Dual-mode Resonator Research Articles

Very Compact Diplexer Based on Dual-Mode Dielectric TM-Mode Resonators

A very compact in-line C-band diplexer is reported in this letter based on dual-mode dielectric TM-mode resonators in planar coupling configuration. In addition to the advantages of substantial volume-saving and easy assembly, the proposed diplexer features high-quality factor, enhanced spurious performance, high-power handling, and efficient tuning process with independent control of each passband. For verification purposes, a C-band diplexer is designed, implemented, and tested. The final assembled diplexer unit has a compact overall volume of 43 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times 40\times15.9$ </tex-math></inline-formula> mm 3. It operates at 4.73 and 5.03 GHz with the same bandwidth of 24 MHz, an insertion loss better than 0.9 dB, and a return loss higher than 21 dB. In addition, a high-power breakdown analysis shows that the introduced diplexer can handle high levels of input power up to 5200 W.

Theoretical and Experimental Analysis of the Spurious Modes and Quality Factors for Dual-Mode AlN Lamb-Wave Resonators

In this paper, the spurious modes and quality-factor (Q) values of the one-port dual-mode AlN lamb-wave resonators at 500-1000 MHz were studied by theoretical analysis and experimental verification. Through finite element analysis, we found that optimizing the width of the lateral reflection boundary at both ends of the resonator to reach the quarter wavelength (λ/4), which can improve its spectral purity and shift its resonant frequency. The designed resonators were micro-fabricated by using lithography processes on a 6-inch wafer. The measured results show that the spurious mode can be converted and dissipated, splitting into several longitudinal modes by optimizing the width of the lateral reflection boundary, which are consistent well with the theoretical analysis. Similarly, optimizing the interdigital transducer (IDT) width and number of IDT fingers can also suppress the resonator's spurious modes. In addition, it is found that there is no significant difference in the Qs value for the two modes of the dual-mode resonator with the narrow anchor and full anchor. The acoustic wave leaked from the anchor into the substrate produces a small displacement, and the energy is limited in the resonator. Compared to the resonator with Au IDTs, the resonator with Al IDTs can achieve a higher Q value due to its lower thermo-elastic damping loss. The measured results show the optimized dual-mode lamb-wave resonator can obtain Qs value of 2946.3 and 2881.4 at 730.6 MHz and 859.5 MHz, Qp values of 632.5 and 1407.6, effective electromechanical coupling coefficient (k2eff) of 0.73% and 0.11% respectively, and has excellent spectral purity simultaneously.

Dual-Passband SAW Filter Based on a 32°YX-LN/SiO2/SiC Multilayered Substrate.

To meet the demands of highly integrated and miniaturized radio frequency front-end (RFFE) modules, multi-passband filters which support multi-channel compounding come to the foreground. In this work, we proposed a new design of a dual-passband surface acoustic wave (SAW) filter based on a 32°YX-LiNbO3 (LN)/SiO2/SiC multilayered structure. The filter is of a standalone ladder topology and comprises dual-mode resonators, in which the shear horizontal (SH) mode and high-order SH mode are simultaneously excited through electrode thickness modulation. The impact of electrode thickness on the performance of the dual-mode resonator was systematically investigated by the finite element method (FEM), and resonators were prepared and verified the simulation results. The electromechanical coupling coefficients (K2) of the SH modes are 15.1% and 17.0%, while the maximum Bode-Q (Qmax) values are 150 and 247, respectively, for the fabricated resonators with wavelengths of 1 μm and 1.1 μm. In terms of the high-order SH modes in these resonators, the K2 values are 9.8% and 8.4%, and Qmax values are 190 and 262, respectively. The fabricated dual-band filter shows the center frequencies (fc) of 3065 MHz and 4808 MHz as two bands, with 3-dB fractional bandwidths (FBW) of 5.1% and 5.9%, respectively. Such a dual-band SAW filter based on a conventional ladder topology is meaningful in terms of its compact layout and diminished area occupancy. This work provides a promising avenue to constitute a high-performance dual-passband SAW filter for sub-6 GHz RF application.

