Triangular Resonator Research Articles

Optical axis maladjustment sensitivity in a triangular ring resonator.

This paper estimates and measures the influences of mismatch and misalignment on continuous-wave cavity ring-down spectroscopy. We describe the theoretical differences in maladjustment effects on power transfer under different resonant cavity configurations and present a method for reducing the impact of maladjustment. Finally, we demonstrate a method for measuring the effect of maladjustment on power transfer when a Gaussian beam is matched to a triangular ring resonator.

Ultra-broadband multilayer absorber with the lumped resistors and solid-state plasma

Abstract In this paper, an ultra-broadband multilayer tunable absorber (MTA) with the lumped resistors (LRs) is proposed, where a dielectric layer is sandwiched between three split square ring resonators and a continuous metallic plane. It is noted that two truncated triangular ring-shaped and Y-shaped solid-state plasma resonators (SSPRs) are embedded in the substrate. Three solid-state plasma cylinders are also inserted between the truncated triangular ring-shaped resonators and Y-shaped SSPRs. External two split square rings and a truncated triangular ring are loaded with the lumped elements. After calculation, for the TE wave, the absorption rate is larger than 90% in a certain frequency region which covers 7–16.25 GHz. Moreover, the proposed MTA is polarization independent at normal incidence. The absorption mechanism and properties also are investigated. The obtained results illustrate that the absorption performance and operating frequencies can be tailored when the different SSPRs are excited.

A novel wideband Minkowski fractal antenna with assistance of triangular dielectric resonator elements

This article concentrates on the design and analysis of a novel Minkowski fractal-based antenna design with the aid of triangular dielectric resonator (TDR) elements for wideband wireless applications. mode is excited inside equilateral TDR antenna with the help of coaxial probe feed. Wide impedance bandwidth has been achieved by reducing the quality factor with the help of increasing surface area-to-volume ratio of radiating structure. Another important feature of this article is that recurrence formulas are derived to calculate the fraction of surface area to volume of proposed fractal antenna up to nth iteration. The proposed antenna design is fabricated and measured up to third iteration to verify its simulated outcomes. Practically measured outcome confirms that the proposed antenna design operates over the frequency range, that is, 2.23-3.1 GHz with the maximum gain of 3.62 dBi. These features make it appropriate for wireless LAN (2.4 GHz) and WiMAX (2.5 GHz) applications.

Equilateral triangular dielectric resonator based co‐radiator MIMO antennas with dual‐polarisation

In this study, two types of dielectric resonator antennas (DRAs) with dual-polarisation are proposed and investigated for multiple-input multiple-output (MIMO) applications. The first design is a dual-slant polarised DRA and exhibits the measured impedance bandwidth of 8.2% (5.27–5.72 GHz) and 11.2% (5.05–5.65 GHz) for Port1 and Port2, respectively. Across the operating frequency band, the isolation between the input ports is better than 22 dB and the measured gain of the antenna varies in the range of 5.99–6.38 dBi. The second design developed here is a dual-linearly polarised DRA which is able to provide horizontal and vertical polarisations and is realised by integrating a two-stage rat-race coupler with the DRA for excitation purpose. In this case, the measured impedance bandwidths are 11.81% (5.18–5.83 GHz) and 15.18% (4.93–5.74 GHz) for Port1 and Port2, respectively, and the inter-port isolation is better than 20 dB throughout the operating frequency band. The antenna exhibits the measured gain variation of 5.94–6.48 dBi for Port1 and 5.54–5.86 dBi for Port2. Furthermore, for both the antennas, the envelope correlation coefficient is below 0.0004 throughout the bandwidth and the total active reflection coefficient is better than −10 dB, confirming the good diversity and radiation performance.

A Band Enhanced Plasma Metamaterial Absorber Based on Triangular Ring-Shaped Resonators

In this paper, a novel way is proposed to realize a broadband absorber, which is based on the plasma metamaterial with the triangular ring-shaped resonators. Each unit cell of the proposed absorber includes three layers, which are metal layer, dielectric layer, and solid-state plasma (SSP) layer, respectively. The top layer is composed of the truncated SSP triangular ring-shaped resonators and the SSP triangular patches, which are situated the middle of triangular rings. An SSP cylinder also is inserted between the central of each SSP triangular patch and the bottom metal layer. The absorption bandwidth can be covered from 11.76 to 14.43 GHz when the absorption rate is larger than 90%, which also is polarization-independent. In addition, the better performances can be realized under different incident angles. To explain the mechanism of high absorption, the electric field, the surface current distribution, and power loss density at different resonant frequencies are present. Moreover, the tunable absorption can be obtained in the proposed absorber while the performance of the absorber can be improved by exciting the different SSP resonators.

