Rectangular and Circular Microstrip Disk Capacitors and Resonators

A simple method is described to calculate the capacitances of rectangular and circular microstrip disk capacitors. From the edge capacitances of the capacitors the influence of the fringing field on the resonance frequencies of microstrip disk resonators is calculated. A theory to compute the resonance frequencies of microstrip resonators with high accuracy is presented. The resonance frequencies are calculated from a resonator model employing an effective width and length or radius, respectively, filled with a medium of a "dynamic dielectric constant." Theoretical and experimental results are compared and found to be in agreement within 1 percent.     

Increased dielectric quality factor in planar resonators byselective dielectric removal

A means for increasing the effective dielectric quality factor by selective removal of dielectric from a microstrip resonator is discussed. Methods for determining the impedance and effective dielectric constant are included. The reduction in loss compared with an equivalent microstrip resonator is presented     

一种带输入输出抽头的新型阶梯式阻抗微带带通滤波器

本文提出了一种利用阶梯式阻抗微带线构造微型带通滤波器的新型结构。在该结构中引入以零相位方式接入的微带抽头，与带集总电容的阶梯式阻抗微带滤波器相配合，通过在通带两侧分别产生两个传输零点，很好地改善了滤波器的带通特性。     

Precision measurement of coupling between microstrip and TE01 mode dielectric resonator

The coupling between a microstrip transmission line and a dielectric resonator with a relative dielectric constant of 80 has been measured as a function of the distance between the resonator and the microstrip. Precision measurement involves the TRL de-embedding procedure, and data fitting to a fractional linear transformation on a complex plane. A comparison is made of covered and uncovered resonators, demonstrating the influence of radiation     

Spectral Domain Analysis of Elliptic Microstrip Disk Resonators

The elliptic microstrip disk resonator in an open microstrip configuration is analyzed using the spectral domain technique under quasi-static approximation. The normalized value of capacitance is presented as a function of the ratio of substrate thickness and semimajor axis of the elliptic disk resonator for different values of eccentricity. The fringing field effects associated with the structure are quantitatively assessed in terms of effective normalized semimajor axis. The resonator frequencies computed incorporating this effect are in good agreement with the experimental values reported in the literature. Results for various dielectric constants are also included.     

Wideband Microstrip Ring Resonator Bandpass Filters Under Multiple Resonances

A new class of wideband microstrip bandpass filters is proposed under multiple resonances of an asymmetric ring resonator. Two capacitive coupling elements are placed at two perpendicular positions of a squared ring, whereas a pair of open-circuited stubs is formed in the symmetrical plane of these two excited ports similar to a dual-mode ring filter in shape. By stretching the paired stubs close to one-eighth of a wavelength, the first two even-order resonances move down to be quasi-equally located at two sides of the first odd-order resonance, thus forming a triple-resonance ring resonator. As interdigital coupled lines are installed at two ports instead of lumped capacitors, two extra resonances can be moved into passband, thereby making up a quintuple-resonance ring resonator. To provide an insight into their operating mechanism, these ring resonators are characterized in terms of transmission line theory. Afterwards, various wideband microstrip ring resonator bandpass filters with one or two asymmetric ring resonators are optimally designed and fabricated. Simulated results are confirmed via experiment, showing good wideband filtering performance with widened/deepened upper stopband and sharpened rejection skirts outside the wide passband.     

空气隙对矩形微带天线性能的影响

论述了通过引入空气隙来改变矩形微带天线性能。首先,根据修改的微带天线的腔模理论,利用电磁场理论推导了具有空气隙的矩形微带天线的等效介电常数和谐振频率的理论计算公式。然后,考虑了边缘场的影响,引入了有效介电常数,对谐振频率的理论公式进行了修正。同时,应用等效原理和镜像原理推导出辐射方向图。最后,对于空气隙高度为不同数值的情况给出矩形微带天线的谐振频率和辐射方向图的数值结果,与文献实测结果很吻合。     

Microwave characterization of a microstrip line using a two-port ring resonator with an improved lumped-element model

