Two Elements Elliptical Slot CDRA Array with Corporate Feeding For X-Band Applications

Very high gain and sharp radiation beam of an original antenna array design, made of 16 linear three stacked cylindrical dielectric resonator antennas (three ScCDRA), is proposed in this work for automotive short-range radar (SRR) applications operating at 79 GHz. Firstly, a single antenna which functions around 79 GHz and reaches a gain value up to 11.8 dB is designed with success by piling three cylindrical DRA having permittivity values, respectively, 17.9, 16.9, and 9. However, relatively near peak values, of the main and the side lobs, makes the preliminary design less efficient for vehicle radar applications. To get a radar design with enhance properties, such as lower return loss, higher gain and especially reduced radiation pattern side lobs, we proceeded with an array design of 16 linear antenna-elements (1×16). As results, the three ScCDRA array structure provides 21.3 dB as gain peak value, a very narrow angular half power beam width (HPBW) of radiation pattern of 0.7 degree at 79 GHz. Feeding network design and positions of the sixteen linear antenna-elements, within this array, have been extensively investigated to carry out an optimal design still resonating around 79 GHz with a lower S11 parameter value up to -40 dB and hilly directional characteristics of radiation diagram.

ABSTRACTThis article presents the design and performance analysis of a high gain dual-polarized two-element cylindrical dielectric resonator antenna (DRA) array excited by two orthogonally placed H-shaped apertures. The antenna is operated in dual linear polarized mode by exciting TM110 (HEM11) mode in two DRAs using aperture coupling. The proposed antenna has a −10 dB impedance bandwidth of 9.52% (6.0–6.6 GHz) with isolation more than 40 dB among the two ports. Realization of gain enhancement and high isolation are accomplished by simultaneously exciting two DR elements using a pair of wideband Wilkinson's power divider placed on the bottom side of the substrate. The measured gain of the proposed antenna for both the ports is found to be 12.5 dB with a front to back ratio of 16 dB. The antenna has an overall radiation efficiency of 94% and symmetrical radiation patterns with co-polarization levels 40 dB higher than the cross-polarization in both the principal planes (XY and XZ) of bore-sight direction.

A millimeter wave dielectric resonator antenna (DRA) array with high-gain and high-selectivity filtering response is proposed, which is composed of stacked feeding network and stacked DRA. The stacked feeding network consisting of two layers of thin substrate has the efficient characteristics to expand and integrate. The band-pass filter formed by complementary split ring resonator (CSRR) structure generates radiation nulls at the edge of the high-frequency band. With the improved filtering stubs loaded at the end of the H-shaped microstrip power divider, a radiation null at the edge of the low-frequency band is obtained and the roll-off degree at the edge of the high-frequency band is improved. By embedding the metal column in the fork-shaped stub, the suppression level of the low-frequency stopband is improved. A prototype of the proposed DRA array is fabricated and measured, which shows 7.2% relative bandwidth and a stable directional pattern in the range of 26.28–28.25 GHz with an average gain of 9.57 dBi. And an out-of-band suppression level of 18 dB is achieved. The DRA array can be applied for 5 G millimeter wave band to support high-speed communications at short distance.

A simple circuit model is presented for modeling substrate integrated waveguide (SIW) series-fed dielectric resonator antenna (DRA) array. The mutual coupling between antenna elements is taken into account in the model. A single-element and a two-element antenna structures are simulated first using full-wave solver. The mutual coupling between antennas is then extracted and subsequently plugged into the circuit model for the antenna array. A millimeter-wave DRA array example is used to validate the model. The S-parameters calculated using the model agrees well with the full-wave solver results.

A novel feeding method for linear DRA arrays is presented, illuminating the use of the power divider, transitions, and launchers, and keeping uniform excitation to array elements. This results in a high-gain DRA array with low losses with a design that is simple, compact and inexpensive. The proposed feeding method is based on exciting standing waves using discrete metallic patches in a simple design procedure. Two arrays with two and four DRA elements are presented as a proof of concept, which provide high gains of 12 and , respectively, which are close to the theoretical limit based on array theory. The radiation efficiency for both arrays is about 93%, which is equal to the array element efficiency, confirming that the feeding method does not add losses as in the case of standard methods. To facilitate the fabrication process, the entire array structure is 3D-printed, which significantly decreases the complexity of fabrication and alignment. Compared to state-of-the-art feeding techniques, the proposed method provides higher gain and higher efficiency with a smaller electrical size.