45°–45°–90° Triangular dielectric resonator antenna with broadside radiation patterns

Theoretical and experimental investigations on isosceles 45°–45°–90° Triangular Dielectric Resonator Antenna (TDRA) is presented here for TMmnpz modes. Approximate expression is given here to predict the resonant frequency for different TMmnpz modes with an accuracy of 2.3%. It is found that isosceles 45°–45°–90° TDRA radiates in the broadside direction at fundamental TM101z mode. One prototype is also fabricated to validate our theory. It is also found that the fundamental TM101z mode produces slanted polarization. The study of 45°–45°–90° TDRA is important as it just takes approximately half volume compared to square Dielectric Resonator Antenna (DRA) for a given resonant frequency. Our theory can easily be extended to design filter, oscillator etc.

Four-Element Composite Triangular Dielectric Resonator Antenna Using Li2O-1.94MgO-0.02Al2O3-P2O5 Ceramic for Wideband Applications

A simulation and fabrication study of a coaxial probe-fed four-element composite triangular dielectric resonator antenna (TDRA) using low loss Li2O-1.94MgO-0.02Al2O3-P2O5 (LMAP) ceramic and Teflon. LMAP ceramic was carried out and the ceramic was synthesized using a solid-state sintering route. The phase, microstructure and microwave dielectric properties of LMAP were investigated using x-ray diffraction pattern, scanning electron microscopy and a network analyzer. A coaxial probe-fed four-element composite TDRA was designed and fabricated using LMAP as one section of each composite element of the proposed antenna. Each triangular element of the proposed dielectric resonator antenna (DRA) consists of two sections of different dielectric constant materials. The inner triangular section touching the coaxial probe at one of its corners is made of the LMAP ceramic (er = 6.2) while othe uter section is made of Teflon (er = 2.1). Four triangular DRA elements are excited bya centrally located 50-Ω coaxial probe. The parametric study of the proposed antenna was performed through simulation using Ansys High Frequency Structure Simulator software by varying the dimensions and dielectric constants of both sections of each triangular element of the TDRA to optimize the results for obtaining a wideband antenna. The simulated resonant frequency of 9.30 GHz with a percentage bandwidth of 61.65% for the proposed antenna is obtained within its operating frequency range of 7.82–14.8 GHz. Monopole-like radiation patterns with low cross-polarization levels and a peak gain of 5.63 dB are obtained for the proposed antenna through simulation. The antenna prototype having optimized dimensions has also been fabricated. The experimental resonant frequency of 9.10 GHz with a percentage bandwidth of 66.09% is obtained within its operating frequency range of 7.70–15.30 GHz. It is found that the simulation results for the proposed antenna are in close agreement with the measured data. The proposed antenna can potentially be used in broadcast base stations, radar and satellite communications.

A comparative study on different types of metamaterials for enhancement of microstrip patch antenna directivity at the Ku-band (12 GHz)

This paper proposes improving the directivity of microstrip patch antennas (MPAs) by using metamaterials. Four different metamaterial types are used as a flat lens in front of the MPA, respectively, which are tuned to 12 GHz (Ku-band) resonance frequency. Thus, it can be decided which metamaterial is more proper for antenna directivity enhancement at this band. One additional new metamaterial structure is proposed in this paper, which is called a Euro-shaped resonator, and other metamaterials used are the triangular split ring resonator, symmetrical ring structure, and split ring resonator. The permeability and permittivity of metamaterials are extracted from the S parameters by using a robust method. Microwave Studio by Computer Simulation Technology is used for modeling and simulation. The MPA and metamaterials are fabricated, and measurements are performed in the Y{\i}ld{\i}z Technical University RF and Microwave Laboratory. It is observed that measured results are in close agreement with the computer simulations.

Compact and high isolated triangular split‐ring diplexer

A compact microstrip diplexer using triangular split-ring resonator bandpass filters with separated electric and magnetic coupling (SEMC) has been presented. The transmission zeros are attributed to the SEMC without requiring more resonators and can be controlled by the electric and magnetic couplings. The diplexer is fabricated, and the design has been demonstrated by measurement. The diplexer has a compact size of 0.264λ 0 × 0.102λ 0, and a measured isolation of no less than 38 dB.

