is loaded above the DRA. It aims to excite an additional TM surface wave above the fundamental TE111 mode of the rectangular DRA. Then, the shorting walls are printed on two sides of the dielectric, thus moving down the operating frequency with respect to its TM surface wave mode. As such, the bandwidth of the antenna is significantly widened with compact-size under the operation of TE111 and TM surface wave modes. Finally, the proposed DRA with enhanced performance is fabricated and tested. The results show that an impedance bandwidth of the antenna is dramatically increased to about 17.2%, covering the frequency range from 1.75 to 2.08 GHz, which is about 9.6 times wider than the traditional DRA at the same thickness (1.8%). Besides, it still maintains the broadside radiation pattern with stable gain of around 6.6 dBi and fairly low cross polarizations of below −26 dB. Particularly, the overall size of the radiator still maintains as small as about $0.32\lambda _{0} \times 0.32\lambda _{0} \times 0.044\lambda _{0}$ . It should be noted that the analysis of the antenna is carried out by using Ansys HFSS software version 14.0 and ADS 2011.

In this paper, a low profile dielectric resonator antenna (DRA) is proposed and investigated. To achieve the broad impedance bandwidth the proposed antenna geometry combines the dielectric resonator antenna and an underlying microstrip-fed slot with a narrow rectangular notch, which effectively broadens the impedance bandwidth by merging the resonances of slot and DRA. The physical insight gained by the detailed parametric study has led to find out a set of guidelines for designing the antennas for any particular frequency band. The design guidelines have been verified by simulating a set of antennas designed for different frequency bands. For validation, a prototype antenna is fabricated and tested experimentally. The measured results show that the proposed DRA offers an impedance bandwidth of about \(125.34\%\) from 1.17 to 5.1 GHz with reasonable gain between 3.5 and 5.7 dBi. The volume of the proposed DRA is \(0.16\lambda _{dr}^{3}\), where \(\lambda _{dr}\) is the wavelength at center operating frequency of the DR. A comprehensive study on bandwidth shows that the proposed DRA provides maximum bandwidth in terms of the DR volume (\(\hbox {BW}/V_{dr}\)) and the DR height (\(\hbox {BW}/h_{dr}\)) than the other similar reported work on hybrid wideband DRA designs.

A low profile dielectric resonator antenna (DRA) using a high permittivity medium was fabricated. The DRA was excited by aperture coupling. The DRA showed an impedance bandwidth of 3.68 % at 3.53 GHz along with a gain of 2.8 dBi. The nature of circular polarization can be revealed from the radiation pattern.

triple‐mode bandpass filter

This study examines a low-profile beam steering rectangular dielectric resonator antenna (DRA) operating in TE mode, using a novel combination of a pair of parasitic strips connected to the microstrip feed at one end and vertical stubs adhered to the sidewall of the dielectric slab at the other. With the aid of only two PIN diodes appropriately positioned to connect vertical stubs and parasitic strips, the beam direction can be switched from ϕ = −46° to + 46°. The antenna’s dimensions are 0.96λo × 0.96λo × 0.06λo, with λo being determined at 4.8 GHz. The improved coupling due to the parasitic strips helps in achieving a maximum gain of 6.78 dBi and efficiency of 83%, a front-to-back ratio (FBR) of 17 dB, a half power beam width (HPBW) of 113°, and |S11| of −23 dB at 4.8 GHz. A prototype of the design has been fabricated and tested. The enhanced gain, higher efficiency, higher HPBW, and directional control, with only two switching elements and lower operating frequency of the antenna, make it well-suited for applications in radar communication and 5G NR bands such as n79.