A two-port ring resonator is used to characterize the microwave properties of a microstrip line printed on Ferro A6-S low-temperature co-fired ceramic. The ring and its coupling gaps are simulated using a simple lumped-element model. The coupling gaps are modeled as capacitors, the values of which are extracted using a commercial two-and-one-half-dimensional electromagnetic simulator. The validity of the lumped-element model is assessed by comparing the simulated and experimental resonant frequencies and, for the first time, the simulated magnitudes of both the reflection and transmission coefficients are also compared with those obtained experimentally. A correction for the frequency pushing due to the capacitive loading of the coupling gaps is also presented. The resulting model is then shown to predict the resonant frequencies to within 0.11% from 5 to 40 GHz. The simulated and experimental reflection magnitudes are within 0.5 dB across the band, whereas the transmission magnitudes are within 3.5 dB up to 22 GHz. Experimental results indicate that the loss of the microstrip ranges from approximately 0.11 to 0.42 dB/cm across the band and that the relative permittivity of the substrate is nearly constant versus frequency with an average value of 6.17.     

新型X波段圆极化介质谐振器天线

提出了一种工作于X波段的新型圆极化矩形介质谐振器天线。该天线是一块矩形介质谐振器嵌入到介质基板中并通过U型微带线激励。天线的接地面采用缺陷地的结构,可以通过调节该缺陷地对角的大小来产生2个正交模式实现圆极化,有效解决了一些圆极化天线馈电网络复杂的缺点。所设计天线的阻抗带宽为8.88~10.22 GHz。天线的轴比带宽为9.56~9.92 GHz,可应用于卫星广播、航空无线电导航业务和无线电定位。     

Dielectric ring-gap resonator for application in MMIC's

A dielectric resonator, the dielectric ring-gap resonator, is introduced and analyzed. The dielectric ring-gap resonator is obtained by sawing a narrow gap into a dielectric resonator. Resonant frequencies and unloaded Q-factors of quasi-TE_0pq mode in the ring-gap resonator have been calculated by an appropriate equivalent circuit starting from the resonant frequencies and the field distributions of the TE_0pq modes in the ring resonator. The calculated resonant frequencies of the fundamental quasi-TE₀₁₁ mode show an accuracy of <1% compared with the experimental results. Coupling techniques to couple the ring-gap resonator to a microstrip line on a thin substrate, using the electric fringing field near the gap, have been experimentally investigated. A rigorous method for determining resonant frequencies and field distributions of TE modes in a multicomposite multilayered cylindrical resonator is presented. This resonator consists of numbers of cylinders that are arbitrarily layered in the axial direction     

Measurement of the complex permittivity of low-loss planarmicrowave substrates using aperture-coupled microstrip resonators

This paper describes a technique for the determination of the complex permittivity of low-loss dielectric substrates at microwave frequencies. The technique utilizes an aperture-coupled microstrip resonator fed using a microstrip line in a two layer configuration. The ends of the resonator are shorted in order to avoid radiation. The technique can also be used for the measurement of the complex permittivity of other electronic materials such as thin and thick film materials at microwave frequencies. Nonresonant modes and conductor losses are taken into account in the analysis to improve the accuracy of the results. Analysis procedure as well as experimental results are presented     

Optimum dielectric overlay thickness for equal even- and odd-mode phase velocities in coupled microstrip circuits

An optimum dielectric overlay thickness was found for achieving the equal even- and odd-mode phase velocities in coupled microstrip lines. The theoretical results were calculated based on a variational method. Coupled linear resonator structures were used to measure both the even- and odd-mode effective dielectric constants and the results agree very well with the theory. A directional coupler, built with overlay, has greater than 60 dB isolation as compared with 20 dB isolation for an uncompensated coupler.<>     

Analysis of the Microstrip and the Electrooptic Light Modulator

Green's function for examples with an isotropic media is obtained using the image-coefficient method. The method is based on the boundary conditions and the reciprocity relation. Using this Green's function and solving directly the charge distribution on the strip, the line capacitances per unit length of a microstrip and of an electrooptic light modulator are obtained. High accuracy of this method is demonstrated by comparing the present results with the results obtained using the conformal mapping and with other data appeared in the literature. The charge distributions are also illustrated. Of particular interest is the effective filling fraction of the dielectric material, which depends mainly on the shape ratio and only slightly on the relative dielectric constant. The effective filling fractions are tabulated for the microstrip with a homogeneous dielectric substrate.     

