Electromagnetically induced transparency (EIT) and electromagnetically induced absorption (EIA) have many applications, especially for achieving slow light and fast light. EIT and EIA have been widely observed in both quantum and classical systems where two transition pathways could interference destructively or constructively. Multipathway interference has been a concern in recent works, however, due to the difficulty of precisely controlling the system parameters, the experimental study of multipathway interference is generally challenging. In this paper, we explore a coupled high-temperature-superconducting (HTS) resonator platform for implementing three-pathway electromagnetically induced transparency (TEIT) and absorption (TEIA). In our system, both resonant frequencies and linewidths (loss) of each resonator as well as their coupling strength can be precisely controlled, thus TEIT and TEIA can be implemented as a set. Our proposed method shows great potential for use in microwave signal processing in the future, such as slow wave, fast wave, and radio-frequency memory. Our results indicate the HTS resonator is an ideal platform for investigating versatile coherent phenomena.

Abstract In this letter, electromagnetically induced transparency (EIT) is implemented in the microwave region with an experimental system composed of two indirectly coupled high‐temperature superconducting resonators. The transition condition between EIT and Autler–Townes splitting is analyzed, giving a physical explanation of this transition based on the superposition of dressed modes in a three‐level system. Benefit from the ultra‐low loss of superconducting circuit, it is experimentally shown that either EIT or Autler–Townes splitting can be explicitly achieved through control of the detuning between the two resonators and a group delay as high as 5 μs is obtained for the EIT case. This work suggests that high temperature superconducting circuit is a concise and explicit platform for investigating indirectly coupled resonators with standing‐wave modes and the physical mechanism underneath coherence phenomena in the microwave region.

In this article, an effective high-order superconducting filter design technique is proposed. The key advancement is the demonstration of neural network high temperature superconducting (HTS) high-order filter design for the first time. An artificial neural network (ANN) combined with the coupling matrix is used as a fast model of the high-order superconducting filters. The initial filter layout is established and characterized by a set of geometric variables. The coupling matrix is extracted from the simulated response of the filter layout, and the ANN is trained to learn the relationship between the coupling matrix and the filter geometric variables. The well-trained neural network model can provide an accurate and fast prediction of filter performance with different input geometric variables in less than one second, which greatly improve the design effectiveness. The experiments show that there is an excellent match between the responses of the simulated data and those from the neural network. Compared with the conventional electromagnetic simulation method, this model is time saving especially in high-order filters design with complex undesired stray couplings.

This article proposes a miniature 3-D system in package (SIP) design of the four-channel RF transceiver. The key advancement is the demonstration of 3-D stacking of silicon carriers and aluminum nitride (ALN) high temperature co-fired ceramic (HTCC) carriers based on $70~\mu \text{m}$ Au micro-bumps. The influences of the carrier on the performance of gallium arsenide (GaAs) monolithic microwave integrated circuits (MMICs) are analyzed in detail. A new silicon carrier with hollow annular through silicon via (TSV) and non-metalized cavity (NMC) is proposed, which is characterized by less impact on MMIC performance, more compact stacking size, and lower fabrication cost. The GaAs MMICs, silicon, and ALN carriers are heterogeneously integrated and stacked vertically to form a 3-D SIP. The proposed hermetic 3-D SIP is highly integrated with a volume of $12.7\times 13.9\times3.6$ mm with $7\times8$ ball grid array (BGA) input and output ports, and capable of working with four different types of passbands for anti-jamming. Measured results indicate that the SIP has the advantages of high reliability, high performance, and mass manufacture.

In order to ensure the normal operation of radio astronomy observations,an extremely sensitive receiver system needs to be equipped in front of the large radio telescope.An 8-pole wideband high-temperature superconducting(HTS)filter using a Coplanar Spiral Resonator Structure with a passband of 1160～1670 MHz is developed to suppress strong radio interference.The filter is fabricated on a 36 mm × 14 mm YBCO HTS film,which is deposited on a 0.5 mm thick MgO substrate.The minimum insertion loss measured in the liquid nitrogen temperature region is 0.03 dB,and the first parasitic passband appears at 2600 MHz.The measured results are in good agreement with the simulations.The filter can be used in radio telescope receivers for the observation of neutral hydrogen and pulsars,as well as in high-sensitivity satellite navigation instruments.