In this paper, a conical dielectric resonator antenna (DRA) array with two linear elements and circular polarization is proposed for C-band applications. The proposed elementary antenna is composed of two layers of the substrate arranged vertically and excited from the feed slots. The first layer is the Rogers RO3010 with $\pmb{\varepsilon_{1}}=\pmb{10.2}$ and tan $\pmb{\delta=0.0035}$, and the second one is the Teflon with $\pmb{\varepsilon_{2}=2.1}$ and tan $\pmb{\delta=0.001}$. The inclination of the two layers relative to the slot feed is equal to 45° thus creating a circular polarization. The main goal of this technique is to increase the antenna performance in terms of bandwidth and gain. The reflection coefficient, radiation patterns, gain and axial ratio of the proposed antenna are simulated using Ansoft HFSS and validated by CST Microwave Studio.

A 1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 3 filtering dielectric resonator antenna (DRA) array is investigated in this communication. The central DRA is excited by a microstrip-coupled slot, while the two side DRA elements are, respectively, excited by the central DRA via a low-profile patch-loaded dielectric bridge laid between them. In order to integrate the filtering function, the open stub of the microstrip feed line is elaborately designed to generate a radiation null at the upper band edge, while two vertical metallic strips are added onto the sidewalls of the central DRA to provide another radiation null at the lower band edge. On the other hand, in order to achieve an enhanced gain in the operating passband, the higher order TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">113</sub> mode of the DRA elements is excited. It is found that due to the loading effects of metallic patches and conformal strips, three stepping resonances of the TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">113</sub> mode are generated in the passband, leading to a wide impedance bandwidth of 13.7% and a stable gain of 11.4 dBi. As a result, both good radiation and filtering performance are achieved without requiring complex filtering circuits. To demonstrate the extensibility of the array, a larger 3 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 3 filtering DRA array with a high peak gain of 14.7 dBi is further designed by just using a three-way power dividing network.

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.

A compact dual band cylindrical dielectric resonator antenna (CDRA) is designed and presented. The CDRA is excited by E-shaped aperture, which is located below the microstrip line feed on the ground plane. The defected ground plane has a conducting strip under the Dielectric Resonator Antenna (DRA) that causes the upper resonance at 5 GHz. The lower band at 2.45 GHz is achieved by applying a metallic top-loaded cylindrical dielectric antenna (CDRA). The experimental results show the antenna covers 2.45 GHz and 5 GHz with −10dB return loss, satisfying the desired standards of WLAN applications.

A finite-difference time-domain (FDTD) approach is proposed in order to obtain suitable criteria for the design of a four-element dielectric resonator antenna (DRA) array. The numerical analysis is focused on the study of the electromagnetic coupling phenomena arising between DRA fed by a microstrip-slot transition. Scattering parameters behavior and radiation patterns are determined by taking advantage of the geometrical symmetry of the structure, analyzing only one half or one quarter of the entire domain through two or four separate FDTD runs.

In this paper, a slot coupled wideband circularly polarized cylindrical ring dielectric resonator antenna (DRA) has been presented. Circular polarization in DRA is generated using slot coupling excited with microstrip feed. Proposed design antenna shows −10 dB input impedance bandwidth of 13.15% and in broadside direction 3-dB axial ratio bandwidth of 10.00%. In addition, proposed antenna shows HEM 12δ mode, stable gain, radiation efficiency and offers right hand circular polarization.

A novel (2£2) high-gain circularly-polarized cylindrical dielectric resonator antenna array integrated with helical exciter is proposed. The array ofiers a maximum gain of 13.8dBi at the operating frequency. The circular polarization is obtained by incorporating helical exciter in the array structure. A prototype of the proposed conflguration integrated with helical exciter has been fabricated, tested and the idea has been verifled. A good agreement has been obtained between the measured and the simulated results.

Communication of present era involves Wi-Fi, Wimax and WLAN. Proposed antenna is designed keeping in mind for these particular requirements. Narrow beam may impart large amount of gain for one particular communication requirements. This paper investigates cylindrical dielectric resonator antenna with introducing band gap structure on the circular patch of DRA for imparting high gain. The application of this antenna can had in the field of WLAN. In this paper characteristics of cylindrical Dielectric Resonator Antenna (DRA) using BaZrO3 (er=27) material, are studied. The DRA antenna is designed by using HFSS software which employs the FDTD method for solution. The characteristics of these antennas are investigated with both co-axial feeding and used for exciting the DRA. The experiment is performed on cylindrical DRA shape fed by coaxial and BaZrO3 material of dielectric constant 27.

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.

The eigenmode expansion method is used to evaluate the resonant frequency of a probe fed cylindrical dielectric resonator (DR) antenna, which radiates above an infinite conducting ground plane. A parallel grounded conducting plane is added above the DR, thus allowing the use of cylindrical harmonic field expansions in the regions between the two parallel ground planes. The eigenmode expansion coefficients are found by enforcing the boundary conditions at conducting surfaces and regional interfaces. Then, from the induced currents on the probe surface, the input impedance and the resonant frequency of the DR antenna are evaluated. The results are compared with those of a previous configuration which has no upper ground plane. It is found that the deviation of the calculated resonant frequency is less than 2% for epsilon εr>9.