Dual-mode Resonator Research Articles

Design of Compact HTS Bandpass Filter with High Selectivity Operating Above 100 k

In this manuscript, a miniature high-temperature superconductor (HTS) bandpass filter (BPF) with multi-transmission zeros (TZs), high selectivity, and great attenuation of stopband is presented. A couple of dual-mode resonator (DMR) is employed to achieve the proposed BPF, which can be characterized by using the classical even-odd mode analysis technique. The presented cascaded DMR can excite four resonant modes, which can be individually managed. Plus, a pair of intrinsic transmission zeros can be yielded at both the lower and upper edges of the passband, which results in sharp shirt performance. As an example, the HTS BPF is designed, fabricated, and tested, in which the center frequency is centred at 3.95 GHz and the 3-dB fractional bandwidth (FBW) is 2.5%. The proposed HTS BPF is implemented by using Tl2Ba2CaCu2O8 (Tl-2212) thin films which are fabricated by two-step processing and the superconducting critical temperatures (Tc) of the HTS films can reach 103 K. The design methodology is confirmed since the experimental results are in good agreement with theoretical results, showing desired bandpass characteristics, high selectivity, and the attenuation of lower and upper stopbands above −50 dB. Further, the circuit size is only 0.4 cm2.

Design of a pHEMT RF mixer based on compact microstrip diplexer

Abstract This paper presents a new topology for a microwave active mixer using compact microstrip diplexer constituted from two dual-mode open loop resonators. The resonators are tuned to the radio frequency (RF) and local-oscillator (LO) frequencies, respectively, to effectively isolate the two input signals, while the diplexer output port is connected to the gate circuit of a commercial low cost GaAs pHEMT transistor. The drain circuit of the active device is connected to the load via an intermediate-frequency (IF)-modified Chebyshev low-pass filter to remove the unwanted RF and LO signals and reduce other spurious frequencies at the output of the mixer circuit. The circuit has been designed and constructed for an RF of 850 MHz, LO frequency of 1050 MHz, and an IF of 200 MHz. Experimental measurements show that the circuit provides a conversion gain of 18 dB at LO drive power of +2 dBm. It also operates satisfactorily over the RF range from 800 to 900 MHz with good image frequency rejection and stable operation.

Hybrid-coupler-based quasi-reflectionless balanced bandpass filter with all common mode suppression

Hybrid-coupler-based quasi-reflectionless balanced bandpass filter (BPF) is proposed and demonstrated in this paper. The reflectionless balanced BPF is comprised of two hybrid couplers and a filtering crossover. The filtering crossover is composed by a dual-mode ring resonator coupled with four short-circuited open-loop resonators, which is used to replace the traditional two BPFs for reduction of interference. Hybrid couplers are used for absorbing the reflected interference to the input and output ports. In order to achieve common-mode (CM) suppression, a double-layer structure with the same microstrip configuration on the upper and lower surfaces is adopted. The absorption characteristics of the differential mode (DM) and CM signals are optimized by hybrid couplers with improved ground. A third-order quasi-reflectionless balanced BPF with central frequency of 2.3 GHz and fractional bandwidth of 14 % is designed, fabricated, and measured. The final measured results demonstrate great consistency with the simulated ones.

Quasi-bound states in the continuum with stable dual-resonance wavelengths in mid-infrared metasurface for ultrasensitive refractive index sensing and molecular vibrations of strong coupling

In this paper, a dual-resonances mid-infrared all-dielectric metasurface sensor based on asymmetric cross dimer, which is driven by quasi-bound states in the continuum (QBIC), is proposed and investigated. The metasurface sensor maintains the total permittivity constant when the asymmetric parameter is adjusted, thereby ensuring the stability of the QBIC resonance wavelengths, which exhibit Q-factors of 6351 and 13561, respectively. The multiple decompositions and electromagnetic field distributions reveal that the toroidal dipole is the dominant component of the dual-resonance modes. The sensitivities to the refractive index are 3559 nm/RIU and 1146 nm/RIU, with corresponding figures of merit of 4449 RIU−1 and 2453 RIU−1, respectively. Further numerical simulations have demonstrated a strong coupling phenomenon between the QBIC and the molecular vibrations of polymethyl methacrylate (PMMA), resulting in a significant enhancement of the infrared absorption signal. With the 50-nm-thick PMMA layer, the enhancement of molecular signal is 90.614%.