In this paper, a new ultra-wideband (UWB) bandpass filter (BPF) based on QMR (quintuple-mode resonator) loaded with quasi-lumped elements is proposed for wide stopband application. The method of connecting five folded U-shaped resonators with rectangular patches to construct a QMR was proposed. By adjusting the relative position of the rectangular patches, the frequency band width of the filter can be freely adjusted. Further, quasi-lumped elements were loaded to the QMR to generate three transmission zeros to enhance stopband performance. The filter designed in this paper can independently adjust both the stopband and the passband, providing greater design flexibility. The passband of the final filter is 3.18-9.43 GHz, and the FBW (fractional relative bandwidth) is 99%. The out-of-band rejection is better than -15 dB in the frequency range of 9.6-28.42 GHz. The measurement results show good performance without any tuning, and are in good agreement with the simulation results. A new ultra-wideband (UWB) bandpass filter (BPF) based on QMR (quintuple-mode resonator) loaded with quasi-lumped elements is proposed for wide stopband application. Five folded U-shaped resonators are connected with rectangular patches to construct the main structure of the QMR, and then quasi-lumped elements are loaded to generate three TZs (transmission zeros) to suppress the higher spurious bands.image

清华大学物理系自2020年10月开始HTML5数值仿真物理实验(Numerical Simula-tion Experiment of Physics,简称NuSEP系统)建设工作,已经建成32个仿真实验,覆盖物理学多个方向.首期目标是全面支持清华基础课课堂教学、实验教学与对外科普宣传.建设过程得到多所院校、专业科研机构的支持.本文首先回顾了NuSEP系统建设背景,之后重点介绍NuSEP系统建设目标、建设思路、建设流程、建设要点与难点以及初步应用体验.期望与国内国际同行探讨合作开发与开放模式.

Storing a very high frequency (VHF) band (30 – 300 MHz) electromagnetic wave has many potential applications, such as phase modulation, buffering, and radio frequency memory. It can be effectively achieved by applying coupled resonator-based electromagnetically induced transparency (EIT) due to its slow light effect. However, the wavelength in the VHF band is too long to design resonators, and the group delay is limited by the high resistive loss of metal. The practical application of EIT in the VHF band is still a big challenge. In this work, we propose and experimentally demonstrate EIT response in a high-temperature superconducting (HTS) microwave circuit with coupled-resonator-induced transparency. The chip size of the HTS circuit is only 34 mm × 20 mm with a very low transparency frequency of 198.55 MHz. In addition, we implement very large group delay higher than 12.3 μ s and 16.2 μ s with working temperatures of 65 K and 50 K separately, which is much longer than the previous reported works on slow wave. The fabricated circuit is planar with working temperature about 65 K, and thus can be easily integrated into other microwave devices under the cryogenic conditions provided by a commercial portable Stirling cryocooler. Our proposed method paves a way for studying EIT in the microwave region due to the high quality factor of the HTS resonator, which has great potential use for radio-frequency memory in the future.

A novel dual-mode optimized patch capacitor loaded T-type resonator is proposed for the design of a dual-band filter (DBF). The resonator has its lowest even- and odd-mode at the two expected passband frequencies and the first spurious mode far away from the passbands. For tuning of the two sets of coupling strengths for both passbands, open/shorted secondary coupling structures are introduced as a fine-tuning coupling structure to increase/decrease the primary coupling strength. A four-pole DBF with passbands centered at 2450 and 3500 MHz, respectively, is proposed and fabricated using the HTS material. The measured results of the filter indicate superior performance and good fitting with the simulation results. The return losses of both passbands and the insertion losses obtained by measurements are greater than 14 dB and less than 0.3 dB, respectively. The stopband rejection exceeds 50 dB up to 8.0 GHz.

