共查询到20条相似文献,搜索用时 15 毫秒
1.
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. 相似文献
2.
N. T. Cherpak Yu. F. Filipov S. N. Kharkovsky A. Ya. Kirichenko 《Journal of Infrared, Millimeter and Terahertz Waves》1993,14(3):617-627
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-Tc superconductor) and for generation obtaining of millimeter wave oscillations has been considered. 相似文献
3.
Kell R.C. Riches E.E. Brigginshaw P. Olds G.C.E. Thomas A.J. Mayo R.F. Rendlf D.F. 《Electronics letters》1970,6(19):614-615
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. 相似文献
4.
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 相似文献
5.
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 相似文献
6.
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. 相似文献
7.
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. 相似文献
8.
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. 相似文献
9.
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. 相似文献
10.
An aperture-coupled equilateral-triangular dielectric resonator antenna (DRA) of very high permittivity (ϵr=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 相似文献
11.
Seungpyo Hong Kai Chang 《Microwave and Wireless Components Letters, IEEE》2005,15(9):582-584
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. 相似文献
12.
13.
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. 相似文献
14.
15.
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. 相似文献
16.
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. 相似文献
17.
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 相似文献
18.
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 相似文献
19.
A. Rydberg 《Journal of Infrared, Millimeter and Terahertz Waves》1985,6(7):635-647
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. 相似文献
20.
Effective permittivity of dielectric mixtures 总被引:7,自引:0,他引:7
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 相似文献