The Influence of a Coupling Film on Ultra-Low-Loss Dielectric Measurement Using an Open Resonator

A Fabry-Perot open resonator excited through a coupling film and loaded with a plane-parallel dielectric plate is analyzed. The eigen equation of the field in the resonator is obtained. The quality factors of the resonator with and without a coupling film are compared. The quality factors of the resonator loaded with a plate that is in resonance and off resonance are also compared. It is shown that the difference in coupling losses between a loaded resonator and an unloaded resonator may strongly affect the accuracy in measuring ultra-low loss dielectric material. Some ways to reduce the influence of coupling loss are discussed. Our experiment results are consistent with the numerical analysis.     

An antenna illuminated by a cavity resonator

A microwave aperture antenna with small phase errors has been constructed by utilizing the plane field configuration inside a box-shaped resonator to directly excite the aperture, which is the same shape as the resonator. The antenna is narrow band, as Q of the resonator should be sufficient for selecting the proper mode in the resonator. The possible bandwidth of the antenna is thus inverse proportional to the desired gain. Reasonable agreement between theory and measurements was obtained.     

基于新颖调谐谐振器的低相噪VCO设计

介绍了一种采用新颖谐振器的低相位噪声窄带压控振荡器(VCO)的设计方法。该谐振器采用源与负载横向交叉耦合结构,形成一个传输零点,提高了谐振器的Q值。该谐振器通过弱耦合与变容二极管连接,从而实现电压控制滤波器通带中心频率调谐。利用该谐振器设计了一个窄带VCO,并在先进设计系统(ADS)软件里仿真验证。该VCO中心频率6.15 GHz,在调谐电压从0到15 V的范围内调谐带宽60 MHz,相位噪声在整个调谐范围内优于-132 dBc/Hz@1MHz,输出功率为8.4 dBm,功率平坦度±0.1 dBm。     

Dielectric resonator with discrete electromechanical frequency tuning

A novel approach for discrete frequency tuning of dielectric resonators based on electromechanical actuators such as the microelectromechanical system is presented. The concept is based on the intermodal coupling between the TE/sub 01/spl delta// mode of a cylindrical dielectric resonator and the radially arranged planar slotline resonators. The resonance frequency of the dielectric resonator is changed by switching a resistive load at the open end of each quarter-wave slotline resonator leading to a variation of the coupling between the slotline resonator mode and the TE/sub 01/spl delta// mode of the dielectric resonator. As a consequence, the resonance frequency of the TE/sub 01/spl delta// mode changes. Based on this novel tuning concept, discrete tuning by 5 MHz in 0.25-MHz frequency steps was demonstrated for a test resonator at 2 GHz. The unloaded quality factor is about 12000 and the measured switching time is about 1 ms.     

A finesse-enhanced Er-doped-fiber ring resonator

A two-coupler-type Er-doped-fiber ring resonator that compensates for the round-trip optical loss by optical amplification is proposed. Also proposed is a mode-filtered heterodyne method for resonant-linewidth measurements which does not demand narrow-linewidth light sources, but uses the beat noise between two uncorrelated lights filtered by the resonator passband. With this method, a finesse ⩾500 and a resonant linewidth ⩽17 kHz were confirmed from the Er-doped fiber ring resonator. The ring resonator was operated as a high-resolution optical spectrum analyzer     

Quasi-TEM rectangular dielectric resonator antenna

A new rectangular dielectric resonator antenna is presented. The dielectric resonator is caught between two metallic plates. As a result, the structure works in a quasi-TEM mode. The proposed antenna exhibits a 22% impedance bandwidth and good radiating characteristics.     

激光器线宽对光纤环形谐振腔谐振特性的影响

采用光波场叠加的方法计算了谐振腔光纤陀螺的核心敏感部件———光纤环形谐振腔 (FRR)的传递系数 ,详细分析了激光器光谱线宽对光纤环形谐振腔谐振特性的影响 ,并进一步分析了在一定激光器光谱线宽条件下 ,由光探测器散弹噪声所限制的谐振腔光纤陀螺极限灵敏度和光纤环形谐振腔光路参数之间的关系 ,从而为谐振腔光纤陀螺的优化设计提供了理论基础     

Robust slot-fed dielectric resonator antenna using an intermediatesubstrate

A new slot-fed rectangular dielectric resonator antenna design is presented. An intermediate substrate is introduced between the slot and the resonator, resulting in a correct excitation of the fundamental mode and a particularly robust structure to adhesive thickness. Comparisons between finite difference time-domain simulations and measurements confirm the good properties of the proposed design     

超宽频单极子陶瓷介质谐振器天线设计与仿真

设计了一种尺寸小、频带宽、结构简单的单板子陶瓷介质谐振器天线,该天线经由在单板子周围加一个环形的介质谐振器而成.该设计主要通过在环形谐振器中使用高介电常数的陶瓷材料降低天线的尺寸,利用环形谐振器与单板子谐振频率之间的耦合展宽天线的频带.利用仿真软件HFSS为该天线建立模型并进行优化仿真,得到了最佳的天线设计参数,优化所...     

Ring resonator fabricated in phosphosilicate glass films deposited by chemical vapor deposition

The design and fabrication of a closed loop (ring) resonator is described. The resonator was fabricated in phosphosilicate glass films deposited by chemical vapor deposition onto oxidized silicon substrates. A channel waveguide-to-channel waveguide tapered mode directional coupler was used to transfer light from the input channel to the ring. To our knowledge this is the first demonstration of the use of such a coupler for coupling between channel waveguides. An analysis is presented for power distribution in the channels of the coupler, for stored, reflected and transmitted powers in the resonator and for resonator finesse. Operation of the resonator was demonstrated experimentally and finesse values of less than 3, comparable to those published elsewhere in the literature, were obtained.     