In this study, we propose a stepped-impedance-stub loaded interdigital capacitor resonator for design of a dual-band band-pass filter with a large bandwidth ratio. The presented resonator has strong and weak couplings in the upper passbands (UPs) and lower passbands (LPs), respectively, so as to form a large upper/lower bandwidth ratio. Adopting a dual-branch phase-matched feedline structure can meet the external quality factors required for the UP/LP. Therefore, these two passbands, defined by their respective center frequencies and bandwidths, can be manipulated independently. A four-pole dual-band example filter with a lower bandwidth of 20 MHz at 1576 MHz and an upper bandwidth of 200 MHz at 2450 MHz is successfully designed on an YBCO/MgO superconducting wafer. The filter exhibits excellent frequency responses. The upper/LPs show insertion losses below 0.07/0.22 dB and return losses above 15.3/15.3 dB. The stopband rejection is better than 57 dB until the first spurious passband up to 6150 MHz (3.9fL).

A novel N-spiral resonator with open-loop secondary coupling structure (OLSCS) is proposed to realize a compactultra-narrowband high temperature superconducting (HTS) filter. The coupling strength and polarity between the resonators can be significantly reduced and changed by introducing OLSCS, thus the required weak coupling can be achieved in a very compact size. A six-pole superconducting filter at 1701 MHz with a fractional bandwidth of 0.19％is designed to validate this method. The filter is fabricated on MgO substrate with a compact size of 15 mm × 10 mm. The measured insertion loss is 0.79 dB, and the return loss is better than 17.4 dB. The experimental results show a good agreement with the simulations.

A wideband wide stopband filter is designed using asymmetric stepped-impedance resonators (ASIRs) connected to a large open stub. The capacitive open stub and the parallel-coupled microstrip line are used to achieve the strong couplings for large fractional bandwidth (FBW). For a wide-stopband performance, the proposed filter uses ASIRs to improve the high-order spurious resonant frequency. The first and last resonators of the proposed filter are further optimized to suppress the spurious resonant frequency caused by open stub. The final filter has a 70% FBW centered at 4.87 GHz with 20-dB-rejection stopband up to 15.78 GHz (approximately 3.24f(0)). The measured insertion loss is less than 0.15 dB and the return loss is better than 17 dB.

This paper analyzes the asymmetrical split phenomenon of the odd and even modes in microstrip for closely coupled resonators. In general, when two resonators are coupled, the odd- and even-mode split is asymmetrical. This paper finds that, for two closely coupled resonators, odd mode always changes faster than even mode. This asymmetrical phenomenon is first predicted by using the effective capacitances of the even and odd mode. Then, the electric, magnetic, and mixed couplings are all discussed to demonstrate this phenomenon. Numerical results help us to control the odd mode in a wide range. This paper presents an ultra-wideband filter by using the interdigital coupled structure for the first time. A high-temperature superconducting filter operating at 7 GHz with -3 dB FBWs of 103% is designed and fabricated. Measured results show good performance and agree well with the simulations.

提出了一种具有可重构带阻特性的超宽带超导滤波器,可有效抑制通带内的干扰信号.该超宽带滤波器基本结构是由改进后的多模谐振器和平行耦合微带馈线构成.2-bit叉指电容(interdigital capacitor,IDC)阵列被加载在平行耦合馈线外端,实现阻带的“开/关”及阻带中心频率的控制.该滤波器是在尺寸为20.0mm×6.0mm的MgO介质基片上实现的.未经调谐的测试结果显示了优异特性,并且和仿真结果吻合得很好.超宽带通带内的阻带可自由“开/关”,中心频率调节范围从7.15到7.49GHz.此外,阻带在所有“开”的状态下显示了高的选择性(10dB带宽小于3％)和高的抑制性(高于38dB).

