- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Electrically tuned microwave CP cross slot patch antenna using liquid crystal technology
摘要： The rapid progress in material science and electronic technology is great possibility in designing reconfigurable wireless devices which are frequency tunable, flexible and consume low energy. In this paper, the anisotropic propriety of a new liquid crystal mixture 'GT3-23001' in their nematic phase are exploited for designing tunable circular polarized cross slot patch antenna for WLAN applications. Reconfiguration of frequency response is controlled through an electrical external command. The proposed reconfigurable antenna based on liquid crystal satisfies a continuous frequency tuning of 15.83% with a global bandwidth of around 467.92 MHz (19.5%). to validate this novel mixture of liquid crystal, the simulated results are compared with the measured data and a good agreement is noticed.
关键词： liquid crystal mixture,Material science,tunable patch,circular polarized,reconfigurable,frequency tuning
更新于2025-09-23 15:23:52
-
Wideband electrically-controlled Vernier frequency tuneable terahertz quantum cascade laser
摘要： Frequency tuning in terahertz frequency quantum cascade lasers is challenging because of low thermal and current tuning coefficients. Moreover, photonic designs like Vernier selection based sampled gratings, used in telecom lasers to tune emission frequency, are unsuitable due to the long terahertz wavelengths and will require impractically long cavities (>15 mm). Here, we report the first wideband frequency tuning from a monolithic device exploiting Vernier selection rules using a coupled-cavity laser with a defect engineered photonic lattice. A precisely positioned defect lattice allows us to engineer the free spectral range and finesse of one of the cavities, similar to a sampled grating but using shorter cavity lengths (<4mm). A coupled-cavity was used to tune the emission frequency. We achieve frequency tuning over 209 GHz, including mode-hop-free continuous tuning of ~6–21 GHz across six frequency bands, controlled through Stark shift, cavity-pulling, localized Joule heating and thermal effects.
关键词： quantum cascade laser,Terahertz,frequency tuning
更新于2025-09-23 15:21:01
-
Increased multiplexing of superconducting microresonator arrays by post-characterization adaptation of the on-chip capacitors
摘要： We present an interdigitated capacitor trimming technique for fine-tuning the resonance frequency of superconducting microresonators and increasing the multiplexing factor. We first measure the optical response of the array with a beam mapping system to link all resonances to their physical resonators. Then, a new set of resonance frequencies with uniform spacing and higher multiplexing factor is designed. We use simulations to deduce the lengths that we should trim from the capacitor fingers in order to shift the resonances to the desired frequencies. The sample is then modified using contact lithography and re-measured using the same setup. We demonstrate this technique on a 112-pixel aluminum lumped-element kinetic-inductance detector array. Before trimming, the resonance frequency deviation of this array is investigated. The variation of the inductor width plays the main role for the deviation. After trimming, the mean fractional frequency error for identified resonators is (cid:1)6.4 (cid:2) 10(cid:1)4, with a standard deviation of 1.8 (cid:2) 10(cid:1)4. The final optical yield is increased from 70.5% to 96.7% with no observable crosstalk beyond (cid:1)15 dB during mapping. This technique could be applied to other photon-sensitive superconducting microresonator arrays for increasing the yield and multiplexing factor.
关键词： interdigitated capacitor trimming,lumped-element kinetic-inductance detector,superconducting microresonators,multiplexing factor,resonance frequency tuning
更新于2025-09-23 15:21:01
-
[IEEE 2018 International Conference on Information and Telecommunication Technologies and Radio Electronics (UkrMiCo) - Odessa, Ukraine (2018.9.10-2018.9.14)] 2018 International Conference on Information and Telecommunication Technologies and Radio Electronics (UkrMiCo) - Micromechanical Tuning of Coplanar Waveguide Based Resonator
摘要： The paper extends idea of micromechanical tuning principle on coplanar waveguide based resonators. Finite elements and finite integral methods were used for electromagnetic problem solution. Presented simulation of signal electrode lift above substrate and dielectric body hover above the line surface demonstrates good tunability accompanied with low loss. Resonator based on tunable coplanar waveguide reaches tuning range up to 50% with displacement under 100 micrometres. Equivalent circuit of tunable CPW based band-stop stub filter is proposed.
关键词： frequency tuning,stub resonator,CPW,effective dielectric permittivity
更新于2025-09-23 15:21:01
-
Interface Stress for Bidirectional Frequency Tuning of Prebuckled Vanadium Dioxide MEMS Resonators
摘要： Interface stress between structural materials and thin film coatings has a significant influence on the resonant frequency of microelectromechanical system (MEMS) resonators. In this work, the axial stress on different types of buckled bridge MEMS resonator structures is controlled through the solid-to-solid phase transition of a VO2 thin film coating. The devices have identical dimensions, but different buckling orientations and profiles due to the combined effect of overetching and residual thermal stress mismatch. Thermal actuation is used to tune the resonant frequency of the device, but the changes in frequency are found to be dependent on the type of buckling for the device. Thermal actuation is achieved by applying an electrical current to integrated heaters, or by uniform substrate heating. Bidirectional tunability is found when substrate heating is used, while Joule heating shows a monotonic change in frequency. This phenomenon can be attributed to the transition in boundary conditions, where the turning points are indicated by the prominent changes in buckling amplitude. In addition, devices with opposite buckling orientations exhibit different tuning behaviors which can be explained by different bending moments induced by beam stress interface modification.
