Suspended Slot Line Using Double Layer Dielectric

This paper presents a rigorous analysis of a) slot line on a double layer dielectric substrate, and b) slot line sandwiched between two dielectric substrates. The structure is assumed to be suspended inside a conducting enclosure of arbitrary dimensions. The dielectric substrates are assumed to be isotropic and homogeneous and are of arbitrary thickness and relative permittivity. The conducting enclosure and the zero thickness metallization on the substrate, are assumed to have infinite conductivity. The effect of shielding on the dispersion, characteristic impedance, and the effective dielectric constant are illustrated. These results should find application in the design and fabrication of MIC components and subsystems.     

Suspended Coupled Slotline Using Double Layer Dielectric

This paper presents a rigorous analysis of coupled slotline a) on a double-layer dielectric substrate, and b) sandwiched between two dielectric substrates. The dielectric substrates are of arbitrary thickness and permittivity and the structure is assumed to be suspended inside a conducting enclosure of arbitrary dimensions. The odd- and even-mode dispersion and characteristics impedance, along with the effect of shielding on these, are illustrated. These structures should find extensive applications in the fabrication of MIC components, such as directional couplers, phase shifters, and mixers.     

Propagation in Broadside-Coupled Suspended-Substrate Stripline in E-Plane

The spectral-domain analysis is applied to the derivation of the propagation characteristics of the even and odd mode, for the broad-sidecoupled suspended-substrate stripline (BCSSS). The characteristic impedance, based on the current-power definition, as well as the effective permittivity are evaluated. Numerical results are presented illustrating the effects of several different dimensional parameters. Numerical results indicate a large spread between even- and odd-mode impedance for thin substrates (D/A < 0.045) and stripwidths ranging 0.046<= W/B<= 0.47, suggesting tight coupling. Negligible frequency dependence on odd-mode impedance is evident, as well as significant frequency effects on even-mode impedance. Considerable dispersion is shown to be present in the odd mode for wider strips. Measured results for a low-pass filter and cascaded transitions are presented.     

Even-mode characteristics of the bilateral slotline

Transmission line data for the even-mode characteristics of a bilateral slotline (double-sided slotline) are presented. The slotline is analyzed by the spectral Galerkin method, and results are presented for the slot wavelength and characteristic impedance for substrates having ε_r=2.22, 3.5, 6.0, 9.8, and 12.8. The results are presented for 0.01⩽√ε_r-1d/λ ₀⩽0.25, where 2d is the substrate thickness and ε_r its dielectric constant     

Accuracy of Equations for Coupled Slab Lines (Letters)

The determination of the characteristic impedance of coupled slab lines has been a subject of investigation for many years. Following on Frankel's pioneering work [1], Chisholm obtained art accurate analytical solution for the odd-mode impedance of a pair of coupled slab lines [2]. In 1980, Levy presented Chisholm's equations, together with those due to McDermott for the even-mode impedance, in a general form suitable for calculation [3]. He also confirmed the accuracy of the equations with an efficient numerical procedure.     

Coupled Rectangular Bars Between Parallel Plates

Curves are presented giving the even-mode fringing capacitance, the odd-mode fringing capacitance, and the difference between odd- and even-mode fringing capacitances for wide ranges of thickness and spacing of rectangular bars centered between parallel plates. Simple formulas are given relating these capacitances to even- and odd-mode characteristic impedances of coupled rectangular bars. possible applications to strip-line and other circuits are described. The appendix gives the derivation of the fringing, capacitances by conformal mapping techniques. The results are exact for bars extending in width infinitely far from the coupling region, and have only small error (less than 1.24 per cent) for bars whose width is greater than about 35 per cent of the difference between plate spacing and bar thickness.     

Approximations to hybrid mode slot line behaviour

New closed form formulas are presented for the dispersion characteristic (?'/ ?) and characteristic impedance (Z0) of single slot line. ?'/? and Z0 are given as functions of the slot width w over substrate thickness H ratio and the ratio H/? where ? is the free-space wavelength. For the ranges of variable considered ?'/? values agree with S. B. Cohn's and Mariani et al. results to within 5% and Z0 agrees to within 14.5% or better.     