Approximate Theoretical Investigations on Isosceles Triangular Dielectric Resonator Antennas and Experimental Validation

Theoretical and experimental investigations on isosceles $\theta _{i}-\theta _{i}-\varphi _{i}$ triangular dielectric resonator antennas (TDRAs) are presented here for TM mode for the first time. Trilinear transformation is slightly modified to obtain the approximate solutions for eigenfunction and eigenvalue. Limitations of the theory are discussed. Closed form expression is given here to predict the resonant frequency with a maximum error of 4%. It is found that isosceles TDRA produces a peak in the broadside direction at fundamental $\text{TM}_{101}^{ {z}}$ and higher order $\text{TM}_{103}^{ {z}}$ modes. Three isosceles TDRAs having $\theta _{i}= 60^{\circ }$ , 70°, and 75° are fabricated $\vphantom {^{\int }}$ for experimental validation.

Design of wideband LTCCBPF with notch band exploiting one‐third isosceles triangular resonator

AbstractThe design of a novel multilayer wideband bandpass filter with one notch band is presented in this letter. The proposed filter structure is composed of one‐third isosceles triangular substrate integrated waveguide (SIW) cavities and the coupled striplines. The SIW cavities structure generates multiple resonant modes which are used to realize the wideband bandpass filter. Owing to the low temperature co‐fired ceramic technology, the stripline and the SIW cavity are printed on multilayer ceramic, which makes the filter compact. The filter have a compact volume of 6.0 × 8.0 × 0.4 mm3. The measured results exhibit the bandpass filter achieves a center frequency of 15 GHz with a 3 dB fractional bandwidth of 33.33% and more than 15 dB attenuation at skirt band. The width of the notch band was about 600 MHz centered at 15.5 GHz. The measured results of fabricated filter are in close agreement with the simulated ones.

A Triangular Complementary Split Ring Resonator Based Compact Metamaterial Antenna for Multiband Operation

In this paper, a triangular complementary split ring resonator (TCSRR) based compact metamaterial antenna for multiband operation is presented. TCSRR is used to achieve a compact antenna structure. The proposed antenna consists of a trapezoidal radiating patch with partial ground plane and loaded TCSRR. The trapezoidal radiating patch is responsible for lower and higher frequencies, wherein the two inner resonance frequencies are obtained by loading TCSRR structure. The negative permittivity characteristics of the TCSRR structure are demonstrated through waveguide setup method. The proposed antenna with compact size of 25 × 25 × 1.6 mm3 is developed and tested. The measured and simulated results are good in agreement with each other and it covers 2.4/5.2 GHz (WLAN), 2.5 GHz (WiMAX), 7.4 GHz (X-band downlink) and 8.2 GHz (ITU band) simultaneously. The proposed antenna design has good radiation pattern for both E-plane and H-plane in all the desired frequencies.

A method to improve phase noise of oscillator based on triangular SIW resonators

AbstractIn this letter, a double cavity high‐mode substrate integrated resonator (DMSIR) is proposed to design a low phase noise X‐band oscillator. The proposed DMSIR is realized by 2 equilateral triangular substrate integrated waveguide (SIW) cavities, and each triangular SIW cavity operates in high‐order mode. The weak coupling in the high‐order mode of the 2 cavities is performed to improve load Q value and reduce phase noise. To validate this method, the oscillators based on the single cavity high‐mode substrate integrated resonator and fundamental mode substrate integrated resonator are designed and implemented, respectively. Measured results show that, the oscillator based on the DMSIR exhibits the lowest phase noise of −143.1 dBc/Hz @ 1 MHz from oscillation frequency of 10.059 GHz, and the figure of merit is −207.5 dBc/Hz.

Circularly Polarized Dual Facet Spiral Fed Compact Triangular Dielectric Resonator Antenna for Sensing Applications

In this article, a dual band circularly polarized compact equilateral triangular dielectric resonator antenna (TDRA) is proposed and validated experimentally for microwave sensing applications. An innovative coupling based on dual facet spiral loop is used to bring down the axial ratio <3dB. It basically creates the phase excitation on two side walls of the TDRA to ensure circular polarization near 7.5 and 8.7 GHz. In addition to this, the TDRA confirms dual impedance band over (7.327.68) GHz and (8.349.44) GHz. The demonstration shows good matching between the simulated and measured results. This model can be a suitable candidate for high-sensitive sensing applications.

