Resonator Antenna Research Articles

Dual-Band Dielectric Resonator Antenna with Filtering Features for Microwave and Mm-Wave Applications.

This paper presents a new design for a dual-band double-cylinder dielectric resonator antenna (CDRA) capable of efficient operation in microwave and mm-wave frequencies for 5G applications. The novelty of this design lies in the antenna's capability to suppress harmonics and higher-order modes, resulting in a significant improvement in antenna performance. Additionally, both resonators are made of dielectric materials with different relative permittivities. The design procedure involves the utilization of a larger cylinder-shaped dielectric resonator (D1), which is fed by a vertically mounted copper microstrip securely attached to its outer surface. An air gap is created at the bottom of (D1), and a smaller CDRA (D2) is inserted inside this gap, with its exit facilitated by a coupling aperture slot etched on the ground plane. Furthermore, a low-pass filter (LPF) is added to the feeding line of D1 to eliminate undesirable harmonics in the mm-wave band. The larger CDRA (D1) with a relative permittivity of 6 resonates at 2.4 GHz, achieving a realized gain of 6.7 dBi. On the other hand, the smaller CDRA (D2) with a relative permittivity of 12 resonates at a frequency of 28 GHz, reaching a realized gain of 15.2 dBi. The dimensions of each dielectric resonator can be independently manipulated to control the two frequency bands. The antenna exhibits excellent isolation between its ports, with scattering parameters (S12) and (S21) falling below -72/-46 dBi at the microwave and mm-wave frequencies, respectively, and not exceeding -35 dBi for the entire frequency band. The experimental results of the proposed antenna's prototype closely align with the simulated results, validating the design's effectiveness. Overall, this antenna design is well-suited for 5G applications, offering the advantages of dual-band operation, harmonic suppression, frequency band versatility, and high isolation between ports.

A new planar feeding method of dielectric rod antenna using dielectric resonator

This article proposes a new method for exciting surface waves in dielectric rod antennas using dielectric resonator antennas. The method involves housing a rectangular dielectric resonator antenna with a dielectric constant of 10.2 inside a hollow cylindrical dielectric rod antenna made of Teflon. By exciting the {TE}_{111}^{y} and {TE}_{113}^{y} modes of the dielectric resonator antenna, a surface wave can be launched along the Teflon tube. This method offers the advantage of integrating the dielectric rod antenna with planar circuits, where maximum radiation in the direction normal to the board is desirable. Compared to other planar feeding methods, this technique leads to lower back lobe and sidelobe levels. I fabricated the proposed structure and conducted tests to measure its performance. The measured results show an impedance bandwidth of 22% from 7.35 to 9.4 GHz and a maximum gain of 14 dB. Additionally, the simulated radiation efficiency of the proposed antenna in the entire band is above 90%.

Dipolectric antenna for high-field MRI.

To introduce the dipolectric antenna: a novel RF coil design for high-field MRI using a combination of a dipole antenna with a loop-coupled dielectric resonator antenna. Simulations in human voxel model Duke involving 8-, 16-, and 38-channel dipolectric antenna arrays for brain MRI were conducted. An 8-channel dipolectric antenna for occipital lobe MRI at 7 T was designed and constructed. The array was built of four dielectric resonator antennas (dielectric constant = 1070) and four segmented dipole antennas. In vivo MRI experiments were conducted in one subject, and the SNR performance was benchmarked against a commercial 32-channel head coil. A 38-channel dipolectric antenna array provided the highest whole-brain SNR (up to a 2.3-fold SNR gain in the center of the Duke's head vs. an 8-channel dipolectric antenna array). Dipolectric antenna arrays driven in dipole-only mode (with dielectric resonators used as receive-only) yielded the highest transmit performance. The constructed 8-channel dipolectric antenna array provided up to threefold higher in vivo peripheral SNR when compared with a 32-channel commercial head coil. Dipolectric antenna can be considered a promising approach to enhance SNR in human brain MRI at 7 T. This strategy can be used to develop novel multi-channel arrays for different high-field MRI applications.

Resonance Analysis and Gain Estimation Using CMA-Based Even Mode Combination Method for Flexible Wideband Antennas.