Theory of waveguide laser resonators with small curvature mirrors

A theoretical investigation into the eigenmodes of a waveguide resonator with small curvature mirrors is presented. Field differential equations are derived. Eigenfunctions and eigenvalues are given approximately. Cut-off curvatures are obtained. A criterion which can help to distinguish between a waveguide laser resonator and an open Fabry-Perot one is proposed     

Coupling Coefficient Between Microstrip Line and Dielectric Resonator

A formula of the coupling coefficient between a dielectric resonator and a microstrip line is derived from an analysis of the transmission characteristics of the microstrip line coupled to the dielectric resonator. A practical method of calculation is developed using Fourier analysis. The calculated values show good agreement with the experimental values.     

A New Type of Isolator for Millimeter-Wave Integrated Circuits Using a Nonreciprocal Traveling-Wave Resonator

A nonreciprocal traveling-wave resonator critically coupled to a waveguide becomes an isolator with high isolation. The dielectric image-line isolator with a magnetized ferrite pillbox as the nonreciprocal traveling-wave resonator is described. The validity of the theory is verified by experiments earned out at the 50-GHz range. The theoretical and experimental estimations of the coupling coefficient between a pillbox resonator and a straight dielectric waveguide are also included.     

Design of Compact Tri-Band Bandpass Filters Using Assembled Resonators

A novel approach for designing tri-band bandpass filters with independently controllable center frequencies and improved stopband rejection characteristic is presented in this paper. The assembled resonator constructed by a stepped impedance resonator and a common half-wavelength resonator is employed to obtain tri-band response. The stepped impedance resonator is designed to operate at the first and third passbands and the other resonator is designed to operate at the second passband. Two kinds of filter configurations with cascaded and pseudointerdigital formats are proposed. Based on lossless lumped-element equivalent circuit, it is found that both filter structures can introduce transmission zeros between passbands. To verify the proposed approach, two filters are designed and fabricated, the measured results exhibit tri-band bandpass responses with high selectivity.     

A novel self-coupled dual-mode ring resonator and its applications to bandpass filters

A novel dual-mode ring resonator with self-coupled segments, called a self-coupled ring resonator, is proposed. The self-coupling between ring segments provides the same mode perturbation effect as the conventional methods of adding stub, cutting notch, or varying line impedance on the ring resonator. The mode perturbation and transmission-zero generation due to the self-coupling effect are analyzed with the even-odd mode theory. The self-coupled ring resonator can have the capacitive or inductive perturbation simply by controlling the impedance ratio and coupling coefficients of self-coupled sections. For both perturbation cases, the transmission zeros exist at even multiples of the passband center frequency, resulting in wide stopband range. Also, only for the capacitive perturbation case, two transmission zeros are found on both sides of the passband, which brings a pseudo-elliptic bandpass response. In comparison with the regular uniform ring resonator, the self-coupled ring resonator takes shorter ring length, giving the compact size feature when applied to a bandpass filter design. A 2.45-GHz low-temperature co-fired ceramic bandpass filter based on the self-coupled ring resonator was designed to verify the proposed theory.     

YIG-tuned Gunn effect oscillator

A mechanical cavity of coaxial or waveguide type is generally used as a resonator of a Gunn oscillator. Reported here is the use of a resonator consisting of a ferrimagnetic sample instead of the mechanical cavity to obtain the electrically tunable Gun oscillator. The coupling between the Gunn diode and the the ferrimagnetic resonator was experimentally observed and oscillation frequency from 3.2 GHz to 2.4 GHz was obtained proportionally to the applied dc magnetic field.     

A differential narrow-band switched capacitor filtering technique

A new resonator loss cancellation technique is described using NMOS technology. It allows the implementation of high Q switched capacitor band-pass filters using single-stage low-gain amplifiers. The approach exchanges the amplifier high DC-gain requirement by a gain matching between amplifiers of the same resonator. A prototype sixth-order bandpass filter with center frequency of 100 kHz and a 5 kHz bandwidth was built to demonstrate the feasibility of the technique. Unloaded resonator quality factors of the order of 400 were achieved using amplifiers with a DC gain of 50.     

多注速调管TM310 模光子晶体谐振腔研究

研究了适用于多注速调管的TM₃₁₀ 模光子晶体谐振腔,发现在此类谐振腔的缺陷中心放置单层光子晶体结构能抑制与主模临近的杂模。进一步研究发现,为了易于工程实现,在不采用光子晶体谐振腔的前提下,在谐振腔中放置单层光子晶体结构,亦能抑制与主模临近的杂模,并能增大主模与非工作模式的频率间隔。利用HFSS 软件对X 波段此类谐振腔进行了模拟计算,验证了该方法的有效性。     

Hybrid Narrow-Band Tunable Bandpass Filter Based on Varactor Loaded Electromagnetic-Bandgap Coplanar Waveguides

A varactor-loaded resonator inserted between two Bragg reflectors has been implemented to design high-selectivity tunable bandpass filters. First, a mechanical tuning method is demonstrated. A varactor tunable bandpass filter is then implemented at 9 GHz, yielding good agreement between computational and experimental results. The tuning range reaches 3.5% with a loaded quality factor$Q_L =40$, a maximum insertion loss of 4.75 dB, and a return loss exceeding 20 dB. The theory is carefully explained, showing the importance of the parameters of the Bragg reflectors and of the resonator, in particular, the effect of diode-case parasitics and varactor position with respect to the resonator. A large-signal experimental analysis is done, showing a maximum allowable input power of a few dBm. Finally, possible filter improvements are discussed, and simulations with a microelectromechanical systems varactor are shown.