Purcell and Collection Efficiency Enhancement of Single NV‐ Center Emission Coupled to an Asymmetric Tamm Structure

AbstractThe resonant modes associated with engineered photonic structures of different spatial‐dimension are essential to obtain bright on‐demand single photon sources for quantum technologies. Negatively‐charged nitrogen‐vacancy (NV‐) center in diamond is proposed as an excellent single‐photon source at room temperature. The possible optical readout of spin states in diamond makes it a good candidate for the spin‐photon interface. However, poor light collection, feeble zero‐phonon line, low emission rate, and broad phonon‐induced emission limit the use of NV‐ centers in quantum technologies. Here, a feasible, easy‐to‐fabricate, asymmetric Tamm structure coupled with a single NV‐ center to enhance the emission rate of zero phonon line (ZPL) with better light collection efficiency is presented. The asymmetric Tamm structure shows dual resonant mode with one of the modes coinciding with NV‐ ZPL wavelength of 640 nm. The mode quality factor (Q‐factor) is 140, which is greater than the Q‐factor of conventional Tamm structure and hence, improved field intensity localization. The authors achieved four times Purcell enhancement and five times enhanced light collection efficiency at 640 nm. The proposed asymmetric Tamm structure helps to generate bright single photons using NV‐ center and improves the efficacy of the spin‐photon interface.

Substrate-Integrated Waveguide Band-Pass Filter and Diplexer With Controllable Transmission Zeros and Wide-Stopband

In this brief, a substrate integrated waveguide (SIW) bandpass filter (BPF) with wide out-of-band rejection is researched and fabricated with the center frequency of 45.8 GHz and 3-dB FBW of 2.18%. Due to the exploitation of electronic excitation, higher order modes mismatch and orthogonal transmission, the simulated and measured out-of-band rejection is better than 20 dB with frequencies up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$7.6f_{0}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.4f_{0}$ </tex-math></inline-formula> , respectively. Diplexer with stopband suppression better than 30 dB up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.87f_{0}$ </tex-math></inline-formula> is proposed based on the theory of the proposed filter. Dual-mode resonator operating with TE301 mode (43.8 GHz) and TE103 mode (45.8 GHz) has been designed to provide the transition of two filter channels. High isolation better than 27 dB over the whole band can be achieved. Transmission zeros (TZs) are generated by spurious resonances under electrical excitation, resulting in high selectively of the passbands. Good agreements between simulations and measurements can be observed.

Wide-Stopband Diplexer With Small Frequency Ratio Based on SIW Dual-Mode Resonators for Millimeter-Wave Applications

A substrate-integrated waveguide (SIW) diplexer has been designed based on the dual-mode resonator operating with TE301 and TE103 modes in this letter. Techniques of harmonic interleaving, negative excitation and planar coupling structure, orthogonal transmission, and slot lines etched on the ground plane are exploited synthetically to extend the range of the out-of-band rejection. The diplexer with lower and upper channels centered at 34.95 and 36.44 GHz is fabricated and measured to verify the proposed concept, which exhibits a wide stopband better than 20 dB up to 82.92 GHz and a high isolation better than 28.9 dB over the whole band with three transmission zeros (TZs) nearby two passbands. Measurements accord well with the simulation results.

A High-Temperature Superconducting Bandpass Dual-Mode Filter with Tunable Relative Bandwidth and Center Frequency.

This study proposes a high-temperature superconducting (HTS) bandpass filter with a continuously tunable bandwidth and center frequency. The proposed filter combines several gallium arsenide varactors and a dual-mode resonator (DMR). The even and odd modes of the DMR can be tuned simultaneously using a single bias voltage. The capacitive value of varactors in the circuit is tuned continuously under continuous voltage and frequency tunability. External couplings and the interstage can be realized using an interdigital coupling structure; a fixed capacitor is added to the feeder to improve its coupling strength. A low-insertion loss within the band is obtained using HTS technology. Additionally, the proposed filter is etched on a 0.5 mm-thick MgO substrate and combined with YBCO thin films for demonstration. For the as-fabricated device, the tuning frequency range of 1.22~1.34 GHz was 9.4%; the 3-dB fractional bandwidth was 12.95~17.39%, and the insertion loss was 2.28~3.59 dB. The simulation and experimental measurement results were highly consistent.

Dielectric TM-Mode Y-Shaped Doublet Structure

This paper discusses dielectric TM-mode filters based on high permittivity Y-shaped ceramics. It is shown that this type of ceramic operates as a dual-mode resonator and therefore contributes two reflection zeros as well as one transmission zero (TZ) to the filter response. Hence, it can be interpreted as a doublet structure and used for the realization of quasi-elliptical filter responses of different order. The dual-mode resonator can be used in multiple different filter set-ups: On the one hand, a combination with classical TM <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_{010}$</tex-math></inline-formula> -mode resonators is possible to allow the realization of TZs in an in-line filter configuration without using cross-coupling apertures. Therefore, negative or diagonal cross-couplings, which are often difficult to realize and handle, can be avoided. On the other hand, several Y-shaped ceramics can be coupled directly with each other to increase the number of TZs to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$n_{fz}=n/2$</tex-math></inline-formula> , where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$n$</tex-math></inline-formula> is the order of the filter. Finally, it is shown that even a combination with extracted pole elements is realizable. Prototypes based on modular segments are manufactured as proof of concept.