A 2.4/3.5/5.2/5.8‐GHz quad‐band BPF using SLRs and triangular loop resonators

A modified triangular loop resonator with an open-circuited stepped-impedance stub, which can generate two closely spaced passbands at 5.2 and 5.8 GHz, is analysed. For verification, the triangular loop resonators along with stub-loaded resonators (SLRs) are then employed to design a compact 2.4/3.5/5.2/5.8-GHz quad-band bandpass filter (BPF) for wireless local area networks as well as worldwide interoperability for microwave access applications. Each of the four centre frequencies in the proposed quad-band BPF is able to be controlled due to the design freedom.

A Multifunctional Antenna with a Small Form Factor: Designing a Novel Series-Fed Compact Triangular Microstrip Ring Resonator Antenna Array

This article examines a noval series-fed triangular microstrip ring resonator (TMRR) antenna array. Each radiating element is made up of a wavelength-long microstrip line with the two ends joined together to form an isosceles triangle. The antenna array is fed by an N-shaped microstrip feed line and excited by a coaxial feed probe. The operational mechanism of the proposed feed system in terms of its electrodynamics is examined with respect to its relative size occupancy, dispersion along the feed line, and the feed effect on the spatial orientation of the propagated radio waves. The size occupancy of the antenna array is 45 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> × 60 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> with a measured reflection coefficient S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> of -27.5 dB at a resonant frequency of 5.76 GHz. The simulated S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> is -29.2 dB at a resonant frequency of 5.8 GHz. The measured gain is roughly 10.46 dBi using the absolute gain method. The resulting antenna array is compact in size and exhibits reasonable performance in terms of gain, reflection coefficient, low mass/volume, and weight.

Multiple Fano-Like MIM Plasmonic Structure Based on Triangular Resonator for Refractive Index Sensing.

In this paper, we present a Fano metal-insulator-metal (MIM) structure based on an isosceles triangular cavity resonator for refractive index sensing applications. Due to the specific feeding scheme and asymmetry introduced in the triangular cavity, the resonator exhibits four sharp Fano-like resonances. The behavior of the structure is analyzed in detail and its sensing capabilities demonstrated through the responses for various refractive indices. The results show that the sensor has very good sensitivity and maximal figure of merit (FOM) value of 3.2 × 105. In comparison to other similar sensors, the proposed one has comparable sensitivity and significantly higher FOM, which clearly demonstrates its high sensing potential.

A New Balanced Bandpass Filter With Improved Performance on Right-Angled Isosceles Triangular Patch Resonator

A new approach for the design of a balanced bandpass filter (BPF) is presented in this paper. Stemming from the mode degeneration properties of a square patch resonator, a complete set of resonant modes in a right-angled isosceles triangular patch resonator (RAITPR) is thoroughly investigated so as to construct a modified RAITPR with one electric wall and two magnetic walls along its three sides for filter design. This proposed resonator can support the half-TM10-mode of the RAITPR, and thus, it is named as the half-mode RAITPR here. By properly adopting the relationship between one RAITPR and two coupled half-mode RAITPRs, a second-order coupling topology is presented. Its working principle is then explained by using the field distribution of the desired resonant modes involved. A few high-order balanced filters are in final implemented and fabricated to evidently demonstrate their good differential-mode filtering selectivity and high common-mode suppression. Good agreement is achieved between the simulated and measured results for all the designed three balanced BPFs. To further improve the concerned out-of-band rejection performance, the feeding scheme of the modified structure has been discussed.

Analysis and Experiment of Equilateral Triangular Uniaxial-Anisotropic Dielectric Resonator Antennas

The design procedure of a uniaxial anisotropic equilateral triangular dielectric resonator antenna (ETDRA) is presented for the first time. The uniaxial material is realized by a periodic stack of sheets of two dissimilar materials with different dielectric constants. It is proven that the increase of the boresight gain and impedance bandwidth of the ETDRA is possible by using the uniaxial material for the antenna prism. The gain improvement is due to the increase in the sidewall radiations and the bandwidth enhancement is owing to the lowering of the effective permittivity of the structure. The fabricated anisotropic ETDRA offers an impedance bandwidth of 27.7% between 3.025 and 4 GHz with a measured gain above 8 dB. The simulation results agree well with the experimental ones.

Compact differential bandpass filter using one-sixth mode and novel one-third mode triangular SIW resonators

Compact differential bandpass filter using one-sixth mode and novel one-third mode triangular SIW resonators