Dual-mode draw resonance instability regulated by concentration fluctuation in the polymer solutions casting

Based on the two-fluid model, we successfully simulated the film casting process of the polymer solution system and observed the unique response wave of the film thickness and the concentration via applying perturbation. We identify that this instability pattern is essentially the product under the coupling effect of viscoelastic stress and osmotic pressure from fluctuations on different scales, which causes it to exhibit biperiodic characteristics. We call this new instability mode known as dual-mode draw resonance instability. Among them, the concentration oscillation predominates, thereby limiting the critical draw ratio Drc of the system. Through sorting out the molecular image of the polymer concentration response to perturbation, the relevant parameters are extracted, and the law of their influence on the Drc further verifies our conclusion and provides guidance for actual production.

Mesoporous Polydopamine Nanotherapeutics for MRI-Guided Cancer Photothermal and Anti-Inflammatory Therapy.

As a burgeoning cancer treatment modality, photothermal therapy (PTT) has shown robust anti-tumor effects. However, it still faces numerous challenges, such as triggering an inflammatory response and potentially increasing the risk of cancer recurrence. To address these concerns, integration of PTT with anti-inflammatory therapies presents a promising approach to enhance the efficacy of cancer treatment and meanwhile reduce the risk of recurrence. In this study, Gd3+ was first chelated with dopamine to create Gd-DA chelates, and then the mesoporous dopamine nanoparticles MX@Arg-Gd-MPDA (MAGM NPs) were synthesized by combining arginine (Arg) and the anti-inflammatory medication meloxicam (MX). The photothermal properties of MAGM NPs were then defined and examined; the in vivo MRI imaging effect, as well as MAGM NPs' anti-cancer and anti-inflammatory efficiency, were tested in a mouse model of breast cancer. The incorporation of Arg doping into MAGM NPs was intended to boost its photothermal conversion efficiency and reactive oxygen species (ROS) scavenging ability. Additionally, synergizing with the anti-inflammatory agent meloxicam (MX) within the nanoparticles aimed to enhance the anti-inflammatory effect following photothermal therapy. Furthermore, gadolinium ions (Gd3+) were chelated into the nanostructure to enable precise T1-T2 dual-mode magnetic resonance imaging (MRI) of the intratumor accumulation profile. This imaging capability was leveraged to guide the implementation of photothermal therapy. Animal experiments demonstrated that MAGM NPs exerted a notable anticancer effect in a 4T1 breast cancer mouse model, under the precise guidance of MRI.

Single-Layer Millimeter-Wave Filtenna With Quasi-Elliptic Gain Response Under Dual-Mode Resonance

Single-Layer Millimeter-Wave Filtenna With Quasi-Elliptic Gain Response Under Dual-Mode Resonance

Highly selective microstrip bandpass filters using dual-mode patch resonator loaded with short via

In this paper, highly selective dual-mode microstrip bandpass filters (BPFs) are presented utilizing novel square patch resonator loaded with short via and periodic metallic vias array. Characteristics of the patch resonator are studied, and a new nondegenerate dual-mode patch resonator operating with the second and third higher-order modes is proposed. A two-pole BPF based on one dual-mode patch cavity is analyzed, and two transmission zeros (TZs) are produced. To realize higher-order filtering responses, four-pole BPFs with two cascaded dual-mode patch resonators are proposed, and different cascaded methods of two dual-mode patch resonators by a λg/4 microstrip connecting line (MCL) are analyzed and compared to maintain high selectivity and small size. For the demonstration, two four-pole filters with the center frequency at 3.3 GHz and five transmission zeros is designed, fabricated and measured.

