Microstrip Cavity Research Articles

Electromagnetic modulating action in a microstrip cavity with embedded two detuned resonators

We present a novel approach for actively controlling electromagnetically induced transparency (EIT) analogs in a single-mode microstrip cavity. This cavity is side-coupled with a pair of varactor-loaded split-ring resonators (SRRs). The EIT-like effect is achieved through resonance hybridization between the paired SRRs with frequency detuning. The microstrip cavity is utilized to enhance the EIT-like transmission properties, including Q-factor and group delay. Varactor diodes, soldered at the gap of the SRRs, are biased electrically through a DC voltage source. This dynamic modulation setup allows for the tuning of the enhanced EIT analog. Experimental results demonstrate that the enhanced EIT-like transmission spectrum can be tuned reversibly by 378 MHz with respect to the transmission dip frequency of 2.464 GHz under the bias voltage ranging from 0 to 5 V. Simultaneously, the controlled transmission spectrum enables a remarkable change in group delay of 10.9 ns. Moreover, the modulation amplitude of the composite SRRs-cavity structure reaches a peak value of up to 34.5 dB, significantly higher than the 6.4 dB of the individual SRRs pair. These results hold promise for inspiring innovation in actively controlled photonic devices for practical applications.

Active control of Fano resonance in side-coupled resonator-cavity systems

The study delves into actively controlling Fano resonance within a single-mode microstrip cavity, coupled with a split ring resonator (SRR) incorporating a varactor diode. This resonance arises from the interference between the SRR and a Fabry–Pérot cavity, resulting in a sharply asymmetric transmission spectrum. The varactor diode, situated within the SRR gap, is biased electrically via an external DC voltage source. Through manipulation of this bias voltage, both the transmission frequency and amplitude of the pronounced Fano resonance can be dynamically adjusted. Notably, a significant frequency shift of 345 MHz is achieved, accompanied by a transmission modulation depth of up to 34.2 dB. Moreover, at the Fano peak frequency of 2.65 GHz, the composite SRR-cavity structure exhibits a notable change in group delay, shifting by 21.3 ns with the bias voltage varying from 5 V to 2.6 V. These findings hold promise for the development of electrically controlled functional photonic devices, facilitating their adaptability and versatility in practical applications.

Electrical Characterization and Analysis of Single Cells and Related Applications.

Biological parameters extracted from electrical signals from various body parts have been used for many years to analyze the human body and its behavior. In addition, electrical signals from cancer cell lines, normal cells, and viruses, among others, have been widely used for the detection of various diseases. Single-cell parameters such as cell and cytoplasmic conductivity, relaxation frequency, and membrane capacitance are important. There are many techniques available to characterize biomaterials, such as nanotechnology, microstrip cavity resonance measurement, etc. This article reviews single-cell isolation and sorting techniques, such as the micropipette separation method, separation and sorting system (dual electrophoretic array system), DEPArray sorting system (dielectrophoretic array system), cell selector sorting system, and microfluidic and valve devices, and discusses their respective advantages and disadvantages. Furthermore, it summarizes common single-cell electrical manipulations, such as single-cell amperometry (SCA), electrical impedance sensing (EIS), impedance flow cytometry (IFC), cell-based electrical impedance (CEI), microelectromechanical systems (MEMS), and integrated microelectrode array (IMA). The article also enumerates the application and significance of single-cell electrochemical analysis from the perspectives of CTC liquid biopsy, recombinant adenovirus, tumor cells like lung cancer DTCs (LC-DTCs), and single-cell metabolomics analysis. The paper concludes with a discussion of the current limitations faced by single-cell analysis techniques along with future directions and potential application scenarios.

Design of a Miniatured, Electromagnetic Quasi-Yagi Antenna with Circularly Polarized Characteristics

A novel low-profile circularly polarized (CP) quasi-Yagi antenna with a wide 3-dB axial ratio (AR) bandwidth is proposed, which generates the endfire beam by combining magnetic microstrip cavity and folded electric dipoles with a 90∘ phase difference. The proposed antenna includes two shorting pins, which are employed to attain wider impedance bandwidth. Then, a phase delay line is added to connects two pairs of folded dipoles and a magnetic microstrip cavity to realize righthanded circularly polarized (RHCP). After optimization, a prototype with an overall size of 1.17×0.91× 0.0387λ30 is designed. Simulated results demonstrate that the final model has 18.1% (5.01-6.01 GHz) 3-dB AR bandwidth and −10dB impedance bandwidth of 5.2%(5.67−5.97GHz), respectively. In addition, experimental results demonstrate that the designed antenna is very applicable to the RFID system.