Quasi-optical integrated antenna and receiver front end

A quasioptical receiver front end applicable to both microwave and millimeter-wave receiver arrays is presented. Two planar microwave integrated circuit (MIC) quasioptical receiver circuit designs that integrate a coupled slot antenna, a Schottky-diode balanced mixer, and a local oscillator on the same substrate are described. The even-mode/odd-mode characteristics of the coupled slotlines are used to achieve intrinsic RF/LO and RF/IF isolation. To demonstrate circuit feasibility, X-band scaled models of the circuit unit using a Gunn-diode oscillator on an Epsilam-10 substrate, and MESFET local oscillator on a R/T Duroid substrate were built and tested. Results of these tests are included     

Picosecond pulse propagation in coplanar waveguide forwarddirectional couplers

The spectral-domain method is used to calculate the frequency-dependent even- and odd-mode effective dielectric constants of symmetric coplanar waveguide forward directional couplers. Comparisons are made with symmetric microstrip forward couplers on the same substrate that have the same line spacing and access port characteristic impedance. Results are shown which indicate that certain coplanar designs will have lower loss and greater bandwidth than the microstrip devices. Picosecond pulse propagation in both structures is studied using the calculated dispersion data     

Analysis and Design of Planar, Spiral-Shaped, Transmission-Line Transformers

Coupled microstrip line theory is applied to analyze planar Ruthroff transmission-line transformers (TLTs). The results demonstrate that the TLT's low frequency response improves as the microstrip line's even-mode impedance increases, whereas the ratio of load impedance to the line's odd-mode impedance controls the high frequency response. Analysis of an approximate model of coupled microstrip lines formed into a spiral leads to a technique for predicting the performance of planar, spiral-shaped, Ruthroff TLTs. Microwave measurements up to 10 GHz are compared with predictions from the model for regular and suspended Ruthroff TLTs fabricated through a multichip-module deposited (MCM-D) process     

A mode projecting method for the quasi-static analysis ofelectrooptic device electrodes considering finite metallizationthickness and anisotropic substrate

The method presented is an extension of the mode matching method (MMM), utilizing the idea of base transformation and vector projection in inner-product space. In contrast to the conventional MMM, this approach decouples the order of the linear equation system from the truncation index of the mode expansion series and is free from the relative convergence phenomenon of the MMM. Coplanar strip electrodes are analyzed, and the effects of the metallization thickness, buffer layer, and conducting enclosure on the effective permittivity, characteristic impedance, and electric field in the substrate are presented     

Characteristics of Inhomogeneous Broadside-Coupled Striplines

A variational method for the analysis of inhomogeneous broadside-coupled striplines is described. The data for even- and odd-mode characteristic impedances, effective dielectric constants, and mode phase velocity ratios are presented. It is found that the phase velocity ratio may be varied over the range 1.14 /spl les/ ( V/sub e/ / V/sub 0/) /spl les/ 3.6 for broadside-coupled suspended microstrip lines (BSML) and 0.36 /spl les/ ( V/sub e/ / V/sub 0/) /spl les/ 0.93 for broadside-coupled inverted microstrip lines (BIML) using materials with dielectric constant less than 16 and S/b /spl ges/ 0.05, W/b /spl les/ 2.0. The effect of nonzero strip thickness is also calculated. It is noticed that the effect of thickness is more pronounced for the odd-mode case than for the even mode. Losses are obtained using the incremental inductance rule of Wheeler. The odd-mode attenuation constant is always higher than the even-mode value.     

Characteristics of Coupled Microstriplines

Semiempirical design equations for the even- and odd-mode characteristics of coupled microstriplines are presented. The characteristics include capacitance, effective dielectric constant, impedance, and losses. The coupled line capacitances are obtained by suitably dividing the total capacitance into parallel plate and fringing capacitances. These capacitances are then used to determine other characteristics. The accuracy of characteristic impedances obtained from these capacitances is better than 3 percent. The sensitivity of the characteristics of coupled microstriplines to the tolerance in parameters is described. It is observed that the effect of tolerances on the coupling constant of a directional coupler increases with the increase in the value of coupling constant. The effects of dispersion and the finite thickness of metal strips have been included. It is noticed that the dispersion is more pronounced for even mode, whereas finite strip thickness affects odd mode to larger extent.     

Propagation Parameters of Coupled Microstrip-Like Transmission Lines for Millimeter-Wave Applications

A variational expression is derived for the propagation parameters of coupled microstrip-like transmission lines for millimeter-wave applications using the "transverse transmission line" method. Numerical results are presented for the coupled inverted microstrip lines, and for the coupled suspended microstrip lines. The effects of the top and sidewalls and also of the finite thickness of strip conductors on the even- and odd-mode impedances are studied. The use of a dielectric overlay in equalizing the even- and odd-mode phase velocities is investigated.     

