Computation of frequency-dependent propagation characteristics of microstriplike propagation structures with discontinuous layers (original) (raw)
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A Method for Calculating the Frequency-Dependent Properties of Microstrip Discontinuities
IEEE Transactions on Microwave Theory and Techniques, 1977
Afrstract-A method is described for enlcrdating the dynamical (frequency-dependent) properties of varions microstrip discontinuities such as unsymmetrical crossings, T junctions, right-angle bends, impedance steps, and filter elements. The method is applied Ito an unsymmetrical T junction with three different linewidths. Using a wavegnide model with frequency-dependent parameters, a field matching method proposed by Kiihn is employed to compute tlhe scattering matrix of the strictures. The elements of the scattering mntrix calculated in this way differ from those derived from static methods by a bigher frequency dependence, especially for frequencies near tlhe cutoff frequencies of the higher order modes on the microstrip lines. The theoretical results are compared with measurements, and theory and experiment are fonnd to correspond closely.
International Journal of Scientific Research in Science and Technology, 2022
In this paper, we studied about static analysis and losses of microwave isolated single stripline structure using conformal mapping method. Microstrip lines due to presence of two different dielectric boundaries does not support a pure TEM wave. It is assumed that only the fundamental mode will propagate, but the propagation constant, γ, is a non¬linear function of frequency. Due to the presence of two dif¬ferent dielectrics, the fringing fields experience an in-homogenous dielectric leading to a discontinuity on the field. A parameter called effective permittivity (ϵ_eff ) is introduced, which is always lesser than the permittivity of the substrate as the fields exists both in air and the substrate. Due to the non-TEM nature of the fields, the effective permittivity is dependent on the frequency. This is due to the fact that more field lines will penetrate the substrate with increasing frequency thus increasing the effective permittivity.
International Journal of RF and Microwave Computer-Aided Engineering, 2003
mm is inset 19.25 mm from the center of a patch edge. The coaxial aperture has radius 1.75 mm. The resonant frequency, resistance, and reactance were measured as 1.55 GHz, 128.1 ⍀, and 48.6 ⍀, respectively. A circular capacitor patch is added. The probe is now penetrating the radiating patch and is connected to the center of the capacitor patch. The radius of the hole in the radiating patch is 2 mm. The impedance was calculated for a range of structures. Four different antenna elements were fabricated and measured. For the fabricated structures the distance between the patch and the capacitor patch is 3.4 mm. The measured resonant frequency in all cases stayed at 1.55 GHz, as expected. In Figure 3, the resonant impedance is given for several distances d 2 between the radiating and capacitor patch and for capacitor patch diameters ranging from 5 to 35 mm. The agreement is very good for the resistance. A small shift is seen in the reactance. It is probably due to the use of the approximate slot model. It is clearly seen that the inductance of the probe can be canceled out by selecting the configuration with zero inductance and 50 ⍀ resistance. This allows the bandwidth to be broadened considerably. IV. CONCLUSION A network model is given for the calculation of the effect of a top capacitor patch on the impedance of a microstrip antenna. The main advantages of the procedure are that it is a very fast a posteriori procedure, it is easily implemented, and it gives full physical insight. Therefore, it is a very practical tool for antenna designers that want to use the concept of capacitive feeding.
Full-wave analysis of radiation effect of microstrip transmission lines
Analog Integrated Circuits and Signal Processing, 1994
A full-wave analysis of radiation effects produced by discontinuities in microstrip and buried microstrip transmission lines is presented. Beginning with the dyadic Green's function for a dielectric slab, with an embedded source, an integral equation is formulated. This equation is then solved by the method of moments to obtain the current distributions along the transmission line, in particular, near the discontinuities. Employing these results, the near-and far-zone fields, as well as radiation patterns are computed. The results from our method showed good agreement with those of previous publications in complex reflection and transmission coefficients, and equivalent capacitance values. It is found that under resonance conditions the radiation efficiency of a simple structure can exceed 41%, which may cause a potential problem in electromagnetic compatibility. Our analytic result also shows that the maximum radiation occurs when the source is located at the height of ko/4fl-~e r from the bottom ground plane, which should be prevented. i i I ~ J J t I J J ~ i I J ~ J i
Full-Wave analysis of microstrip lines with variable thickness substrates using the method of lines
IEICE Electronics Express, 2004
In this paper, we present a full-wave analysis of microstrip lines printed on variable thickness substrates using the method of lines (MoL). The propagation constant of a microstrip line in the interface of one dielectric is computed as a function of different shape characteristics. The results are compared with those obtained in previous research, especially with those using the discrete mode matching technique (DMM). Good agreement is found between the results. Furthermore, the convergence behavior of the method of lines is examined and finally, we show some numerical results, obtained with analyzing this structure in a large band of frequencies.
Mode matching analysis of the coplanar microstripline on a layered dielectric substrate
1989
In this project, mode matching was used to calculate the propagation constant and the characteristic impedance of a coplanar coupled microstrip line. The Striplines are considered to be perfect electric conductors of negligible thickness, and are separated from the ground plane by three layers of dielectric material. The layer with the higher dielectric constant is sandwiched between two layers of lower dielectric constants, such that the field is confined to this middle layer, which is called the conducting layer of the microstrip line. By confining the field to this layer, losses at the metal conductor are minimized.
IEEE Transactions on Electromagnetic Compatibility, 1994
time-stepping method, it is necessary to have sufficient time-domain results provided by many time divisions such that good resolution is achieved with the use of the FFT. yields frequency-domain information such as cutoff frequencies, without any time divisions or involvement of the FFT, as developed in this short paper. Having implemented the analyses of the static and dynamic characteristics, a reasonable physical structure of the T E M cell could then be resolved. Further experimental work is needed to construct a real TTEM cell based on the present computer simulation.
IEEE Transactions on Microwave Theory and Techniques, 1995
A Wiener-Hopf-type analysis of the canonical problem of a TEM wave obliquely incident at the edge of the truncated upper conductor of a parallel plate waveguide loaded with a uniaxial anisotropic dielectric is presented. A numerical integration scheme as well as a thin substrate approximation for the reflection coefficient is given. The influence of the dielectric anisotropy and the slab thickness on the reflection coefficient and the edge admittance are investigated. Numerical results show the importance of the dielectric anisotropy and the expected effects in microstrip applications.