Temperature compensated,high permittivity dielectric resonators for millimeter wave systems

The properties of selected low loss, temperature compensated high permittivity microwave and millimetre wave dielectrics are summarised and experimental convenience suggests that planar hybrid microstrip is the preferred circuit technology for the initial studies of dielectric resonators at the millimetre wavelengths. Data are presented for temperature stabilised oscillators and some simple band pass filters are discussed.     

Quasioptical dielectric resonators in millimeter-wave band experiments

New results of theoretical and experimental investigations of non-uniform dielectric resonators with the higher order azimuthal waves (whispering gallery modes) have been presented. Their application for study of various materials (dielectric, high-T_c superconductor) and for generation obtaining of millimeter wave oscillations has been considered.     

Novel temperature-stable ceramics for microwave dielectric resonators and microstrip substrates

Ceramics comprising homogeneous single-phase zirconate solid solutions of suitable composition have very low temperature coefficients of permittivity, low-frequency permittivities of 30?40 and low losses. Dielectric resonators give Q values up to 4000 and permittivities of 28?35 at 4?5 GHz. The effective permittivity measured on a microstrip ring resonator on a calcium-zirconate substrate shows the dispersion predicted theoretically; the effective permittivity increases from 17 to 23 over the frequency range 1?12 GHz and gives 28.1 as the calculated real value of the permittivity of the substrate. The measured Q value of 200 indicates negligible dielectric losses compared with the I2R losses.     

An experimental investigation of the microstrip step discontinuity

A simple, inexpensive technique for performing wideband (multidecade) validation measurements is introduced. The authors emphasize scaling the desired validation frequencies and dimensions so that both the measurement and the fabrication can be performed accurately and inexpensively. The utility of a composite structure (rather than a single discontinuity) is also demonstrated, and the sensitivity of the structure to changes in the discontinuity is checked. The technique allows an inexpensive validation to be performed which previously could be realized only with large scatter, if at all     

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     

High frequency permittivity determination by spectra simulation and measurement of microstrip ring resonators

The S/sub 21/ spectra of microstrip ring resonators have been measured experimentally and also computed using the finite-difference time-domain (FDTD) method. The dielectric constant of the substrate was determined by fitting the simulation results to the experimental data. The results are more self-consistent than those obtained using the Wheeler-Hammerstad method.     

An experimental investigation of electrically thick rectangular microstrip antennas

The electromagnetic properties of electrically thick rectangular microstrip antennas were investigated experimentally. Antennas were fabricated with different patch sizes and with electrical thicknesses ranging from 0.03 to 0.23 wavelengths in the dielectric substrate. The resonant frequencies were measured and compared to existing formulas. The bandwidth was calculated as a function of electrical thickness and the antenna radiation patterns were measured.     

Experimental study of a microstrip array on high permittivity substrate

The results of an experimental study of microstrip patch antennas on moderately thick (0.02-0.03lambda_{0}) substrates with relative permittivities of 10 and 13 are reported. Measured input impedances are qualitatively similar to those of antennas on thinner substrates with lowerepsilon_{r}, but significant differences in resonant resistance are observed for probe-fed and microstripline-fed antennas. Radiation patterns of individual elements exhibit deep scallops that appear to be caused by surface wave diffraction at the edges of the substrate, but four-element monopulse patterns exhibit a usable main beam and tracking null.     

Open resonators for the measurement of permittivity

A small modification to Yu's model leads to more consistent values of permittivity. The difference is insignificant for confocal resonators but is appreciable if the resonator is very short or very long.     

Low profile equilateral-triangular dielectric resonator antenna ofvery high permittivity

An aperture-coupled equilateral-triangular dielectric resonator antenna (DRA) of very high permittivity (ϵ_r=82) is investigated experimentally. The triangular DRA is more compact in size than rectangular and circular disk DRAs operating at the same frequency. The impedance matching, radiation patterns and antenna gain of the triangular DRA are presented     

Stub-tuned microstrip bandpass filters for millimeter-wave diplexer design

This letter presents a new design for microstrip bandpass filters and its application to a millimeter-wave diplexer. Basically, parallel-coupled microstrip lines are utilized for bandpass response and non-uniform open-circuited stubs are added to tune the bandwidth of the passband and improve out-of-band rejection. The designed filters are connected to make a diplexer, which can be used in a phased-array transceiver system operating in millimeter-wave range. The diplexer is designed to separate an input signal containing both 32GHz and 35GHz into two signals of 32GHz and 35GHz, respectively or to combine two signals at 32GHz and 35GHz into one signal.     