Arbitrary Termination Complex Impedances Tunable Bandpass Filter Using Single and Dual-Mode Resonators

This paper presents a design of microstrip line tunable bandpass filter (BPF) with a transmission zero (TZ) that can accommodate arbitrarily terminated input and output port impedances ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Z_s</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Z_L</i> ≠ 50 Ω). We extracted a new coupling matrix to design the proposed tunable BPF and presented intuitive circuit-level implementation using a single dc-bias controlled single and dual-mode resonators. The proposed tunable BPF integrates the function of tunable filter and matching network into a single circuit. To validate the design, three filter prototypes with different input and output port termination impedances (filter A: 50-to-50 Ω, filter B: 20-to-50 Ω, and filter C: (25+j10)-to-50 Ω) are manufactured and their performances were measured. The experimental results are consistent with the simulation showing that the passband frequency of the BPF can be tuned from 1.65 GHz to 2.08 GHz (23.06%) with the insertion loss variation from 3.40 dB to 4.69 dB. The proposed tunable BPFs achieved frequency selectivity characteristics by locating the TZ at a lower stopband. The proposed arbitrary terminated tunable BPF can allow direct connection between power amplifier (PA)/low noise amplifier (LNA) and antenna without extra matching networks, resulting in smaller circuit size and can enhance overall performance of RF front-end.

Electroformed Dual-Mode Waveguide Filter With No Tuning Screws

This letter presents an X-band dual-mode rectangular waveguide resonator filter with transmission zeros fabricated by electroforming. The reason of employing electroforming in filter fabrication is that the rectangular waveguide resonators can avoid having rounded corners which are inevitable for filters fabricated by a commonly used method, milling. Having no rounded corners enables fast and accurate design supported by electromagnetic simulations. Hence, the fabricated filter produces the frequency response that agrees well with the simulated response although the filter employs the dual-mode technique and there are no tuning screws at all for fine tuning the resonant frequency of each resonator and the coupling values.

Dual-Band Uniaxial Dielectric Anisotropy Sensor Using Coupled-Line Resonators

In this paper, a new dual-band sensor to measure uniaxial anisotropy at two frequency bands is proposed. This sensor is composed of two dual-mode resonators separated by a T-shaped structure implemented in microstrip technology. The configuration of vertical and horizontal electric field lines for the two resonance modes allows for the characterization of a uniaxial anisotropic sample placed on top of the sensor. The resonance frequencies of different modes are separated using active S-parameters measured at the input port. They are subsequently used in the space mapping process to extract the dielectric constants of the sample in two directions, parallel and normal to the surface of the sensor, by means of electromagnetic analyses. The sensor is used to extract the dielectric constants of anisotropic FR4, RO4003C, and RO3010 samples at 2.4 and 3.4 GHz. An isotropic PTFE sample is also characterized to verify the reliability of the proposed method. Two single-band sensors are also implemented to measure RO3010 sample and the extracted dielectric constants are compared to those resulted from the proposed dual-band sensor.

AlScN-Based Dual-Mode Devices With Temperature Compensated Strategy and Process Optimization

MEMS resonators with interdigital transducer (IDT) based on aluminum nitride (AlN) thin-film (a few micrometers thickness) materials gradually arouse researchers’ interest due to their ability to excite multiple modes of acoustic waves. However, the low electromechanical coupling coefficient is still one of the main reasons that limit the AlN-based resonators. In this article, we demonstrate a design journey for 10% scandium-doped AlN-based dual-mode acoustic wave resonators. Also, we investigated the influence of stack architectures with and without introduced AlN interlays, as well as the influence of stacked film thicknesses, on the performance of resonators. Simulation results show that changes in the SiO2 film thickness have different effects on the TCF of the two acoustic wave modes, providing a way for sensors to decouple two parameters that jointly affect the frequency drift. Moreover, measured results show that the introduced AlN interlayer (AlN-IL) induces a better crystalline orientation of the scandium-doped AlN (AlScN) thin film and a higher coupling coefficient of the leaky longitudinal (LL) mode ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${K}^{{2}}$ </tex-math></inline-formula> : from 4.19% to 4.96%), which make the resonators have great potential in surface acoustic wave (SAW)-based applications such as sensors and high-frequency applications.