Design of Novel Filtenna for Wireless Applications

In this paper, a novel design based on a dual-mode ring resonator, the filtering balun, feeding the printed dipole antenna, the filter balun antenna (FBA), is presented. One port on the structure allows the signals to be phase-shifted 180 degrees from one unbalanced port to two balanced signals. The suggested designs use a single dual-mode ring resonator to operate as both a filter and a balun at the same time. Compact designs are achieved by applying feeding to the second layer. Another unique characteristic of the filtering balun is its ability to alter, based on perturbation size, the phase error and magnitude imbalance of the two balanced signals. With the use of the Advanced Design System (ADS) software, numerous structures have been developed, modeled, and evaluated. To achieve the highest performance, every section of the design is assessed and optimized. Because the substrate is a lossy type (FR4), the realized transmission coefficients, which are poorer than expected ideal values, make the suggested design a strong contender for narrow-band wireless applications. For S2,1 and S3,1, the signal is routed through two viasand fed into a dipole antenna in the opposite phase by employing the zero iteration for filtering the balun in the first layer to condense with the second layers. The antenna structure is a printed dipole antenna operating at 2.4 GHz

Dual-mode microring resonator for humidity sensing with temperature compensation

On-chip refractive index (RI) sensors, which use resonant shifts of micro-cavities to detect environment change, have the advantages of high sensitivity, real-time detection, and compact footprints. However, the cross-sensitivity of the temperature variation severely interferes with sensing results. In this paper, we present a dual-mode microring resonator (MRR) with a cladding layer of polyhexamethylene biguanide hydrochloride (PHMB) for relative humidity (RH) sensing to overcome the limitation. Specifically, the influences of the RH-induced RI change of the PHMB cladding and temperature variations on the effective RIs of TE0 and TE1 modes can be decoupled based on the transmission spectral measurements. Using this method, we have demonstrated the temperature-compensated RH sensing which achieved a maximum sensitivity of −54.7 pm/%RH and a limit of detection of 0.8 %RH under the room temperature condition. Besides, a computational model based on the sensing response of the device was proposed and verified, which demonstrated that the structure can accurately measure changes in RH and temperature simultaneously. Our methodology has the potential to become a new reference for developing on-chip RI sensors with temperature compensation.

Advancing MicroRNA Detection: Enhanced Biotin-Streptavidin Dual-Mode Phase Imaging Surface Plasmon Resonance Aptasensor.

MicroRNAs (miRNAs) are novel tumor biomarkers owing to their important physiological functions in cell communication and the progression of multiple diseases. Due to the small molecular weight, short sequence length, and low concentration levels of miRNA, miRNA detection presents substantial challenges, requiring the advancement of more refined and sensitive techniques. There is an urgent demand for the development of a rapid, user-friendly, and sensitive miRNA analysis method. Here, we developed an enhanced biotin-streptavidin dual-mode phase imaging surface plasmon resonance (PI-SPR) aptasensor for sensitive and rapid detection of miRNA. Initially, we evaluated the linear sensing range for miRNA detection across two distinct sensing modalities and investigated the physical factors that influence the sensing signal in the aptamer-miRNA interaction within the PI-SPR aptasensor. Then, an enhanced biotin-streptavidin amplification strategy was introduced in the PI-SPR aptasensor, which effectively reduced the nonspecific adsorption by 20% and improved the limit of detection by 548 times. Furthermore, we have produced three types of tumor marker chips, which utilize the rapid sensing mode (less than 2 min) of PI-SPR aptasensor to achieve simultaneous detection of multiple miRNA markers in the serum from clinical cancer patients. This work not only developed a new approach to detect miRNA in different application scenarios but also provided a new reference for the application of the biotin-streptavidin amplification system in the detection of other small biomolecules.

Stub Asymmetry-Enabled Self-Phase-Shift Circularly Polarized Antenna under Dual-Mode Resonance

In this article, a novel design approach to wideband dual-mode resonant circularly polarized (CP) antenna is advanced. An analytical design approach with low complexity as supported by a set of closed-form formulas is presented. Thus, the wideband dual-mode CP characteristics can be forward predicted and simply realized by incorporating stub asymmetry-enabled self-phase-shift dipoles and unequal feeding branches. At first, stubs are employed to broaden the impedance bandwidth by simultaneously exciting dual resonant modes. Then, the phase quadrature and equal magnitude conditions for wideband CP can be automatically realized by incorporating unequal Y-shaped microstrip branches and asymmetric slotline stubs. Finally, the coincidence between the simulated and measured results of the fabricated prototype antenna further confirms the feasibility of the design approach. It is shown that the presented antenna can exhibit an impedance bandwidth of 20.1% and a 3 dB axial ratio bandwidth of 16.3% in the boresight direction.