Near‐field sensor based on substrate integrated waveguide microstrip cavity resonator with a circular aperture

A near-field planar sensor fabricated from a substrate integrated waveguide (SIW) cavity resonator is presented. The SIW cavity resonator is a modification of a rectangular microstrip antenna. The rectangular microstrip antenna radiates from two radiating edges that produce far-field radiation, which is undesired for near-field sensing. To suppress the radiation from the edges, the microstrip antenna is modified to have conducting vias that short all four edges of the patch to the ground plane. A circular hole is placed on the patch surface in the middle of the patch to form a sensing aperture. The field is thus confined inside the cavity with leakage only allowed through a small aperture, which is used for sensing surrounding objects in the vicinity of the aperture. This cavity resonator operates in the TM21 mode of the SIW cavity. Full-wave simulations are performed and the results are consistent with the theoretical analysis as well as CAD formulas that are derived. The performance of the sensor as a near-field sensing device and as a near-field imager is explored.

Broadband and switchable fast–slow light in the YIG-microstrip cavity system

We experimentally study the fast–slow light induced by multiple-path microwave interference in the yttrium iron garnet (YIG)-microstrip cavity system. The destructive interference between two types of paths, the direct path through the traveling wave and the indirect paths through the magnon and the resonator, leads to a nearly blocking of microwave transmission when the magnon mode resonates at a particular frequency. This phenomenon is accompanied by a dramatic evolution to the phase of microwave transmission, which strongly adjusts the group velocity of light. Tuning the magnon mode crossing the particular frequency by controlling the external magnetic field, the polarity of phase evolution will be reversed, which presents as a switch between phase delay (slow-light) and phase advance (fast-light). And we experimentally achieve the broadband fast–slow light by tuning the external damping of the magnon. Furthermore, we predict the broadband fast–slow light in different physical parameters. Our results demonstrate that the destructive interference in the YIG-microstrip cavity system is a way to manipulate fast–slow light, which has a great significance in quantum information processing and storage.

Interference induced microwave transmission in the YIG-microstrip cavity system

We reveal the multiple-path microwave interference induced microwave transmission in a cavity-magnonic system composed of a yttrium-iron-garnet (YIG) film and a microstrip cavity circuit. By changing the position of the YIG in the circuit, we identify that the magnon in YIG is driven by the standing microwave from the cavity or by the traveling wave through the microstrip. We observe that the microwave transmission spectra show an anti-crossing dispersion named mode repulsion and an anomalous dispersion named mode attraction, respectively. The characteristic of anti-cross dispersion spectra is theoretically predicted using the coupling between the magnon and the cavity. Without coupling, the anomalous dispersion in our experiment is well interpreted by the multiple-path microwave interference between the indirect paths through the cavity and the magnon and the direct path through the traveling wave. And the anomalous dispersion is caused by the redistribution of the microwave transmission intensity. We also find the phases of the magnon in two cases changes π, which can be the key physical factor to understand the change of microwave transmission characteristics. Our work highlights the role played by the multiple-path microwave interference in magnonic microwave devices, which will be an important issue in designing microwave circuits based on the magnon.

A Novel Combined Microstrip Resonator/Nanospray Ionization Source for Microwave-Assisted Trypsin Digestion of Proteins.

Enzymatic digestion of proteins is a critical step in bottom-up and middle-down proteomics. Here, we demonstrate a method for decreasing the time required for proteolytic digestion of proteins from multiple hours to minutes by using an in-line microstrip cavity for programmed microwave heating. When a nanospray emitter tip, containing a digestion sample, is exposed to a region of highly focused microwave field, the rate of proteolytic digestion is enhanced and the time required for digestion greatly decreased. The design is advantageous for mass spectrometry because the solution-based digestion can then be directly sprayed from a nanoelectrospray tip emitter, decreasing sample transfer loss and allowing the system to be used in a flow-through proteolytic workflow. Microwave-assisted digestion using this method is evaluated against standard overnight digestion protocols using a variety of proteins, evaluating sequence coverage and observed peptide location, digestion rate, and overall efficacy. The influence of applied microwave power is investigated, and enzymatic kinetic parameters are evaluated to estimate temperature within the microreactor. Finally, the modulation of the proteolytic digestion of proteins based upon the modulation of applied microwave power is demonstrated on a time scale of seconds in a flow-through system.