This work presents an efficient design and optimization method based on characteristic mode analysis (CMA) to predict the resonance and gain of wideband antennas made from flexible materials. Known as the even mode combination (EMC) method based on CMA, the forward gain is estimated based on the principle of summing the electric field magnitudes of the first even dominant modes of the antenna. To demonstrate its effectiveness, two compact, flexible planar monopole antennas designed on different materials and two different feeding methods are presented and analyzed. The first planar monopole is designed on Kapton polyimide substrate and fed using a coplanar waveguide to operate from 2 to 5.27 GHz (measured). On the other hand, the second antenna is designed on felt textile and fed using a microstrip line to operate from about 2.99 to 5.57 GHz (measured). Their frequencies are selected to ensure their relevance in operating across several important wireless frequency bands, such as 2.45 GHz, 3.6 GHz, 5.5 GHz, and 5.8 GHz. On the other hand, these antennas are also designed to enable competitive bandwidth and compactness relative to the recent literature. Comparison of the optimized gains and other performance parameters of both structures are in agreement with the optimized results from full wave simulations, which process is less resource-efficient and more iterative.

Triple-Mode Resonant Backfire Feed Antenna With Nearly Equal E-/H-Plane and Inverse Taper Patterns

A design approach to triple-mode resonant feed antenna is advanced for parabolic reflector antenna system. The antenna is composed of a slit-loaded 1.5-wavelength sectorial dipole, a primary corner reflector, and an auxiliary circular reflector. The corner angle of the primary reflector can be employed to properly narrow down the H-plane half-power beam width (HPBW), while with the E-plane one rarely affected, such that equal E-/H-plane characteristic can be yielded accordingly. Unlike traditional backfire antennas, high-order resonant modes are employed to generate inverse taper radiation pattern at the high frequency band. As is numerically demonstrated and experimentally validated, the corner angle of the primary reflector can be eventually determined as 45∘. The antenna exhibits an impedance bandwidth of up to about 79.7%, and a nearly equal E-/H-plane bandwidth of up to about 29.4%. Average HPBW of about 65∘, gain up to about 8.9 dBi with fluctuation of less than 1 dB can be achieved within the equal E-/H-plane bandwidth. The inverse taper radiation pattern at the high frequency band can provide effective edge illumination and uniform aperture field distribution in parabolic reflector antenna systems.

A Wideband Differential-Fed Microstrip Patch Antenna Based on Quad-Mode Resonance With Radiation Patterns Correction

A wideband differential-fed microstrip patch antenna (DMPA) based on quad-mode resonance with radiation patterns correction is proposed in this paper. First, the common problems presented in multi-mode resonant microstrip patch antenna (MPA) are introduced: it is difficult for the numbers of operation modes to exceed two, and there are radiation nulls emerged in the broadside. Second, the physical structure and mode combination process of the DMPA are demonstrated in detail. Third, through the equivalent magnetic current array model, we comprehensively introduce the principles and processes of radiation patterns correction. Finally, a prototype is fabricated and measured. The measuring results are consisted with simulation ones. The proposed DMPA achieves 29.4% (3.22 GHz – 4.33 GHz) impedance bandwidth at the profile of 0.058λ (center frequency wavelength), and it has a stable gain in broadside without radiation nulls.

Wideband Circularly Polarized Millimeter-Wave DRA Array for Internet of Things

This work proposes a novel millimeter-wave wideband circularly polarized antenna array for Internet of Things (IoT) applications. The proposed design addresses the issues of having IoT sensors deployed in remote locations or over large geographical regions. Elliptically-shaped dielectric resonator antennas (DRAs) are used as array elements to improve radiation characteristics and achieve circular polarization over a wide impedance bandwidth around 28 GHz. Two different sequential-phase corporate feed networks are studied and compared to obtain wider impedance, 3-dB gain, and axial ratio (AR) bandwidths. Furthermore, a ridge gap waveguide technique based on the low-cost PCB technology is adopted to reduce the transmission losses in the considered sequential-phase feed networks. The proposed millimeter-wave antenna exhibits an impedance bandwidth of 35% (28.1-40 GHz) and 3-dB gain bandwidth of 19.3% (27.6-33.5 GHz). The achieved 3-dB AR bandwidth is 22.6% (27.5-34.5 GHz). The proposed antenna was fabricated and measured, and good agreement between measured and simulated results was obtained. The reported results show that the suggested wideband circularly polarized millimeter-wave antenna has a lot of promise in preventing polarization mismatch losses between IoT devices and satellites caused by their varying orientations.