Researchers from the Samsung Electronics Network R&D Center in Shenzhen, China, have fabricated and tested a prototype compact substrate-integrated-waveguide (SIW) cavity multiple-input-multiple-output (MIMO) antenna with potential applications in 5G communications. The triangular half mode design achieves an enhanced bandwidth by merging together two coupled modes in the required operating band and boasts high isolation and radiation efficiency. Since it was first introduced a decade ago, SIW technology has drawn significant attention from researchers, with particular appeal in the antenna community. It can be fabricated in planar form using periodic metallic vias and has the advantages of high-Q factor and high-power capacity. In addition to this, cavity antennas resonating at cavity modes and radiating energy through opened cavity edges or etched slots are well-known for good radiation performance. The SIW cavity antenna is an antenna type created by introducing SIW technology into a cavity antenna design. Antennas transmitting and receiving wireless signals are important components in communication systems. The SIW cavity antenna can not only combine the attractive characteristics of conventional cavity antennas, such as good radiation performance and unidirectional radiation pattern, and but also offers the advantages of planar SIW technology, such as low profile, convenient fabrication, and easy integration with planar circuits. Author Bing-Jian Niu in anechoic chamber holding the proposed antenna. Analytical model of the proposed SIW cavity antenna. The SIW cavity antenna reported in the teams published Letter is designed for MIMO applications. By etching three slots, a half-mode SIW cavity was divided into four eighth-mode sub-cavities. Two large sub-cavities are excited by two coaxial ports to construct two antenna elements and cavity energy is coupled from the excited sub-cavities to the unexcited sub-cavities to enhance bandwidth. Thus, a compact two-element MIMO antenna with enhanced bandwidth can be designed and achieved. As is well-known, MIMO antennas have been widely adopted in modern wireless systems. Co-author Bing-Jing Niu, however, notes that: “Two major challenges faced in the design are narrow bandwidth and poor isolation among antenna elements. In our proposed design, three slots are etched in the half-mode SIW cavity. The width, length, and position of these slots are carefully selected in our Letter.” To meet the stringent requirements on antenna fabrication for wearable and portable devices, antenna designs are becoming more and more complex. Compact two-element MIMO antennas with enhanced bandwidth and high isolation are in great demand. With an enhanced bandwidth of 160 MHz, high isolation of 19.5 dB, antenna gain of 4.9 dBi, and radiation efficiency of 72.8%, the proposed SIW cavity MIMO antenna has good specifications and properties, making it suitable for potential applications for forthcoming fifth-generation wireless communications. Etched slots in the antenna provide new perspectives and opportunities for designing SIW cavity antennas, which not only radiate cavity energy into free space but also control the coupling between adjacent sub-cavities. The challenges the group overcome were the ideal selection of slot width, length, and position to optimise their prototype for its intended applications. In the proposed design, a wide rectangle slot is considered as the de-coupler to enhance the antenna isolation while two narrow T-shaped slot are utilised as the coupler to enhance the impedance bandwidth. The novel design makes it possible to increase the channel capacity and link reliability in wireless communication channels. In the short term, this work is expected to be utilised in the sub-6 GHz band. In the longer term, massive MIMO antenna based on SIW cavities will likely be successfully developed and integrated successfully into communication networks. Mr Niu discusses the groups upcoming work and views on the future of the field: “To improve the conformal performance of planar antennas, we are considering liquid crystal polymers (LCP) as a manufacturing substrate. It has the ability to support 3D integration and low tangents up to and including millimetre-wave (MMW) applications. In addition, to improve the MIMO performance, multiple-element MIMO antennas such as four-element and eight-element, have been developed in our own research group. As one of the most pervasive core technologies, massive MIMO antennas will lead to an accelerated pace of research and development in wireless communication with the promise of significant new breakthroughs over the next decade. An unprecedented number of antennas result in major technical challenges as well as new opportunities in antenna design, channel propagation, electronic components and circuit design, and communication theory. We hope the SIW cavity antenna is a good candidate to address this issue.”

The dielectric resonator antenna (DRA) with wide bandwidth, compact size and low profile is considered as an attractive candidate for 5G wireless communications. However, most of the reported DRAs either have bulky volumes or have limited bandwidths. In this paper, a kind of compact and low-profile DRA with extended bandwidth is proposed. By observing the E-field distribution differences between the two target modes and modifying the dielectric characteristics (such as material and dimension) of the designated region where the E-field is very weak for fundamental TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">111</sub> mode but quite strong for high-order TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">131</sub> mode, the frequency of TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">131</sub> mode can be significantly affected and shifted down to merge with that of TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">111</sub> mode which is less affected. As a result, extended operating bandwidth can be obtained. This technique also benefits from not having to enlarge the planar size of the high permittivity DR, therefore making the antenna compact enough for 5G beam-scanning and low profile applications. For demonstration, linear- and circular- polarization antenna prototypes were designed and measured. The LP antenna has a −10 dB impedance bandwidth of 17.3% and a peak gain of 7.1 dBi while the CP antenna achieves a 3-dB axial ratio (AR) bandwidth of 12% and a peak gain of 6.6 dBic. Both the antennas have compact volumes of no larger than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.35{\lambda } _{0} \times 0.35{\lambda } _{0} \times 0.11{\lambda } _{0}$ </tex-math></inline-formula> . Based on the LP and CP antenna elements, two <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times5$ </tex-math></inline-formula> antenna arrays with the capability of beam scanning are designed and simulated. Wide scanning angles of ±45° and ±40° can be obtained for the LP and CP arrays, respectively.

Compact, vertically-integrated dual- and tri-band filtering antennas based on multi-mode substrate integrated waveguide (SIW) cavities are developed. The electric filed distributions of the resonant modes in a SIW cavity are firstly analyzed. And then, a dual-band SIW filtering antenna is developed by employing a dual-mode SIW cavity and a slot-loaded SIW cavity. In the dual-band design process, a SIW cavity, operating at its TE <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">110</inf> and TE <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">120</inf> modes, is utilized as the feeding cavity, and a slot-loaded SIW cavity is stacked over the dual-mode SIW feeding cavity to simultaneously realize the dual-band function and facilitate the filtering response for both two passbands. Finally, in order to achieve the tri-band function, a multi-mode SIW cavity, operating at its TE <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">110</inf> , TE <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">120</inf> , and TE <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">210</inf> modes, is selected as the feeding cavity. According to properties of the electric field magnitude distributions of the three modes in SIW cavity, the position of the feeding line is elaborately designed to simultaneously excite these three modes. Likewise, a slot-loaded SIW cavity is employed to stack with the multi-mode SIW feeding cavity to accomplish the tri-band function and improve the frequency selectivity for three passbands. The simulated results demonstrate that both the dual-band and tri-band SIW filtering antennas possess good in-band and out-of-band performance characteristics.