大功率介质腔滤波器设计

针对腔体滤波器在低气压环境下容易发生功率击穿的难题,提出了一种高Q值介质腔滤波器的设计方法,可以有效地提高滤波器低气压功率放电的阈值,按照此方法,设计了一款TM模介质腔滤波器,使用CST、Ansoft Designer软件进行仿真和优化,使用矢量网络分析仪对制作的产品进行了性能测试,测试曲线和仿真曲线完全吻合,此滤波器能够在低气压(13~101 000 Pa)环境中通过20 W的功率信号,且滤波器Q值高,体积小。     

Dynamic permittivity of microstrip ring resonator

A simplified method for calculation of the dynamic dielectric constant for a microstrip ring resonator is presented. Attention is also given to the sectors of the annular structure. The new results are compared with earlier work.     

硅基无源器件介电薄膜相对介电常数表征方法研究

介电薄膜的相对介电常数是介电材料的重要表征参数之一。在表征未知材料之前,需要用已知材料——二氧化硅验证表征方法的准确性。针对这一问题,提取了两组不同长度硅基共面波导型传输线的S参数,基于保角映射原理,使用三种不同的方法,先得到器件的有效介电常数以及结构参数,然后表征得到介电薄膜的相对介电常数。结果表明:S21表征法的平均偏差约1.435%,单线表征法的平均偏差约为0.483%,双线表征法的平均偏差约为0.448%。因此,可以得出结论:三种方法均可以准确地表征相对介电常数。     

Complementary split ring resonators for microstrip diplexer design

A new topology for the design of microstrip microwave diplexers, based on the use of quasi-lumped resonators, is presented. Specifically, the receiver (Rx) and transmitter (Tx) filters of the diplexer are implemented by etching complementary split ring resonators (CSRRs) in the ground plane as well as series capacitive gaps and shunt inductive strips in the upper metal level. By this means, narrowband microwave diplexers with transmission zeros can be synthesised, which allow for the improvement of Rx/Tx isolation. A prototype device operative in the 2.4-3.0 GHz frequency band is presented. Measured insertion losses are lower than 2 dB while the isolation between Rx/Tx channels is in the vicinity of 40 dB. Diplexer dimensions (29.8/spl times/16.3 mm), which are small on account of the semi-lumped resonators employed, and performance point to the practical application of these structures in communication transceiver front-ends.     

Compact microstrip resonators for 900 MHz frequency band

A technique to reduce the size of planar resonators is investigated using a transmission line model and a finite-difference time-domain (FDTD) method. New miniaturized square microstrip resonators are proposed for 900 MHz band. The resonators offer low impedance sections leading to a better handling of power. The feasibility of compact filters using the proposed resonators is demonstrated. The input/output coupling lines of a two-pole filter have been positioned in a way that produces a filter response with transmission zeros on the both sides of the pass-band. Sharper skirts and higher out-of-band rejection are obtained for four-pole filters with cross-coupled resonators.     

New experimental results of millimetre-wave whispering gallery modedielectric resonators excited by microstrip lines

Presents an experimental investigation of planar millimetre-wave dielectric resonators acting on whispering gallery modes and excited by microstrip lines. Experimental results including measured resonant frequencies and loaded quality factors obtained in both Ka bands (26.5-40 GHz and 90-100 GHz) are presented     

Bandwidth enhancement of dielectric resonator antenna by loading alow-profile dielectric disk of very high permittivity

The aperture-coupled cylindrical dielectric resonator (DR) antenna loaded by a low-profile DR disk of very high permittivity is studied experimentally. By using the low-profile parasitic DR disk the antenna bandwidth can be increased from 8% bandwidth to 25%. The characteristics of the new configuration are measured and discussed     

Theoretical and experimental investigation of millimeter-wave TED's in cross-waveguide oscillators

Theoretical and experimental investigations of millimeterwave GaAs second harmonic transferred electron device (TED) oscillators using separate circuits for frequency and power optimization, are described. The theory predicts the oscillation frequency with less than 2% error for the second harmonic. Apart from the 2d and 3d, a 4'th harmonic from the TED was observed up to 130 GHz.     

Effective permittivity of dielectric mixtures

General mixing formulas are derived for discrete scatterers immersed in a host medium. The inclusion particles are assumed to be ellipsoidal. The electric field inside the scatterers is determined by quasi-static analysis, assuming the diameter of the inclusion particles to be much smaller than one wavelength. The results are applicable to general multiphase mixtures, and the scattering ellipsoids of the different phases can have different sizes and arbitrary ellipticity distribution and axis orientation, i.e. the mixture may be isotropic or anisotropic. The resulting mixing formula is nonlinear and is suitable for iterative solutions. The formula contains a quantity called the apparent permittivity, and with different choices of this quantity, the result leads to the generalized Lorentz-Lorenz formula, the generalized Polder-van Santen formula, and the generalized coherent potential-quasicrystalline approximation formula. The results are applied to calculating the complex effective permittivity of dry and wet snow, and sea ice