Adjustable Dielectric Resonator Antenna With Parasitic Elements for 5G SAGOI-IoT Applications

Adjustable Dielectric Resonator Antenna With Parasitic Elements for 5G SAGOI-IoT Applications

A Frequency-Reconfigurable Dielectric Resonator Antenna With a Water Layer

This letter introduces a frequency-reconfigurable dielectric resonator antenna (DRA) with a water layer integration. The proposed method is based on the strategy-combination of mode reconfiguration and dielectric loading. Firstly, the frequency band of the DRA is reconfigured between the resonant frequencies of the fundamental <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$TE^\rm{y}_{111}$</tex-math></inline-formula> and quasi- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$TE^\rm{y}_{111}$</tex-math></inline-formula> modes by flowing liquid control of water pumping in and out of the microfluidic cavity. Then, the frequency response of quasi- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$TE^\rm{y}_{111}$</tex-math></inline-formula> mode is continuously swept by altering the thickness of water layer. For demonstration, the DRA is designed with a solid dielectric material of K9 glass with the permittivity of 6.25 and loaded with a layer of fresh water with the permittivity of 77. Finally, the proposed antenna is fabricated and measured, which performs with a wideband reconfigurability and stable far-field performance corresponding to the different frequency responses.

3-D printed dual-band, dual-sense circularly polarized dielectric resonator antenna with a bandstop filtering response using planar via-free D-CRLH feeding network

A novel concept to design a dual-band, dual-sense circularly polarized (CP) antenna with a bandstop filtering response is presented by adopting an elaborate-designed irregular-shaped dielectric resonator (ISDR) and a dual-composite right/left-handed (D-CRLH)-based feeding network. First, the TEy111 and TEy113 modes of a rectangular DR (rDR) are simultaneously excited using an offset feeding slot, to realize the dual-band, linearly polarized (LP) operation in the x-direction. To eliminate the effects of the offset feeding on antenna performance, two types of edge-cuts and an impedance transformer are introduced. Secondly, another microstrip line and offset feeding slot are utilized to excite TEx111 and TEx113 modes of the DRA, obtaining dual-LP in two bands, and the corner truncation is introduced to reduce the cross-polarized field. Accordingly, a dual-band, dual-LP DRA with boresight radiation and low cross-polarization is achieved. After that, building on this design, a dual-band feeding network based on the D-CRLH resonator is employed to further implement the dual-sense CP operation. Finally, the ISDR is manufactured using 3-D printed technology for demonstration. The measured results show that the proposed antenna obtains a 3-dB axial ratio (AR) bandwidth of 9.3 % for the left-hand circular polarization (LHCP) at the lower band and 3.6 % for the right-hand circular polarization (RHCP) at the upper band. Moreover, the proposed antenna also features good suppression between two bands as the D-CRLH resonator offers a stopband filtering effect.

Design and analysis of a super compact UWB antenna for accurate detection of breast tumors using monostatic radar‐based microwave imaging technique

AbstractThis article proposes a low‐profile ultra‐wideband (UWB) antenna for breast tumor detection using the monostatic radar‐based microwave imaging (RBMI) technique. The proposed UWB antenna consists of a circular patch and ground plane along with a modified tapered feed line having a total size of 13 × 9 × 1.6 mm3. The designed antenna operates from 4 to 11 GHz based on a −10 dB reflection coefficient with a peak gain of 9.5 dBi at 4.8 GHz. Experimental validation is carried out after fabricating the prototype of the UWB antenna and the breast mimic. The measured backscattered signals are captured using the vector network analyzer (E‐5063A) by keeping the antenna at 10 mm from the breast phantom. After that, post‐processing of the measured data is done to detect the exact depth and location of the malignant tissue. The proposed antenna uses UWB band frequency of operation because it has some unique features, that is, it provides immunity to multipath fading, has a simple design, has a low cost of fabrication, and has biological friendliness. Moreover, due to the proposed antenna's resonance at a lower resonant frequency better depth of penetration is achieved in human body phantoms and the proposed antenna provides specific absorption rates (SAR) of 0.877 W/kg over 1 g of tissue at 4.8 GHz, which is an acceptable limit for SAR as per FCC guidelines. Therefore, the proposed antenna and monostatic RBMI technique are good candidates for breast tumor detection.

