Resonant label-free biosensors using silicon-on-insulator substrates represent a cutting-edge domain in optical sensing. These devices leverage the high refractive index contrast of ...silicon-on-insulator materials to create highly sensitive, compact sensors. They are crucial for real-time, precise biomolecular detection in healthcare diagnostics, environmental monitoring, and drug discovery, marking a significant stride in microphotonic technology and its practical applications. Different ring-based resonant configurations have been explored in this context, but a definitive comparative assessment of them was previously lacking in the literature. In our work, we experimentally compare four different ring configurations in terms of figure-of-merit, showing that the slotted ring performs better than competitive approaches. A silicon photonic chip including tens of ring resonators was fabricated and optically characterized considering air and aqueous solutions as cladding. The best sensitivity achieved was 64nm/RIU for the slotted ring configuration. The ring displayed a Q-factor in the order of 2.57 × 10 4 , and the best estimated resolution was in the order of 10 -4 RIU in water. The measured figure-of-merit was grater than 200RIU -1 .
A novel single-feed filtering dielectric resonator antenna (FDRA) with quasi-elliptic bandpass response is proposed in this brief. The proposed FDRA consists of a shunted slotline stepped-impedance ...resonator (SSIR), a rectangular dielectric resonator antenna (DRA) and a microstrip feedline with a pair of transverse arms. The antenna is excited in the fundamental TE<inline-formula> <tex-math notation="LaTeX">_{11\delta } </tex-math></inline-formula> mode, the transverse arm mode and the two SSIR modes. Moreover, three radiation nulls are produced near the edges of the passband by the SSIR and the transverse arm of microstip feedline, respectively. A prototype FDRA is fabricated and measured, which offers a bandwidth (<inline-formula> <tex-math notation="LaTeX">| S_{11} | < -10 </tex-math></inline-formula> dB) of 21.14% (3.13 - 3.87 GHz), and a peak realized gain of 5.3 dBi within passband. The realized gain shows a decline of 20 dB at passband-edge, which exhibits high selectivity.
Acoustic Wave Filter Technology-A Review Ruppel, Clemens C. W.
IEEE transactions on ultrasonics, ferroelectrics, and frequency control,
09/2017, Letnik:
64, Številka:
9
Journal Article
Recenzirano
Today, acoustic filters are the filter technology to meet the requirements with respect to performance dictated by the cellular phone standards and their form factor. Around two billion cellular ...phones are sold every year, and smart phones are of a very high percentage of approximately two-thirds. Smart phones require a very high number of filter functions ranging from the low double-digit range up to almost triple digit numbers in the near future. In the frequency range up to 1 GHz, surface acoustic wave (SAW) filters are almost exclusively employed, while in the higher frequency range, bulk acoustic wave (BAW) and SAW filters are competing for their shares. Prerequisites for the success of acoustic filters were the availability of high-quality substrates, advanced and highly reproducible fabrication technologies, optimum filter techniques, precise simulation software, and advanced design tools that allow the fast and efficient design according to customer specifications. This paper will try to focus on innovations leading to high volume applications of intermediate frequency (IF) and radio frequency (RF) acoustic filters, e.g., TV IF filters, IF filters for cellular phones, and SAW/BAW RF filters for the RF front-end of cellular phones.
A dual-functional reconfigurable filter is explored for the application in wideband and triple band pass filter. The wideband configuration is implemented by parallel combination of open stub loaded ...and short circuited stub loaded resonators to exhibit a passband from 2.0 GHz-6.1 GHz. Tight coupling generates transmission zeroes at the either side of passband, which enhances the selectivity. The proposed tri-band BPF offers passbands at 2.4 GHz, 3.5 GHz and 5.2 GHz where two-stepped impedance resonators (SIRs) and one uniform impedance resonator (UIR) are assembled to accomplish such behavior. The two short circuited stubs are connected to the feed line to extend the range of upper stopband. PIN diodes are effectively utilized to switch the operation from wideband to tri-band or vice versa. Detailed design guidelines are provided to design the proposed filter. The behavior of the proposed filter topology is investigated by even and odd mode analysis. The developed reconfigurable filter is fabricated and measured to verify the anticipated and simulated results. A close agreement is observed between them. The fabricated reconfigurable BPF has a very compact size, high selectivity, less insertion loss and good return loss profile.
In this paper, a novel complementary split-ring resonator (CSRR)-based sensor for full characterization of magneto-dielectric materials is proposed. In general, the operation of microwave ...resonance-based sensor hinges on the shift in the resonance frequency and the change in the quality factor of the loaded structure. However, both the electric permittivity and the magnetic permeability of the material under test (MUT) have similar effect on the response of the sensor that makes the simultaneous determination of the permittivity and permeability challenging. To remove this difficulty, the main idea behind this paper is to localize the highest intensity of the electric and magnetic fields in two separate zones. By the analysis of the measured resonance frequency and quality factor, the real and imaginary parts of the electric permittivity and the magnetic permeability of the MUT can be determined. Although the characterization of the permittivity and permeability of materials using split-ring resonator and CSRR-based sensors has been widely used, to the best of our knowledge, the full characterization of magneto-dielectric materials using a single sensor has not yet been reported in this paper. As a proof of concept, the sensor was fabricated and used to measure the permittivity and permeability of several materials. Strong agreement between the extracted values and the reference data was achieved.