Compact Power Divider Integrated with Coupler and Microstrip Cavity Filter for X-band Surveillance Radar System

This paper present the compact power divider integrated with coupler and microstrip cavity filter for x-band surveillance radar system. These modules consist of several devices (splitter, filter and coupler) it is integrated in a single module aims to reduce the loss in the joint connectors. The bandpass filter is use microstrip cavity filter for operating on X-Band Frequency and deployed on RT/duroid 5880. The power divider and coupler is designed using quarter wavelength transformer. A theoretical analytical circuit model will be presented, from the theoretical model, a compact integrated module will be designed and simulated. The proposed compact integrated module is small in dimension and performs a compact size. The compact integrated devices design on X-Band frequency is simulated and the result is presented.

A Microstrip Probe Based on Electromagnetic Energy Tunneling for Extremely Small and Arbitrarily Shaped Dielectric Samples

An energy-tunneling sensor is fabricated by joining two air-suspended short-circuited microstrip cavities with a common ground interconnected by a half-wavelength wire. Due to tunneling, highly concentrated fields are created at the tip of the wire. In this letter, we propose to exploit these concentrated fields to detect the presence of extremely small and arbitrary shaped samples and their dielectric properties. The simulation and measurement results show respective frequency shifts of 60 and 80 MHz in the tunneling frequency when 2 ×2 ×1.6 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> samples of FR4 and Rogers 6006 materials are placed on the wire tip. This kind of energy tunneling probe can bring a special advantage in the area of biomedical and forensic analysis where, usually the samples are small in size with no defined shape.

Detailed modelling of the susceptibility of a thermally populated, strongly driven circuit-QED system

We present measurements and modelling of the susceptibility of a 2D microstrip cavity coupled to a driven transmon qubit. We are able to fit the response of the cavity to a weak probe signal with high accuracy in the strong coupling, low detuning, i.e., non-dispersive, limit over a wide bandwidth. The observed spectrum is rich in multi-photon processes for the doubly dressed transmon. These features are well explained by including the higher transmon levels in the driven Jaynes–Cummings model and solving the full master equation to calculate the susceptibility of the cavity.

COMPACT HALF-MODE SUBSTRATE INTEGRATED WAVEGUIDE (HMSIW) FILTER WITH DUAL-MODE MICROSTRIP RESONATOR

Abstract—A novel fourth-order half-mode substrate integrated waveguide (HMSIW) filter with dual-mode microstrip resonator is presented. The dual-mode resonator is etched on the top metal layer of HMSIW cavity, so the size can be reduced greatly. The filter has compact size and wide stopband in comparison with conventional SIW filters. Microstrip resonators and cavity resonators are integrated in one filter to achieve the goal of smaller size and better performance. Two filter samples are designed and fabricated, with good agreement between the measured and the simulated S-parameters.

Application of microstrip cavity couplers for wideband bandpass filters

AbstractThis article presents a design for wideband bandpass filters using a microstrip cavity coupler. The broadband nature of the cavity‐coupled designs is fully exploited for this application. Two additional circuits are introduced to improve the stopband performance of the cavity‐coupled bandpass filter. A prototype design example is presented with its center frequency located at 6.28 GHz. The design has the merits of wide bandwith of more than 140%, flat group delay within the passband, good insertion/return loss, and stopband attenuation of nearly 30 dB up to 30 GHz. The validity of the simulation results is verified experimentally. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2814–2817, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26410

Magnetization pinning in conducting films demonstrated using broadband ferromagnetic resonance

The broadband microstrip ferromagnetic resonance (FMR), cavity FMR, and Brillouin light scattering spectroscopy techniques have been applied for detection and characterization of a magnetic inhomogeneity in a film sample. In the case of a 100 nm thick permalloy film, an additional magnetically depleted top sublayer has been detected due to pinning effect it produces on the magnetization in the bulk of the film. The pinning results in appearance of an exchange standing spin wave mode in the broadband FMR absorption spectrum, whose amplitudes are different depending on whether the film or the film substrate faces the microstrip transducer. Comparison of the experimental amplitudes for this mode with results of our theory for both film placements revealed that the depleted layer is located at the film surface facing away from the film substrate. Subsequent broadband FMR characterization of a large number of other presumably single-layer films with thicknesses in the range 30–100 nm showed the same result.