Analyse des coupleurs directifs coplanaires

Conformai mapping techniques are used to give design information for coplanar directional couplers with finite or infinite substrate thickness. These calculations lead to analytic closed-form expressions for the coupler parameters (characteristic impedance and, even and odd-mode phase propagation velocities). Experimental results on two coplanar directional couplers are in good agreement with theoretical calculations.     

High precision analysis of finlines on semiconductor substrate

In this study, the effect of the metallization thickness in finlines on semiconcuctor substrate is researched. The propagation parameters are computed to measure the inluence of the metallization. The theory and numerical results are presented to the propagation constant and characteristic impedance of the bilateral and unilateral finlines. The full wave analysis of the transverse transmission line — TTL method is used to determine the electromagnetic fields of the structure in Fourier transform domain — FTD. Applying the suitable boundary conditions, the moment method and expanding the fields in a set of suitable bases functions, a homogeneous matrix system is obtained and the propagation constant is computed. The characteristic impedance is obtained using the relation of the voltage in the slot and the transmitted power by the structure. Computational programs are developed to obtain numerical results to the propagation parameters composed by the propagation constant and characteristic impedance.     

Investigation of wide-band microstrip slot antenna

This paper presents the simulation and experimental investigations of a printed microstrip slot antenna. It is a quarter wavelength monopole slot cut in the finite ground plane edge, and fed electromagnetically by a microstrip transmission line. It provides a wide impedance bandwidth adjustable by variation of its parameters, such as the relative permittivity and thickness of the substrate, width, and location of the slot in the ground plane, and feed and ground plane dimensions. The ground plane is small, 50 mm/spl times/80 mm, and is about the size of a typical PC wireless card. At the center frequency of 3.00 GHz, its width of 50 mm is about /spl lambda//2 and influences the slot impedance and bandwidth significantly. An impedance bandwidth (S/sub 11/=-10 dB) of up to about 60% is achieved by individually optimizing its parameters. The simulation results are confirmed experimentally. A dual complementary slot antenna configuration is also investigated for the polarization diversity.     

宽频带耦合带状线魔T的设计方法

给出一种宽频带耦合带状线90°移相器的工程设计方法。通过适当选取耦合带状线奇偶模阻抗比ρ、介质基片的相对介电常数εr与厚度s,以及带状线地板间距b,频带宽度可达1∶2.34倍频程可以实现所需带宽内90°移相,与宽频带3dB电桥组合可实现宽频带魔T,同时推导给出了3dB电桥耦合度κ、εr、s/b的设计关系公式。通过仿真给出了修正量。     

More investigations of leakage and nonleakage conductor-backedcoplanar waveguide

Through rigorous full-wave analysis, the effective dielectric constant, normalized attenuation constant, characteristic impedance, and radiation pattern of two types of conductor-backed coplanar waveguides are obtained. The analytic results show that the leakage effect is not only controlled by the thickness and dielectric constant of the substrate but also by the slot width. The leakage power transforms to a radiation space wave and a surface wave, the transverse electric field diagrams in the substrate and the far-zone radiation pattern verify the leakage phenomenon. The first structure has the maximum radiation intensity in the endfire direction, while the second one which has more leaky waves radiates into the air, is better served as a radiating device. For both structures under the nonleakage condition, the characteristic impedance is sensitive to the change of the strip width but not the slot width. Using these properties, the nonleaky and leaky circuits can exist on the same circuit board by choosing appropriate circuit dimensions     

Effect of Loss and Frequency Dispersion on the Performance of Microstrip Directional Couplers and Coupled Line Filters (Short Papers)

The effect of ohmic and dielectric losses, conductor thickness, and frequency dispersion on the performance of edge-coupled microstrip directional couplers and interdigital filters have been determined in this short paper. The odd- and even-mode attenuation constants due to ohmic losses in the conductor have been calculated using Wheeler's inductance formula. The theoretical results for the characteristic impedance and propagation constants are in good agreement with the experimental results of Napoli and Hughes. Among the parameters that can be calculated from this theory are the isolation, directivity, and coupling coefficients of lossy directional couplers and the midband insertion loss of interdigital filters.