A design method for filter to achieve arbitrary distribution of multiple transmission zeros without cross-coupling

This paper proposes a method for introducing transmission zeros (TZs) in filters using dual-mode resonators. By loading a dual-mode resonator as a second-order extracted-pole unit (EPU) at the input or output of the filter, a pair of finite TZs can be introduced without cross-coupling. This approach reduces the size of the filter while generating two finite transmission zeros compared to conventional methods. Since the dual-mode resonator is characterized by its separable odd and even modes, and by adjusting the resonant frequency of the EPU, it can achieve an arbitrary distribution of TZs. It is worth noting that the EPU does not affect the insertion loss of the filter because it operates mainly outside the passband. Furthermore, this work delves into the EPU’s mechanism for generating TZs and the method of adjusting TZ position by designing filters of second, fourth, sixth, and eighth orders, providing a solid foundation for the creation of higher-order filter circuits.

A high-selective multiple-mode bandpass filter design, applicating in both millimeter-wave 5G and WiFi systems

This paper proposes a millimeter-wave bandpass filter (BPF) with high selectivity, which can be applied in both 5G and WiFi systems. Two dual-mode resonators (DMRs) are adopted and analyzed coupled microstrip lines (CMLs) and can form six transmission poles (TPs) and four transmission zeros (TZs). Furthermore, a multiple-mode resonator (MMR) is presented based on the DMRs to realize a high selective passband. Additionally, five extra TZs are introduced by two pairs of open-circuited stubs and transversal signal interference (TSI), which are introduced by cross-coupling of two signal paths. These TZs significantly enhance out-of-band suppression performance. The proposed BPF is fabricated in ceramic process, and measurement results demonstrate a minimum insertion loss of −1.52 dB, a 3-dB passband from 38.3 to 48.2 GHz, a 30-dB rectangular coefficient of 1.21, and a 30-dB stopband extending to the test limit of 67 GHz.

A novel compact microstrip dual-band bandpass filter with independently controlled center frequencies based on dual-mode resonators concept

This letter presents a novel ultra-compact microstrip dual-band bandpass filter (DBBPF) with independently controlled center frequencies, and high Q-factor. The recommended DBBPF is realized by combining two different microstrip dual-mode resonators. One is a short-end stub-loaded resonator used to produce the first passband and the other one is an open-end stub-loaded resonator operating at the second passband which serves as part of the feed lines for the lower passband. To validate the performance of the proposed configuration, a novel compact DBBPF with center passband frequencies of 2.4 and 3.55 GHz is designed, simulated, fabricated and tested. A good agreement has been found between the simulation and measurement results. The designed microstrip DBBPF occupies a small area which is only about 0.19 λg × 0.15 λg. The presented microstrip DBBPF has many advantages in terms of compact size, low insertion loss, good frequency selectivity, easy fabrication, and high selectivity.

A dual-band wideband high-gain slot loaded microstrip patch antenna

This paper presents a dual-band, wideband, high-gain microstrip patch antenna applied to 5G band. The antenna consists of two rectangular radiation patches of different sizes, connected by a microstrip line and fed by a coaxial line. The dual-band is achieved by both rectangular radiation patches producing dual target resonant frequency points. This antenna provides the freedom for adjusting both resonant frequencies independently. To increase the antenna bandwidth, long slots are loaded at specific positions on each rectangular patch, allowing for dual-mode resonance radiation in each frequency band. This antenna operates in a shorted-edge resonant mode, where metal grounding holes added on the patch act as shorting walls. The size of a radiation patch is only half that of a standard resonant mode patch, making this antenna compact in size. Measurement results show that the antenna has an impedance bandwidth of 4.98–5.56 GHz (11.0%) and 5.74–6.62 GHz (14.2%), which completely cover the 5G band of China (5.18–5.52 GHz and 5.74–5.82 GHz). The maximum measured realized gain is 8.1 dB in the low-frequency band and 10.2 dB in the high-frequency band. This antenna offers advantages of dual-band operation, broadband, low-profile, high-gain, which is suitable for 5G band applications with targeted coverage requirements.