Plasmonic biosensor based on metal antenna on graphene for detection and counting of nanoparticles

Plasmons in graphene present desirable electronic properties and unique opportunities to enhance light–matter interactions and control light at nanoscale dimensions. The combination of graphene with metal nanostructures is promising for optical science and plasmonic manipulations. We propose a graphene plasmonic system based on a resonant metal antenna for detection and counting of nanoparticles. The performance of the proposed system relies on the intrinsic properties of particles, including the refractive index, which can be used to modulate the transmitted power. Simulations show that, by a small change in the refractive index of the particle, the transmitted output power changes significantly. A local change of ±10% in the refractive index of a 50-nm dielectric particle around the nanopore results in a ∓2.3% variation in the transmitted power corresponding to a sensor sensitivity of 415 nm/RIU. Small particles with a diameter of 20 ​nm can be detected using this configuration. The placement of a nanopore and nanoparticle in front of the metal antenna can change the spatial near-filed distribution of graphene plasmons and control their propagation wavefronts. Furthermore, the proposed structure with its small footprint can be readily integrated into lab-on-a-chip devices for practical biosensing applications. This plasmonic device is promising for use in single-particle detection and biological applications.

A novel wideband dielectric resonator antenna with compact size

ABSTRACT In this paper, a wideband dielectric resonator antenna with compact size is presented. The proposed antenna is formed by four dielectrics. Non-adjacent dielectrics have same permittivity constant. A 50-ohm micro strip feed line is used to exciting the antenna through the coupling slot. By optimizing the dimensions and structure of the antenna, impedance bandwidth of 3.25 to 4.4 GHz is obtained. Impedance bandwidth of the proposed antenna is a very wide bandwidth compared to the previous dielectric antennas. The antenna gain is about 9.6 dB.

Novel corrugated rectangular dielectric resonator antenna with wide half power beam width

ABSTRACT In this work, a dielectric resonator antenna element is corrugated in a specific way, which led to increase its half power beam width (HPBW). The HPBW of the antenna is investigated for different values of corrugation depth and it has been concluded that HPBW can be increased by increasing this depth. By embedding periodic grooves in the DRA walls, it is possible to adjust the radiation intensity ratio of the upper wall to the side walls. By increasing this ratio, the HPBW of the antenna can be increased. To confirm the concept of beam widening method, a prototype of the corrugated DRA is fabricated and measured. Measured results show an impedance bandwidth of 23% (3.8–4.8 GHz). The measured E- and H-plane HPBWs at 4.1 GHz are 137° and 123°, respectively. Measured and simulated results are in a good agreement.

Ultra wideband (UWB) dielectric resonator antenna using fractal‐inspired feeding mechanism

SummaryThis article examines a compact dielectric resonator antenna (DRA) for UWB applications. Here a composite feeding structure excites a dielectric resonator which in tern provides the resonant modes TE111, TE121, TE212, and TE222. The dielectric resonator (DR), built of alumina ceramic (εr, DR = 9.8), is mounted on a fractal triangular patch, inspired by Sierpinski Gasket. The suggested DRA is supported by a FR4 substrate (εr, sub = 4.4) and measures compactly 40 × 30 × 8.5 mm3. To confirm the results of its simulations, the proposed antenna's prototype is prepared and measured up to the second iteration. The measured outcome demonstrates that the suggested antenna has a frequency range of 3.38–10.71 GHz (104%) for S11 &lt; −10 dB and provides a maximum gain of 7.23 dBi at 8 GHz along with highest possible simulated efficiency of 98%. The suggested DRA is appropriate for small‐range future 4G/5G UWB wireless multimedia applications due to its ultrawide bandwidth, excellent gain, reasonable efficiency, omnidirectional radiation features, and compact construction. This DRA is also suitable for repeaters of mobile and vehicular communications.

DESIGN OF A UAV BLADE MONOPOLE WITH THE USE OF DIFFERENT RTADIATING ELEMENTS AND SIMULATION OF DRA ANTENNA

Because of its small size, light weight, and aerodynamic design that causes the least amount of drag blade monopole antennas are favored for usage in airborne applications. Consequently, their radiation patterns are unipolar and produce deep nulls in the upward direction. Such patterns will cause severe blind spots for the aircraft above and below this plane, which is undesirable for avionics networks. [1] To solve this problem, a dielectric resonator antenna (DRA) is attached to the blade antenna and thus a different design is formed. In this paper a rectangular DRA is used to illustrate the main idea.The antenna is housed inside the aerodynamically designed radome to reduce air drag (large dome-shaped structures which protect the radars from the bad weather conditions but at the same time allow the electromagnetic signals to be received by the radar without any distortion or attenuation). [11] An air core coil is also provided for DC grounding proposes. The antenna configuration is first optimized using HFSS based Ansys Electronics Desktop Student 2021 R2 simulation software and latter practically implemented. The comparison of simulated results is also presented in this paper.