Offset-fed metamaterial antenna for radiation mode generation with efficiency improvement

In this paper, a new offset-fed metamaterial antenna based on a slot-loaded composite right/left-handed transmission line is proposed. Two antennas, namely a centre-fed metamaterial antenna and an offset-fed one, have been investigated. The offset-fed metamaterial antenna generates additional resonant modes with endfire radiation like a patch antenna, whereas the centre-fed one produces only broadside radiation like a monopole antenna. The one-dimensional equivalent circuit model is applied to analyse the slot-loaded structure and the two-dimensional microstrip cavity model is employed for the offset-fed structure. The measured results are in good agreement with the theoretical analysis, especially in radiation pattern and radiation efficiency. The radiation efficiency is pronouncedly enhanced up to 27.6% at the zeroth-order resonant mode and to 56.8% at the additionally generated mode (quasi-TM010) because of the slot effect on the ground plane.

Microstrip resonator for microwaves with controllable polarization

In this work, the authors implemented a resonator based on microstrip cavities that permit the generation of microwaves with arbitrary polarization. Design, simulation, and implementation of the resonators were performed using standard printed circuit boards. The electric field distribution was mapped using a scanning probe cavity perturbation technique. Electron spin resonance using a standard marker was carried out in order to verify the polarization control from linear to circular.

Ultra-long-distance interaction between spin qubits

We describe a method for implementing deterministic quantum gates between two spin qubits separated by centimeters. Qubits defined by the singlet and triplet states of two exchange coupled quantum dots have recently been shown to possess long coherence times. When the effective nuclear fields in the two asymmetric quantum dots are different, total spin will no longer be a good quantum number and there will be a large electric dipole coupling between the two qubit states. We show that when such a double-quantum-dot qubit is embedded in a superconducting microstrip cavity, the strong coupling regime of cavity quantum electrodynamics lies within reach. Virtual photons in a common cavity mode could mediate coherent interactions between two distant qubits embedded in the same structure; the range of this two-qubit interaction is determined by the wavelength of the microwave transition.

Quantum-state transfer in imperfect artificial spin networks

High-fidelity quantum computation and quantum state transfer are possible in short spin chains. We exploit a system based on a dispersive qubit-boson interaction to mimic XY coupling. In this model, the usually assumed nearest-neighbors coupling is no more valid: all the qubits are mutually coupled. We analyze the performances of our model for quantum state transfer showing how pre-engineered coupling rates allow for nearly optimal state transfer. We address a setup of superconducting qubits coupled to a microstrip cavity in which our analysis may be applied.

Characterization of Liquid Crystal Polymer (LCP) Material and Transmission Lines on LCP Substrates From 30 to 110 GHz

Liquid crystal polymer (LCP) is a material that has gained attention as a potential high-performance microwave substrate and packaging material. This investigation uses several methods to determine the electrical properties of LCP for millimeter-wave frequencies. Microstrip ring resonators and cavity resonators are measured in order to characterize the dielectric constant (/spl epsi//sub r/) and loss tangent (tan/spl delta/) of LCP above 30 GHz. The measured dielectric constant is shown to be steady near 3.16, and the loss tangent stays below 0.0049. In addition, various transmission lines are fabricated on different LCP substrate thicknesses and the loss characteristics are given in decibels per centimeter from 2 to 110 GHz. Peak transmission-line losses at 110 GHz vary between 0.88-2.55 dB/cm, depending on the line type and geometry. These results show, for the first time, that LCP has excellent dielectric properties for applications extending through millimeter-wave frequencies.

Specific features of the dielectric spectra of the liquid crystal 5CB in the decimeter wavelength range

The dispersion and anisotropy of the permittivity of the liquid crystal 5CB in the solid, nematic, and isotropic phases are investigated at frequencies ranging from 50 to 1000 MHz using discretely tunable hybrid microstrip cavities. Resonance features which grow with increasing temperature are observed in the dielectric spectra. It is found that the section of the dispersion which is due to oriented vibrations of the mesophase molecules covers the frequency range almost up to 300 MHz, and the resonances found could be due to conformational vibrations of the molecules.