A stepped-impedance resonator with an interdigital capacitor (IDC) structure has been proposed to design a wideband filter with a wide and deep stopband. With the increase of the IDC part, there is always a maximum ratio of a spurious resonance frequency to a fundamental resonance frequency whether we change the length or number of interdigital fingers. We increase the width of a microstrip line loaded with the IDC structure to reduce the fundamental resonance frequency and increase the spurious resonance frequency. The harmonic ratio of the proposed resonator is raised to 5.6. Moreover, we bend the narrow microstrip line into a meander line to realize the strong coupling for a wideband filter. A ten-pole high-temperature superconducting filter centered at 2.128 GHz with a 22.7% bandwidth is fabricated for demonstration. The filter is fabricated on a 0.5-mm-thick MgO substrate with a circuit size of 26 x 10 mm. The measured maximum insertion loss in passband is 0.11 dB and the return loss is better than 17.3 dB. The measured out-of-band rejection is better than 80 dB up to 8.728 GHz, which is about 4.1 times of the center frequency.

A twin spiral-in-spiral-out (SISO) resonator has been proposed in the design of a compact ultra-narrows band high temperature superconducting filter. We systematically investigated the relationship between the coupling characteristics and the structure of the twin SISO resonator. Coupling strength and polarity can be effectively changed by adjusting the resonator structural ratio. This method of optimizing the ratio of the twin SISO resonator structure has an advantage of achieving stable and weak coupling, even if the resonator distance is relatively narrow, thereby promoting the miniaturization of the filter. Moreover, the three methods of optimizing ratio, distance, and staggering of adjacent resonators could be regarded as three degrees of freedom for adjusting the adjacent coupling to meet design needs. To demonstrate this method, we designed and fabricated a six-order superconducting filter with a fractional bandwidth of 0.18% at 2258 MHz based on the optimized twin SISO resonator. The resulting measurement shows a good agreement with the simulation.

A high-temperature superconducting wideband bandpass filter based on a triple-mode resonator is developed in this letter. A novel triple-mode resonator, which can not only generate a wide passband at low frequency but also suppress the harmonic responses and obtain a wide stopband, is proposed. To further improve the selectivity, we load two stubs at the input and output ports to generate one transmission zero at the low passband. The simulation results show that the filter is centered at 1 GHz (f(c)) with 111% 3-dB fractional bandwidth and has an upper stopband to 3.5f(c). The measured results show that the return loss is larger than 15 dB, and the insertion loss is less than 0.26 dB.

In this paper, an interdigital-type resonator with strong electric coupling is proposed for the wideband high-frequency (> 10 GHz) filter design. The proposed microstrip resonator consists of an H-shaped main line part with its both ends installed with interdigital finger parts. Strong electric coupling is achieved between adjacent resonators. A six-pole high-temperature superconducting filter at Ku-band using this resonator is designed and fabricated. The filter has a center frequency of 15.11 GHz with a fractional bandwidth of 30%. The insertion loss of the passband is less than 0.3 dB, and the return loss is greater than 14 dB without any tuning. (c) 2017 Elsevier B.V. All rights reserved.

A stepped-impedance-stub loaded stepped-impedance resonator (SISLSIR) is proposed to design a dual-band bandpass filter. The even- and odd-mode frequencies and the coupling strength of the proposed resonators can be independently designed and adjusted. A dual-feedline structure is used to meet the required external couplings of the 2 passbands. Thus, both the center frequencies and the bandwidths of the 2 passbands can be independently controlled. A 6-pole dual-band filter with the passbands of 3300 approximate to 3600 MHz and 4800 approximate to 5000 MHz is successfully designed using the proposed method and fabricated with YBCO/MgO high-temperature superconducting (HTS) wafer. The measured results of the filter exhibit high performance and match well with the simulations. The measured insertion losses are less than 0.2/0.3 dB, and the return losses are greater than 15/14 dB for the lower/upper passbands, respectively. The out-of-band rejection is greater than 68 dB up to 12 GHz.