Dual-mode aperture-coupled patch resonator based dual-band higher-order frequency selective surfaces

In this article, a low profile aperture coupled dual band higher order bandpass frequency selective surface (FSS) is proposed. To begin, a simple patch resonator with an L-shaped truncated corner is theoretically examined such that two orthogonal modes can be activated at the same time. Following that, a combination of four identical L-shape truncated patch resonators with 90° rotation between two adjacent patches is developed and analyzed to avoid the reflection of cross-polarized produced by orthogonal modes. Further, by arranging two of such combination resonators placed back-to-back through aperture coupling metallic layer in the middle, a three layer single mode fourth order bandpass FSS is designed. The proposed bandpass FSS is twice the performance of traditional aperture coupled patch resonators (AC-PRs). It provides more flexibility at higher order filtering responses. To endorse the design concept, a dual-band fourth order bandpass FSS is simulated to initiate magnetic and electric coupling through the aperture metallic layer. Moreover, an equivalent circuit model for even and odd mode analysis is examined for the principle of operation. Finally, the proposed bandpass FSS is fabricated and tested in a vector network analyzer (VNA) setup. The measured and simulated results are compared and validated.

Turn-key Kerr soliton generation and tunable microwave synthesizer in dual-mode Si3N4 microresonators.

This study investigates the thermal compensation mechanism in dual-mode Si3N4 microresonators that demonstrates the ease of generation of single-solitons with nearly octave-wide spectral bandwidth. The deterministic creation of soliton frequency combs is achieved by merely switching the wavelength of a tunable laser or a semiconductor diode laser in a single step. The pump frequency detuning range that can sustain the soliton state is 30 gigahertz (GHz), which is approximately 100 times the resonance linewidth. Interestingly, these dual-mode resonators also support the coexistence of primary combs and solitons, enabling their utilization as functional microwave synthesizers. Furthermore, these resonators readily facilitate the generation of diverse multi-solitons and soliton crystals. This work presents a simplified system to access high-performance and versatile Kerr solitons, with wide-ranging applications in optical metrology, microwave photonics, and LiDAR.

Design of Miniaturized Microwave Filtering-Balun Component for Wireless Applications

This research paper introduces a new design being Minkowski-like fractal filtering-balun MLFFB based on the dual-mode ring resonator. The structure has three ports, converting the signal from one unbalanced port to two balanced ports (i.e., 180° phase shift). The proposed design can act as a filter and balun simultaneously using one dual-mode ring resonator. The fractal curves are applied to have compact designs. The 0th, 1st, and 2nd iterations of the Minkowski-like fractal curves are applied to demonstrate the miniaturization ratio obtained in the proposed work. The miniaturization ratios are 47.8% and 73% of the 1st iteration and 2nd iteration of the Minkowski balun-filtering components, respectively, compared to the 0th iteration. Also, the filtering balun has a distinctive feature, which is the control of the phase error and magnitude imbalance of the two balanced ports, depending on the size of the perturbation part. Several structures have been designed, modeled, and analyzed utilizing the Advanced Design System (ADS) software. Each design iteration is evaluated and optimized to attain the best performance. The operating frequency is 2.4 GHz, and the realized transmission coefficients are S21 = -7 dB and S31 = -6.5 dB, which are less than expected ideal values because the substrate is a lossy type, being FR4. The S11 is less than -10 dB. The proposed design is a good candidate for narrow-band wireless applications.

Dual-Mode Thermal-Piezoresistive Coupled Resonators for Fast and Stable NIR Measurements with Differential Output

Dual-Mode Thermal-Piezoresistive Coupled Resonators for Fast and Stable NIR Measurements with Differential Output