A novel wideband cube resonator antenna with metasurfaces

AbstractA novel wideband cube resonator antenna (CRA) composed of metasurfaces is proposed in this letter, which can be applied to an active integrated antenna system. The resonant region of the CRA is formed by six metasurfaces of 4 × 4 arrays. The six surfaces can be equivalent to ideal electric walls. With the improved feeding slot, the dominant mode TE1δ1 and high‐order mode TE1δ3 are effectively excited, which enables a wideband and high gain performance for the CRA. A prototype of the antenna is fabricated and measured to verify the antenna design principle. The antenna has a measured impedance bandwidth of 17.0% (4.42–5.24 GHz) and a peak gain of 8.51 dBi, and good agreement between the simulated results and measured results is obtained. The proposed CRA shows resonant mode and radiation performance similar to those of traditional dielectric resonator antennas, which provides a new technique for the design of resonator cavity antennas.

Multipactor-Triggering Powers’ Modelling of a WEST ICRH Antenna During RF Conditioning

During radio frequency (RF) conditioning of the ion cyclotron resonance heating (ICRH) system on WEST, under vacuum, pressure rises are measured inside the antennas. A proposed hypothesis for the cause of this phenomenon is multipactor, an electron multiplication process taking place in RF devices under vacuum. Modelling multipactor conditions in a resonant antenna, i.e., under high standing wave (SW) ratio, requires particular precautions. This article proposes a methodology to determine the multipactor conditions in such a context. Using the proposed approach, the operational conditions, expressed as the generator’s RF powers, of the appearance of multipactor inside a WEST ICRH antenna during its RF conditioning under vacuum, are deduced. Calculations are performed for two different surface states: when the surface is baked but nonconditioned, and when it is baked and fully conditioned. For the nonconditioned surface state, it is shown that when only one side of the under-conditioning ICRH antenna is powered, the off-mode side is prone to multipactor when its capacitors are tuned. Detuning the capacitors on the off-mode side suppresses almost the multipactor on the nonpowered side for the frequency range of interest. Moreover, it is shown that the fully conditioned antenna surface state can suppress the appearance of multipactor in some regions of the antenna.

A Dual-Polarized Aperture-Sharing Phased-Array Antenna for 5G (3.5, 26) GHz Communication

Integrating the sub-6 GHz antenna and the millimeter-wave (mm-wave) antenna in one radiating aperture is a promising approach to support different frequency bands for the incoming communication system. In this paper, an mm-wave dual-polarized 64-element phased-array antenna is integrated into the partially reflective surface (PRS) of a sub-6 GHz resonant cavity antenna (RCA). The PRS consists of two multi-layer printed circuit boards (PCBs), which are stacked together and connected by solder joints. The thick PRS unit cell is designed with a miniaturized footprint at 3.5 GHz and can also contain a 2 × 2 mm-wave active subarray, including four stacked-patch antennas, a beamformer IC (BFIC), and some other input circuits. A copper plate is also inserted in the PRS for thermal control. A prototype antenna is fabricated and measured. Measurement results agree well with the simulation. In the sub-6 GHz band, the proposed antenna demonstrates dual-polarized radiation over the frequency band from 3.45 GHz to 3.58 GHz. In the high-frequency band, the dual-polarized mm-wave array driven by the built-in active beamforming network is capable of scanning ± 45° both in azimuth and elevation over the frequency band from 24.5 GHz to 27 GHz.

Compact Shared-Aperture Slot/DR Antenna With Large Frequency Ratio

A compact shared-aperture antenna with a large frequency ratio is proposed. It consists of a low-frequency (LF) slot antenna and a high-frequency (HF) dielectric resonator antenna (DRA). The LF slot antenna is etched in the ground and loaded by the HF DRA. It employs a low-permittivity substrate, thus giving a wide bandwidth. The HF DRA is excited by a dual-microstripline-fed slot. The operating frequencies of these two antenna parts can be tuned independently. A prototype is fabricated and measured to verify the simulation. It has a very compact electrical size of 0.27×0.08×0.03 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> , where λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the wavelength in air at the center frequency of the LF band. Its measured frequency ratio is 7.6, with reasonable agreement between the measured and simulated results.