This paper proposes a novel diplexer based on triple-mode dielectric-loaded cylindrical cavities. Such two metal cavities are designed to achieve two different frequency bands, while three resonant ...modes of a single cavity are classified as a TM mode and a pair of hybrid (HE) degeneration modes. An off-centered dielectric resonator instead of a traditional corner cuts perturbation or screws perturbation properly perturbs the two degenerate modes in the same cavity. Extensive study is then conducted to design this proposed diplexer. Finally, a diplexer prototype is fabricated using a brass cavity and it is tested for experimental verification of the predicted results. Good agreement between measurement and simulation is achieved.
In this communication, a four-port cylindrical pattern-diversity and polarization-diversity dielectric resonator antenna (DRA) for multiple-input multiple-output (MIMO) applications is presented for ...the first time. The design utilizes two degenerate <inline-formula> <tex-math notation="LaTeX">\mathrm {HEM}_{12 \delta + 1 } </tex-math></inline-formula> modes and two degenerate <inline-formula> <tex-math notation="LaTeX">\mathrm {HEM}_{21 \delta } </tex-math></inline-formula> modes of the cylindrical DRA, with unidirectional radiation and quasi-omnidirectional radiation, respectively. The resonant frequencies of four modes can be predicted by the radar cross section characteristic of an isolated DRA. By optimizing the dimension of DRA and loading technology, the <inline-formula> <tex-math notation="LaTeX">\mathrm {HEM}_{12 \delta + 1} </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">\mathrm {HEM}_{21 \delta } </tex-math></inline-formula> modes can operate in the same band. The <inline-formula> <tex-math notation="LaTeX">\mathrm {HEM}_{12 \delta + 1} </tex-math></inline-formula> modes are effectively excited by two polarization orthogonal slot pairs while two coaxial probes are utilized for exciting the <inline-formula> <tex-math notation="LaTeX">\mathrm {HEM}_{21 \delta } </tex-math></inline-formula> modes. The power divider with tapered end is presented to expand bandwidth of <inline-formula> <tex-math notation="LaTeX">\mathrm {HEM}_{21 \delta } </tex-math></inline-formula> modes. In addition, the method based on mode orthogonal to utilize two degenerate <inline-formula> <tex-math notation="LaTeX">\mathrm {HEM}_{21 \delta } </tex-math></inline-formula> modes with high isolation is proposed. To verify design, a four-port diversity DRA operating at 2.4 GHz band (2.4-2.48 GHz) was simulated, fabricated, and measured. The S parameters and radiation characteristics were measured and discussed. Moreover, the calculated indoor communication performance including the envelop correlation coefficient (ECC), mean effective gain (MEG), and channel capacity as the proposed four-port DRA used for MIMO element are given and discussed.
A novel method to design substrate integrated waveguide (SIW) filters with odd-order response is presented in this letter. By combining SIW and stripline technologies, a fully closed, third-order ...filter consisting of two SIW resonators and one stripline resonator is proposed. The stripline resonator provides a coupling path for the TE 101 mode to form a passband, while the couplings for TE 102 and TE 201 modes are very weak, resulting in the suppression of their propagation. The principle for higher order mode suppression is carefully illustrated. On the basis of this filter, another two filters are designed by introducing different cross couplings, which generate extra transmission zeros (TZs) to enhance the selectivity. These two filters exhibit flexible response with controllable TZs. All these three filters are fabricated and measured. The measured results are in good agreement with the simulation, which validates the proposed design methodology and the idea of incorporating the stripline resonator into the SIW. They demonstrate a low insertion loss, high selectivity, and wide stopband. In addition, the proposed filters are featured by a reduced size due to the applications of the double-layer structure and miniaturized stripline resonators.
For the first time, a hollow coaxial cable Fabry-Perot resonator (FPR)-based liquid-level sensor with centimeter dynamic range and micrometer resolution is proposed and demonstrated. The hollow ...coaxial cable, as the novel sensing platform, is homemade, in which air replaces the traditional dielectric layer. The FPR consists of two highly reflective reflectors, i.e., an artificial cylindrical steel bar and the air-liquid interface. The liquid level is directly transferred to the cavity length of the FPR, and the cavity length can be calculated by the resonant frequency/wavelength of the resonator. The experimental results show that our prototype liquid-level sensor has a sensitivity of 0.51 mm/mm (resonant wavelength change/liquid level) over a dynamic range of around 200 mm. The temperature dependence was also investigated. The novel liquid-level sensor, with high robustness, ease of fabrication, cost effective, wide dynamic range, and high resolution, is expected to have high potential applications in chemical industry, fuel storage, and water-level monitoring.
This article focuses on the comparison of quarter-wavelength and open-end half-wavelength four-section coaxial stepped impedance resonators (SIRs) for the design of Tx bandpass filters with high ...multipactor thresholds. To obtain a half-wavelength configuration with open ends in an enclosed space, the coaxial sections are stacked on two levels. Despite the strong geometrical difference between the two structures, the same analytical formalism can be used to model their frequency behavior. The synthesis equations show that the first three frequencies (fundamental, first transmission zero, and second harmonic) are independent, making the three impedance ratios between two adjacent coaxial sections, very practical degrees of freedom. They impact sensitivity to technological variations in manufacture and misalignments, power handling, and quality factors. Moreover, the two-level topology makes it possible to obtain another shape factor, and thus, push back size and performance limitations. A comparison was made of the values of the quality factor, obtained with eigenmode and a numerical method. To compare the two configurations, we designed a quarter-and a half-wavelength four-section fourth-order filter in the <inline-formula> <tex-math notation="LaTeX">L</tex-math> </inline-formula>-band. These two four-section filters were also compared with their two-and three-section quarter-wavelength counterparts in terms of electrical performances, bulk, and multipactor threshold. Finally, a comparison with the state-of-the-art is given.