A Dual-Polarized 2-D Monopulse Antenna Array Based on Substrate Integrated Waveguide

A dual-polarized 2-D monopulse antenna based on substrate-integrated waveguide (SIW) is proposed in this article. First, a novel single-layer 2-D monopulse comparator with four dual-mode resonators (DMRs) is presented, which exhibits excellent amplitude-phase consistency and high isolations between input ports. The dual-polarized monopulse performances are realized by exciting the two comparators. Then, a dual-polarized slot coupling radiation element is designed. Based on the proposed comparator and radiation part, a monopulse antenna prototype is fabricated and measured. The measured results show that the −10 dB shared bandwidth is 2.03% (9.75–9.95 GHz) on eight ports, with the null depths of the difference patterns less than −28 dB. The isolations between ports are better than 25 dB due to the orthogonality of the DMR. The measured results are in good agreement with the simulated results.

On-Chip Frequency Tuning of Fast Resonant MEMS Scanner

The development and characterisation of a piezoelectric actuated high-frequency MEMS scanning mirror with on-chip frequency tuning capability is reported. The resonant scanner operates at frequencies in excess of 140 kHz, generating scan angles of 10° and 6° for two orthogonal movement modes with 40 V actuation. On-chip frequency tuning is achieved through electrothermal actuators fabricated adjacent to the mirror main suspension. The electrothermal actuators produce a global and local temperature increase which changes the suspension stiffness and therefore the resonant frequency. A resonance frequency tuning range of up to 5.5 kHz is achieved, with tuning dominant on only one of the two orthogonal scan movement modes. This opens the possibility for precise tuning of a 2D Lissajous scan pattern using a single resonant MEMS scanner with dual orthogonal resonant modes producing full frame update rates up to 20 kHz while retaining the full angular range of both resonant movement modes.

Single-Polarized Low-Profile High-Order Bandpass Frequency Selective Surfaces Based on Aperture-Coupled Patch Resonators Under TM and TM Modes

This communication presents a methodology to construct the aperture-coupled dual-mode patch resonators (AC-DMPRs)-based periodic element to realize single- and dual-band high-order bandpass frequency selective surfaces (FSSs). Initially, a single patch resonator (PR) loaded with two sets of shorting pins is theoretically studied by using the characteristic mode analysis (CMA) method and by applying periodic boundary conditions, respectively. The results demonstrate that the radiation pattern and resonant frequency of TM00 mode in the PR can be effectively reshaped and controlled by the shorting pins, so that the TM00 and TM01 modes can be simultaneously excited under the normal incidence of a plane wave. As such, the single-mode PR is transformed into a DMPR. Moreover, such DMPRs are arranged in a back-to-back manner with coupling apertures etched on the common middle metallic layer to form an AC-DMPR-based bandpass FSS element. By reasonably reallocating the resonant frequencies of these two resonant modes and etching different apertures to provide magnetic and/or electric couplings in the AC-DMPR, single- and dual-band high-order bandpass FSSs can be conveniently and flexibly constructed, respectively. Finally, the conceptual designs are validated by measurements.

Miniaturized Dual-Band Filter Using Dual-Mode Dielectric Waveguide Resonator

This letter presents a novel miniaturized dual-band bandpass filter (BPF) using a dual-mode dielectric waveguide resonator (DWR). The DWR is a cylinder dielectric block with the surface being silver-coated. The two modes are TM010 and TM011 modes, which are used to construct the two passbands. The frequency of them can be adjusted by changing the radius and the height of the cylinder DWR and the frequency space can be controlled independently. The BPF is composed of three cylindrical cavities, which are arranged in an equilateral triangle. The three cavities construct a cascaded trisection (CT) unit, which creates a transmission zero (TZ) at the upper side of the two passbands. Finally, a dual-band BPF using DWR is simulated, manufactured, and measured to exhibit the feasibility of the proposed design. Their results are in good agreement, showing good performance, such as miniaturization, good return loss (RL), and upper stopband selectivity.