关键词： MEMS resonators,interface stress,buckling,vanadium dioxide,resonant frequency tuning
更新于2025-09-19 17:13:59
-
[IEEE 2019 Thirteenth International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Rome, Italy (2019.9.16-2019.9.21)] 2019 Thirteenth International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Frequency Tunable Monopole Patch Antenna Using Broadside Coupled Split Ring Resonator for Wireless Communication Applications
摘要： This paper presents metamaterial based monopole patch antenna capable of tuning the radiating frequency over a wide bandwidth. The proposed novel antenna structure makes use of the metamaterial properties of Broadside Coupled Split Ring Resonator (BCSRR) for frequency tuning. The magnetic resonant frequency of the proposed antenna can be tuned by slightly adjusting the interplanar distance between the rings of the BCSRR so that the coupling due to effective capacitance and inductance between them can be changed. The desired range of frequency tuning for potential applications like Global System for Mobiles (GSM), Bluetooth, Wi-Fi, Wi-Max, WLAN etc. is achieved by proper designing of the geometrical parameters of BCSRR. The different antennas for different applications in a single device can be replaced with the proposed novel metamaterial based antenna structure.
关键词： monopole patch antenna,wireless communication,frequency tuning,metamaterial,Broadside Coupled Split Ring Resonator
更新于2025-09-16 10:30:52
-
A 230-GHz High-Power and Wideband Coupled Standing Wave VCO in 65-nm CMOS
摘要： This article presents a 230-GHz wideband harmonic voltage-controlled oscillator (VCO) with large output power based on a compact and low-loss structure of coupled standing wave oscillators. In order to boost the output power, oscillators are coupled together without adding extra passive loss to the circuit. Transistors with inductive drain impedances provide the necessary negative resistance to the oscillators while simultaneously acting as active variable capacitors for frequency tuning and generate the desired second-harmonic power through their nonlinearities. Transmission lines at the drains are responsible for creating the inductive impedance as well as coupling adjacent oscillators and routing and combining the output power. Therefore, the circuit has a compact structure that minimizes passive losses. A varactor-less frequency tuning scheme is used and allows for wideband operation without sacrificing the output power. In addition to oscillator coupling and minimizing the losses, the output power has been boosted by engineering the harmonic impedance that is seen by the transistors in the circuit. The prototype chip was implemented in a 65-nm CMOS process. The output power of the VCO covers 219–238 GHz frequency band (8.35% tuning range) and delivers 3.4-dBm maximum output power. The minimum measured phase noise is ?105.8 dBc/Hz (at 10-MHz offset) while consuming 195 mW from a 1.5-V supply.
关键词： standing wave,low-loss,THz,wideband,frequency tuning,Compact structure,millimeter-wave (mm-Wave),voltage-controlled oscillator (VCO),mm-wave/terahertz (THz) power generation,harmonic oscillator,varactor-less
更新于2025-09-12 10:27:22
-
A Novel Approach for Computation of High-Order Axial Modes in a Gyrotron Resonator
摘要： This paper presents a novel approach for computation of high-order axial modes (HOAMs) in a conventional and uptapered gyrotron resonator. A code has been developed which computes the eigenfrequency, Q-factor and axial ?eld pro?le of HOAMs in the absence of electron beam in the resonator. Cyclic coordinate search method has been used for the optimization of complex eigenfrequencies, which obviates the computation of gradients of radiation boundary conditions and, hence, reduces computational complexity. HOAMs have been computed for resonators operating at 10, 132, 203, and 424 GHz, and the results obtained have been found to be in good quantitative agreement with the experimental and numerical data available in the published literature. Broadband continuous frequency tuning bandwidth found for subterahertz resonators also agrees well with the published results. HOAMs computed for 1-THz gyrotron resonator designed at CSIR-CEERI have also been presented.
关键词： Broadband continuous frequency tuning (CFT),subterahertz,optimization,open resonator,terahertz,high-order axial modes (HOAMs),gyrotron
更新于2025-09-11 14:15:04
-
Analysis of the Methods of Discrete and Smooth Frequency Tuning in Gyrotrons for Spectroscopy, on the Example of a Generator Operated in the 0.20–0.27 THz Frequency Range
摘要： We consider the main features of a low-power frequency-tunable gyrotron with an oversized cavity, which is designed for the purposes of nuclear magnetic resonance spectroscopy and other applications and operates in the 0.20–0.27 frequency range producing an output power of 200 W. We study the possibilities of wideband output frequency tuning by exciting a sequence of modes with similar caustics using magnetic-?eld variations and smooth tuning due to the excitation of modes with a great number of longitudinal variations. Aiming at widening the frequency tuning range, we also analyzed the possibility of smooth frequency tuning determined by controlled variations of the cavity temperature. Speci?c features of the electron-optical system of such a gyrotron is discussed, along with the possibility of increasing its e?ciency by means of single-stage recovery of the residual energy of the electron beam.
关键词： gyrotron,frequency tuning,nuclear magnetic resonance spectroscopy,electron-optical system,efficiency
更新于2025-09-10 09:29:36
-
Continuously tunable crossover based on HMSIW
摘要： A frequency-tuning crossover based on half-mode substrate-integrated waveguide (HMSIW) is presented for the ?rst time. Two HMSIW transmission lines are parallelly arranged to form the four-port crossover. Three tunable capacitors placed between the HMSIW transmission lines are used to obtain the tunable passband. For veri?cation, both simulated and measured results are given and good agreement between the simulation and measurement is observed. The measured passband can be tuned in a frequency range from 2.2 to 5.0 GHz (tuning range of 78%) with better than 19 dB return loss and 15 dB isolation, while the insertion loss varies from 0.93 to 1.97 dB.
关键词： half-mode substrate-integrated waveguide,frequency-tuning crossover,tunable passband,HMSIW
更新于2025-09-10 09:29:36