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.     

Microstrip circuit applications of high-Q open microwaveresonators

An open microwave resonator can be formed above a planar microstrip substrate by suspending a spherical reflector above it. A theory is developed to account for the coupling between such an open resonator mode and a microstrip line. The open resonator is shown to have useful circuit properties similar to a dielectric resonator, but with the potential of efficient operation well into the millimeter-wave range. Experimental confirmation of the theory is demonstrated by a scale model of a microstrip-based single-pole bandpass filter, which shows a loaded Q of 860 and a minimum loss of 0.8 dB±0.4 dB at 10 GHz     

Microstrip resonators on anisotropic substrates

The spectral domain method is applied to study shielded microstrip resonators printed on anisotropic substrates. A Green's function that takes into account the dielectric anisotropy effects is derived through a fourth-order formulation. Galerkin's method is then applied to form the characteristic equation from which the resonant frequency of the microstrip resonator is numerically obtained. Results for a microstrip situated on an isotropic substrate are used to validate the theory     

Comparative study on the mutual coupling between different sized cylindrical dielectric resonators antennas and circular microstrip patch antennas

A systematic comparative study on the mutual coupling (S/sub 21/) between dielectric resonator antennas (DRAs) and microstrip patch antennas is presented. The mutual coupling between two cylindrical probe-fed DRAs is studied for different radius to height (a/L) ratios. It is found that the mutual coupling decreases with the radius to height ratio. Comparison between mutual coupling of probe-fed cylindrical DRAs and circular microstrip patch antennas with different dielectric substrates are also studied. The mutual coupling between DRAs is 2 dB stronger than between microstrip patch antennas when the patch is etched on a dielectric substrate of a dielectric constant close to the permittivity of the DRA. The mutual coupling of the circular patch antennas reduces with the dielectric constant of the substrate.     

Embedded Capacitors in Printed Wiring Board: A Technological Review

This paper reviews the technology of embedded capacitors, which has gained importance with an increase in the operating frequency and a decrease in the supply voltage of electronic circuits. These capacitors have been found to reduce the number of surface-mount capacitors, which can assist in the miniaturization of printed wiring boards. This paper describes various aspects of embedded capacitors, such as electrical performance, available dielectric materials, manufacturing processes, and reliability. Improvement in electrical performance is explained using a cavity model from the theory of microstrip antennas. The advantages and disadvantages of dielectric materials such as polymers, ceramics, polymer–ceramic composites, and polymer–conductive filler composites are discussed. Various manufacturing techniques that can be used for the fabrication of embedded capacitors are also discussed. Embedded capacitors have many advantages, but failure of an embedded capacitor can lead to board failure since these capacitors are not reworkable. The effect of various environmental stress conditions on the reliability of embedded capacitors is reviewed.     

A Proposal of a New Dielectric Resonator Construction for MIC's

A compact and high-temperature-stable dielectric resonator having no shielding metal walls nor a conventional frequency tuning screw is described. This resonator consists of a high epsilon/sub r/ dielectric resonator element mounted on a low-loss dielectric mount, a dielectric disk with thin metal film fixed on the resonator element, and a microstrip line substrate on which to mount the constituents. The resonant frequency tuning is made by trimming the metal film on the disk. The TE/sub 01delta/ -mode resonant frequencies are analyzed through dielectric waveguide model application. Less than 1-percent analytical error is presented in comparison with the experimental data for a practical resonator. The frequency tuning limit by metal film trimming is about 7 percent. The unfoaded Q value of 2700 at 8.8 GHz and a 4.4-ppm/deg frequency temperature coefficient are obtained.