Compact Multichannel Filters and Multiplexers Based on Dual-Coaxial Resonators

In this brief, compact multi-channel bandpass filters and diplexers are proposed based on dual-coaxial resonators. One coaxial resonator is embedded into the other to form a dual-mode resonator without increasing the size, where the resonant section of one resonator acts as the shielding cavity of the other one. In this way, the two modes of the dual-coaxial resonator are ideally isolated and can be controlled independently. By properly designing the feeding and coupling structures between resonators, the two modes in one dual-coaxial resonator can be excited and coupled to construct different filter channels without influencing each other. Accordingly, multi-channel filters are realized. For verification, a dual-channel and a triple-channel filters are presented. Moreover, the filter channels in a dual-channel filter can be applied to design the diplexer, resulting in a compact size. Experimental results are presented with good in-band responses and high isolation.

IPD Millimeter-Wave Bandpass Filter Chip Based on Stepped-Impedance Coupled-Line Dual-Mode Resonator for 5G Application

A novel stepped-impedance coupled-line dual-mode resonator (SICLDMR) is presented and analyzed in this brief. The resonator is a closed ring structure, constructed by two coupled lines with different impedances. The even- and odd-mode resonance frequencies of this SICLDMR are created due to the different effective dielectric constants of the two modes. Based on the proposed resonator, a simple bandpass filter (BPF) is designed by adding two symmetric open-stub feeding structures. For demonstration, a narrowband BPF operating at 35 GHz is simulated, fabricated by using the 100- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mu }\text{m}$ </tex-math></inline-formula> -thick-GaAs integrated passive device (IPD) technology. And the measured results show that the BPF with a good fractional bandwidth of 13% realizes a low insertion loss of 0.74 dB, sharp roll-off skirt of passband, and wide stopband rejection. The advantages of the proposed IPD BPF indicate that it has a promising application prospect in 5G millimeter-wave systems.

A Tunable Bandpass Filter with Arbitrarily Terminated Port Impedance Using Dual-Mode Resonator

This paper presents a design for a compact arbitrarily terminated port impedance tunable bandpass filter (BPF) with transmission zeros (TZs) that employs a dual-mode resonator. The proposed dual-mode resonator comprises two varactors along with series transmission lines and a shunt short-circuited stub. The resonant frequency separation of the dual-mode resonator can be adjusted by changing the length or characteristic impedance of the short-circuited stub. To achieve arbitrarily terminated port impedances, the coupling between the source/load and the dual-resonator is modified from the originally designed 50-to-50 Ω termination filter. Frequency selective characteristics are achieved by generating two TZs at the lower and upper frequencies of the passband. The location of the TZs can be changed by controlling the source-load coupling. To experimentally validate the proposed tunable BPF, three prototypes (50-to-50 Ω BPF, 25-to- 50 Ω BPF, and 20 + &lt;i&gt;j&lt;/i&gt;10-to-50 Ω BPFs) are designed and fabricated. The measurement results revealed that the center frequency can be tuned from 2.10 GHz to 3.02 GHz (920 MHz tunability), where the insertion loss varies from 1.50 to 2.5 dB.

A versatile metal–organic nanoplatform in combination with CXCR4 antagonist and PD-L1 inhibitor for multimodal synergistic cancer therapy and MRI-guided tumor imaging

Currently, multimodal synergistic nanoplatform emerges as an important cancer therapy paradigm, however, multimodal synergistic theranostic nanoplatform remains to be developed. Herein, using the mouse model of breast cancer, a versatile multimodal synergistic theranostic nanoplatform is rationally designed and synthesized for enhancing chemodynamic therapy (CDT), overcoming immunosuppression within tumor microenvironment, and inhibiting metastasis as well as tracking tumor. To fulfill our design, a composite Fe/Mn magnetic nanoparticle is first synthesized by loading with Fe3O4 and BMS-202 (PD-L1 inhibitor) within a poly(lactide-co-glycolide)-based nanoparticle core, which are further modified with in situ synthesis of MnO2 layer. Then, the composite metal-organic nanoparticle is coated with two targeting moieties hyaluronic acid (HA) and AMD3100 (CXCR4 antagonist), respectively, to achieve the multimodal synergistic theranostic nanoplatform (FMN-BMS@HA+AMD). With surface targeting modification, FMN-BMS@HA+AMD exhibits enhanced tumor accumulation, where it effectively consumes endogenous glutathione to generate Mn2+ allowing for the enhanced CDT effect, alleviates tumor hypoxia by O2 generation and reverses the tumor immunosuppression. FMN-BMS@HA+AMD blocks CXCR4 receptor on cancer cells, thus suppressing the CXCR4-mediated cancer metastasis and invasion. Additionally, FMN-BMS@HA+AMD would synchronously be achieving tumor tracking by T1-T2 dual-mode magnetic resonance imaging. Collectively, this strategy holds a novel multimodal synergistic theranostics for effective cancer management.